Heat stress does not exacerbate tennis-induced alterations in physical performance

Tournament Recovery Profiles and Physical Demands in a Collegiate Women's Tennis Team

ABSTRACT

Tendero-Ortiz, E, Johnson, MJ, Horsfall, CM, Vondrasek, JD, Grosicki, GJ, Riemann, BL, and Flatt, AA. Tournament recovery profiles and physical demands in a collegiate women's tennis team. J Strength Cond Res 38(10): 1786-1792, 2024-We aimed to characterize recovery profiles and tournament physical demands in women's collegiate tennis players. A Division 1 team ( n = 9) participated in the study. Markers of cardiac autonomic (resting heart rate [HR], HR variability), neuromuscular (isometric handgrip strength, seated single-arm shot-put test [SSAPT], hexagon agility, countermovement jump characteristics), and perceptual recovery were obtained before the tournament (baseline) and again 1 and 2 days posttournament. Cardiorespiratory (HR) and movement characteristics from matches were quantified with wearable devices. p values < 0.05 were statistically significant. No recovery markers differed from baseline ( p > 0.05), although small effect size reductions 1 day posttournament were noted for SSAPT, hexagon agility, and select countermovement jump characteristics. In addition, hexagon agility times and SSAPT were slower ( p < 0.01) and shorter ( p < 0.05), respectively, at 1 versus 2 days posttournament. Similarly, relative to 1 day posttournament, perceptual makers were improved 2 days posttournament ( p s < 0.05). Mean and peak HR were higher for singles versus doubles matches  ( p < 0.05). Except for average speed, movement parameters were greater during singles versus doubles matches ( p < 0.05). Markers of recovery were minimally affected 1 day posttournament relative to baseline, but perceptual and select neuromuscular markers were most improved 2 days posttournament. Thus, passive rest or limited intensity training 1 day posttournament seems advisable. Competition HR and movement profiles inform practitioners of the cardiorespiratory and locomotor demands of women's collegiate tennis, which may be useful in designing preparatory conditioning programs to ensure that players attain match-specific physical capacities in training before competition.

Core Body Temperatures in Intermittent Sports: A Systematic Review

BACKGROUND

Hyperthermia (and associated health and performance implications) can be a significant problem for athletes and teams involved in intermittent sports. Quantifying the highest thermal strain (i.e. peak core body temperature [peak Tc]) from a range of intermittent sports would enhance our understanding of the thermal requirements of sport and assist in making informed decisions about training or match-day interventions to reduce thermally induced harm and/or performance decline.

OBJECTIVE

The objective of this systematic review was to synthesise and characterise the available thermal strain data collected in competition from intermittent sport athletes.

METHODS

A systematic literature search was performed on Web of Science, MEDLINE, and SPORTDiscus to identify studies up to 17 April 2023. Electronic databases were searched using a text mining method to provide a partially automated and systematic search strategy retrieving terms related to core body temperature measurement and intermittent sport. Records were eligible if they included core body temperature measurement during competition, without experimental intervention that may influence thermal strain (e.g. cooling), in healthy, adult, intermittent sport athletes at any level. Due to the lack of an available tool that specifically includes potential sources of bias for physiological responses in descriptive studies, a methodological evaluation checklist was developed and used to document important methodological considerations. Data were not meta-analysed given the methodological heterogeneity between studies and therefore were presented descriptively in tabular and graphical format.

RESULTS

A total of 34 studies were selected for review; 27 were observational, 5 were experimental (2 parallel group and 3 repeated measures randomised controlled trials), and 2 were quasi-experimental (1 parallel group and 1 repeated measures non-randomised controlled trial). Across all included studies, 386 participants (plus participant numbers not reported in two studies) were recruited after accounting for shared data between studies. A total of 4 studies (~ 12%) found no evidence of hyperthermia, 24 (~ 71%) found evidence of 'modest' hyperthermia (peak Tc between 38.5 and 39.5 °C), and 6 (~ 18%) found evidence of 'marked' hyperthermia (peak Tc of 39.5 °C or greater) during intermittent sports competition.

