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INTRODUCTION: Hydrotherapy strategies such as cold, hot and contrast water immersion are used by athletes on completion of, and in preparation for, training and competition. The current study investigated the acute (<36 h) effects of post-exercise hydrotherapy on lower-body performance following a whole-body resistance exercise session. METHODS: Junior, international, male, volleyball athletes (n=15, 19.8 ± 3.7 y, 192.5 ± 11.8 cm, 80.2 ± 8.4 kg) were assessed for squat jump (SJ), counter-movement jump (CMJ) and isometric mid-thigh pull (IMTP) performance before and after a single whole-body resistance exercise and post-exercise hydrotherapy session. Athletes completed one of four 15min recovery strategies (control [CON]: passive seated rest at 23.7 ± 0.4°C; cold water immersion [CWI]: 14.8 ± 0.2°C; contrast water therapy [CWT]: 7 x 2 min, alternating hot 39.1 ± 0.5°C and cold 14.8 ± 0.2°C; and hot water immersion [HWI]: 39.1 ± 0.5°C), in a randomised crossover design, with >96 h between trials. SJ, CMJ and IMTP performance was assessed pre (-8 h) and at 0, 2, 4, 12 and 36 h post-resistance exercise. Mean percent change (%Δ) was calculated using a post-exercise (0 h) baseline. Jump height and vertical velocity was determined for SJ (SJ-HT%Δ and SJ-VEL%Δ) and CMJ (CMJ-HT%Δ and CMJ-VEL%Δ). Absolute (IMTP-PF%Δ) and relative (IMTP-relPF%Δ) peak force was determined for IMTP. Eccentric Utilization Ratio (EUR) and Dynamic Strength Index (DSI_SJ:IMTP and DSI_CMJ:IMTP) was calculated. Repeated-measures ANOVA was used to analyse main and interaction effects with significance accepted at p<0.10. The magnitude of change is interpreted using partial eta squared (ƞ²) and Cohen d effect size statistics. RESULTS: No significant main interactions were observed for SJ and CMJ variables (SJ-HT%Δ: p=0.679, ƞ²=0.039; SJ-VEL%Δ: p=0.642, ƞ²=0.041; CMJ-HT%Δ: p=0.545, ƞ²=0.043; CMJ-VEL%Δ: p=0.527, ƞ²=0.045). A significant main interaction was observed for IMTP-relPF%Δ (p=0.095, ƞ²=0.086) with relative IMTP peak force significantly (p=0.09, d=0.41) lower 12 h post-exercise in CWI (367.0 ± 52.6 N.kg-1) vs HWI (388.4 ± 60.1 N.kg-1), however there was no significant main interaction in IMTP-PF%Δ (p=0.43, ƞ²=0.051). No significant main interactions were observed for EUR (p=0.777, ƞ²=0.03), DSI-SJ:IMTP (p=0.242, ƞ²=0.083) or DSI-CMJ:IMTP (p=0.224, ƞ²=0.065). DISCUSSION: Previous research is inconsistent on the application of CWI as a post-exercise recovery strategy, with negative and positive effects on subsequent muscular performance. This research suggests that hydrotherapy strategies such as CWI and CWT do not appear to substantially influence post-exercise changes in SJ, CMJ and IMTP for <36 h following a single bout of resistance exercise. However, HWI optimises maximum isometric strength when compared with CWI at 12 h post-resistance exercise. PRACTICAL APPLICATION: Choice of hydrotherapy strategy may influence muscular contractions for up to 36 h post-exercise with small to medium interaction effects observed in dynamic strength indices. On days where multiple, same day resistance exercise bouts are performed, this data suggests that hydrotherapy would not be beneficial in between sessions. However, when resistance exercise is performed on subsequent days (~12 h apart), practitioners should prescribe post-exercise HWI to maximise isometric strength performance, while being cognisant of the effects that diurnal variation may have on muscular performance. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Following resistance training the acute effects of cold water immersion (CWI), contrast water therapy (CWT) and hot water immersion (HWI) on performance and perceived muscle soreness are not well characterised. This study assessed the effects of an acute bout of hydrotherapy compared with passive seated rest for 15 min (CON) on recovery (<48h) after a single, whole-body resistance training session. METHODS: Male sub-elite volleyball players (n=19, 24.1±5.5y, 181.9±8.9m, 78.4±11.2kg) were assessed for perceived muscle soreness (DOMS) and countermovement jumps (CMJ) performance prior to and immediately following a resistance training session. Athletes completed one of four 15min hydrotherapy strategies (CWI: 15°C; CWT: 7x2min, alternating hot 38°C and cold; HWI: 38°C), in a randomised order with at least 96h between trials with DOMS and CMJ reassessed immediately (0), 2, 24 and 48h post-resistance training. Flight time to contraction time (FT:CT) and a modified Reactive