Risk Factors for Self-Reported Exercise-Related Leg Pain in High School Cross-Country Athletes

Context:

Prevention of exercise-related leg pain (ERLP) has not been successful because ERLP risk factors are not well known.

Objective:

To determine the percentage of high school cross-country (XC) athletes who reported a history of ERLP in their running careers, to identify the percentage of athletes who reported an occurrence of ERLP during 1 XC season, and to investigate the association of selected factors (age, high school year, years of high school running, sex, ERLP history, body mass index [BMI], foot type, and training distance) and the occurrence of ERLP.

Design:

Prospective cohort study.

Setting:

Six local high schools.

Patients or Other Participants:

One hundred twenty-five high school XC athletes (62 females, 63 males).

Main Outcome Measure(s):

All athletes completed an initial ERLP questionnaire, and foot type was visually assessed. After the season, athletes were asked to complete a Web-based questionnaire regarding the seasonal occurrence of ERLP. Statistical analyses of differences (t tests) and associations (χ², relative risk) were conducted.

Results:

A total of 103 of the 125 athletes (82.4%) reported a history of ERLP, with 81 athletes reporting ERLP occurrence within the month preceding completion of the initial questionnaire. Bilateral medial leg pain was the most common ERLP presentation. More than half of the athletes (58.4%) with an ERLP history reported that the pain had interfered with XC participation. Ninety-three athletes responded to the postseason questionnaire, and 45 (48.0%) reported ERLP seasonal occurrence. Most athletes (97.8%) who experienced the seasonal occurrence of ERLP had a history of ERLP. No associations were noted between ERLP history or seasonal occurrence and age, high school year, years of high school running, sex, BMI, foot type, or training distance.

Conclusions:

Both a history of ERLP and the seasonal occurrence of ERLP were common among these XC athletes. The only risk factor identified for ERLP season occurrence was ERLP history.     

Knee Joint Kinematics and Kinetics During a Lateral False-Step Maneuver

Context:

Cutting maneuvers have been implicated as a mechanism of noncontact anterior cruciate ligament (ACL) injuries in collegiate female basketball players.

Objective:

To investigate knee kinematics and kinetics during running when the width of a single step, relative to the path of travel, was manipulated, a lateral false-step maneuver.

Design:

Crossover design.

Setting:

University biomechanics laboratory.

Patients or Other Participants:

Thirteen female collegiate basketball athletes (age  =  19.7 ± 1.1 years, height  =  172.3 ± 8.3 cm, mass  =  71.8 ± 8.7 kg).

Intervention(s):

Three conditions: normal straight-ahead running, lateral false step of width 20% of body height, and lateral false step of width 35% of body height.

Main Outcome Measure(s):

Peak angles and internal moments for knee flexion, extension, abduction, adduction, internal rotation, and external rotation.

Results:

Differences were noted among conditions in peak knee angles (flexion [P < .01], extension [P  =  .02], abduction [P < .01], and internal rotation [P < .01]) and peak internal knee moments (abduction [P < .01], adduction [P < .01], and internal rotation [P  =  .03]). The lateral false step of width 35% of body height was associated with larger peak flexion, abduction, and internal rotation angles and larger peak abduction, adduction, and internal rotation moments than normal running. Peak flexion and internal rotation angles were also larger for the lateral false step of width 20% of body height than for normal running, whereas peak extension angle was smaller. Peak internal rotation angle increased progressively with increasing step width.

Conclusions:

Performing a lateral false-step maneuver resulted in changes in knee kinematics and kinetics compared with normal running. The differences observed for lateral false steps were consistent with proposed mechanisms of ACL loading, suggesting that lateral false steps represent a hitherto neglected mechanism of noncontact ACL injury.     

Comparison of Lower Extremity Kinematics and Hip Muscle Activation During Rehabilitation Tasks Between Sexes

Context:

Closed kinetic chain exercises are an integral part of rehabilitation programs after lower extremity injury. Sex differences in lower extremity kinematics have been reported during landing and cutting; however, less is known about sex differences in movement patterns and activation of the hip musculature during common lower extremity rehabilitation exercises.

