Effects of whole-body cryotherapy (-110 °C) on proprioception and indices of muscle damage

The purpose of this study was to investigate the effects of whole-body cryotherapy (WBC) on proprioceptive function, muscle force recovery following eccentric muscle contractions and tympanic temperature (T(TY) ). Thirty-six subjects were randomly assigned to a group receiving two 3-min treatments of -110 ± 3 °C or 15 ± 3 °C. Knee joint position sense (JPS), maximal voluntary isometric contraction (MVIC) of the knee extensors, force proprioception and T(TY) were recorded before, immediately after the exposure and again 15 min later. A convenience sample of 18 subjects also underwent an eccentric exercise protocol on their contralateral left leg 24 h before exposure. MVIC (left knee), peak power output (PPO) during a repeated sprint on a cycle ergometer and muscles soreness were measured pre-, 24, 48 and 72h post-treatment. WBC reduced T(TY) , by 0.3 °C, when compared with the control group (P<0.001). However, JPS, MVIC or force proprioception was not affected. Similarly, WBC did not effect MVIC, PPO or muscle soreness following eccentric exercise. WBC, administered 24 h after eccentric exercise, is ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results of this study also indicate no increased risk of proprioceptive-related injury following WBC.     

The effects of contrast bathing and compression therapy on muscular performance

Contrast bathing (CB) and compression garments (CG) are widely used to promote recovery. PURPOSE: To evaluate CB and CG as regeneration strategies after exercise-induced muscle damage (EIMD). METHODS: Baseline values of muscle soreness, serum creatine kinase (CK) and myoglobin (Mb), joint range of motion, limb girth, 10- or 30-m sprint, countermovement jump (CMJ), and five repetition maximum squat were completed by 26 young men who then undertook a resistance exercise challenge (REC) to induce EIMD: 6 x 10 parallel squats at 100% body weight with 5-s one repetition maximum eccentric squat superimposed onto each set. After the REC, subjects were separated into three intervention groups: CB, CG, and control (CONT). Forty-eight hours after REC, the subjects exercise performance was reassessed. CK and Mb were also measured +1, +24, and +48 h post-REC. RESULTS: CK was elevated at +24 h ( upward arrow140%; upward arrow161%; upward arrow270%), and Mb was elevated at +1 h ( upward arrow523%; upward arrow458%; upward arrow682%) in CB, CG, and CONT. Within-group large effect sizes for loge[CK] were found for CB at +24 h (0.80) and +48 h (0.84). Area under the [Mb] curve was lower in CB compared with CG and CONT (P < or = 0.05). At +48 h, significant differences from baseline were found in all groups for CMJ (CG, downward arrow5.1%; CB, downward arrow4.4%; CONT, downward arrow8.5%) and soreness ( upward arrow213%; upward arrow284%; upward arrow284%). Soreness transiently fell at +1 h compared with post-REC in the CB group. At +48 h, midthigh girth increased in CB ( upward arrow1.4%) and CONT ( upward arrow1.6%), whereas 30-m sprint time increased in CG ( upward arrow2%). CONCLUSION: No hierarchy of recovery effects was found. Neither contrast bathing nor compression acted to promote acute recovery from EIMD any more effectively than passive conditions, although contrast bathing may transiently attenuate postexercise soreness.     

Partial-body cryotherapy (−135°C) and cold-water immersion (10°C) after muscle damage in females

