Stress reaction of the humerus in tennis players

Background

Overuse injuries are a frequent occurrence among competitive athletes. When analysing the incidence of overuse injuries in tennis players, it has been determined that a significant number of these injures occur in the upper limb area. In this study, we describe five cases of a stress‐induced injury to the middle and distal humerus occurring mainly due to repetitive serving.

Methods

Athletes studied were competitive tennis players and elite junior players, two of whom played at international level. Four of the five were male. In all cases, diagnosis was confirmed by magnetic resonance imaging examination. The treatment of middle and distal humeral stress reactions consisted of physical therapy, which focused on analgesia and muscle strengthening. In addition, we analysed each tennis player''s strokes in order to identify modifications that would decrease the amount of stress that the upper limbs were subjected to during the service motion.

Results

The players in our study missed on average 3 weeks of play and at follow‐up after 1 year were able to play symptom free.

Conclusions

Our study highlights the need for coaches, physicians and players to be aware of distal humeral pain and understand treatment options in order to prevent further injury, including stress fractures.The motions associated with certain tennis strokes have been shown to place the upper limbs of competitive and professional tennis players at risk of injury. Recently published studies have reported chronic injuries in this region.^1,2,3,4 As a consequence of these injuries, the athlete is required to spend weeks or even months recovering and is unable to participate in on‐court activities. Muscle and tendon overuse injuries have been well documented in tennis players.² However, only a limited number of studies have focused on bone stress injuries associated with overuse.^3,4,5 Furthermore, most of the studies examining tennis‐related bone stress injuries concentrate on injuries to the trunk and lower limbs.^5,6 In fact, only three articles were retrieved that reported stress reactions involving the humerus in tennis players.^3,4,7It has been well documented that the elbow, as well as the middle and distal humerus, are prone to overuse injuries.^4,7 Injuries to this portion of the arm occur primarily during the acceleration phase of the service motion, when the arm moves into internal rotation.⁸ Valgus stress of the elbow also is a common occurrence during this motion.⁸ The repetition of strokes during practice and matches can lead to symptoms of pain and weakness in that region that if left untreated can progress from a bone stress reaction to a complete stress fracture.This study examined five cases in which overuse resulted in an injury to the middle and distal humerus of competitive tennis players. Our objective was to illustrate the importance of this differential diagnosis to prevent stress fractures in competitive tennis players.     

Experiences of Australian professional female tennis players returning to competition from injury

Background

This study examined the experiences of professional female tennis players returning to competition from injury.

Methods

In a study commissioned by Tennis Australia, 55 Australian professional female tennis players responded anonymously to a questionnaire developed for the purposes of this study. The questionnaire consisted of open and closed questions that assessed a player''s attribution style, the occurrence and effect of minor and major injuries, frequency and type of treatment sought, attitudinal chances following injury and preventative injury factors.

Results

The quantitative and qualitative analyses of participants'' responses revealed players generally displayed an internal attribution style with the majority of minor injuries involving lower limb injuries (attributed to playing on hard surfaces). Players reported these injuries were addressed in a variety of ways including self‐treatment. The majority of severe injuries were upper limb/shoulder and these were generally treated at tournament sites with some requiring surgery.

Conclusions

Players adopted a range of measures to assist recovery from severe injury including the services of health professionals. In further findings, a player''s attribution style was not a predictive variable, except in terms of the number of tournaments missed for minor injuries. Implications of the study''s results and future research directions for cross‐cultural studies are highlighted.For elite athletes to achieve their goals in sport, it is generally accepted that the athlete will need to overcome numerous setbacks and challenges along the way. Some of the most critical challenges arise in dealing with injuries sustained in training and/or competition. Incidences of injuries are on the increase despite improvements in training facilities, equipment, physical conditioning and coaching.^1,2Research suggests psychosocial factors, together with physical and environmental factors, might predispose one to injury.^3,4,5,6 In a recent study, Devonport, Lane and Hanin⁷ examined psychological states experienced by athletes prior to becoming injured, as well as their best and worst performances. “Best” performances were associated with lower scores on depression and fatigue, but higher on vigour, than “injured” and “worst” performances, and “worst” performances were associated with higher fatigue and confusion than “injured” performance. Further, recall of mood before their “injured” performance most closely resembled the “best” performance, with the authors suggesting that this might be attributed to the players taking more risks as they strive to maintain their (superior) performance level, or merely from trying too hard (ie, increasing the effort expended). Their third suggestion was that the players became over‐confident and complacent, causing them to underestimate the task demands and be less alert in pre‐event and mid‐event situations.Devonport et al⁷ recommended that future researchers try to tease out the above possibilities acknowledging that a limitation of their study was they did not examine the types of injury (ie, to what body part, how severe it was etc), and whether the injury resulted from external factors (ie, from opponents) or from internal or self‐generated sources (ie, excessive training). Finally, they suggest that research should also include qualitative methodologies to allow the athlete to fully describe their experiences regarding injury.Research into the retirement experiences of elite female tennis players⁸ revealed a degree of frustration with Australia''s governing body of tennis, Tennis Australia (TA), in terms of a perceived lack of support and recognition for the country''s former players. In their willingness to further explore issues of player well being, TA commissioned this study to investigate the experiences of professional tennis players, currently competing and retired, who had suffered minor and severe injuries. The aims of the study were to examine in elite Australian female tennis players:

• type of injury sustained and its effect on ability to train and compete;
• if attribution style was associated with frequency of injury, number of tournaments missed, success in ranking and playing career length;
• if attitude changes had occurred for players as a result of their injury; and
• how TA might assist players.

Preliminary data from this study has been published in abstract form.⁹     

Eccentric treatment for patellar tendinopathy: a prospective randomised short-term pilot study of two rehabilitation protocols

Objective

To compare the efficacy and safety of two eccentric rehabilitation protocols for patients with symptomatic patellar tendinopathy. A new eccentric overload training device was compared with the present standard eccentric rehabilitation programme on a decline board.

Design

Prospective, randomised clinical trial.

Setting

Sports rehabilitation clinic, university sports laboratory, supplemented with home exercises.

Patients

20 competitive and recreational athletes, all with clinical diagnosis of patellar tendinopathy, verified by MRI or ultrasound imaging.

Interventions

A 12‐week rehabilitation period, either with bilateral eccentric overload strength training using the Bromsman device twice a week or with unilateral eccentric body load training using a decline board twice a week, supplemented with daily home exercises.

Outcome measures

The primary outcome was pain and function, assessed by the Swedish Victorian Institute of Sport Assessment for Patella (VISA‐P) score. Secondary outcome measures were isokinetic muscle torque, dynamic function and muscle flexibility, as well as pain level estimations using visual analogue scale (VAS). Side effects were registered.

Results

Both treatment groups improved in the short term according to the VISA‐P scores during the 12‐week rehabilitation period. However, there were no significant differences between the groups in terms of pain and function. After a 3‐month rehabilitation period, most patients could be regarded as improved enough to be able to return to training and sports. No serious side effects were detected in either group.