Objective:

To determine whether lower extremity kinematics and muscle activation levels differ between sexes during closed kinetic chain rehabilitation exercises.

Design:

Cross-sectional with 1 between-subjects factor (sex) and 1 within-subjects factor (exercise).

Setting:

Research laboratory.

Patients or Other Participants:

Participants included 21 women (age  =  23 ± 5.8 years, height  =  167.6 ± 5.1 cm, mass  =  63.7 ± 5.9 kg) and 21 men (age  =  23 ± 4.0 years, height  =  181.4 ± 7.4 cm, mass  =  85.6 ± 16.5 kg).

Intervention(s):

In 1 testing session, participants performed 3 trials each of single-leg squat, lunge, and step-up-and-over exercises.

Main Outcome Measure(s):

We recorded the peak joint angles (degrees) of knee flexion and valgus and hip flexion, extension, adduction, and external rotation for each exercise. We also recorded the electromyographic activity of the gluteus maximus, rectus femoris, adductor longus, and bilateral gluteus medius muscles for the concentric and eccentric phases of each exercise.

Results:

Peak knee flexion angles were smaller and peak hip extension angles were larger for women than for men across all tasks. Peak hip flexion angles during the single-leg squat were smaller for women than for men. Mean root-mean-square amplitudes for the gluteus maximus and rectus femoris muscles in both the concentric and eccentric phases of the 3 exercises were greater for women than for men.

Conclusions:

Sex differences were observed in sagittal-plane movement patterns during the rehabilitation exercises. Because of the sex differences observed in our study, future researchers need to compare the findings for injured participants by sex to garner a better representation of altered kinematic angles and muscle activation levels due to injury.     

Generalized Joint Laxity Associated With Increased Medial Foot Loading in Female Athletes

Context:

The relationship between generalized joint laxity and plantar pressure distribution of the foot and the potential implications for lower extremity injury have not been studied.

Objective:

To determine the relationship between generalized joint laxity and dynamic plantar pressure distribution. We hypothesized that individuals with greater generalized joint laxity, or hypermobility, would have greater dynamic medial midfoot pressure and loading during walking than nonhypermobile individuals.

Design:

Case control.

Setting:

Institutional biomechanics laboratory.

Patients or Other Participants:

Participants included 112 female soccer players between 11 and 21 years of age.

Main Outcome Measure(s):

Each participant was tested for generalized joint laxity using the Beighton and Horan Joint Mobility Index (BHJMI; range, 0–9) and was categorized as having either high (BHJMI score ≥4) or low (BHJMI score <4) generalized joint laxity. Peak pressure and maximum force were calculated from a dynamic, barefoot plantar pressure distribution system.

Results:

Peak pressure and maximum force were greater in the 27 participants categorized as having high generalized joint laxity than in the 85 participants categorized as having low generalized joint laxity. The midfoot region exhibited greater loading in participants with high generalized joint laxity than in the other participants. We found an effect of BHJMI classification in the medial midfoot; peak pressure in the dominant (F_1,109  =  11.262, P  =  .001) and nondominant (F_1,109  =  14.32, P < .001) sides and maximum force in the dominant (F_1,109  =  7.88, P  =  .006) and nondominant (F_1,109  =  9.18, P  =  .003) sides were greater in the high generalized joint laxity group than in the low generalized joint laxity group.

Conclusions:

Athletes classified as having high generalized joint laxity demonstrated increased midfoot loading. Delineation of risk factors for medial collapse of the foot, which include hypermobility in athletes, may help clinicians evaluate and prevent lower extremity injury with treatments, such as orthoses.     

Internal Rotation and Scapular Position Differences: A Comparison of Collegiate and High School Baseball Players

Context:

Conditions such as labral and rotator cuff injuries have been linked with decreases in glenohumeral internal-rotation and increases in external-rotation motion. Also, decreased glenohumeral internal rotation is strongly associated with scapular dyskinesis.