This randomized controlled trial examined the effects of cold-water immersion (CWI), partial-body cryotherapy (PBC), or a passive control (CON) on physiological and recovery variables following exercise-induced muscle damage (EIMD, 5 × 20 drop jumps) in females. Twenty-eight females were allocated to PBC (30 seconds at −60°C, 2 minutes at −135°C), CWI (10 minutes at 10°C), or CON (10 minutes resting). Muscle oxygen saturation (SmO₂), cutaneous vascular conductance (CVC), mean arterial pressure (MAP), and local skin temperature were assessed at baseline and through 60 minutes (10-minute intervals), while delayed onset of muscle soreness (DOMS), muscle swelling, maximum voluntary isometric contraction (MVIC), and vertical jump performance (VJP) were assessed up to 72 hours (24-hour intervals) following treatments. SmO₂ was lower in PBC (Δ-2.77 ± 13.08%) and CWI (Δ-5.91 ± 11.80%) compared with CON (Δ18.96 ± 1.46%) throughout the 60-minute follow-up period (P < .001). CVC was lower from PBC (92.7 ± 25.0%, 90.5 ± 23.4%) and CWI (90.3 ± 23.5%, 88.1 ± 22.9%) compared with CON (119.0 ± 5.1 and 116.1 ± 6.6%, respectively) between 20 and 30 minutes (P < .05). Mean skin temperature was lower from CWI vs PBC (between 10 and 40 minutes, P < .05). Mean skin temperature was higher in CON compared with CWI up to 60 minutes and compared with PBC up to 30 minutes (P < .05). DOMS was lower following both PBC and CWI compared with CON through 72-hour (P < .05), with no difference between groups. No main group differences for swelling, MVIC, and VJP were observed. In conclusion, CWI elicited generally greater physiological effects compared with PBC while both interventions were more effective than CON in reducing DOMS in females, but had no effect on functional measures or swelling.     

Dosages of cold‐water immersion post exercise on functional and clinical responses: a randomized controlled trial

Cold‐water immersion (CWI) is one of the recovery techniques commonly used by athletes for post‐exercise recovery. Nevertheless, the effects of CWI using different temperatures and the dose–response relationship of this technique have not yet been investigated. The aims of this study were to compare the effects of two strategies of CWI, using different water temperatures with passive recovery post exercise in the management of some markers of muscle damage, and to observe whether any of the techniques used caused deleterious effects on performance. Sixty healthy male participants performed an eccentric protocol to induce muscle damage and were then randomized to one of three groups (CWI1: 15 min at 9 °C; CWI2: 15 min at 14 °C; CG: control group). Levels of creatine kinase, muscle soreness, pain threshold, perception of recovery, and maximal voluntary isometric contraction were monitored up to 96 h post exercise. A large effect for time for all outcomes was observed [P < 0.001; CK (ES = 0.516), muscle soreness (ES = 0.368); pain threshold (ES = 0.184); perception of recovery (ES = 0.565); MVIC (ES = 0.273)]. CWI groups presented an earlier recovery for muscle soreness with lower ratings immediately post recovery. For delayed effects, the application of CWI2 (15 min at 14 °C) presented earlier recovery compared with CWI1 and control condition for maximal voluntary isometric contraction (P < 0.05). There were no significant group and interaction (Group × Time) effects. CWI groups acted more efficiently for muscle soreness and performance considering the time of recovery was observed. No evidence was found to suggest dose–response relationship and deleterious effects.     

One session of partial‐body cryotherapy (−110 °C) improves muscle damage recovery

To evaluate the effects of a single session of partial‐body cryotherapy (PBC) on muscle recovery, 26 young men performed a muscle‐damaging protocol that consisted of five sets of 20 drop jumps with 2‐min rest intervals between sets. After the exercise, the PBC group (n = 13) was exposed to 3 min of PBC at ?110 °C, and the control group (n = 13) was exposed to 3 min at 21 °C. Anterior thigh muscle thickness, isometric peak torque, and muscle soreness of knee extensors were measured pre, post, 24, 48, 72, and 96 h following exercise. Peak torque did not return to baseline in control group (P < 0.05), whereas the PBC group recovered peak torques 96 h post exercise (P > 0.05). Peak torque was also higher after PBC at 72 and 96 h compared with control group (P < 0.05). Muscle thickness increased after 24 h in the control group (P < 0.05) and was significantly higher compared with the PBC group at 24 and 96 h (P < 0.05). Muscle soreness returned to baseline for the PBC group at 72 h compared with 96 h for controls. These results indicate that PBC after strenuous exercise may enhance recovery from muscle damage.     