Conclusion

In patients with patellar tendinopathy pain, two‐legged eccentric overload training twice per week, using the new device (Bromsman), was as efficient and safe as the present standard daily eccentric one‐legged rehabilitation‐training regimen using a decline board.Proximal patellar tendon pain (patellar tendinopathy) occurs typically in sports characterised by high demands on force and power of the leg extensor muscles, such as basketball, volleyball, tennis and soccer. Controlled eccentric strengthening of the muscle–tendon complexes involved seems to be important for successful rehabilitation.^1,2,3,4,5 Eccentric squat training on a decline board has been shown to have a superior therapeutic effect in reduction of pain compared with squatting on a flat surface.⁶ One‐legged squatting, using the decline board, resulted in encouraging results with, for example, earlier return to a functional level of sport.^7,8 By contrast, Visnes et al⁹ showed no significant improvements of eccentric training on patellar tendinopathy among volleyball players when instituted during the playing season.Previous research suggests that the efficacy of eccentric squatting rehabilitation may be correlated with the load applied to the quadriceps muscle. The aim of the present prospective randomised short‐term study was to evaluate and compare clinical outcomes in terms of knee pain and function after eccentric training, using either a novel eccentric overload training device (Bromsman, Lidingö, Sweden)¹⁰ or the current standard programme of one‐leg squatting exercises.¹¹     

Physiological upper limits of left ventricular dimensions in highly trained junior tennis players

Background

The differentiation between physiological cardiac enlargement and cardiomyopathy is crucial, considering that most young non‐traumatic deaths in sport are due to cardiomyopathy. Currently, there are few data relating to cardiac dimensions in junior elite tennis players. The aim of this study was to define the upper limits of left ventricular dimensions in a large cohort of national adolescent tennis players.

Methods

Between 1996 and 2003, 259 adolescent tennis players (152 males), mean (SD) age 14.8 (1.4) years (range 13–19) and 86 healthy age, gender and body surface matched sedentary controls underwent 12‐lead ECG and 2D‐transthoracic echocardiography.

Results

Inter‐ventricular septal end diastolic dimension (IVSd), left ventricular end diastolic dimension (LVEDd) and left ventricular end diastolic posterior wall dimension (LVPWd) in tennis players were significantly higher than in controls (8.9 mm vs 8.3 mm p<0.001, 48.9 mm vs 47.9 mm p<0.05 and 9 mm vs 8.3 mm p<0.001 respectively), however in absolute terms, the difference did not exceed 7%. None of the tennis players had a wall thickness exceeding 12 mm or a left ventricular cavity size exceeding 60 mm.

Conclusions

Tennis players exhibit modest increases in cardiac dimensions, which do not resemble those seen in individuals with cardiomyopathy affecting the left ventricle.The differentiation between physiological cardiac adaptation (athlete''s heart) and cardiomyopathy is crucial, as up to 40% of all non‐traumatic sudden cardiac deaths in young athletes are either due to hypertrophic or dilated cardiomyopathy.^1,2 The vast majority of echocardiographic studies have evaluated only adult athletes, however, there are few data assessing physiological adaptation in adolescent athletes in whom sudden death from cardiomyopathy is most prevalent.³ The steady trickle of sudden cardiac deaths in high profile athletes including tennis players^4,5 has prompted some sporting bodies to implement compulsory cardiovascular evaluation of all junior recruits specifically aimed at excluding cardiomyopathy prior to acceptance for competition.Tennis is a popular sport attracting millions of players and fans worldwide.⁶ The British Lawn Tennis association was the first elite sporting organisation in the UK to adopt cardiovascular screening of all their national junior athletes for conditions predisposing to sudden cardiac death. Our group has been responsible for performing cardiovascular evaluation on all junior national tennis players since 1996. The aim of this study was to identify physiological upper limits of cardiac enlargement in junior tennis players to help facilitate the differentiation between physiological and pathological cardiac enlargement should other countries decide to follow suit.     

Pre- and post-impact muscle activation in the tennis volley: effects of ball speed, ball size and side of the body

Aim

To examine the pre‐ and post‐impact activation of five upper extremity muscles in the tennis volley across conditions of ball speed, ball type and side of the body.

Methods

A repeated measures design in a biomechanics laboratory setting was used. A total of 24 recreational tennis players (mean (SD) age 24 (5) years, height 176 (10) cm, mass 76 (13) kg) were recruited from a university. Participants performed tennis volleys under 18 ball conditions: three ball speeds (slow, medium and fast), with three ball types (two oversize and one regular size) each from two sides (forehand and backhand). Average normalised electromyographic levels of the flexor carpi radialis, extensor carpi radialis, triceps brachii, anterior/middle deltoid and posterior/middle deltoid of the hitting arm during pre‐ and post‐impact phases (200 ms before and after ball–racquet impact, respectively) were assessed.

Results

For the pre‐impact phase, a significant muscle and side interaction (p<0.001) and significant main effects for speed (p = 0.002) and muscle (p<0.001) were observed. For the post‐impact phase, significant interactions were observed for ball type and side (p = 0.002), ball speed and side (p = 0.011) and muscle and side (p = 0.001), as well significant main effects for muscle (p<0.001), speed (p = 0.035) and side (p<0.001).

Conclusion

Oversize tennis balls do not significantly increase upper extremity muscle activation compared to regular size balls during a tennis volley. The highest post‐impact activation was observed in the ECR indicating a vigorous wrist stabilisation role that could irritate players with lateral epicondylalgia.There has been considerable revision of the rules of tennis by International Tennis Federation (ITF) in the past few decades. One of the most recent changes involving equipment was the introduction of a larger tennis ball. The use of a 6% wider ball with the same mass as a regular ball was approved as a possible remedy for the increasing speed of the game.^1,2Studies of match play statistics³ and aerodynamics^4,5 have reported data supporting the logic of increasing ball diameter to slow ball speeds in tennis. However, manufacturers selling the larger (type 3) tennis balls found most tennis players were not interested in using them. Some recreational tennis players have been concerned about the long‐term effect of the larger ball on arm injuries.^6,7Research on the immediate effects of play with the larger ball on risk of overuse injuries has focused on impulsive loading and muscle activation. Several studies have shown that post‐impact racquet accelerations are similar between the regular and the oversize ball in a variety of strokes.^8,9,10 Muscle activation is also not significantly different across subjects between the two types of ball in the forehand and serves.^9,10When compared to more complex tennis strokes such as the forehand and serve, the volley requires significantly less movement from the player. Furthermore, while the mechanics of the forehand and serve have changed dramatically over the past few decades due to alterations in typical grips, swing paths and lower extremity loading preferences, the biomechanics of the volley have remained relatively unchanged despite advances in racquet technology. There is evidence, however, that the temporal demands of intercepting volleys can be affected by the larger tennis ball.⁸Muscle activity immediately before impact (pre‐activation) during drop landing and downward stepping, for example, serves to stiffen the lower extremity joints in preparation for the impact.^11,12,13,14 In drop landings, a higher lower limb muscle pre‐activation was observed with increasing drop height indicating that preparatory muscle activity varies with the anticipated demands of impact.¹¹ Muscle activity, specifically coactivity, immediately after the initial contact also helps to stabilise the joints involved.^11,13 Although muscle activation during different phases of the tennis volley has been reported,^14,16,17 no attempts have been made to examine pre‐ and post‐impact muscle activity of upper extremity muscles during a tennis volley. For example, Chow and colleagues examined the activity of different muscles of the stroking arm and shoulder and lower extremities during the tennis volley and reported average electromyographic (EMG) levels for different phases between 200 ms before ball release from a ball machine and the instant of ball impact.¹⁶ However, they did not analyse the post‐impact muscle activity.Andrew et al⁸ reported a significant interaction of ball size and shot speed on stroke technique in volleys, so that the larger ball significantly increased the movement time (17–29 ms) to intercept higher speed shots. It is unknown if variation in the time to intercept shots or flight properties of the larger ball affects the activation of muscles required to execute volleys Information on pre‐ and post‐impact muscle activation would provide insights into demands placed on muscles of the hitting arm and likely muscular loads. Therefore, it was the purpose of this investigation to compare selected upper extremity muscle activation immediately before and after ball–racquet impact in the tennis volley across ball types, ball speed and sides of the body. Based on the association between preparatory muscle activation and drop height reported by Arampatzis et al¹¹ and the fact that larger balls travel slower in the air,⁸ we hypothesised that pre‐ and post‐impact activation would increase with increasing ball speed and decrease with increasing ball size for forehand and backhand volleys.     

