Repeat Effort Performance Is Reduced 24 Hours After Acute Dehydration in Mixed Martial Arts Athletes

Weight cutting in female UFC fighters

BACKGROUND

It is common practice for fight sport athletes to use a variety of weight manipulation strategies to compete in desired weight classes. Although numerous studies have highlighted rapid weight loss (RWL) strategies and the magnitude of weight loss, few have focused specifically on weight loss in female fighters. The purpose of this study was to provide descriptive information on professional UFC female fighters engaging in RWL in all women's UFC weight divisions: strawweight (52.2 kg): flyweight (56.7 kg); bantamweight (61.2 kg); featherweight (65.8 kg).

METHODS

All fighter's weights were obtained at five separate time points: 72 hrs. pre-weigh-in, 48 hrs. pre-weigh-in, 24hrs. pre-weigh-in, official weigh-in, and 24 hrs. post-weigh-in (competition weight). Mixed effects models and random effects analysis were used to assess changes in weight and differences between weight divisions. All statistics were analyzed, and significance was set at p ≤0.05. Significant changes in weight between all time points were reported.

RESULTS

No statistical differences between weight divisions were observed. Female fighters lost 4.5-6.6% of their weight prior to the official weigh-in.

CONCLUSION

Females engaged in RWL practices lose weight in a similar fashion irrespective of weight class.

Rapid Weight Loss Practices Within Olympic Weightlifters

ABSTRACT

Gee, TI, Campbell, P, Bargh, MJ, and Martin, D. Rapid weight loss practices within Olympic weightlifters. J Strength Cond Res 37(10): 2046-2051, 2023-Rapid weight loss (RWL) practices are common among athletes to "make weight" for a chosen bodyweight class. This study's purpose was to investigate RWL prevalence, magnitude, and methods within Olympic weightlifters from Great Britain. Subjects (n = 39, male = 22, female = 17) were recruited from International Weightlifting Federation lifting populations (mandatory two-hour competition weigh-in). Subjects were categorized into competitive groups based on Sinclair coefficient total (high, mid, low) and also gender (male, female). The validated Rapid Weight Loss Questionnaire was used to establish RWL magnitude and practices. Of respondents, 33 of 39 (84.6%) had purposely acutely reduced body mass to compete, a higher proportion present within females (94.1%) than males (77.3%). The cohort's mean habitual precompetition acute body mass loss was 3.8 ± 1.7% and the "rapid weight loss score" (RWLS) was 23.6 ± 9.5. Across competitive groups there were no significant differences in habitual or highest precompetition body mass loss, postcompetition body mass gain or RWLS (p > 0.05). However, females attributed a significantly greater "highest" relative precompetition body mass loss compared with males (7.4 vs 4.9%, p = 0.045). For RWL methods used, frequencies of "always" and "sometimes" were reported highest for "restricting fluid ingestion" (81.8%), "gradual dieting" (81.8%), and "water loading" (54.5%). The prevalence of RWL is high among competitive Olympic weightlifters, and especially within the sampled female athletes. Magnitude of RWL was similar across different standards of athlete; however, female lifters demonstrated a higher maximum precompetition RWL.

Effect of rapid weight loss incorporating hot salt water immersion on changes in body mass, blood markers, and indices of performance in male mixed martial arts athletes

Purpose

To investigate the effects of rapid weight loss (RWL), incorporating comparison of hot water immersion (HWI) in fresh or salt water, on changes in body mass, blood markers, and indices of performance in mixed martial arts athletes.

Methods

In a crossover design comparing fresh water (FWB) to salt water (SWB; 5.0%wt/vol Epsom salt) bathing, 13 males performed 20 min of HWI (~ 40.3 °C) followed by 40 min wrapped in a heated blanket, twice in sequence (2 h total). Before bathing, ~ 26 to ~ 28 h of fluid and dietary restriction was undertaken, and ~ 24 to ~ 26 h of a high carbohydrate diet and rehydration was undertaken as recovery.