Objective:

To compare healthy collegiate and high school baseball players'' glenohumeral joint range of motion and scapular position.

Design:

Cross-sectional study.

Setting:

Institutional research laboratory.

Patients or Other Participants:

Thirty-one male National Collegiate Athletic Association Division I collegiate (age  =  20.23 ± 1.17 years, height  =  186.24 ± 5.73 cm, mass  =  92.01 ± 7.68 kg) and 21 male high school baseball players (age  =  16.57 ± 0.76 years, height  =  180.58 ± 6.01 cm, mass  =  79.09 ± 11.51 kg).

Main Outcome Measure(s):

Glenohumeral internal and external rotation and scapular upward rotation were measured with a digital inclinometer. Scapular protraction was measured with a vernier caliper. All variables except scapular upward rotation were calculated as the difference between the dominant and nondominant sides.

Results:

Collegiate baseball players had more glenohumeral internal-rotation deficit (4.80°, P  =  .028) and total motion deficit (5.73°, P  =  .009) and less glenohumeral external-rotation gain (3.00°, P  =  .028) than high school players. Collegiate baseball players had less scapular upward rotation than high school players at the 90° (4.12°, P  =  .015, versus 3.00°, P  =  .025) and 120° (4.00°, P  =  .007, versus 3.40°, P  =  .005) positions. The scapular protraction difference was greater in collegiate baseball players than in high school players in the hands-on-hips and 90° positions (0.77 cm, P  =  .021, and 1.4 cm, P  =  .001).

Conclusions:

When comparing high school with collegiate baseball players, these data suggest that glenohumeral internal-rotation deficit and scapular position change as the level of competition increases.     

Sleep Disorders and their Association with Laboratory Pain Sensitivity in Temporomandibular Joint Disorder

Study Objectives:

We characterized sleep disorder rates in temporomandibular joint disorder (TMD) and evaluated possible associations between sleep disorders and laboratory measures of pain sensitivity.

Design:

Research diagnostic examinations were conducted, followed by two consecutive overnight polysomnographic studies with morning and evening assessments of pain threshold.

Setting:

Orofacial pain clinic and inpatient sleep research facility

Participants:

Fifty-three patients meeting research diagnostic criteria for myofascial TMD.

Interventions:

N/A

Measurements and Results:

We determined sleep disorder diagnostic rates and conducted algometric measures of pressure pain threshold on the masseter and forearm. Heat pain threshold was measured on the forearm; 75% met self-report criteria for sleep bruxism, but only 17% met PSG criteria for active sleep bruxism. Two or more sleep disorders were diagnosed in 43% of patients. Insomnia disorder (36%) and sleep apnea (28.4%) demonstrated the highest frequencies. Primary insomnia (PI) (26%) comprised the largest subcategory of insomnia. Even after controlling for multiple potential confounds, PI was associated with reduced mechanical and thermal pain thresholds at all sites (P < 0.05). Conversely, the respiratory disturbance index was associated with increased mechanical pain thresholds on the forearm (P < 0.05).

Conclusions:

High rates of PI and sleep apnea highlight the need to refer TMD patients complaining of sleep disturbance for polysomnographic evaluation. The association of PI and hyperalgesia at a non-orofacial site suggests that PI may be linked with central sensitivity and could play an etiologic role in idiopathic pain disorders. The association between sleep disordered breathing and hypoalgesia requires further study and may provide novel insight into the complex interactions between sleep and pain-regulatory processes.

Citation:

Smith MT; Wickwire EM; Grace EG; Edwards RR; Buenaver LF; Peterson S; Klick B; Haythornthwaite JA. Sleep disorders and their association with laboratory pain sensitivity in temporomandibular joint disorder. SLEEP 2009;32(6):779–790.     

Isokinetic Peak Torque Ratios and Shoulder Injury History in Adolescent Female Volleyball Athletes

Context:

Few researchers have examined shoulder strength in adolescent volleyball athletes despite increasing levels of participation in this age group.