Core body temperature during competition in the heat: National Boys' 14s Junior Championships

Objective

To examine on‐court core body temperature (T_C) and sweat loss, as well as pre‐ and post‐play hydration status, in elite adolescent tennis players during a national championships event in a hot climate.

Methods

Eight healthy, fit, young male tennis players (mean (SD) age 13.9 (0.9) years; mass 56.0 (10.7) kg; height 169.2 (14.7) cm) were evaluated during first‐round singles competition at the National Boys'' 14s Junior Championships in the heat (wet‐bulb globe temperature (WBGT) 29.6 (0.4) °C). Five of those same players were also evaluated during a same‐day doubles match (WBGT 31.3 (0.5) °C).

Results

During doubles (4.37 (0.35) h after singles), pre‐play urine specific gravity (USG) (1.025 (0.002); p = 0.06) and total sweat loss (1.9 (0.2) litres; p = 0.10) tended to be higher before and during doubles, respectively, compared to singles. However, percentage change in body mass (−0.5 (0.3) %) tended to be comparatively less (p = 0.08), even though the doubles matches were generally longer (106.6 (11.2) vs 78.8 (10.9) min; p = 0.09) and the degree minutes total was greater (p = 0.04). T_C increased (p<0.001) during singles and remained elevated, even after 10 min following the end of play. Notably, pre‐play (singles) USG was strongly associated (p = 0.005) with the players'' final T_C (38.7 (0.3) °C) recorded at the end of singles play.

Conclusion

Junior tennis players who begin a match not well hydrated could have progressively increasing thermal strain and a greater risk for exertional heat illness as the match advances.Most junior tennis tournaments are played outdoors in warm to hot climates. Even as the level of play and depth of competition continue to improve, the toughest opponent these young players often face is the heat. The consequent effects on a child''s health, safety and performance are well recognised.^{1,2,3,4,5,6,7,8} To date, only one study has examined core body temperature (T_C) responses on‐court in junior tennis players.⁹ Notably, however, there have been no assessments of T_C during actual competition, where the levels of stress and effort are likely to have a comparatively greater effect on behaviour and physiological responses.In this study, we examined T_C in adolescent tennis players during a national championships event in a very hot climate. Hydration status and sweat loss were also examined. We were not only interested in assessing the degree of heat strain incurred on the court; we also wanted to particularly determine the associations between pre‐ and post‐match hydration status and T_C. Recently, the relationship between level of hydration and T_C as observed in laboratory studies, respective to its relevance in field settings, has been a contentious issue in the literature.^10,11,12 We hypothesised that hydration status before and after play would be related to the degree of thermal strain at least during singles play. We also wanted to examine on‐court T_C responses during a second (doubles) match on the same day, given that doubles is often perceived as not as likely to elicit an appreciable thermal challenge.These findings provide unique insight to T_C responses in elite adolescent tennis players during actual competition. The combination of heat stress and scheduling of multiple same‐day matches in junior tennis can measurably impact performance¹³ and often prompts incidents of heat illness (M F Bergeron, unpublished observations). Our goal is that, as more research such as this is conducted, there will be enough information and insight to establish more specific and effective guidelines for enhancing the safety and performance of junior tennis players during tournaments through more appropriate scheduling of matches and events, as well as match preparation and recovery strategies.     

Echocardiographic characterisation of left ventricular geometry of professional male tennis players

Background

The cardiac characteristics of various types of athletes have been defined by echocardiography. Athletes involved in predominately static exercise, such as bodybuilders, have been found to have more concentric hypertrophy, whereas those involved in dynamic exercise, such as long distance runners, have more eccentric hypertrophy. Tennis at the elite level is a sport that is a combination of static and dynamic exercise.

Objective

To characterise left ventricular geometry including left ventricular hypertrophy by echocardiography in male professional tennis players.

Design

Retrospective study of screening echocardiograms that were performed on male professional tennis players.

Setting

All echocardiograms were performed at the Mayo Clinic (Jacksonville, Florida, USA) between 1998–2000.

Participants

A total of 41 male professional tennis players, with a mean age of 23.

Results

Left ventricular hypertrophy was present in 30 of 41 subjects (73%, 95% CI: 57%–86%). The majority of players manifested eccentric hypertrophy (n = 22, 54%). Concentric hypertrophy (n = 9, 22%) and normal geometry (n = 7, 17%) were encountered with similar frequency. Only 7% (n = 3) manifested concentric remodelling. The mean thickness of both the interventricular septum and the posterior wall was 11.0 mm. The mean LVEDd was 55 mm. The mean RWT was 0.41. The mean LVMI was 130 gm/m² and the mean EF was 64%. Five of the 41 subjects had an abnormal septal thickness of 13 mm.

Conclusion

This was the first study to specifically describe the full range of echocardiographically‐determined left ventricular geometry in professional male tennis players. The majority of subjects exhibited abnormal geometry, predominantly eccentric hypertrophy.Tennis, as a sport, combines dynamic and static exercise, imposing components of unique cardiac demand on athletes participating in this activity. A single point in tennis can consist of a series of repetitive sprints and explosive ball‐striking. Short breaks are taken between each point, with longer breaks between cross‐overs (when the players change sides of the court). Matches can last 3–4 h, incorporating stamina into the physical demands required for competition. Furthermore, the tennis season is one of the longest professional seasons, lasting about 10.5 months.In 1975, Morganroth et al¹ first proposed that endurance (dynamic) training caused primarily an increase in left ventricular cavity dimensions and strength (static) training caused primarily an increase in left ventricular wall thickness. Many subsequent studies have helped define echocardiogram dimensions in various elite athletic populations.^{2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18} The purpose of this study is to characterise echocardiographically‐defined left ventricular geometry in professional male tennis players, including the prevalence of left ventricular hypertrophy.     

Do sensorial manipulations affect subjects differently depending on their postural abilities?

Objectives

To examine whether sensorial manipulation affects subjects differently according to their postural performance and the strategies used. The literature showed that the level of competition of soccer players influences their postural performance and strategy.

Methods

Eight high‐level (HL) professional soccer players and nine regional‐level (RL) soccer players were tested (1) in a reference condition and (2) in a manipulated sensorial condition (MAN). The MAN condition consisted of perturbing the proprioceptive and exteroceptive information. For each postural condition, balance was assessed by measuring the centre of foot pressure using a force platform during a test of bipedal standing posture.

Results

The postural control was less perturbed in the HL than in the RL players in the two postural conditions. Moreover, the group–condition interaction showed that the postural control was less disturbed in the HL than in the RL players when the sensory information was manipulated.