Results

During the entire RWL process, participants lost ~ 5.3% body mass. Body mass lost during the 2 h hot bath protocol was 2.17 ± 0.81 kg (~ 2.7% body mass) and 2.24 ± 0.64 kg (~ 2.8% body mass) for FWB and SWB, respectively (P = 0.647 between trials). Blood urea nitrogen, creatinine, sodium, chloride, hemoglobin, and hematocrit were increased (all P < 0.05), and plasma volume was decreased (~ 14%; P < 0.01), but did not differ between FWB and SWB, and were similar to baseline values after recovery. No indices of performance (e.g., countermovement jump, isometric strength, and functional threshold power) were impacted when RWL was followed by the recovery process.

Conclusion

Under the conditions of this hot bath protocol, fluid loss was not augmented by the addition of ~ 5.0%wt/vol of Epsom salt during HWI, and RWL of ~ 5.3% body mass followed by > 24 h of recovery did not impact indices of performance.

Acute Dehydration Impairs Performance and Physiological Responses in Highly Trained Judo Athletes

Background: The present study investigated highly trained male judo athletes and how a 5% body mass dehydration affects their judo-specific performance and physiological responses. Methods: Nine highly trained international-level male judo athletes who are weight-cyclers voluntarily participated in the study. The study had a controlled crossover design in nature. Athletes completed three sessions, including a familiarisation session and two experimental sessions (dehydration (DEHY) and control (CON)) with judo-specific tests, including maximal handgrip strength test (HGS), judogi grip strength tests (JGST), and the Special Judo Fitness Test (SJFT). Results: Intergroup analysis revealed a significant increase in urine specific gravity (USG) and decreased body mass following DEHY condition compared to CON. Furthermore, significant decreases were determined in HGS, JGSTs, and a number of throws in the first and third series of SJFTs, as well as higher heart rate (HR) responses in the second and third series of SJFT and worse SJFT index in DEHY condition (p < 0.05). Conclusions: We concluded that 5% dehydration of body mass led to impairment in dynamic and isometric strength in upper limbs and in judo-specific performance, as well as elevated HR during the SJFT.

Patterns of weight cycling in youth Olympic combat sports: a systematic review

BACKGROUND

Patterns of weight cycling in adult combat sports have been extensively studied, yet data on this matter in youth combat athletes is rather scarce.

METHODS

PubMed, EBSCOhost and Web of Science were used to retrieve relevant data. Eligible studies had to record the methods used to elicit rapid weight loss (RWL) and/or record the oscillations in bodyweight during the RWL phase. Only studies conducted in the context of an official competition were considered for inclusion in the present review.

RESULTS

RWL is highly prevalent in children and adolescent combat athletes, ranging from 25 to 94% depending on the type of combat sport, age and level of competition. These athletes regularly prompt RWL by increasing exercise frequency and intensity, decreasing fluid and food intake, training in impermeable suits and using sauna frequently. Overall, the magnitude of RWL was ranging from ~ 1% to 6.3 ± 3.7% with significant RWL variations within individual studies and individuals within those studies.

CONCLUSION

Acquired data indicated that RWL patterns in young combat athletes are similar to those found in their adult counterparts. Knowing that childhood and adolescence are critical periods for growth and development, RWL needs to be stringently regulated and ideally banned in this population.

Exploratory Systematic Review of Mixed Martial Arts: An Overview of Performance of Importance Factors with over 20,000 Athletes

This review aimed to analyze the findings in the literature related to Mixed Martial Arts (MMA) through an exploratory systematic review and to present the state of the art from a multifactorial perspective. The review was conducted in accordance with the PRISMA statement, with a search performed in the Scopus, PubMed, and Web of Science databases. Participants were competitive athletes (amateurs or professionals) of regional, national, or international levels. Of the 2763 registries identified, 112 studies met the eligibility criteria. The pooled sample size and age were 20,784 participants, with a mean age of 27.7 ± 6 years for male and 28.9 ± 3 years for female, with the vast majority of athletes being male (94.9%). MMA athletes were 17.2% amateurs, 73.8% professionals, and 9% were not reported. The scientific literature related to MMA reported injuries (n = 28), weight loss (n = 21), technical and tactical analysis (n = 23), physical fitness (n = 8), physiological responses and training characteristics (n = 13), psychobiological parameters (n = 12), and interventions applied to MMA athletes (n = 7). Therefore, this exploratory systematic review presents practitioners and researchers with seven broad summaries of each facet of performance of importance in this population of athletes.