Strength Index (RSImod) were calculated from each CMJ. Data are presented as mean percent (%) change x/÷ 90% confidence intervals (CI) factor with the magnitude interpreted using effect size (ES, partial eta squared) and a linear mixed model was used to analyse the main and interaction effects. RESULTS: Immediately post-intervention RSImod and FT:CT increased compared to baseline (<8.1% x/÷ 0.02, p=0.02, ES=0.35-0.46) in CON and small effects were observed for CWI and CWT (<7.7% x/÷ 0.06, ES=0.37-0.53). Performance decreased 2h post exercise in CWT and HWI conditions (-5% x/÷ 0.05, ES=0.20). During CON RSImod and FT:CT (8x/÷ 0.02, ES=0.31-0.36) were increased at 48h while other conditions returned to baseline. Large correlations were observed between FT:CT and RSImod across all time points (r=0.77-0.94); however, greater main effects were observed in FT:CT. No significant intervention x group interaction for FT:CT and RSImod was observed. DOMS increased in all conditions at 24 and 48h (p<0.03, ES=0.80-1.61) with the large effects observed in CWT and HWI (ES=1.40-1.61). DISCUSSION: Hydrotherapy does not appear to influence CMJ performance following a resistance training bout, but may substantially effect the perception of recovery. Although a large correlation was observed between jumping variables across time, an increased number of effects were observed for FT:CT. Suggesting, that in a semi-elite male habituated jumping cohort, FT:CT has a greater sensitivity to fatigue post-resistance training than RSImod. PRACTICAL APPLICATIONS: When monitoring neuromuscular fatigue using CMJ, FT:CT may provide a more sensitive measure. CON may be more effective for recovery post-resistance training at 48h than CWI, CWT and HWI on jumping performance. HWI and CWT may have detrimental effects on jump performance 2h post resistance-training and therefore, should be used with caution if prescribed as an intervention between successive training sessions performed on the same day. [ABSTRACT FROM AUTHOR]

INTRODUCTION: International long haul (>5h) air travel is a necessity for many highly trained athletes as part of their training or competition schedules. Negative effects associated with long haul travel may impair an athlete's neuromuscular function. Countermovement jumps (CMJ) are frequently used to assess an athlete's lower body neuromuscular status. This study assessed the impact of westbound trans-meridian travel and intensified training on changes in CMJ performance. METHODS: Highly trained rowers (n=21, 23.7±1.4y, 190.9±7.5cm, 86.9±9.9kg) completed a single set of 6 loaded CMJ's weekly with performance measured using a digital optical encoder attached to a 20kg barbell. Each CMJ was assessed for mean concentric velocity (MV), jump height (JH) and dip. Data collection occurred four weeks prior to (T-4), week of (T-1), week post (T+1) and up to four weeks post (T+3 and T+4) travel. Athletes undertook a westbound flight incurring 22h flight time with 30h total travel time across nine time zones. Descriptive data is reported as mean (SD) with changes between time points reported as Cohen's d (90% CL) using criteria of <0.2=trivial, 0.2-0.6=small, 0.6-1.2=moderate and >1.2=large. RESULTS: Small changes were observed in JH and MV following westbound trans-meridian travel, and continued small changes were observed in these variables and dip up to 4 weeks post travel (Table 1). Trivial changes were observed for all variables between the T+3 and T+4 time periods. DISCUSSION: Westbound travel results in small differences in JH and MV. We hypothesise that this small change is due to athletes' retaining a high training load prior to travel, while the travel time worked as a forced rest period. Greater changes in JH and MV post travel may have been stifled by athletes being in a fatigued state prior to travel, small reductions in dip and MV during the pre-travel period support this, while only trivial reductions in JH were observed. Previous research indicates changes in dip may be a better indicator of fatigue. During intensified training there were small changes in JH, MV and dip, with a trivial reduction in JH and MV T+3 to T+4. A trivial increase in dip occurred concurrently, suggesting that despite an intensified training period athletes were able to maintain performance. This may be characteristic of this athlete cohort, which regularly undertake large training volumes and are potentially training in a compromised state. Analysis suggests westbound trans-meridian travel may have a greater impact on this athlete cohort than changes in training intensity (trivial changes T+3 to T+4 during the period of greatest load of the intensified training period). PRACTICAL APPLICATIONS: Reductions in CMJ performance are likely following westbound trans-meridian travel, however this may also be impacted by training fatigue prior to travel. Athletes may be able to maintain velocity and displacement based variables during periods of intensified training. [ABSTRACT FROM AUTHOR]