Conclusions

The HL soccer players probably possessed a better internal model of verticality than the RL players. Subjects who had a better postural control level were less disturbed by sensorial manipulation than the others in postural regulation.Postural regulation requires the integration of proprioceptive and exteroceptive information. When this information is perturbed or manipulated, postural control is altered. Indeed, cutaneous sensory disturbance by hypothermic anaesthesia,¹ myotendinous interference by muscle vibration,² pain by stimulation of skin thermoreceptors,³ electromyostimulation,⁴ galvanic vestibular stimulation⁵ or visual manipulation by stroboscopic light⁶ affects postural stability in healthy subjects. Keshner et al⁷ showed that combined disturbances (ie, visual, proprioceptive, vestibular) caused greater disturbance than any one presented alone. However, combined perturbations might not disturb all subjects in the same way. We do not know whether subjects who present a better postural performance level counteract differently to the effects of manipulating proprioceptive and exteroceptive information in postural regulation than the others. Moreover, the postural strategy—that is, preferential involvement of short (visuovestibular contribution) or long (myotatic participation) neuronal loops in postural regulation—can also influence the effects of sensorial perturbation. To study this, sportsmen at different levels of competition should be studied.Indeed, the level of competition influences the postural performance: the higher the level of competition, the more stable the posture.^8,9 The level of competition also influences the preferential use of the different neuronal loops involved in balance regulation as Paillard et al⁹ showed with soccer players. Hence, one can wonder (1) whether high‐level soccer players can preserve better postural control than players at a lower level when their proprioceptive and exteroceptive informations are disturbed and (2) whether these two categories of players are differently affected by sensorial manipulation.The aim of this work was to compare the postural behaviour between high‐level soccer players and players at a lower level in two different postural conditions. The first condition was the reference (no sensorial perturbation), whereas in the second condition proprioceptive and exteroceptive information was disturbed.     

Relationship between hip strength and frontal plane posture of the knee during a forward lunge

Objective

Excessive frontal plane knee movement during forward lunge movements might be associated with the occurrence of knee injuries in tennis. Here, we attempt to determine whether hip muscle strength is related to the frontal plane motion of the knee during a functional lunge movement.

Design

A correlational study.

Participants

A total of 84 healthy subjects (76 men, 8 women), with no history of knee or lower leg complaints.

Interventions

Muscle strength of six hip muscle groups was measured using a handheld dynamometer. Subjects were videotaped during a forward lunge and peak knee valgus or varus angles were determined using a digital video analysis software program.

Main outcome measurements

A correlation was examined between hip muscle strength and the amount of frontal plane movement of the knee during a forward lunge.

Results

There were no significant differences in hip muscle strength between the valgus group and the varus group during the forward lunge movement. No significant correlation was found between the strength of the assessed hip muscles and the amount of movement into valgus/varus. In the varus group a moderate positive correlation was found between the External Rotation/Internal Rotation force ratio and the amount of knee varus during the forward lunge movement (r = 0.31, p = 0.03).

Conclusions

The findings suggest that in healthy subjects hip muscle strength is not correlated to the amount of valgus/varus movement of the knee during a forward lunge. This suggests that other factors (eg, proprioception, core hip stability) might be more important in controlling knee movement during this tennis‐specific movement.Tennis is one of the most popular sports worldwide. Due to the rising number of participants practicing tennis, the increasing pressure to practice, higher expectations of performance and, hence, increased demands on the human body, the injuries associated with tennis are becoming a matter of increasing concern in the world of sports medicine.¹ Modern tennis involves powerful movements that place a heavy load on the musculoskeletal system and thus exposes tennis players to a high risk of overuse injuries.² Lower extremity injury occurs consistently more frequently than other injuries in tennis, and in tennis more than other racquet sports.^3,4,5 The knee accounts for the majority of lower limb injuries with tendon injuries, patellofemoral problems and intra‐articular knee injuries predominating in tennis.^1,3,6,7 A study by Hutchison et al,⁸ which followed 1440 tennis players over a 6 year period, showed that the lower extremities provided the majority of sprain type injuries with 87,5% of ligament sprains coming from the knee and ankle.To our knowledge, in the current literature there are no studies regarding the movement patterns of the lower extremities during tennis. However, when one observes the lower limbs of players during tennis, a forward lunge movement is one of the most frequently exerted movements during the game. Because of the load these movements place on the knee joint, problems in the knee are related to the constant pounding that occurs during play.^9,10 Therefore, as forward lunges are performed very frequently during tennis, it is of great importance that the player exerts this movement in a correct physiological way with respect to the knee joint to prevent injury. This implies that during the forward lunge the movement of the knee in the frontal plane is to be kept within “its physiological limits”, ie, a quadriceps (Q) angle not exceeding the purported pathological limit of 15–20°.¹²The Q angle is a clinical measure of the alignment of the quadriceps femoris musculature relative to the underlying skeletal structures of the pelvis, femur and tibia.¹¹ This angle is formed by the imaginary line from the anterior superior iliac spine to the centre of the patella and from the centre of the patella to the middle of the anterior tibial tuberosity.It has been stated that when the Q angle exceeds 15–20°, it is commonly thought to contribute to knee extensor dysfunction and hence knee injuries such as patellofemoral pain.¹²In the literature it is an accepted fact that proximal core hip strength is needed for control of distal segments.¹³ Therefore, the force of the muscles surrounding the hip might play an important role in controlling the movement of the knee in the frontal and transversal plane. Ireland et al¹⁴ postulated that uncontrolled femoral adduction and internal rotation secondary to hip weakness results in an increase in the dynamic Q angle at the knee. Repetitive activities with this malalignment could eventually lead to knee injury. Hence, hip muscle weakness might be associated with impaired biomechanics and postures of the leg that contribute to lower extremity injuries.¹⁵ It is therefore currently targeted as one of the possible predisposing factors for knee overuse injuries, such as anterior knee pain and iliotibial band friction syndrome, and lower leg injuries such as medial tibial stress syndrome.^13,14,16,17Although there is reason to assume that hip muscle weakness could effect the frontal plane movement of the knee during lunge movements in tennis, to our knowledge no studies have been published that have investigated the relationship between hip muscle strength and the movement pattern of the knee in the frontal plane during this manoeuvre. Therefore, the purpose of this study was to test the hypothesis that the strength of the muscles around the hip are related to the frontal plane motion of the knee during a functional lunge movement.     

Shoulder joint kinetics of the elite wheelchair tennis serve

Background

The shoulder is a key joint in wheelchair locomotion and commonly implicated in injury among virtually all wheelchair populations. In tennis, quantification of the shoulder joint kinetics that characterise the wheelchair serve could enhance injury prevention and rehabilitation practices as well as assist coaches evaluate the efficacy of their current technical instruction.

Methods

A 12‐camera, 250 Hz Vicon motion analysis system (Oxford Metrics Inc., UK) recorded the 3D flat (WFS) and kick serve (WKS) motions of two male top 30‐ranked international wheelchair players. Mechanical comparisons between wheelchair players, as well as to the previously captured data of 12 high‐performance able‐bodied players executing the same types of serves, were undertaken.

Results

Without the benefit of a propulsive leg action, wheelchair players developed lower peak absolute (∼32 m/s) and horizontal (∼28 m/s) pre‐impact racquet velocities than able‐bodied players (∼42 m/s, ∼38 m/s). Wheelchair serve tactics nevertheless necessitated that higher pre‐impact horizontal and right lateral racquet velocities characterised the WFS (∼29 m/s, WKS: ∼26 m/s) and WKS (∼4 m/s, WFS: ∼11 m/s) respectively. The shoulder joint kinetics that contributed to the differential racquet velocity profiles were mostly developed independent of wheelchair serve type, but varied with and were likely related to the level and severity of spinal cord injury of the individual players.

Conclusions

Compared with able‐bodied players, wheelchair players experienced matching pre‐ and post‐impact shoulder joint loads, such that wheelchair and able‐bodied playing populations appear subject to similar shoulder joint injury risk.Current technical instruction of the wheelchair tennis serve is largely intuitive, guided to some extent by the substantiated biomechanical information describing the able‐bodied serve. The link between shoulder pain and wheelchair serve performance has similar origins, especially as wheelchair players, like their able‐bodied counterparts, commonly suffer from shoulder overuse injuries.^1,2 Delineation of the shoulder joint kinetics that contribute to the development of racquet velocity in the flat (WFS) and kick (WKS) wheelchair serves, and that are associated with shoulder joint injury, is thus important and was the focus of the present study. Further consideration of this data alongside the shoulder joint kinetics associated with able‐bodied serve performance provided for comparative comment.     