Effect of exercise-induced muscle damage on endurance running performance in humans

Exercise-induced muscle damage (EIMD) is known to decrease muscle strength and power but its effect on endurance performance is unclear. Thirty moderately trained adult runners (24 men and six women) were randomly assigned to EIMD or control. The EIMD group jumped 100 times from a 35 cm bench, while controls did not perform any muscle-damaging exercise. Before and 48 h after treatment, subjects were tested on markers of EIMD, steady-state cardiorespiratory, metabolic and perceptual responses during a constant speed submaximal run; distance ran in 30 min on a treadmill. There were significant changes in muscle soreness, creatine kinase, and knee extensors strength (P<0.01). This EIMD significantly reduced self-paced time trial performance by 4% (P<0.01) because subjects reduced running speed (P=0.02), with no change in perceived exertion (P=0.31). No significant alterations in running economy and other physiological responses to submaximal running were found. However, there was a trend (P=0.08) for increased perceived exertion, which was correlated with decreased time trial performance (P<0.01). In conclusion, EIMD has a significant impact on endurance running performance in humans, and this effect seems to be mediated by alterations in the sense of effort.     

Changes in urinary titin N-terminal fragments as a biomarker of exercise-induced muscle damage in the repeated bout effect

ObjectivesMuscle damage symptoms induced by unaccustomed eccentric contraction exercise can be reduced by repeating the experience several times. This phenomenon is termed the repeated bout effect. Although traditional biochemical markers require invasive blood sampling, biochemical measurements have recently been developed that can be non-invasively performed using urinary titin N-terminal fragment (UTF). However, it is unclear whether UTF can reflect the repeated bout effect. Therefore, the aim of the present study was to clarify whether UTF decreased with the repeated bout effect.DesignThis study compared changes in muscle damage markers between bouts of exercise performed for the first and second time.MethodsEight young men performed 30 eccentric exercises of the elbow flexor on the first day of the first week (Bout 1). A second bout of eccentric exercises, same as the first, was performed 2 weeks later, (Bout 2). The dependent variables were muscle soreness (SOR), maximal voluntary isometric contraction (MVIC), range of motion (ROM), creatine kinase (CK), and UTF. All dependent variables were analyzed using two-way analysis of variance.ResultsNo significant difference was observed in workload or peak torque between the first and second exercise bouts. SOR as well as CK and UTF were significantly lower and ROM and MVIC were significantly higher in Bout 2 in comparison to Bout 1.ConclusionsThese results suggest that UTF sensitively reflects the repeated bout effect and exercise-induced muscle damage can be non-invasively measured.     

Moderate intensity cycling is better than running on recovery of eccentric exercise-induced muscle damage

ObjectiveTo compare the effects of moderate intensity running and cycling on markers of exercise-induced muscle damage in men.Study designRandomized controlled trial.SettingLaboratory.ParticipantsThirty volunteers were randomized in three groups [running (RG; n = 10), cycling (CG; n = 10) and control (CON; n = 10)] and were evaluated at baseline, post 24, 48 and 72 h of knee extensors’ muscle damage protocol. CON performed passive recovery, while RG and CG performed active recovery immediately after the protocol, as well as 24 h and 48 h afterwards.Main outcomes(i) maximal voluntary isometric contraction (MVIC); (ii) delayed-onset muscle soreness (DOMS); (iii) plasma creatine kinase (CK) and lactate dehydrogenase (LDH) levels.ResultsNo group-by-time interaction was found in any outcome evaluated (p > 0.05). All groups presented decreases in MVIC and increases in DOMS (p < 0.001), without differences in CK and LDH. Compared with CON, exercise groups presented likely beneficial effects for LDH, while only CG had a likely beneficial effect for DOMS. Lastly, CG presented likely/very likely beneficial effects for MVIC and DOMS compared to RG.ConclusionAlthough the null hypothesis analysis did not find differences, the magnitude-based inference analysis suggested that moderate intensity cycling have likely beneficial effects on knee extensor muscle recovery after eccentric exercise protocol.     