Objective:

To compare medial and lateral isokinetic peak torque of the rotator cuff among skill levels and between athletes with and without a history of shoulder injury.

Design:

Cross-sectional design.

Setting:

The Human Performance Lab and Athletic Training Lab.

Patients or Other Participants:

Thirty-eight female adolescent club volleyball athletes from 10 to 15 years of age (mean  =  13.02 ± 1.60 years).

Main Outcome Measure(s):

We measured concentric and eccentric peak torque of the medial and lateral rotators of the shoulder and calculated resultant cocking and spiking ratios based on peak torque values.

Results:

Athletes at higher skill levels had higher peak torque measurements in concentric and eccentric medial and lateral rotation compared with the athletes at lower skill levels. No differences in peak torque existed between participants with or without an injury history 6 months before the study. Strength ratios did not differ across skill levels, but previously injured participants produced lower eccentric medial rotation to concentric lateral rotation ratios compared with participants without a history of injury (P  =  .02). At the highest skill level, previously injured participants produced lower eccentric lateral rotation to concentric medial rotation ratios compared with participants without an injury history (P  =  .04).

Conclusions:

Differences in medial and lateral shoulder rotator strength ratios appear to be related more to injury prevalence than to absolute strength. Shoulder dysfunction related to strength ratio deficits also may exist in adolescent female volleyball athletes. Preventive shoulder strengthening programs focused on improving eccentric strength and correcting imbalances between medial and lateral rotators may be warranted for all female adolescent volleyball athletes.     

Randomized study assessing the influence of supervised exercises on ankle joint mobility in patients with venous leg ulcerations

Introduction

The aim of the study was to assess the influence of a supervised programme of exercises on ankle joint mobility in patients with venous leg ulcerations.

Material and methods

The study was carried out between 2008 and 2009 at the Venous Ulcer Treatment Outpatient Clinic and Clinic of General and Vascular Surgery of the Dr Jan Biziel University Hospital no. 2 in Bydgoszcz. It was a randomized control study in which 32 patients with venous leg ulcerations were qualified. Patients with ulcerations were randomized to 2 groups – 16 patients were included in the group with a supervised programme of exercises and the other 16 patients were included in the control group performing physical exercises by themselves, without supervision. The ranges of ankle joint mobility were assessed before, during and after the end of the 9-week exercise programme. A 32 cm goniometer with a scale from 0° to 180° with accuracy to 1° was used for measurements.

Results

In both groups a substantial increase of ankle joint mobility (p < 0.05) was observed. The total ankle joint mobility after completion of the exercises was significantly higher in the group performing exercises under the supervision of a nurse. Having a significant effect on the mobility of the ankle were the ulceration area, the extent of lipodermatosclerosis, and the intensity of symptoms and signs of CVI (p < 0.05).

Conclusions

Supervised physical exercises broaden the range of ankle joint mobility. They should constitute an integral part of a holistic model of care for patients with venous leg ulcerations.     

Isokinetic analysis of ankle and ground reaction forces in runners and triathletes

OBJECTIVE:

To analyze and compare the vertical component of ground reaction forces and isokinetic muscle parameters for plantar flexion and dorsiflexion of the ankle between long-distance runners, triathletes, and non-athletes.

METHODS:

Seventy-five males with a mean age of 30.26 (±6.5) years were divided into three groups: a triathlete group (n = 26), a long-distance runner group (n = 23), and a non-athlete control group. The kinetic parameters were measured during running using a force platform, and the isokinetic parameters were measured using an isokinetic dynamometer.

RESULTS:

The non-athlete control group and the triathlete group exhibited smaller vertical forces, a greater ground contact time, and a greater application of force during maximum vertical acceleration than the long-distance runner group. The total work (180°/s) was greater in eccentric dorsiflexion and concentric plantar flexion for the non-athlete control group and the triathlete group than the long-distance runner group. The peak torque (60°/s) was greater in eccentric plantar flexion and concentric dorsiflexion for the control group than the athlete groups.