Air temperature and physiological and subjective responses during competitive singles tennis

Objectives

This report describes the thermal stresses and strains during competitive singles tennis.

Methods

Thermoregulatory responses were investigated during best of three set tennis matches among 25 players. A total of 86 observations were made from 43 matches played, covering each season, with ambient temperatures ranging from 14.5 to 38.4°C. Core body temperature and skin temperature were recorded each minute throughout the match, whilst heart rate was logged every 15 s. Body mass and fluid intake were measured before the match, after 30 min of play and at the completion of the match to determine sweat rate. Subjective ratings of thermal strain included thermal comfort, sweatiness and perceived exertion. The thermal environment was assessed by dry bulb, wet bulb and natural wet bulb temperatures, globe temperature and wind speed.

Results

Mean (SD) core temperature after 30 min of play was 38.4°C (0.4°C), and demonstrated no association with air temperature or wet bulb globe temperature. Mean skin temperature was 31.8°C (2.3°C) ranging from 25.7 to 36.5°C, and showed a positive association with air temperature (p<0.001). Heart rate varied widely during play, resulting in a mean (SD) response of 136.1 (13.7) beats/min and no association with air temperature. Sweat rate averaged 1.0 (0.4) litres/h (0.2–2.4 litres/h) or 12.8 (5.5) ml/kg/h (2.7–26.0 ml/kg/h), and demonstrated a positive relationship with air temperature (p<0.001). All subjective responses showed positive correlations with air temperature (p<0.001).

Conclusions

Stressful environmental conditions produce a high skin temperature and rating of thermal discomfort. However, overall thermoregulatory strain during tennis is moderate, with core temperature remaining within safe levels.Tennis is played by people of all ages and standards around the world in a wide range of climates. Despite this, the thermoregulatory stresses and strains experienced by tennis players are poorly understood.All tennis players, whether professional or amateur, would benefit from a greater understanding of the environmental stresses and thermoregulatory strains associated with playing tennis. Individuals and organisations with a duty of care towards players also require objective information on which to base recommendations and policies for managing heat stress in training and competition.Thermal stress is the combination of six factors that combine to burden the thermoregulatory system in the effort to maintain core body temperature within tolerable limits.¹ The six factors comprising heat stress are: (1) metabolic heat production, (2) air temperature, (3) absolute humidity, (4) radiant temperature, (5) air movement, and (6) clothing.¹ Thermal strain refers to the thermoregulatory and subjective responses to a thermal stress. Thermoregulatory strains include core body temperature, skin temperature, sweat rate, and heart rate, whilst subjective strains include thermal sensation and perceived exertion.¹ Empirical observations of thermal stress and the corresponding thermoregulatory strains during tennis play are required to determine whether players are at risk of heat illness, and similarly to determine whether they are able to maintain thermal comfort.No previously published studies have made a thorough assessment of the thermal environment and players'' corresponding thermoregulatory responses during tennis. Heart rate, oxygen consumption, core body temperature, skin temperature, and sweat rate have been measured during tennis in a number of studies.^{2,3,4,5,6,7,8,9,10} However, in general these studies have not described the demands of tennis in competition in a wide range of environmental conditions and have not represented the wider tennis community. Only one known study included both genders,⁶ and one other study was the only one to make observations during a best of three sets singles match¹² rather than a time‐restricted match. All of these studies used a relatively small sample of subjects and often only one match was played per subject. A number of the observations in these studies caused disruption to normal player behaviour and performance, and/or the rules of tennis. For example, observations were often measured at various intervals during play, which might not be representative of the activity periods of a real match. The heart rate response in tennis demonstrates a wide variation, therefore continuous recording throughout the match at frequent intervals would be more accurate. It was also be advantageous to continuously record core body temperature throughout the match in order to determine: (1) whether thermal equilibrium is achieved and core temperature is controlled or rises continuously, and (2) the change in core temperature. A single measurement at the end of the match would not provide such information. Furthermore, air temperature and relative humidity were the only environmental stresses measured, not providing a complete assessment of the thermal stress.This paper reports the thermoregulatory and subjective responses to singles tennis in a wide range of thermal environments. This information is required as the basis for developing predictive models for assessing heat stress in tennis.     

An uncommon ankle sprain

Objective

Ankle sprain is the most frequently occurring acute injury in tennis, accounting for 20–25% of all injuries. In the current paper, we assess the cause of ankle sprain and suggest possibilities to be considered during diagnosis.

Methods

We assessed a professional tennis player with a partial tear of the long peroneal tendon after an ankle sprain by physical exam, X‐ray and MRI.

Results

Conservative treatment by means of soft cast and propriocepsis training led to full recovery.

Conclusion

Peroneal tendon disorders must be part of the differential diagnosis after ankle sprain in the professional athlete.An ankle sprain is the most frequent occurring acute injury in tennis, accounting for 20–25% of all injuries. A flexion supination trauma is commonly the cause of this sprain, in which the lateral ligaments are most often affected.⁴However, an ankle sprain may lead to other injuries in the leg and a peroneal tendon lesion must be part of the differential diagnosis.     

Physical performance changes after unsupervised training during the autumn/spring semester break in competitive tennis players

Background

All competitive tennis players take time away from coaches throughout the year; however, little information is available as to the short‐term physiological effect of these breaks.

Objective

The purpose of this investigation was to evaluate the impact of a 5 week off‐campus structured, yet unsupervised, break from regular training in top collegiate tennis players.

Methods

A nationally ranked collegiate NCAA Division I male tennis team (n = 8) performed a test battery in December and again in January after a 5 week period of recommended, yet unsupervised, training. The tests performed were 5, 10 and 20 m sprints, spider agility test, medicine ball power throws, standing long jump, Wingate anaerobic power test, VO_2max, push‐up and sit‐up test, grip strength and range of motion (ROM) measures (goniometer) of the shoulder, hip, hamstring and quadriceps.

Results

Paired t tests (p<0.05) showed significant decreases in mean (SEM) Wingate power measurements in Watts/kg (pre: 8.35 (0.19) w/kg ; post: 7.80 (0.24) w/kg ), minimum Wingate power (pre: 5.89 (0.27) w/kg; post: 5.10 (0.38) w/kg) and VO_2max values (pre: 53.90 (1.11) ml/kg/min; post: 47.86 (1.54) ml/kg/min). A significant increase was seen in the athlete''s fatigue index (pre: 44.26 (2.85)%; post: 51.41 (3.53)%), fastest 5 m (pre: 1.07 (0.03) s; post: 1.12 (0.02) s), 10 m (pre: 1.79 (0.03) s; post: 1.84 (0.04) s) and 20 m (pre: 3.07 (0.05) s; post: 3.13 (0.05) s) sprint times. No significant differences were seen for the other variables tested.