Effects of Weight Cutting on Exercise Performance in Combat Athletes: A Meta-Analysis

Weight cutting in combat sports is a prevalent practice whereby athletes voluntarily dehydrate themselves via various methods to induce rapid weight loss (RWL) to qualify for a lower weight category than that of their usual training body weight. The intention behind this practice is to regain the lost body mass and compete at a heavier mass than permitted by the designated weight category. The purpose of this study was to quantitatively synthesize the available evidence examining the effects of weight cutting on exercise performance in combat-sport athletes. Following a systematic search of the literature, meta-analyses were performed to compare maximal strength, maximal power, anaerobic capacity, and/or repeated high-intensity-effort performance before rapid weight loss (pre-RWL), immediately following RWL (post-RWL), and 3 to 36 hours after RWL following recovery and rapid weight gain (post-RWG). Overall, exercise performance was unchanged between pre-RWL and post-RWG (g = 0.22; 95% CI, -0.18 to 0.62). Between pre-RWL and post-RWL analyses revealed small reductions in maximal strength and repeated high-intensity-effort performance (g = -0.29; 95% CI, -0.54 to -0.03 and g = -0.37; 95% CI, -0.59 to -0.16, respectively; both P ≤ .03). Qualitative analysis indicates that maximal strength and power remained comparable between post-RWL and post-RWG. These data suggest that weight cutting in combat-sport athletes does not alter short-duration, repeated high-intensity-effort performance; however, there is evidence to suggest that select exercise performance outcomes may decline as a product of RWL. It remains unclear whether these are restored by RWG.

Effect of Rapid Weight Loss on Hydration Status and Performance in Elite Judo Athletes

Background: This study aimed to investigate the effect of 5% rapid weight loss on hydration status and judo performance in highly trained judo athletes. Methods: Eighteen male judo athletes participated in the study and were divided into two groups: control and rapid weight loss (RWL). RWL athletes were given 48 h to cut 5% of their body mass while the control group followed their routines. Athletes performed three measurements, including hydration, body mass and three consecutive special judo fitness tests (SJFTs). At the 1st and 6th minutes following each SJFT and 1st, 6th and 15th minutes following the last SJFT, blood lactate and heart rate (HR) was monitored. Results: The effect of RWL on variables was tested with split-plot ANOVA. RWL significantly affected urine specific gravity with a higher value following weight loss compared to baseline and recovery (F2-32 = 13.2, p < 0.001). In addition, athletes’ SJFT total throw numbers differed among measurements (F2-32 = 7.70, p < 0.001). Athletes presented worse SJFT index after weight loss (F2-32 = 8.05, p = 0.01; F1-16 = 6.43, p = 0.02, respectively). HR changed significantly among measurements days and times (F28-448 = 143.10, p < 0.001). Conclusion: RWL induced dehydration and impaired heart rate recovery in highly trained judo athletes, and they could not rehydrate between competition simulated weigh-in and 15 h of recovery.