Purpose: Following resistance exercise, uncertainty exists as to whether the regular application of cold water immersion attenuates lean muscle mass increases in athletes. The effects of repeated post-resistance exercise cold versus hot water immersion on body composition and neuromuscular jump performance responses in athletes were investigated. Methods: Male, academy Super Rugby players (n = 18, 19.9 ± 1.5 y, 1.85 ± 0.06 m, 98.3 ± 10.7 kg) participated in a 12-week (4-week × 3-intervention, i.e., control [CON], cold [CWI] or hot [HWI] water immersion) resistance exercise programme, utilising a randomised cross-over pre–post-design. Body composition measures were collected using dual-energy X-ray absorptiometry prior to commencement and every fourth week thereafter. Neuromuscular squat (SJ) and counter-movement jump (CMJ) performance were measured weekly. Linear mixed-effects models were used to analyse main (treatment, time) and interaction effects. Results: There were no changes in lean (p = 0.960) nor fat mass (p = 0.801) between interventions. CON (p = 0.004) and CWI (p = 0.003) increased (g = 0.08–0.19) SJ height, compared to HWI. There were no changes in CMJ height (p = 0.482) between interventions. Conclusion: Repeated post-resistance exercise whole-body CWI or HWI does not attenuate (nor promote) increases in lean muscle mass in athletes. Post-resistance exercise CON or CWI results in trivial increases in SJ height, compared to HWI. During an in-season competition phase, our data support the continued use of post-resistance exercise whole-body CWI by athletes as a recovery strategy which does not attenuate body composition increases in lean muscle mass, while promoting trivial increases in neuromuscular concentric-only squat jump performance. [ABSTRACT FROM AUTHOR]

Athletes use water immersion strategies to recover from training and competition. This study investigated the acute effects of postexercise water immersion after resistance exercise. Eighteen elite and subelite male volleyball athletes participated in an intervention using a randomized cross-over design. On separate occasions after resistance exercise, subjects completed 1 of 4 15-minute interventions: control (CON), cold water immersion (CWI), contrast watertherapy (CWT), or hot water immersion (HWI). Significance was accepted at p # 0.05. Resistance exercise induced significant temporal changes (time effect) for inflammatory, anthropometric, perceptual, and performance measures. Serum creatine kinase was reduced (g = 0.02-0.30) after CWI (p = 0.007), CWT (p = 0.006), or HWI (p < 0.001) vs. CON, whereas it increased significantly (g = 0.50) after CWI vs. HWI. Contrast water therapy resulted in significantly higher (g = 0.56) interleukin-6 concentrations vs. HWI. Thigh girth increased (g = 0.06-0.16) after CWI vs. CON (p = 0.013) and HWI (p < 0.001) and between CWT vs. HWI (p = 0.050). Similarly, calf girth increased (g = 0.01-0.12) after CWI vs. CON (p = 0.039) and CWT (p = 0.018), and HWI vs. CON (p = 0.041) and CWT (p = 0.018). Subject belief in a postexercise intervention strategy was associated with HSP72 ("believer">"nonbeliever," p = 0.026), muscle soreness ("believer">"nonbeliever," p = 0.002), and interleukin-4 ("nonbeliever">"believer," p = 0.002). There were no significant treatment x time (interaction effect) pairwise comparisons. Choice of postexercise water immersion strategy (i.e., cold, contrast, or hot) combined with a belief in the efficacy of that strategy to enhance recovery or performance improves biological and perceptual markers of muscle damage and soreness. On same or subsequent days where resistance exercise bouts are performed, practitioners should consider athlete beliefs when prescribing postexercise water immersion, to reduce muscle soreness. [ABSTRACT FROM AUTHOR]