Effect of water immersion methods on post-exercise recovery from simulated team sport exercise

This study aimed to compare the efficacy of hot/cold contrast water immersion (CWI), cold-water immersion (COLD) and no recovery treatment (control) as post-exercise recovery methods following exhaustive simulated team sports exercise. Repeated sprint ability, strength, muscle soreness and inflammatory markers were measured across the 48-h post-exercise period. Eleven male team-sport athletes completed three 3-day testing trials, each separated by 2 weeks. On day 1, baseline measures of performance (10 m × 20 m sprints and isometric strength of quadriceps, hamstrings and hip flexors) were recorded. Participants then performed 80 min of simulated team sports exercise followed by a 20-m shuttle run test to exhaustion. Upon completion of the exercise, and 24 h later, participants performed one of the post-exercise recovery procedures for 15 min. At 48 h post-exercise, the performance tests were repeated. Blood samples and muscle soreness ratings were taken before and immediately after post-exercise, and at 24 h and 48 h post-exercise. In comparison to the control and CWI treatments, COLD resulted in significantly lower (p < 0.05) muscle soreness ratings, as well as in reduced decrements to isometric leg extension and flexion strength in the 48-h post-exercise period. COLD also facilitated a more rapid return to baseline repeated sprint performances. The only benefit of CWI over control was a significant reduction in muscle soreness 24 h post-exercise. This study demonstrated that COLD following exhaustive simulated team sports exercise offers greater recovery benefits than CWI or control treatments.     

Effects of Kinesio taping in patients with quadriceps inhibition: A randomized,single-blinded study

ObjectiveTo determine effects of Kinesio taping (KT) on quadriceps activation and maximal voluntary isometric contraction (MVIC) in patients with quadriceps inhibition.DesignRandomized, single-blinded.SettingLaboratory.PatientsSixteen participants (9 males, 7 females) with quadriceps inhibition, as determined by 90% or lower in central activation ratio (CAR), participated.Main outcome measuresHoffmann reflex (H-reflex) of the vastus medialis and quadriceps CAR and MVIC were measured before taping, and participants were randomly allocated to either KT (KT application with tension) or sham (non-elastic tape application without tension) group. H-reflexes were assessed immediately and 20 min after tape was applied over the rectus femoris. All outcomes were measured again after tape was removed when participants returned the laboratory 24–48 h after taping.ResultsTwo-way repeated ANOVA found no group-by-time interaction for: H-reflex (F_3,42 = 1.94, P = 0.14), CAR (F_1,14 = 0.03, P = 0.86), or MVIC (F_1,14 = 0.007, P = 0.93). None of the outcome measures differed between groups or over time (P > 0.05).ConclusionsKT applied to the rectus femoris did not change H-reflex of the vastus medialis and quadriceps CAR and MVIC in patients with quadriceps inhibition.     

Changes in exercise characteristics, maximal voluntary contraction, and explosive strength during prolonged tennis playing

Objectives

To examine changes in exercise characteristics, maximal voluntary contraction, and explosive strength during prolonged tennis playing.

Methods

Maximal isometric voluntary contraction (MVC), leg stiffness (hopping), and peak power in squat (SJ) and countermovement (CMJ) jumps were measured before, every 30 minutes during, and 30 minutes after a three hour tennis match in 12 well trained players. Heart rate (HR), the effective playing time (EPT), rating of perceived exertion (RPE), and muscle soreness of knee extensors were also measured.