CONCLUSIONS:

The athlete groups exhibited less muscle strength and resistance than the control group, and the triathletes exhibited less impact and better endurance performance than the runners.     

Two Modes of Weight Training Programs and Patellar Stabilization

Context:

Underconditioned patellar stabilizing muscles could be a predisposing factor for patellar instability.

Objective:

To examine the effect of 2 modes of weight training on the size of the vastus medialis obliquus (VMO), the resting position and passive mobility of the patella, and the strength of the knee extensor muscles.

Design:

Prospective intervention, repeated measures in 3 groups.

Setting:

Orthopaedic and sports sciences research laboratory.

Patients or Other Participants:

48 healthy adults free from back and lower extremity injuries.

Intervention(s):

Participants were randomly assigned to muscle hypertrophy training, muscle strength training, or the control group. Those in the training groups pursued training 3 times per week for 8 weeks.

Main Outcome Measure(s):

Magnetic resonance imaging and ultrasound cross-sectional area of the VMO, patellar tilt angle on magnetic resonance imaging, instrumented passive patellar mobility, and isometric knee extension torque of the dominant leg.

Results:

Participants in both training groups had comparable gains in VMO size, passive patellar stability, and knee extension force, all of which were greater than for the control group (P < .05).

Conclusions:

Both short-term muscle hypertrophy and strength training programs can reinforce the patellar stabilizers in previously untrained volunteers.     

Changes in knee biomechanics after a hip-abductor strengthening protocol for runners with patellofemoral pain syndrome

Context:

Very few authors have investigated the relationship between hip-abductor muscle strength and frontal-plane knee mechanics during running.

Objective:

To investigate this relationship using a 3-week hip-abductor muscle-strengthening program to identify changes in strength, pain, and biomechanics in runners with patellofemoral pain syndrome (PFPS).

Design:

Cohort study.

Setting:

University-based clinical research laboratory.

Patients or Other Participants:

Fifteen individuals (5 men, 10 women) with PFPS and 10 individuals without PFPS (4 men, 6 women) participated.

Intervention(s):

The patients with PFPS completed a 3-week hip-abductor strengthening protocol; control participants did not.

Main Outcome Measure(s):

The dependent variables of interest were maximal isometric hip-abductor muscle strength, 2-dimensional peak knee genu valgum angle, and stride-to-stride knee-joint variability. All measures were recorded at baseline and 3 weeks later. Between-groups differences were compared using repeated-measures analyses of variance.

Results:

At baseline, the PFPS group exhibited reduced strength, no difference in peak genu valgum angle, and increased stride-to-stride knee-joint variability compared with the control group. After the 3-week protocol, the PFPS group demonstrated increased strength, less pain, no change in peak genu valgum angle, and reduced stride-to-stride knee-joint variability compared with baseline.

Conclusions:

A 3-week hip-abductor muscle-strengthening protocol was effective in increasing muscle strength and decreasing pain and stride-to-stride knee-joint variability in individuals with PFPS. However, concomitant changes in peak knee genu valgum angle were not observed.     

Comparison between proximal row carpectomy and four-corner fusion for treating osteoarthrosis following carpal trauma: a prospective randomized study

OBJECTIVE:

To compare the functional results of carpectomy and four‐corner fusion surgical procedures for treating osteoarthrosis following carpal trauma.

METHODS:

In this prospective randomized study, 20 patients underwent proximal row carpectomy or four‐corner fusion to treat wrist arthritis and their functional results were compared. The midcarpal joint was free of lesions in all patients.

RESULTS:

Both proximal row carpectomy and four‐corner fusion reduced the pain. All patients had a decreased range of motion after surgery. The differences between groups were not statistically significant.

CONCLUSIONS:

Functional results of the two procedures were similar as both reduced pain in patients with scapholunate advanced collapse/scaphoid non‐union advanced collapse (SLAC/SNAC) wrist without degenerative changes in the midcarpal joint.     