Background: Repeat power ability (RPA) assessments traditionally use discrete variables, such as peak power output, to quantify the change in performance across a series of jumps. Rather than using a discrete variable, the analysis of the entire force-time curve may provide additional insight into RPA performance. The aims of this study were to (1) analyse changes in the force-time curve recorded during an RPA assessment using statistical parametric mapping (SPM) and (2) compare the differences in the force-time curve between participants with low and high RPA scores, as quantified by traditional analysis., Materials and Methods: Eleven well-trained field hockey players performed an RPA assessment consisting of 20 loaded countermovement jumps with a 30% one repetition maximum half squat load (LCMJ20). Mean force-time series data was normalized to 100% of the movement duration and analysed using SPM. Peak power output for each jump was also derived from the force-time data and a percent decrement score calculated for jumps 2 to 19 (RPA %dec ). An SPM one-way ANOVA with significance accepted at α  = 0.05, was used to identify the change in the force-time curve over three distinct series of jumps across the LCMJ20 (series 1 = jumps 2-5, series 2 = jumps 9-12 and series 3 = jumps 16-19). A secondary analysis, using an independent T -test with significance accepted at p  < 0.001, was also used to identify differences in the force-time curve between participants with low and high RPA %dec ., Results: Propulsive forces were significantly lower ( p  < 0.001) between 74-98% of the movement compared to 0-73% for changes recorded during the LCMJ20. Post hoc analysis identified the greatest differences to occur between jump series 1 and jump series 2 ( p  < 0.001) at 70-98% of the movement and between jump series 1 and jump series 3 ( p  < 0.001) at 86-99% of the movement. No significant differences were found between jump series 2 and jump series 3. Significant differences ( p  < 0.001) in both the braking phase at 44-48% of the jump and the propulsive phase at 74-94% of the jump were identified when participants were classified based on low or high RPA %dec scores (with low scores representing an enhanced ability to maintain peak power output than high scores)., Conclusion: A reduction in force during the late propulsive phase is evident as the LCMJ20 progresses. SPM analysis provides refined insight into where changes in the force-time curve occur during performance of the LCMJ20. Participants with the lower RPA %dec scores displayed both larger braking and propulsive forces across the LCMJ20 assessment., Competing Interests: Justin W.L. Keogh is an Academic Editor for PeerJ., (©2024 Natera et al.)

Purpose: Uncertainty exists if post-resistance exercise hydrotherapy attenuates chronic inflammatory and hormone responses. The effects of repeated post-resistance exercise water immersion on inflammatory and hormone responses in athletes were investigated., Methods: Male, academy Super Rugby players (n = 18, 19.9 ± 1.5 y, 1.85 ± 0.06 m, 98.3 ± 10.7 kg) participated in a 12-week programme divided into 3 × 4-week blocks of post-resistance exercise water immersion (either, no immersion control [CON]; cold [CWI]; or hot [HWI] water immersion), utilising a randomised cross-over pre-post design. Fasted, morning blood measures were collected prior to commencement of first intervention block, and every fourth week thereafter. Linear mixed-effects models were used to analyse main (treatment, time) and interaction effects., Results: Repeated CWI (p = 0.025, g = 0.05) and HWI (p < 0.001, g = 0.62) reduced creatine kinase (CK), compared to CON. HWI decreased (p = 0.013, g = 0.59) interleukin (IL)-1ra, compared to CON. HWI increased (p < 0.001-0.026, g = 0.06-0.17) growth factors (PDGF-BB, IGF-1), compared to CON and CWI. CWI increased (p = 0.004, g = 0.46) heat shock protein-72 (HSP-72), compared to HWI., Conclusion: Post-resistance exercise CWI or HWI resulted in trivial and moderate reductions in CK, respectively, which may be partly due to hydrostatic effects of water immersion. Post-resistance exercise HWI moderately decreased IL-1ra, which may be associated with post-resistance exercise skeletal muscle inflammation influencing chronic resistance exercise adaptive responses. Following post-resistance exercise water immersion, CWI increased HSP-72 suggesting a thermoregulatory response indicating improved adaptive inflammatory responses to temperature changes, while HWI increased growth factors (PDGF-BB, IGF-1) indicating different systematic signalling pathway activation. Our data supports the continued use of post-resistance exercise water immersion recovery strategies of any temperature during in-season competition phases for improved inflammatory adaptive responses in athletes., (© 2024. The Author(s).)