CONCLUSIONS

Practitioners and coaches supporting intermittent sport athletes are justified to seek interventions aimed at mitigating the high heat strain observed in competition. More research is required to determine the most effective interventions for this population that are practically viable in intermittent sports settings (often constrained by many competing demands). Greater statistical power and homogeneity among studies are required to quantify the independent effects of wet bulb globe temperature, competition duration, sport and level of competition on peak Tc, all of which are likely to be key modulators of the thermal strain experienced by competing athletes.

REGISTRATION

This systematic review was registered on the Open Science Framework ( https://osf.io/vfb4s ; https://doi.org/10.17605/OSF.IO/EZYFA , 4 January 2021).

Change-of-Direction Speed Assessments and Testing Procedures in Tennis: A Systematic Review

ABSTRACT

Schneider, C, Rothschild, J, and Uthoff, A. Change-of-direction speed assessments and testing procedures in tennis: a systematic review. J Strength Cond Res 37(9): 1888-1895, 2023-Change-of-direction speed (CODS) plays an essential role in tennis match play, and CODS performance is, therefore, commonly assessed and monitored in tennis players. Thus, the aim of this systematic review was to describe test characteristics, performance metrics, test-retest reliability, construct validity, and test outcomes of tests that are used to assess CODS in tennis players. A literature search conducted on PubMed and SPORTDiscus yielded 563 results. After applying the eligibility criteria, a total of 27 studies were included in the present review. Ten unique CODS tests were identified. 505 test variations were most frequently used across all studies, and total time required to complete the test was the predominant performance metric investigated. Intrasession test-retest reliability ranged from "moderate" to "excellent." Intersession test-retest reliability as well as the effects of tennis performance, sex, and age on CODS performance were unclear given the subject demographics and the limited number of studies that investigated these aspects. In conclusion, most studies included CODS tests that exhibit longer COD entry and total distances but similar COD angles to those seen during tennis match play. All CODS tests have at least "moderate" intrasession test-retest reliability. However, to improve CODS assessment methods and to increase our current understanding of CODS performance in tennis players, there is a need to conduct more research on the intersession test-retest reliability, construct validity, and the effects of sex, age, and tennis performance and to investigate other performance metrics that might provide additional insights into CODS (e.g., phase-specific performance variables).

Cold-water immersion and whole-body cryotherapy attenuate muscle soreness during 3 days of match-like tennis protocol

PURPOSE

This study aimed to investigate the effect of whole-body cryotherapy (WBC), cold-water immersion (CWI) and passive recovery (PAS) on tennis recovery.

METHODS

Thirteen competitive male tennis players completed three consecutive match-like tennis protocols, followed by recovery (WBC, CWI, PAS) in a crossover design. Five tennis drills and serves were performed using a ball machine to standardize the fatiguing protocol. Maximal voluntary contraction (MVC) peak torque, creatine kinase activity (CK), muscle soreness, ball accuracy and velocity together with voluntary activation, low- and high-frequency torque and EMG activity were recorded before each protocol and 24 h following the third protocol.

RESULTS

MVC peak torque (- 7.7 ± 11.3%; p = 0.001) and the high- to low-frequency torque ratio (- 10.0 ± 25.8%; p < 0.05) decreased on Day 1 but returned to baseline on Day 2, Day 3 and Day 4 (p = 0.052, all p > 0.06). The CK activity slightly increased from 161.0 ± 100.2 to 226.0 ± 106.7 UA L-1 on Day 1 (p = 0.001) and stayed at this level (p = 0.016) across days with no differences between recovery interventions. Muscle soreness increased across days with PAS recovery (p = 0.005), while no main effect of time was neither observed with WBC nor CWI (all p > 0.292). The technical performance was maintained across protocols with WBC and PAS, while it increased for CWI on Day 3 vs Day 1 (p = 0.017).

CONCLUSION

Our 1.5-h tennis protocol led to mild muscle damage, though neither the neuromuscular function nor the tennis performance was altered due to accumulated workload induced by consecutive tennis protocols. The muscle soreness resulting from tennis protocols was similarly alleviated by both CWI and WBC.