Weight-Cutting Implications for Competition Outcomes in Mixed Martial Arts Cage Fighting

ABSTRACT

Brechney, GC, Chia, E, and Moreland, AT. Weight-cutting implications for competition outcomes in mixed martial arts cage fighting. J Strength Cond Res 35(12): 3420-3424, 2021-Weight cutting is common among amateur and professional mixed martial arts (MMA) competitors because of the belief that it provides an advantage in combat sports. This study aimed to identify whether fight outcome (win vs. loss vs. type of loss) was influenced by magnitudes of body mass (BM) lost through weight cutting and BM regained before the fight after official weigh-in in amateur and professional MMA athletes with previous weight-cutting experience. Body mass data were collected using self-report from 75 MMA athletes (59 amateur and 16 professional) before commencing weight-cutting practices 7 days before weigh-in, by the regulating body at their official weigh-in 24 hours before the fight and through direct measurement immediately before competition. Data were analyzed according to win; loss by technical knockout or knockout (KO); loss by submission; or loss by the judge's decision. Athletes who lost their fight cut significantly more BM (10.6%) compared with athletes who won (8.6%) (p = 0.04, d = 0.48, 95% confidence interval [CI] = 0.02-0.93), but there were no differences between types of loss. There were no significant differences in recovered BM between athletes who won (6.8%) vs. lost (7.4%), or type of loss. Furthermore, there was a significant relationship between greater magnitudes of BM cut and greater likelihood of losing the fight (B = -0.12, P = 0.048), odd ratio 0.89 (95% CI: 0.79-1.00). This study provides the first line of evidence that excessive weight cutting may be detrimental to fight outcome in MMA.

Effects of Rapid Weight Loss on Kidney Function in Combat Sport Athletes

Even though scientific literature shows numerous heath complications and performance decrements associated with rapid weight loss (RWL), its prevalence remains exceedingly high across various combat sports. The aim of this study was to thoroughly search the existing literature to explore the influence of RWL on kidney function in Olympic and non-Olympic combat sport athletes. PubMed and Web of Science were searched for the relevant studies. Only original articles published from 2005 onwards, written in English, that included healthy males and females who prompted ~5% weight loss within a week or less, were included in the study. Retrieved studies showed that creatinine, blood urea nitrogen and urine specific gravity values were significantly increased after RWL in the majority of the included studies. This observation indicates that RWL caused dehydration and subsequent acute kidney damage despite various degrees of weight lost during the RWL phase, which can lead to adverse events in other body systems. Alternative methods of weight reduction that prioritize athletes' health should be considered.

Pre-competition body mass loss characteristics of Brazilian jiu-jitsu competitors in the United Kingdom

BACKGROUND

Brazilian jiu-jitsu (BJJ) is a grappling-based combat sport in which competitors engage in pre-competition acute 'weight' loss (AWL) and rapid 'weight' loss (RWL) to achieve the body mass (BM) required for their desired division. AWL/RWL practices of UK BJJ competitors have not previously been reported.

AIM

Our aim in this study was to determine the prevalence, magnitude and stakeholder influences of AWL and RWL amongst BJJ participants in the United Kingdom (UK). A secondary aim was to explore whether there is any influence of time spent in the sport or competition frequency on AWL/RWL practices.

METHODS

In this study we used the rapid weight loss questionnaire (RWLQ) adapted for BJJ to determine the prevalence and magnitude of AWL/RWL in UK BJJ, the prevalence of methods used and the key stakeholder influences on these practices. As a secondary investigation we aimed to determine whether there was any effect of age starting BJJ on AWL/RWL.

RESULTS

Of 115 completed responses, 59% stated they performed AWL/RWL before competition. Mean BM loss for this competition was 1.9 ± 3.8 kg (2.3 ± 4.6%), with 34% of participants starting BM loss 3-7 days prior and 16% starting 0-2 days prior. Methods used tend to be achieving calorie deficit via exercise and diet rather than hypohydration, with little advice from formally qualified personnel. Participants who perform AWL/RWL started training (BF₁₀ = 199, d = .72) and competing (BF₁₀ = 107, d = .68) in BJJ younger than those who do not perform AWL/RWL.

CONCLUSIONS

AWL/RWL is prevalent in UK BJJ, but not at the magnitude of other combat sports or countries. Though negative effects of extreme hypohydration are unlikely, there may be a higher chance of eating disorders in BJJ, particularly due to the young age of AWL/RWL commencement.