Sprinting plays a significant role in determining the results of road cycling races worldwide. However, currently, there is a lack of systematic research into the kinematics of sprint cycling, especially in an outdoor, environmentally valid setting. This study aimed to describe selected joint kinematics during a cycling sprint outdoors. Three participants were recorded sprinting over 60 meters in both standing and seated sprinting positions on an outdoor course with a baseline condition of seated cycling at 20 km/h. The participants were recorded using array-based inertial measurement units to collect joint excursions of the upper and lower limbs including the trunk. A high-rate GPS unit was used to record velocity during each recorded condition. Kinematic data were analyzed in a similar fashion to running gait, where multiple pedal strokes were identified, delineated, and averaged to form a representative (average ± SD) waveform. Participants maintained stable kinematics in most joints studied during the baseline condition, but variations in ranges of movement were recorded during seated and standing sprinting. Discernable patterns started to emerge for several kinematic profiles during standing sprinting. Alternate sprinting strategies emerged between participants and bilateral asymmetries were also recorded in the individuals tested. This approach to studying road cycling holds substantial potential for researchers wishing to explore this sport., Competing Interests: The authors declare no conflicts of interest.

Objectives: To explore the practicality of using functional principal components analysis (fPCA) and intra-athlete z-score changes for individual athlete monitoring post-ACL injury and surgery., Design: A single athlete case study using within-athlete repeated measures in the context of applied athlete monitoring., Methods: Using single leg (left) drop landing (3 landings per session) onto a force plate, the athlete completed 6 sessions prior (healthy) and 3 sessions post-ACL injury/surgery. Maximum vertical ground reaction force (vGRF), time to stabilisation (TTS) and outputs from fPCA (fPC scores) for the healthy sessions were used to develop intra-athlete means and standard deviations for each variable. Post-surgery measures were given z-scores relative to the healthy mean and standard deviation for each variable. The standard normal deviate (z = 1.96) was used as a threshold to flag landings that could be indicative of changes in movement behaviour., Results: Maximum vGRF revealed no post-surgery trials that exceeded the standard normal deviate threshold based on the healthy data. TTS identified one landing post-surgery that exceeded the threshold. Scores for fPC2, fPC3 and fPC4 revealed landings that exceeded the threshold, with fPC4 demonstrating landings greater than the threshold for every trial (except two) post-surgery., Conclusions: Including fPCA identified significant and stable changes to the landing strategy (particularly within fPC4). When used in conjunction with other measures such as maximum vGRF and TTS, fPCA has the potential to provide meaningful insights into athlete monitoring models regarding changes to movement characteristics after injury., (Copyright © 2019 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

In combat sports, athletes are divided into categories based on gender and body mass. Athletes attempt to compete against a lighter opponent by losing body mass prior to being weighed (i.e., 'weight-cutting'). The purpose of this narrative review was to explore the current body of literature on weight-cutting and outline gaps for further research. Methods of weight-loss include energy intake restriction, total body fluid reduction and pseudo extreme/abusive medical practice (e.g., diuretics). The influence of weight-cutting on performance is unclear, with studies suggesting a negative or no effect. However, larger weight-cuts (~5% of body mass in <24 h) do impair repeat-effort performance. It is unclear if the benefit from competing against a smaller opponent outweighs the observed reduction in physical capacity. Many mechanisms have been proposed for the observed reductions in performance, ranging from reduced glycogen availability to increased perceptions of fatigue. Athletes undertaking weight-cutting may be able to utilise strategies around glycogen, total body water and electrolyte replenishment to prepare for competition. Despite substantial discussion on managing weight-cutting in combat sports, no clear solution has been offered. Given the prevalence of weight-cutting, it is important to develop a deeper understanding of such practices so appropriate advice can be given.