Conclusions

These results suggest that a 5 week interruption of normal training can result in significant reductions in speed, power and aerobic capacity in competitive tennis players, likely owing to poor compliance with the prescribed training regimen. Therefore, coaches and trainers might benefit from techniques (eg, pre‐ and post‐testing) requiring athletes'' to have accountability for unsupervised workouts.Training for competitive tennis requires year‐long training in all aspects of physical performance. Throughout the training cycle, there will be periods where the athlete will be away from the home facility, coaches and medical staff and could reduce training volume or intensity without continual supervision. This period is not usually designed for competitive tournaments, yet substantial training is still planned and expected. The US Collegiate tennis environment provides opportunities to study these short‐term breaks from regular supervised training. The collegiate tennis season is divided into three distinct periods: autumn, spring and summer. Autumn (August–December) is the traditional pre‐season where training is designed to improve performance variables and training volume is high. Spring (February–May) is the major competition period. Between the autumn and spring, most programs allow their athletes to leave campus to see family and friends during the 3–5 week break period. This time period will be referred to as the “break”.A number of physiological variables are important in tennis play including speed, agility, strength, muscular endurance, anaerobic power, aerobic capacity and joint specific flexibility.^1,2,3 These are variables that could result in impaired performance if inadequate training takes place over the break that would result in performance akin to detraining.It has been shown that maximal measures (VO_2max, speed) can be maintained up to 28 days with a reduced training volume of 70%–80% of pre‐reduction training.⁴ If the athletes perform less than is required to maintain these values, aerobic capacity (VO_2max) can decline between 4–14% in as little as 4 weeks.⁵Power output has been shown to be reduced in as little as 3 weeks of strength training cessation.⁶ However, single movement explosive activity (vertical jump) has been shown to no be affected by 6 weeks cessation of training.⁶To date, no data are available describing the tennis athletes'' physiological response to a typical off‐campus autumn/spring break period. Therefore, the purpose of this study was to observe how unsupervised, yet “prescribed” training (3 days a week strength training program and 2 day/week speed and conditioning program) during a 5 week period between the autumn and spring seasons could impact physiological variables in high level NCAA Division I collegiate male tennis players'' upon returning to campus.     

Biochemical evidence of myocardial fibrosis in veteran endurance athletes

Background

Studies on exercise‐induced left ventricular hypertrophy (LVH) in veteran athletes suggest the presence of abnormal diastolic filling and incomplete regression of LVH on cessation of exercise.

Hypothesis

Myocardial fibrosis occurs in exercise induced LVH in veteran athletes.

Aim

To document non‐invasively the presence of fibrosis in veteran athletes

Design

Prospective case–control study.

Setting

City centre district general hospital.

Participants

45 normotensive elite veteran athletes and 45 normal sedentary subjects.

Interventions

Echocardiographic assessment was made of LV mass, LV systolic and LV diastolic function. Plasma carboxyterminal propeptide of collagen type I (PICP), carboxyterminal telopeptide of collagen type I (CITP) and tissue inhibitor of matrix metalloproteinase type I (TIMP‐1) were measured as markers of collagen synthesis, degradation and inhibition of degradation, respectively.

Results

Veteran athletes had significant elevation in LV dimensions and calculated LV mass index (LVMI). Diastolic and systolic function was normal. Plasma PICP (259 vs 166 μg/l, p<0.001), CITP (5.4 vs 2.9 μg/l, p<0.001) and TIMP‐1 (350 vs 253 ng/ml, p = 0.01) were elevated in the cohort of athletes. There was a further elevation of TIMP‐1 in athletes with echocardiographic LVH, defined as an LVMI >130 g/m² (417 vs 266 ng/ml, p = 0.02).

Conclusion

There is biochemical evidence of disruption of the collagen equilibrium favouring fibrosis in veteran athletes with LVH. This may suggest that fibrosis occurs as part of the hypertrophic process in veteran athletes.Chronic high‐intensity exercise results in structural cardiac changes in the human heart. Henschen¹ first described this at the end of the nineteenth century. The changes are characterised by an increase in left ventricular chamber dimensions and an increase in left ventricular wall thickness.² This is traditionally thought to be non‐pathological, as the hypertrophy regresses on cessation of exercise,^3,4 it is thought to consist mostly of myocyte hypertrophy, and Doppler indices of diastolic filling are on the whole within age‐matched limits.^5,6This situation may, however, be different in veteran athletes. The limited data available for this cohort suggest that diastolic function is abnormal, and, more importantly, that incomplete regression of LVH occurs on cessation of exercise.^7,8 Our hypothesis was that these findings could be explained by the presence of co‐existent fibrosis.Fibrosis occurring in the context of LVH has important pathological consequences,⁹ and therefore the demonstration of fibrosis present in exercise‐induced LVH would be a key finding in our understanding of the clinical significance and potential long‐term consequences of LVH.The biochemical assessment of fibrosis using collagen markers represents a practical, validated and non‐invasive method for the assessment of fibrosis in this cohort of veteran athletes. The clinical utility of this technique in the context of left ventricular hypertrophy has been demonstrated by our group,¹⁰ and also, most notably, by Diez et al.^11,12,13The aim of this study was to show, using biochemical markers, the presence of fibrosis in exercise‐induced LVH in a cohort of veteran athletes.     

Effects of short-term treatment strategies over 4 weeks in Achilles tendinopathy

Background

The therapeutic efficacy of non‐surgical treatment strategies in Achilles tendinopathy (AT) has not been well clarified. Time‐consuming and costly combinations of treatment for pain, physiotherapy and biomechanical procedures are often applied.

Objective

To analyse the efficacy of single therapeutic regimens commonly used over a short period of 4 weeks.

Methods

31 male runners (mileage >32 km/week) with unilateral, untreated AT completed 4 weeks of either physiotherapy (10 treatments: deep‐friction, pulsed ultrasound, ice, sensory motor training; (P)), wearing custom fit semirigid insoles (I) or remained without treatment (control group C). Before and after treatment, all patients underwent a treadmill test and a plantar flexion strength exercise. Subjective pain (Pain Disability Index, Pain Experience Scale), as well as strength performance capacity (peak torque), was analysed (mean, 95% CI, repeated measures analysis of variance, α = 0.05).

Results

Pain was reduced to <50% of the baseline value after physiotherapy or after wearing insoles (p<0.05). Individual pain reduction was >50% (25%) in 89% (100%) of subjects in I and 55% (73%) in P. Higher eccentric plantar flexion peak torques after treatment were observed in I and P.

Conclusions

Most patients with AT experience a reduction in pain after only 4 weeks of differentiated, non‐surgical treatment consisting of physiotherapy or semirigid insoles.Problems of Achilles tendon overuse are cited as one of the major pathologies that reduce physical capacity in everyday living, occupation and sports.^1,2,3 Owing to the long duration of problems and widely varying, individual responses to treatment, the efficacy of single or combined therapeutic measures still remains a matter of debate.^4,5 Thus, treatment is usually complex, time consuming and costly.^3,5It has often been assumed that Achilles tendon problems are caused by an inflammation.⁶ However, recent histological studies show that inflammatory cells and mediators, usually present after acute mechanical stress, are absent in tendon overuse.^7,8,9 On the other hand, high concentrations of glycosaminoglycans and a loss of the hierarchical collagen structure have been found.^10,11The mechanism of pain development is not well understood. Competing explanatory models describe increased mechanical tendon vulnerability, microruptures and the supplanting of collagen type I by type III. Pain is also ascribed to the mechanical irritation of ingrown nerve endings due to neovascularisation.^1,9 Reduced perfusion is now considered less important since it was demonstrated that blood supply and oxygen extraction clearly increase during physical exercise.^12,13 It thus seems certain that tendon tissue must be considered metabolically active to a far greater extent than has been assumed to date.^8,9Pain reduction has traditionally been the main outcome variable of non‐surgical treatment in Achilles tendinopathy (AT).³ In daily practice, local physiotherapeutic measures such as deep friction massages, ice and ultrasound are usually applied.^14,15,16 However, despite broad acceptance and pain reduction in individual cases, scientific evidence of short‐term physiotherapy is still lacking.¹⁴ Currently, adjuvant use of sensory motor training¹⁸ and eccentric exercises^18,19,20 are increasingly being discussed. Shalabi et al²¹ demonstrated that eccentric exercises led to an improved clinical outcome, reduction in tendon diameter and reduced intratendinous lesions. Alfredson et al^18,19 had comparably good clinical results after 12 weeks of predominantly eccentric exercise training.In addition to physiotherapy and training, custom‐made insoles are frequently used, but evidence of their efficacy is still lacking.^15,16 Recent studies using bone pins have shown that the mechanical effect of insoles, understood as an alignment of the skeleton, is unspecific and only slight during walking and running.²² Currently, sensory motor effects of semirigid insoles are being discussed.^23,24The aim of this study was to analyse whether standardised short‐term physiotherapy or wearing individually fitted insoles over a period of 4 weeks reduces pain in patients with unilateral AT.     