Factors Influencing Weight Loss Practices in Italian Boxers: A Cluster Analysis

It is common practice in combat sports that athletes rapidly lose body weight before a match, by applying different practices-some safer and others possibly dangerous. The factors behind the choice of practices utilised have not been fully studied. This study aimed to investigate the weight loss strategies used by Italian boxers and to look at the difference between higher and lower risk practice adaptors. A modified version of a validated questionnaire has been sent to 164 amateur (88%) and professional (12%) boxers by email. A heatmap with hierarchical clustering was used to explore the presence of subgroups. Weight loss strategies were used by 88% of the athletes. Two clusters were found, defined by the severity of weight loss behaviours. Professional fighters, high-level athletes and females were more represented in Cluster 2, the one with more severe weight-loss practices. These athletes were characterised by a higher weight loss magnitude and frequency throughout the season and reported being more influenced by physicians and nutritionists, compared with the boxers in Cluster 1. Not all the weight loss practices are used with the same frequency by all boxers. The level of the athlete and the boxing style have an influence on the weight-cutting practices.

Reviewing the current methods of assessing hydration in athletes

Background

Despite a substantial body of research, no clear best practice guidelines exist for the assessment of hydration in athletes. Body water is stored in and shifted between different sites throughout the body complicating hydration assessment. This review seeks to highlight the unique strengths and limitations of various hydration assessment methods described in the literature as well as providing best practice guidelines.

Main body

There is a plethora of methods that range in validity and reliability, including complicated and invasive methods (i.e. neutron activation analysis and stable isotope dilution), to moderately invasive blood, urine and salivary variables, progressing to non-invasive metrics such as tear osmolality, body mass, bioimpedance analysis, and sensation of thirst. Any single assessment of hydration status is problematic. Instead, the recommended approach is to use a combination, which have complementary strengths, which increase accuracy and validity. If methods such as salivary variables, urine colour, vital signs and sensation of thirst are utilised in isolation, great care must be taken due to their lack of sensitivity, reliability and/or accuracy. Detailed assessments such as neutron activation and stable isotope dilution analysis are highly accurate but expensive, with significant time delays due to data analysis providing little potential for immediate action. While alternative variables such as hormonal and electrolyte concentration, bioimpedance and tear osmolality require further research to determine their validity and reliability before inclusion into any test battery.

Conclusion

To improve best practice additional comprehensive research is required to further the scientific understanding of evaluating hydration status.

Effects of Rapid Weight Loss on Judo Athletes: A Systematic Review

Rapid weight loss (RWL) is commonly practiced among judo athletes. Although it helps them to gain the advantage over their lighter opponents, previous studies have shown that RWL can have a negative impact on the athlete's performance and overall well-being. This systematic review aimed to synthesize the evidence that examines the influence of rapid weight loss on physiological parameters, biomarkers, and psychological well-being in judo athletes. We followed the preferred reporting items for systematic reviews and meta-analyses guidelines. We searched for studies on Web of Science and PubMed that elaborate on the influence of ≥5% RWL achieved over ≤7-day period in judokas. Out of 52 studies initially found, 14 studies met our eligibility criteria and were included in the review. In total, we examined data from 1103 judo athletes. Retrieved studies showed conflicting data concerning physiological parameters and biomarkers, while psychological well-being parameters were more consistent than physiological and biomarkers. The feeling of tension, anger, and fatigue significantly increased while a decrease in vigor was demonstrated among athletes who lost weight rapidly. The evidence on the impact of RWL on performance remains ambiguous. More studies under standardized conditions are needed in order to provide firm evidence. Considering the harmful effects of RWL outlined in the existing literature, it is important to determine and monitor athlete's minimal competitive weight to prioritize the health and safety of the athlete, emphasize fairness, and ultimately benefit the sport.

The Influence of Heat Acclimation and Hypohydration on Post-Weight-Loss Exercise Performance

PURPOSE

To examine the influence of fluid intake on heat acclimation and the subsequent effects on exercise performance following acute hypohydration.