Leg Immersion in Warm Water,Stretch-Shortening Exercise,and Exercise-Induced Muscle Damage

Context:

Whether muscle warming protects against exercise-induced muscle damage is unknown.

Objective:

To determine the effect of leg immersion in warm water before stretch-shortening exercise on the time course of indirect markers of exercise-induced muscle damage.

Design:

Crossover trial.

Setting:

Human kinetics laboratory.

Patients or Other Participants:

Eleven healthy, untrained men (age  =  21.5 ± 1.7 years).

Intervention(s):

Participants'' legs were immersed in a water bath at 44 ± 1°C for 45 minutes.

Main Outcome Measure(s):

Creatine kinase changes in the blood, muscle soreness, prolonged (within 72 hours) impairment in maximal voluntary contraction force and height of drop jump, and electrically evoked muscle force at low and high stimulation frequencies at short and long muscle lengths.

Results:

Leg immersion in warm water before stretch-shortening exercise reduced most of the indirect markers of exercise-induced muscle damage, including creatine kinase activity in the blood, muscle soreness, maximal voluntary contraction force, and jump height. The values for maximal voluntary contraction force and jump height, however, were higher during prewarming than for the control condition at 48 hours after stretch-shortening exercise, but this difference was only minor at other time points. Muscle prewarming did not bring about any changes in the dynamics of low-frequency fatigue, registered at either short or long muscle length, within 72 hours of stretch-shortening exercise.

Conclusions:

Leg immersion in warm water before stretch-shortening exercise reduced most of the indirect markers of exercise-induced muscle damage. However, the clinical application of muscle prewarming may be limited, because decreasing muscle damage did not necessarily lead to improved voluntary performance.     

Insomnia with Objective Short Sleep Duration is Associated with Deficits in Neuropsychological Performance: A General Population Study

Study Objectives:

To examine the joint effect of insomnia and objective short sleep duration on neuropsychological performance.

Design:

Representative cross-sectional study.

Setting:

Sleep laboratory.

Participants:

1,741 men and women randomly selected from central Pennsylvania.

Interventions:

None.

Measurements:

Insomnia (n = 116) was defined by a complaint of insomnia with a duration ≥ 1 year and the absence of sleep disordered breathing (SDB), while normal sleep (n = 562) was defined as the absence of insomnia, excessive daytime sleepiness, and SDB. Both groups were split according to polysomnographic sleep duration into 2 categories: ≥ 6 h of sleep (“normal sleep duration”) and < 6 h of sleep (“short sleep duration”). We compared the groups'' performance on a comprehensive neuropsychological battery that measured processing speed, attention, visual memory, and verbal fluency, while controlling for age, race, gender, education, body mass index, and physical and mental health.

Results:

No significant differences were detected between insomniacs and controls. However, the insomnia with short sleep duration group compared to the control with normal or short sleep duration groups showed poorer neuropsychological performance in variables such as processing speed, set-switching attention, and number of visual memory errors and omissions. In contrast, the insomnia with normal sleep duration group showed no significant deficits.

Conclusions:

Insomnia with objective short sleep duration is associated with deficits in set-switching attentional abilities, a key component of the “executive control of attention.” These findings suggest that objective sleep duration may predict the severity of chronic insomnia, including its effect on neurocognitive function.

Citation:

Fernandez-Mendoza J; Calhoun S; Bixler EO; Pejovic S; Karataraki M; Liao D; Vela-Bueno A; Ramos-Platon MJ; Sauder KA; Vgontzas AN. Insomnia with objective short sleep duration is associated with deficits in neuropsychological performance: a general population study. SLEEP 2010;33(4):459-465.     

Muscle coactivation before and after the impact phase of running following isokinetic fatigue

Context:

The effects of fatigue on impact loading during running are unclear, with some authors reporting increased impact forces and others reporting decreased forces.