Results

Decreases in MVC (−9%; p<0.05) and leg stiffness (−9%; p  =  0.17) were observed after the match and were significantly correlated (r  =  0.66; p  =  0.05). Peak power in SJ and CMJ tests was maintained during the match but was lower (p<0.001) 30 minutes after. Average HR and EPT were 144 (8) beats/min and 21 (4)% respectively. A strong correlation was found between EPT and HR (r  =  0.93; p<0.05). RPE and muscle soreness increased linearly during the exercise and were significantly correlated (r  =  0.99; p<0.001).

Conclusions

Progressive reductions in maximal voluntary strength and leg stiffness highly correlated with increases in perceived exertion and muscle soreness were observed throughout a three hour tennis match, whereas explosive strength was maintained and decreased only after the match. These alterations may result in less efficient on‐court movement and stroke production. They are, however, lower than those reported during continuous exercise of the same duration. The intermittent pattern of tennis and the numerous stretch‐shortening cycle movements partly explain these results.     

The repeated bout effect can occur without mechanical and neuromuscular changes after a bout of eccentric exercise

Changes in muscle fascicle mechanics have been postulated to underpin the repeated bout effect (RBE ) observed following exercise‐induced muscle damage (EIMD ). However, in the medial gastrocnemius (MG ), mixed evidence exists on whether fascicle stretch amplitude influences the level of EIMD , thus questioning whether changes in fascicle mechanics underpin the RBE . An alternative hypothesis is that neural adaptations contribute to the RBE in this muscle. The aim of this study was to investigate the neuromechanical adaptations during and after repeated bouts of a highly controlled muscle lengthening exercise that aimed to maximize EIMD in MG . In all, 20 subjects performed two bouts of 500 active lengthening contractions (70% of maximal activation) of the triceps surae, separated by 7 days. Ultrasound constructed fascicle length‐torque (L‐T) curves of MG , surface electromyography (EMG ), maximum torque production, and muscle soreness were assessed before, 2 hours and 2 days after each exercise bout. The drop in maximum torque (4%) and the increase in muscle soreness (24%) following the repeated bout were significantly less than following the initial bout (8% and 59%, respectively), indicating a RBE . However, neither shift in the L‐T curve nor changes in EMG parameters were present. Furthermore, muscle properties during the exercise were not related to the EIMD or RBE . Our results show that there are no global changes in gastrocnemius mechanical behavior or neural activation that could explain the observed RBE in this muscle. We suggest that adaptations in the non‐contractile elements of the muscle are likely to explain the RBE in the triceps surae.     

Perceived load,fatigue and recovery responses during congested and non-congested micro-cycles in international football tournaments

ObjectivesTo describe the perceived load, fatigue and recovery profiles during congested and non-congested schedules in international football tournaments.DesignRetrospective single-cohort observational study.MethodsInternal load (session-rating of perceived exertion [s-RPE]) and perceived ratings of fatigue, muscle soreness, psychological status, sleep quality, and sleep duration were recorded daily from 37 national team footballers during the competition phase of 3 international tournaments. ANOVA and Effect Size (ES) analyses compared individualised internal load and perceived response profiles between congested and non-congested acute 2-match schedules. Conditions included Acute Congestion (≤4 days between two matches), Non-Congestion (>4 days between two matches), Single-Match, and No-Match.ResultsSignificantly higher s-RPE match loads (p < 0.001) within the single- and multi-match conditions resulted in significantly worsened (p < 0.05) subjective ratings of perceived fatigue, muscle soreness and sleep duration in the 24–48 h post-match. Internal load profiles were not different between the Acute-Congestion or Non-congestion conditions (p > 0.05); though Acute-Congestion had significantly worsened pre-match subjective ratings compared to Non-Congestion on both MD1 (p = 0.040; ES = 0.94) and MD2 (p = 0.033; ES = 0.94). However, between-match differences in Acute-Congestion showed no further impairments in perceived response between the first and second matches (p > 0.05).ConclusionsDuring international tournaments, internal load and perceived fatigue/recovery profiles are largely determined by their exposure (or lack thereof) to match-play. Periods of acute match congestion impaired players pre-match perceived status when compared to non-congested microcycles. However, acute match congestion does not appear to exacerbate players post-match fatigue/recovery response within the context of international football tournaments.     