TRIAL REGISTRATION

IRB No. 2017-A02255-48, 12/05/2017.

Reduced running performance and greater perceived exertion, but similar post-exercise neuromuscular fatigue in tropical natives subjected to a 10 km self-paced run in a hot compared to a temperate environment

Environmental heat stress impairs endurance performance by enhancing exercise-induced physiological and perceptual responses. However, the time course of these responses during self-paced running, particularly when comparing hot and temperate conditions, still needs further clarification. Moreover, monitoring fatigue induced by exercise is paramount to prescribing training and recovery adequately, but investigations on the effects of a hot environment on post-exercise neuromuscular fatigue are scarce. This study compared the time course of physiological and perceptual responses during a 10 km self-paced treadmill run (as fast as possible) between temperate (25°C) and hot (35°C) conditions. We also investigated the changes in countermovement jump (CMJ) performance following exercise in these two ambient temperatures. Thirteen recreational long-distance runners (11 men and 2 women), inhabitants of a tropical region, completed the two experimental trials in a randomized order. Compared to 25°C, participants had transiently higher body core temperature (TCORE) and consistently greater perceived exertion while running at 35°C (p < 0.05). These changes were associated with a slower pace, evidenced by an additional 14 ± 5 min (mean ± SD) to complete the 10 km at 35°C than at 25°C (p < 0.05). Before, immediately after, and 1 h after the self-paced run, the participants performed CMJs to evaluate lower limb neuromuscular fatigue. CMJ height was reduced by 7.0% (2.3 ± 2.4 cm) at 1 h after the race (p < 0.05) compared to pre-exercise values; environmental conditions did not influence this reduction. In conclusion, despite the reduced endurance performance, higher perceived exertion, and transiently augmented TCORE caused by environmental heat stress, post-exercise neuromuscular fatigue is similar between temperate and hot conditions. This finding suggests that the higher external load (faster speed) at 25°C compensates for the effects of more significant perceptual responses at 35°C in inducing neuromuscular fatigue.

Relationship Between Change of Direction, Speed, and Power in Male and Female National Olympic Team Handball Athletes

Pereira, LA, Nimphius, S, Kobal, R, Kitamura, K, Turisco, LAL, Orsi, RC, Cal Abad, CC, and Loturco, I. Relationship between change of direction, speed, and power in male and female National Olympic Team handball athletes. J Strength Cond Res 32(10): 2987-2994, 2018-The aims of this study were to (a) assess the relationship between selected speed- and power-related abilities (determined by 20-m sprint, unloaded countermovement jump [CMJ] and squat jump [SJ], and loaded jump squat [JS]) and performance in 2 distinct change of direction (COD) protocols (Zigzag test and T-test) and (b) determine the magnitude of difference between female and male Brazilian National Olympic Team handball athletes. Fifteen male and 23 female elite handball athletes volunteered to perform the following assessments: SJ and CMJ; Zigzag test and T-test; 20-m sprint with 5-, 10-, and 20-m splits; and mean propulsive power in JS. Pearson's product-moment correlation (p ≤ 0.05) was performed to determine the relationship between the COD tests (Zigzag test and T-test) and speed-power measures (sprint, SJ, CMJ, and JS). The differences between male and female performances were determined using the magnitude-based inference. Moderate to very large significant correlations were observed between both COD tests and the speed-power abilities. Furthermore, male athletes demonstrated likely to almost certainly higher performances than female athletes in all assessed variables. The results of the current study suggest that different speed-power qualities are strongly correlated to the performance obtained in various COD assessments (r values varying from 0.38 to 0.84 and from 0.34 to 0.84 for correlations between speed and power tests with Zigzag test and T-test, respectively). However, the level of these associations can vary greatly, according to the mechanical demands of each respective COD task. Although COD tests may be difficult to implement during competitive seasons, because of the strong correlations presented herein, the regular use of vertical jump tests with these athletes seems to be an effective and applied alternative. Furthermore, it might be inferred that the proper development of loaded and unloaded jump abilities has potential for improving the physical qualities related to COD performance in handball athletes.