Objective:

To examine the effects of isokinetic fatigue on muscle cocontraction ratios about the knee and ankle during running.

Design:

Cross-sectional study.

Setting:

Neuromechanics laboratory.

Patients or Other Participants:

Female middle-distance runners (age  =  21.3 ± 1.93 years) with at least 5 years of training experience.

Intervention(s):

Participants ran on the treadmill at 3.61 m/s before and immediately after the fatigue protocol, which consisted of consecutive, concentric knee extension-flexion at 120°/s until they could no longer produce 30% of the maximum knee-extension moment achieved in the familiarization session for 3 consecutive repetitions.

Main Outcome Measure(s):

Electromyographic (EMG) amplitude of the vastus medialis (VM), biceps femoris (BF), gastrocnemius (GAS), and tibialis anterior (TA) was recorded using surface electrodes. Agonist∶antagonist EMG ratios for the knee (VM∶BF) and ankle (GAS∶TA) were calculated for the preactivation (PR), initial loading response (LR₁), and late loading response (LR₂) phases of running. Hip-, knee-, and ankle-joint angular displacements at initial foot contact were obtained from 3-dimensional kinematic tracings.

Results:

Fatigue did not alter the VM∶BF EMG ratio during the PR phase (P > .05), but it increased the ratio during the LR₁ phase (P < .05). The GAS∶TA EMG ratio increased during the LR₁ phase after fatigue (P < .05) but remained unchanged during the PR and LR₂ phrases (P > .05).

Conclusions:

The increased agonist EMG activation, coupled with reduced antagonist EMG activation after impact, indicates that the acute decrease in muscle strength capacity of the knee extensors and flexors results in altered muscle-activation patterns about the knee and ankle before and after foot impact.     

Alterations in Knee Kinematics and Dynamic Stability Associated With Chronic Ankle Instability

Context:

Chronic ankle instability (CAI) has been previously and separately associated with deficits in dynamic stability and proximal joint neuromuscular alterations, but how the 2 factors relate is unclear.

Objective:

To examine the contributions of lower extremity kinematics during an assessment of dynamic stability in participants with CAI.

Design:

Repeated-measures case-control design.

Setting:

Research laboratory.

Patients or Other Participants:

Thirty-eight volunteers were categorized into groups of those with unilateral CAI (10 men, 9 women; age  =  20.3 ± 2.9 years, height  =  1.77 ± 0.1 m, mass  =  76.19 ± 13.19 kg) and those without (10 men, 9 women; age  =  23.1 ± 3.9 years, height  =  1.72 ± 0.1 m, mass  =  72.67 ± 16.0 kg).

Intervention(s):

Participants performed 10 jump landings on each limb with a rest period between test limbs.

Main Outcome Measure(s):

Ankle plantar flexion, knee flexion, and hip flexion were captured with an electromagnetic tracking device at the point of ground impact. Ground reaction force data were used to calculate time to stabilization in the anteroposterior and mediolateral planes.

Results:

For the anteroposterior plane, we found a group-by-side interaction (P  =  .003), with the injured side of the CAI group demonstrating reduced dynamic stability. For knee flexion, a group main effect (P  =  .008) showed that the CAI group landed with less knee flexion than the control group.

Conclusions:

Diminished dynamic stability and decreased knee flexion angle at initial contact were apparent in the CAI group and may play a role in contributing to CAI. This altered kinematic pattern may influence preventive and therapeutic interventions for those with CAI.     

Perceptions of joint pain and feeling well in older people who reported being healthy: a qualitative study

Background

Older people often view osteoarthritis as a part of normal ageing and see themselves as healthy despite painful joints. Professionals have mixed views about this. One concern is that seeing osteoarthritis as a result of ‘wear and tear’ leads to restricting exercise in order to avoid further wear.

Aim

To explore lay perceptions of wellness and joint pain, and their implications for consulting healthcare professionals and taking exercise.

Design of study

Qualitative, longitudinal study.

Setting

General practice in the North Midlands.