Effects of rugby sevens matches on human neutrophil-related non-specific immunity

Aims

To evaluate the influences of the accumulative effect of two consecutive rugby sevens matches (Sevens) on aspects of human neutrophil‐related non‐specific immunity.

Methods

In seven players participating in the Japan Sevens, neutrophil reactive oxygen species (ROS) production capability and phagocytic activity were measured using flow cytometry, and serum opsonic activity (SOA) was assessed by measuring neutrophil ROS using the peak height of lucigenin‐dependent chemiluminescence before and after two consecutive matches.

Results

ROS showed no change immediately after the first match, and had significantly (P<0.05) increased 4 h later, but showed a decrease after the second match. Phagocytic activity showed no change immediately after the first match, but had significantly (P<0.01) decreased 4 h later, and showed a further decrease after the second match, although it was not significant. SOA significantly (P<0.01) increased after the first match, and still maintained its high 4 h later, but decreased after the second match. ROS production capability, phagocytic activity and SOA significantly (P<0.01) decreased after the second match.

Conclusions

When rugby players play two consecutive Sevens matches, the exercise loading is thought to be hard, similar to that experienced during a marathon race and intensive or long training in a training camp, although the expected changes were not seen after the first match. Differences between after the first and the second matches may be due to the “cumulative effect”.Rugby is a competitive ball game with a long history, which usually has 15 players per team. The rugby sevens match (Sevens), played with seven players, was recently derived from the original game of rugby, with its own World Cup, and many competitions are held in and outside Japan.Rugby is one of the most intense contact sports among competitive sports, and requires a high degree of physical fitness. The incidence of injuries during rugby matches is higher compared with other sports.¹ The basic rules of Sevens, including the size of the pitch, are the same as for an ordinary rugby match, except for a shorter match duration. As Sevens players must play on a full‐sized pitch, it follows that they have a potentially higher exercise loading than under the conditions of a normal game. Usually, more than two games are held on the same day. It can thus be assumed that Sevens players experience high levels of physiological stress, and the incidence of injury will probably be higher than in the case of a 15‐a‐side game. However, to the best of our knowledge, no study on sports medicine concentrating on Sevens players has ever been carried out.Some reports have shown that intense exercise can adversely affect the immune system. The incidence of upper respiratory tract infection among endurance athletes is notably high, and may be due to decreased neutrophil function.^2,3 In addition, decreases in neutrophil functions have been reported after a rugby match.⁴Neutrophils are one of the cellular factors playing an important part in the first line of defence against foreign substances, including microorganisms. Neutrophils engulf microorganisms (phagocytic activity) and produce reactive oxygen species (ROS).^5,6 Serum opsonic activity (SOA) contributes to this microbicidal activity through opsonisation of microorganisms—that is, an acceleration of adhesion of neutrophils to opsonised substances via immunoglobulin (Ig) G, C3 and others. The expression of CD11b (complement receptor type 3; CR3) and CD16 (Fc γ receptor type 3; FcγR3) on the surface of neutrophils facilitates efficient phagocytosis of opsonised foreign bodies and consequent production of ROS.^7,8A single bout of exercise has been reported to change the neutrophil functions. Depending on the report one reads, ROS production increases^9,10 or decreases after acute exercise.^11,12,13 Phagocytic activity decreases after intense exercise^9,12,14 or increases or does not change after moderate exercise.^15,16,17 SOA does not change or increase after a long‐distance race.^18,19 As changes in these functions are linked to the intensity and duration of exercise, measurements of these functions become interesting when the immune response to repeated bouts of exercise is assessed. The influence of repeated bouts of intense exercise on the same day, such as Sevens matches, on immune function has not been investigated. In addition, as recovery of neutrophil function needs >2 days,⁴ repeated bouts of intense exercise with incomplete immunological recovery might increase the risk of infection.In this study, we examined the influence of two consecutive Sevens games on neutrophil function (ROS and phagocytic activity) and neutrophil‐related activity (SOA).     

Short-term effects of light and heavy load interventions on service velocity and precision in elite young tennis players

Objective

This study was conducted to investigate the acute effects of a complex throwing intervention set‐up, with light or heavy loads, on the service velocity of elite junior tennis players.

Methods

On 3 separate test days, 13 elite juniors (mean (SD) 12.3 (0.8) years, 149 (9) cm, 37.5 (5.5) kg) performed four sets of six serves with different between‐set conditions. In a cross‐over design, the players performed respectively 6, 4 and 2 maximum effort throws with a 200 g ball (LI, light intervention), 6, 4 and 2 maximum effort throws with a 600 g ball (HI, heavy intervention) and no throws (NI, no intervention) during the 2 min in between‐set period. Participants were instructed to serve, with maximum speed, to a target near the midline of the deuce court service box. A two‐factor analysis of variance was used to determine the effects of intervention type and set number on “service velocity”, “service precision” (eg, percentage of serves in) and “service touch” (11 point rating scale).

Results

Mean (SD) service velocity decreased significantly in HI (124.3 (7.8) km/h) as compared to NI (126.6 (9.3) km/h, p<0.05, effect size d = 0.26), yet no such differences were found between LI (125.2 (7.9) km/h) and NI. Service velocity also remained constant between sets (p = 0.406). Service precision and service touch were unaffected by the interventions.

Conclusions

Under the conditions of our study, a heavy throwing intervention during service training has no beneficial effect on service velocity in young elite tennis players (under 14).Several studies have focused on the kinematics of the tennis service, on the importance of service speed in determining match outcomes and on different training concepts to improve the service performance.^1,2,3 The major contributors to the linear velocity of the racquet head at serve impact are reported as internal rotation of the upper arm (54.2%) and flexion of the hand (31%).³ Similar mechanics are seen in other overhead throwing actions,⁴ reinforcing the strong and established link between service and throwing velocity in tennis players.Modern training concepts highlight the value of complex exercise programming during the same training unit.^5,6 Short‐term improvements in movement speed through contrast or complex training methods invoking “post‐activation potentiation” and increased muscle stiffness have been observed.⁷ There remain, however, two conflicting theories regarding the optimum loads that should be used for the improvement of mechanical power and movement speed.^8,9 That is, where heavy loads are reported to induce greater recruitment of the high‐threshold fast type II motor units, via the size principle,¹⁰ light loads are suggested to better allow for the assimilation of high‐speed movement velocities and thus maximise the mechanical power output.¹¹Several tennis coaching experts have advanced the use of complex training, with light and heavy loads, to immediately increase the serve velocity and therefore combine technical skill development with the training of overhead power and throwing performance.^12,13 However, the exact short‐ or long‐term effects of such protocols on the functional tennis serve performance have not yet been investigated. Therefore, in this study we have addressed the question of whether a light or a heavy throwing intervention should be advocated for young elite players during a complex service training setting.     