Heat stress incident prevalence and tennis matchplay performance at the Australian Open

OBJECTIVES

To examine the association of wet bulb globe temperature (WBGT) with the occurrence of heat-related incidents and changes in behavioural and matchplay characteristics in men's Grand Slam tennis.

DESIGN

On-court calls for trainers, doctors, cooling devices and water, post-match medical consults and matchplay characteristic data were collected from 360 Australian Open matches (first 4 rounds 2014-2016).

METHODS

Data were referenced against estimated WBGT and categorised into standard zones. Generalised linear models assessed the association of WBGT zone on heat-related medical incidences and matchplay variables.

RESULTS

On-court calls for doctor (47% increase per zone, p=0.001), heat-related events (41%, p=0.019), cooling devices (53%, p<0.001), and post-match heat-related consults (87%, p=0.014) increased with each rise in estimated WBGT zone. In WBGT's >32°C and >28°C, significant increases in heat-related calls (p=0.019) and calls for cooling devices (p<0.001), respectively, were evident. The number of winners (-2.5±0.006% per zone, p<0.001) and net approaches (-7.1±0.008%, p<0.001) reduced as the estimated WBGT zone increased, while return points won increased (1.75±0.46, p<0.001). When matches were adjusted for player quality of the opponent (Elo rating), the number of aces (5±0.02%, p=0.003) increased with estimated WBGT zone, whilst net approaches decreased (7.6±0.013%, p<0.001).

CONCLUSIONS

Increased estimated WBGT increased total match doctor and trainer consults for heat related-incidents, post-match heat-related consults (>32°C) and cooling device callouts (>28°C). However, few matchplay characteristics were noticeably affected, with only reduced net approaches and increased aces evident in higher estimated WBGT environments.

Thermal, physiological and perceptual strain mediate alterations in match-play tennis under heat stress

OBJECTIVES

This study compared the thermal, physiological and perceptual responses associated with match-play tennis in HOT (∼34°C wet-bulb-globe temperature (WBGT)) and COOL (∼19°C WBGT) conditions, along with the accompanying alterations in match characteristics.

METHODS

12 male tennis players undertook two matches for an effective playing time (ie, ball in play) of 20 min, corresponding to ∼119 and ∼102 min of play in HOT and COOL conditions, respectively. Rectal and skin temperatures, heart rate, subjective ratings of thermal comfort, thermal sensation and perceived exertion were recorded, along with match characteristics.

RESULTS

End-match rectal temperature increased to a greater extent in the HOT (∼39.4°C) compared with the COOL (∼38.7°C) condition (p<0.05). Thigh skin temperature was higher throughout the HOT match (p<0.001). Heart rate, thermal comfort, thermal sensation and perceived exertion were also higher during the HOT match (p<0.001). Total playing time was longer in the HOT compared with the COOL match (p<0.05). Point duration (∼7.1 s) was similar between conditions, while the time between points was ∼10 s longer in the HOT relative to the COOL match (p<0.05). This led to a ∼3.4% lower effective playing percentage in the heat (p<0.05). Although several thermal, physiological and perceptual variables were individually correlated to the adjustments in time between points and effective playing percentage, thermal sensation was the only predictor variable associated with both adjustments (p<0.005).

CONCLUSIONS

These adjustments in match-play tennis characteristics under severe heat stress appear to represent a behavioural strategy adopted to minimise or offset the sensation of environmental conditions being rated as difficult.

Coping with heat stress during match-play tennis: does an individualised hydration regimen enhance performance and recovery?

Objectives

To determine whether an individualised hydration regimen reduces thermal, physiological and perceptual strain during match-play tennis in the heat, and minimises alterations in neuromuscular function and physical performance postmatch and into recovery.

Methods

10 men undertook two matches for an effective playing time (ball in play) of 20 min (∼113 min) in ∼37°C and ∼33% RH conditions. Participants consumed fluids ad libitum during the first match (HOT) and followed a hydration regimen (HYD) in the second match based on undertaking play euhydrated, standardising sodium intake and minimising body mass losses.