Method

Semi-structured interviews with 27 older people who reported a joint problem but rated themselves as healthy. Diary sheets were sent for 11 consecutive months to record changes in health and circumstances. Thematic data analysis was facilitated by NVivo 8.

Results

A key element of wellness was being able to continue with everyday roles and activities. ‘Wear and tear’ was used to categorise arthritis that is a normal part of old age. New joint symptoms that came on suddenly and severely were not necessarily attributed to ‘wear and tear’ arthritis, and were likely to lead to a professional consultation. Physical activity was not restricted to prevent further wear of affected joint(s). Keeping joints mobile was important in order to maintain independence.

Conclusion

Professionals should explore patients'' ideas and concerns about their joint problem, in order to individually tailor explanations and advice. Patients are likely to be receptive to recommendations that promote independence, but advice needs to be set into patients'' existing ways of living and coping with joint pain.     

Tibiofemoral Joint Positioning for the Valgus Stress Test

Context:

Recommendations on the positioning of the tibiofemoral joint during a valgus stress test to optimize isolation of the medial collateral ligament (MCL) from other medial joint structures vary in the literature. If a specific amount of flexion could be identified as optimally isolating the MCL, teaching and using the technique would be more consistent in clinical application.

Objective:

To determine the angle of tibiofemoral joint flexion between 0° and 20° that causes a difference in the slope of the force-strain line when measuring the resistance to a valgus force applied to the joint.

Design:

Cross-sectional study.

Setting:

University research laboratory.

Patients or Other Participants:

Twelve healthy volunteers (6 men, 6 women: age  =  26.4 ± 5.6 years, height  =  170.9 ± 8.4 cm, mass  =  75.01 ± 14.6 kg).

Intervention(s):

Using an arthrometer, we applied a valgus force, over a range of 60 N, to the tibiofemoral joint in 0°, 5°, 10°, 15°, and 20° of flexion.

Main Outcome Measure(s):

Force-strain measurements were obtained for 5 positions of tibiofemoral joint flexion.

Results:

As knee flexion angle increased, slope values decreased (F_4,44  =  17.6, P < .001). The slope at full extension was not different from that at 5° of flexion, but it was different from the slopes at angles greater than 10° of flexion. Similarly, the slope at 5° of flexion was not different from that at 10° of flexion, but it was different from the slopes at 15° and 20° of flexion. Further, the slope at 10° of flexion was not different from that at 15° or 20° of flexion. Finally, the slope at 15° of flexion was not different from that at 20° of flexion.

Conclusions:

When performing the manual valgus stress test, the clinician should fully extend the tibiofemoral joint or flex it to 5° to assess all resisting medial tibiofemoral joint structures and again at 15° to 20° of joint flexion to further assess the MCL.     

Changes in Serum TSH and Free T4 during Human Sleep Restriction

Study Objectives:

To examine whether recurrent sleep restriction is accompanied by changes in measures of thyroid function.

Design:

Two-period crossover intervention study.

Setting:

University clinical research center and sleep laboratory.

Participants:

11 healthy volunteers (5F/6M) with a mean (± SD) age of 39 ± 5 y and BMI 26.5 ± 1.5 kg/m².

Intervention:

Randomized exposure to 14 days of sedentary living with ad libitum food intake and 5.5- vs. 8.5-h overnight sleep opportunity.

Measurements and Results:

Serum thyroid-stimulating hormone (TSH) and free thyroxine (T4) were measured at the end of each intervention. Partial sleep restriction was accompanied by a modest but statistically significant reduction in TSH and free T4, seen mainly in the female participants of the study.

Conclusions:

Compared to the well-known rise in TSH and thyroid hormone concentrations during acute sleep loss, tests obtained after 14 days of partial sleep restriction did not show a similar activation of the human thyroid axis.

Citation:

Kessler L; Nedeltcheva A; Imperial J; Penev PD. Changes in serum TSH and free T4 during human sleep restriction. SLEEP 2010;33(8):1115-1118.