Muscle activation in coupled scapulohumeral motions in the high performance tennis serve

Objective

To evaluate muscle activation patterns in selected scapulohumeral muscles in the tennis serve. These patterns of muscle activation have not been evaluated in other studies of the tennis serve. Fine wire and surface EMG was used to calculate onset and offset timing of muscle activation.

Design

Controlled laboratory study.

Setting

Biomechanical laboratory.

Subjects

16 tennis players (age 18–40) with rated skills (National Tennis Rating Program (NTRP) rating 4.5–6.5; club tournament level or higher) were subjects.

Main outcomes measure

Dependent variables of muscle activation onset and offset as well as sequencing of the stabilising muscles of the scapula (upper trapezius, lower trapezius, serratus anterior; the muscles that position the arm) anterior deltoid and posterior deltoid; and the muscles of the rotator cuff muscles (supraspinatus, infraspinatus, teres minor) during the tennis serve motion.

Results

Patterns of muscle activation were observed during the tennis serve motion. The serratus anterior (−287 ms before ball impact) and upper trapezius (−234 ms) were active in the early cocking phase, while the lower trapezius (−120 ms) was activated in the late cocking phase just before the acceleration phase. The anterior deltoid (−250 ms) was activated in early cocking, while the posterior deltoid (−157 ms) was activated later. The teres minor (−214 ms) was activated early in the cocking phase. The supraspinatus (−103 ms) was activated in late cocking. The infraspinatus (+47 ms after ball impact) was activated in follow‐through. All muscles except infraspinatus were activated in duration of more than 50% of the service motion.

Conclusions

This study demonstrates that there are patterns of activation of muscles around the scapulohumeral articulation in the normal accomplished tennis serve. Rehabilitation and conditioning programs for tennis players should be structured to restore and optimise the activation sequences (scapular stabilisers before rotator cuff), task specific functions (serratus anterior as a retractor of the scapula, lower trapezius as a scapular stabiliser in the elevated rotating arm) and duration of activation of these muscles.The tennis serve motion places high demands on the shoulder. It requires large ranges of motion of the glenohumeral and scapulothoracic joint and produces large rotational velocities and forces on the joint.^1,2,3 Motions and forces around the shoulder are produced and controlled by sequenced activation of muscles in force couple patterns.^4,5,6,7,8 Because of the importance of muscle activations, knowledge of the intensity and patterning of muscle activations can be key in understanding performance, injury and rehabilitation.Previous muscle activation studies in tennis have concentrated on the intensity of activation in each of the phases of throwing or serving.⁹ This study showed that this type of analysis gives information about how intensely a muscle is activated, but does not give information to determine how the muscles are coordinated in patterns of activation to produce the motions and forces. There have been no studies on activation sequencing patterns in tennis.A study in baseball players did evaluate activation sequencing and did document a pattern of peak individual muscle activation that started in the trunk, continued into the scapular stabilisers, and then continued into the deltoid and arm muscles.⁷ Initial peak activation was noted in the contralateral gluteus maximus and external oblique muscles, followed by bilateral rectus abdominis. The activation progressed into the ipsilateral upper and lower trapezius and latissimus dorsi around the scapula. Deltoid and rotator cuff muscles achieved peak activation at the end of the sequencing. These patterns were considered to be the basic patterns for the throwing motion.The present study investigated muscle activation patterns in tennis in order to evaluate the sport‐specific muscle activation patterns in this particular sport. It evaluated the activation sequencing of selected muscles that have roles to maximise anatomic congruence and mechanical efficiency, and have been identified to act to coordinate joint motions in the high‐performance tennis serve.The study''s research goals were to evaluate muscle activation using “on/off” electromyographic (EMG) analysis, to elucidate the patterns of activation, to relate the patterns to the observed scapulohumeral motions, and to use the information to set up appropriate clinical applications for sport‐specific conditioning programs and sport‐specific rehabilitation programs for optimal tennis performance. The research hypothesis was that the activation patterns would be similar to patterns in other sports and activities, and that they could be related to specific scapulohumeral motions.     

A randomised, controlled study on the effects of a short-term endurance training programme in patients with major depression

Objective

To evaluate the short‐term effects of exercise in patients with major depression.

Design

Prospective, randomised, controlled study.

Setting

A university hospital.

Patients

A consecutive series of 38 inpatients with a major depression episode undergoing standard clinical antidepressant drug treatment.

Interventions

Patients were randomly assigned to an exercise (walking, n = 20) or placebo (low‐intensity stretching and relaxation exercises, n = 18) group. Training was carried out for 10 days.

Main outcome measurements

Severity of depression assessed with the Bech‐Rafaelsen Melancholy Scale (BRMS) and the Center for Epidemiologic Studies Depression scale (CES‐D).

Results

After 10 days, reduction of depression scores in the exercise group was significantly larger than in the placebo group (BRMS: 36% v 18%; CES‐D: 41% v 21%; p for both  = 0.01); the proportion of patients with a clinical response (reduction in the BRMS scores by more than six points) was also larger for the exercise group (65% v 22%, p<0.01).

Conclusions

Endurance exercise may help to achieve substantial improvement in the mood of selected patients with major depression in a short time.Exercise has been shown to improve mood and to reduce anxiety in healthy people.^1,2 These findings have led to a growing interest in the effects of physical activity in patients with affective disorders. However, although exercise is often used as an additional treatment for depression, scientific evidence about the effects of this intervention is lacking. Although two meta‐analyses suggested that exercise may be as effective as psychotherapy^3,4 and more effective than other behavioural interventions⁴ for treating depression, a meta‐analysis could not determine the effects of exercise on depression because of a lack of good‐quality research on clinical populations.⁵A growing body of evidence shows that regular physical activity results in functional and morphological adaptations in the brain. Exercise increases the expression of growth factors (insulin‐like growth factor‐I, nerve growth factor and brain‐derived neurotrophic factor), which trigger the production of proteins of signal transduction cascades associated with memory processes.^6,7 Indeed, research in animal models has shown that endurance training increases cortical capillary supplies, the number of synaptic connections and the development of new neurones.⁸ These processes may result in a higher efficiency, plasticity and adaptability of the brain.Several randomised controlled trials have shown that physical activity improves the mood of patients with mild to moderate depression after several weeks.^9,10,11 However, experiments in animals indicate that even a single exercise bout generates considerable changes in the brain concentration of neurotransmitters involved in the pathophysiology of depression.¹² We have previously reported that exercise may substantially improve the mood of patients undergoing bone marrow transplantation¹³ or with therapy‐resistant depression¹⁴ in a short time. The results of a trial suggest that even a single exercise bout may improve the mood of patients with clinical depression.¹⁴ Further, two randomised controlled trials showed an association between exercise amount¹⁵ and duration^11,15 and reduction of symptoms in patients with depression. Finally, a recent study provided evidence for exercise as a possible adjuvant treatment for patients with poor response to antidepressant drugs.¹⁶These findings could be of clinical relevance, as about 30% of patients do not respond to conventional pharmacotherapy, and antidepressants require 1–4 weeks before they show any therapeutic effect. The introduction of exercise programmes in the early treatment of depression could help reduce the duration of therapeutic latency. However, there is a lack of information about several critical features of exercise in the treatment of mood disorders. The diversity of potential clinical populations, the multiple therapeutic settings (single or adjuvant treatment, augmentation to improve remission rates or long‐term treatment) and the variety of exercise programmes are factors that may substantially affect treatment response. Therefore, there is a need for information about the possibilities and mechanisms of action of diverse exercise programmes in patients with depression in different settings. In the present study, we evaluated the effect of a short‐time exercise programme as adjuvant treatment on patients with major depression undergoing standard clinical antidepressant drug treatment.