The magnitude of muscle damage induced by downhill backward walking

While various models for exercise-induced muscle damage (EIMD) have been introduced, many of them use maximal voluntary contractions of the elbow flexors and knee extensors performed on isokinetic dynamometers. Few studies have used exercise protocols that attempt to replicate submaximal eccentric muscle actions that commonly occur during daily activities. Downhill backwards walking has been used previously as an EIMD model. However, the common markers of muscle damage have not been systematically examined for this model. The purpose of this study was to determine the magnitude of muscle damage induced by downhill backward walking with regard to changes in commonly-used indirect markers of EIMD. Twenty subjects aged between 19 y and 42 y completed a bout of 60 min of downhill (-15%) backward walking in which a single limb performed submaximal eccentric actions at a stepping rate of 30 - 35 strides per min. A repeated measures ANOVA revealed significant (p < 0.05) increases from baseline for soreness (24 hr- 96 hr), tenderness (24 hr - 96 hr), and plasma creatine kinase activity (0.5 hr - 96 hr), and significant decreases (p < 0.05) in maximal voluntary isometric (approximately 25%) and isokinetic (-15%) strength (0.5 hr - 96 hr) post-walk for the exercised limb. The time course of observed changes in these markers was similar to that reported for EIMD models of the elbow flexors and knee extensors. However, the magnitude of muscle damage appeared more consistent with that demonstrated following submaximal eccentric exercise.     

Concentric not eccentric cycling sprint intervals acutely impair balance and jump performance in healthy active young adults: A randomized controlled cross-over study

IntroductionModerate aerobic, high-intensity and sprint running or cycling training can transiently impair postural control. However, the acute effects of modified sprint interval training (mSIT) at different muscle working modes have not yet been examined. Thus, this study aimed at investigating acute effects of time-matched eccentric (ECC) versus concentric mSIT cycling session (CON) on jumping and functional balance performance.MethodsTwenty-five healthy and active males (30.0 ± 6.0 years; 80.1 ± 9.1 kg; V̇O_2max: 64.2 ± 7.9 mL kg⁻¹ min⁻¹) were enrolled in this acute randomized controlled crossover trial. Counter-Movement-Jump (CMJ) and functional balance testing (Y-Balance-Test composite score [YBT_CS]; Posturomed total distance: Posturomed_TD) were assessed as primary outcomes before, and immediately after cessation of ECC and CON (10 × 10 s maximum sprints and 50 s of active recovery).ResultsA significant mode × time interaction effect for CMJ (F = 9.620, p = 0.005, η_p² = 0.29) was observed. Subsequent post-hoc testing revealed significant moderate reductions in jumping height after CON (0.31 ± 0.06 vs. 0.27 ± 0.06m; p = 0.004, SMD = 0.59), whilst ECC remained unchanged. YBT_CS (mode × time interaction: F = 6.880, p = 0.015, η_p² = 0.22) showed small but significant balance impairments after CON (0.964 ± 0.068 vs. 0.960 ± 0.063 AU; p = 0.009, SMD = 0.28) and did not significantly change after ECC. Although large significant interaction effects (p = 0.029, η_p² = 0.18) were observed for Posturomed_TD, follow up post-hoc testing did not reveal relevant pre-post differences, neither for ECC nor CON.ConclusionBoth functional balance and jumping performance are deteriorated after acute concentric but not eccentric mSIT cycling. Although higher pedal forces at lower perceived efforts and heart rates during eccentric mSIT were observed, it seems that the cardiocirculatory demanding CON session elicited more pronounced balance and jump performance impairments than eccentric cycling.     