Results

HYD improved prematch urine specific gravity (1.013±0.006 vs 1.021±0.009 g/mL; p<0.05). Body mass losses (∼0.3%), fluid intake (∼2 L/h) and sweat rates (∼1.6 L/h) were similar between conditions. Core temperature was higher during the first 10 min of effective play in HOT (p<0.05), but increased similarly (∼39.3°C) on match completion. Heart rate was higher (∼11 bpm) throughout HOT (p<0.001). Thermal sensation was higher during the first 7.5 min of effective play in HOT (p<0.05). Postmatch knee extensor and plantar flexor strength losses, along with reductions in 15 m sprint time and repeated-sprint ability (p<0.05), were similar in both conditions, and were restored within 24 h.

Conclusions

Both the hydration regimen and ad libitum fluid consumption allowed for minimal body mass losses (<1%). However, undertaking match-play in a euhydrated state attenuated thermal, physiological and perceptual strain. Maximal voluntary strength in the lower limbs and repeated-sprint ability deteriorated similarly in both conditions, but were restored within 24 h.

The impact of match-play tennis in a hot environment on indirect markers of oxidative stress and antioxidant status

Objectives

The purpose of this study was to determine the impact of changes in oxidative stress and antioxidant status in response to playing tennis in HOT (∼36°C and 35% relative humidity (RH)) and COOL (∼22°C and 70% RH) conditions.

Methods

10 male tennis players undertook two matches for an effective playing time (ie, ball in play) of 20 min, corresponding to ∼122 and ∼107 min of total play in HOT and COOL conditions, respectively. Core body temperature, body mass and indirect markers of oxidative stress (diacrons reactive oxygen metabolic test) and antioxidant status (biological antioxidant potential test) were assessed immediately prematch, midmatch and postmatch, and 24 and 48 h into recovery.

Results

Regardless of the condition, oxidative stress remained similar throughout play and into recovery. Likewise, match-play tennis in the COOL had no impact on antioxidant status. However, antioxidants status increased significantly in the HOT compared with COOL environment (p<0.05). Body mass losses (∼0.5 kg) were similar between conditions. Rectal temperature increased during both matches (p<0.05), but with a greater magnitude in the HOT (39.3±0.5°C) versus COOL (38.7±0.2°C) environment (p<0.05).

Conclusions

Match-play tennis in the heat does not exacerbate the development of oxidative stress, but significantly increases antioxidant status. These data suggest that the heat stress observed in the HOT environment may provide a necessary signal for the upregulation of antioxidant defence, dampening cellular damage.

Tennis in hot and cool conditions decreases the rapid muscle torque production capacity of the knee extensors but not of the plantar flexors

OBJECTIVES

To assess the time course of changes in rapid muscle force/torque production capacity and neuromuscular activity of lower limb muscles in response to prolonged (∼2 h) match-play tennis under heat stress.

METHODS

The rates of torque development (RTD) and electromyographic activity (EMG; ie, root mean square) rise were recorded from 0 to 30, -50, -100 and -200 ms during brief (3-5 s) explosive maximal isometric voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), along with the peak RTD within the entirety of the torque-time curve. These values were recorded in 12 male tennis players before (prematch) and after (postmatch, 24 and 48 h) match-play in HOT (∼37°C) and COOL (∼22°C) conditions.

RESULTS

The postmatch core temperature was greater in the HOT (∼39.4°C) vs COOL (∼38.7°C) condition (p<0.05). Reductions in KE RTD occurred within the 0-200 ms epoch after contraction onset postmatch and at 24 h, compared with prematch, independent of environmental conditions (p<0.05). A similar reduction in the KE peak RTD was also observed postmatch relative to prematch (p<0.05). No differences in KE RTD values were observed after normalisation to MVC torque. Furthermore, the rate of KE EMG activity rise remained unchanged. Conversely, the PF contractile RTD and rate of EMG activity rise were unaffected by the exercise or environmental conditions.

CONCLUSIONS

In the KE, a reduction in maximal torque production capacity following prolonged match-play tennis appears to account for the decrease in the rate of torque development, independent of environmental conditions, while remaining unchanged in the PF.