Cold water immersion in the management of delayed-onset muscle soreness: Is dose important? A randomised controlled trial

BackgroundCold Water Immersion (CWI) is commonly used to manage delayed onset muscle soreness (DOMS) resulting from exercise. Scientific evidence for an optimal dose of CWI is lacking and athletes continue to use a range of a treatment protocols and water temperatures.ObjectivesTo compare the effectiveness of four different water immersion protocols and a passive control intervention in the management of DOMS.DesignRandomised controlled trial with blinded outcome assessment.SettingUniversity Research Laboratory.Participants50 healthy participants with laboratory induced DOMS randomised to one of five groups: Short contrast immersion (1 min 38 °C/1 min 10 °C × 3), Short intermittent CWI (1 min × 3 at 10 °C); 10 min CWI in 10 °C; 10 min CWI in 6 °C; or control (seated rest).Main outcome measuresmuscle soreness, active range of motion, pain on stretch, muscle strength and serum creatine kinase.Results10 min of CWI in 6 °C was associated with the lowest levels of muscle soreness and pain on stretch however values were not statistically different to any of the other groups. There were no statistically significant differences between groups for any other outcomes.ConclusionAltering the treatment duration, water temperature or dosage of post exercise water immersion had minimal effect on outcomes relating to DOMS.     

Effects of mild heat exposure on fatigue responses during two sets of repeated sprints matched for initial mechanical output

ObjectivesWe examined whether mild heat exposure alters performance, perceptual responses and neural drive to the quadriceps during two sets of repeated sprints matched for initial mechanical output.DesignRepeated measures.MethodsTwelve males performed 10 × 6-s sprints (recovery = 30 s), followed 6 min later by 5 × 6-s sprints (recovery = 30 s) in either COOL (24 °C/30% rH) or HOT (35 °C/40% rH) conditions. Subsequently, two sets of five consecutive sprints matched for initial mechanical output were compared.ResultsOn the basis of peak power, performance in sprint 2 was not significantly different to sprint 11 in both conditions (p ≥ 0.32). Average peak power across the five sprints compared (i.e., sprints 2–6 and 11–15, respectively) was 2.6 ± 3.4% higher in HOT compared to COOL (p = 0.025). Electromyographic activity (root mean square value) of the vastus lateralis muscle remained unchanged. Core (sprints 2–6: 37.85 ± 0.21 vs. 37.53 ± 0.19 °C, sprints 11–15: 38.26 ± 0.33 vs. 37.89 ± 0.24 °C; p < 0.001) and skin (sprints 2–6: 36.21 ± 0.29 vs. 30.72 ± 0.52 °C, sprints 11–15: 36.37 ± 0.28 vs. 30.99 ± 0.55 °C; p < 0.001) temperatures were overall higher in HOT compared to COOL. Heart rate, thermal sensation and comfort were significantly elevated in HOT compared to COOL (p ≤ 0.02), irrespective of sprint number.ConclusionsWhen two sets of repeated sprints were matched for initial mechanical output, performance was enhanced with mild heat exposure. This occurred despite higher thermal, cardiovascular, and perceptual strain, and without alterations in quadriceps neural drive.     

The prevention and treatment of exercise-induced muscle damage

Exercise-induced muscle damage (EIMD) can be caused by novel or unaccustomed exercise and results in a temporary decrease in muscle force production, a rise in passive tension, increased muscle soreness and swelling, and an increase in intramuscular proteins in blood. Consequently, EIMD can have a profound effect on the ability to perform subsequent bouts of exercise and therefore adhere to an exercise training programme. A variety of interventions have been used prophylactically and/or therapeutically in an attempt to reduce the negative effects associated with EIMD. This article focuses on some of the most commonly used strategies, including nutritional and pharmacological strategies, electrical and manual therapies and exercise. Long-term supplementation with antioxidants or beta-hydroxy-beta-methylbutyrate appears to provide a prophylactic effect in reducing EIMD, as does the ingestion of protein before and following exercise. Although the administration of high-dose NSAIDs may reduce EIMD and muscle soreness, it also attenuates the adaptive processes and should therefore not be prescribed for long-term treatment of EIMD. Whilst there is some evidence that stretching and massage may reduce muscle soreness, there is little evidence indicating any performance benefits. Electrical therapies and cryotherapy offer limited effect in the treatment of EIMD; however, inconsistencies in the dose and frequency of these and other interventions may account for the lack of consensus regarding their efficacy. Both as a cause and a consequence of this, there are very few evidence-based guidelines for the application of many of these interventions. Conversely, there is unequivocal evidence that prior bouts of eccentric exercise provide a protective effect against subsequent bouts of potentially damaging exercise. Further research is warranted to elucidate the most appropriate dose and frequency of interventions to attenuate EIMD and if these interventions attenuate the adaptation process. This will both clarify the efficacy of such strategies and provide guidelines for evidence-based practice.     

Considerations in interpreting neuromuscular state in elite level Australian Rules football players

ObjectivesExamine the influence of test modality, season stage, match load and physical qualities on the interpretation of neuromuscular function (NF) post Australian Rules Football (ARF) matches.DesignRepeated measures design.MethodsThirty-two elite ARF players’ NF was assessed 72 h following competitive matches (7 ± 2) via the counter movement jump (CMJ) and isometric mid-thigh pull (IMTP). Influence of season stage, external load parameters (GPS; 10 Hz) and moderating influences of lower body strength (LBS), lower body power (LBP) and intermittent exercise capacity upon NF recovery were assessed using linear mixed effects models.ResultsModerate negative seasonal trends were evident for both rate of force development (RFD) 0?100 ms (d = ?0.86, 95%, CI: ±0.57) and 0?200 ms (d = ?0.76, CI: ±0.64). Significant but trivial effects of match load were observed between one standardised unit increase in high speed running (HSR) versus CMJ: Force at zero velocity (d = 0.12, CI: ±0.12), and sum of high intensity accelerations and CMJ: Eccentric deceleration RFD (d = ?0.18, CI: ±0.14). Accounting for baseline LBS better explained (weight of evidence: W = 87%) seasonal trends observed in IMTP: peak force, with lower LBS showing greater capacity for improvement. Positive moderating influences were observed with baseline LBS and LBP (W = 91 & 75%) on CMJ: eccentric mean power responses to HSR, and CMJ: jump height responses to very-HSR, respectively.ConclusionsInterpretation of athlete NF responses is complicated by the inconsistent and interacting influence of contextual factors (assessment modality, stage of season, load), in-particular higher baseline LBS and LBP may improve acute load related responses of NF.     

Cardiovascular and blood lactate responses to acute plyometric exercise in female volleyball and handball players

Although plyometrics are widely used in athletic conditioning, the acute cardiovascular responses to plyometric exercise in female subjects have not been described. The purpose of this study was to assess the acute effects of plyometric exercise on cardiovascular responses, as well as blood lactate concentrations in female volleyball and handball players. Eight semiprofessional volleyball plays and ten handball players volunteered to participate in this study. Subjects performed five sets of box jumps and depth jumps with ten repetitions, respectively. After each set of exercises, blood pressure and heart rate were assessed. Blood lactate concentration was measured before and after exercise. Muscle soreness was also measured immediately before and immediately after plyometric exercise as well as 24, 48 and 72 h after plyometric exercise. No differences were found in any physiological indices between volleyball and handball players, except heart rate during box jump set 2 and the rate pressure product (RPP) during box jump sets 2 and 5 and depth jump set 1 (P > 0.05). Plyometric exercise increased heart rate, systolic and diastolic blood pressure, and RPP after each set of exercises (P < 0.05). Also, heart rate and RPP were higher during the depth jump exercise (P < 0.05). Plyometric exercise did not induce any significant changes in muscle soreness (P > 0.05). The blood lactate concentrations were significantly increased above resting levels (P < 0.05). These findings suggest that plyometric box and depth jumping can be used in an overall programme to properly prepare athletes for competition in events that require both aerobic and anaerobic metabolism components.