METHODS

Participants were randomly assigned to 1 of 2 groups, either able to consume water ad libitum (n = 10; age 23 [3] y, height 1.81 [0.09] m, body mass 87 [13] kg; HAW) or not allowed fluid (n = 10; age 26 [5] y, height 1.76 [0.05] m, body mass 79 [10] kg; HANW) throughout 12 × 1.5-h passive heat-acclimation sessions. Experimental trials were completed on 2 occasions before (2 baseline trials) and 1 following the heat-acclimation sessions. These sessions involved 3 h of passive heating (45°C, 38% relative humidity) to induce hypohydration followed by 3 h of ad libitum food and fluid intake after which participants performed a repeat sled-push test to assess physical performance. Urine and blood samples were collected before, immediately, and 3 h following hypohydration to assess hydration status. Mood was also assessed at the same time points.

RESULTS

No meaningful differences in physiological or performance variables were observed between HANW and HAW at any time point. Using pooled data, mean sprint speed was significantly (P < .001) faster following heat acclimation (4.6 [0.7] s compared with 5.1 [0.8] s). Furthermore, heat acclimation appeared to improve mood following hypohydration.

CONCLUSIONS

Results suggest that passive heat-acclimation protocols may be effective at improving short-duration repeat-effort performance following acute hypohydration.

Effects of a hot ambient operating theatre on manual dexterity, psychological and physiological parameters in staff during a simulated burn surgery

OBJECTIVES

Hot environmental conditions can result in a high core-temperature and dehydration which can impair physical and cognitive performance. This study aimed to assess the effects of a hot operating theatre on various performance, physiological and psychological parameters in staff during a simulated burn surgery.

METHODS

Due to varying activity levels, surgery staff were allocated to either an Active (n = 9) or Less-Active (n = 8) subgroup, with both subgroups performing two simulated burn surgery trials (CONTROL: ambient conditions; 23±0.2°C, 35.8±1.2% RH and HOT: 34±0°C, 28.3±1.9% RH; 150 min duration for each trial), using a crossover design with four weeks between trials. Manual dexterity, core-temperature, heart-rate, sweat-loss, thermal sensation and alertness were assessed at various time points during surgery.

RESULTS

Pre-trials, 13/17 participants were mildly-significantly dehydrated (HOT) while 12/17 participants were mildly-significantly dehydrated (CONTROL). There were no significant differences in manual dexterity scores between trials, however there was a tendency for scores to be lower/impaired during HOT (both subgroups) compared to CONTROL, at various time-points (Cohen's d = -0.74 to -0.50). Furthermore, alertness scores tended to be higher/better in HOT (Active subgroup only) for most time-points (p = 0.06) compared to CONTROL, while core-temperature and heart-rate were higher in HOT either overall (Active; p<0.05) or at numerous time points (Less-Active; p<0.05). Finally, sweat-loss and thermal sensation were greater/higher in HOT for both subgroups (p<0.05).

CONCLUSIONS

A hot operating theatre resulted in significantly higher core-temperature, heart-rate, thermal sensation and sweat-loss in staff. There was also a tendency for slight impairment in manual dexterity, while alertness improved. A longer, real-life surgery is likely to further increase physiological variables assessed here and in turn affect optimal performance/outcomes.

Anthropometric and Physiological Profile of Mixed Martial Art Athletes: A Brief Review

The aim of this review was to analyze the existing knowledge of the anthropometric and physiological characteristics of MMA (mixed martial arts). A computerized search was performed in the PubMed and Google Scholar databases for English-language, peer-reviewed investigations using the term "mixed martial arts" or "MMA" alone and in combination with "physiological characteristics", "physiological profile", "body composition", "strength", "power", "endurance", "aerobic", and "anaerobic". The main findings of this review suggested an overall profile of low body fat, high flexibility, muscle strength, muscle endurance, and anaerobic power, and average cardiovascular endurance. Nevertheless, no differences in anthropometric and physiological characteristics by performance level of the athletes were observed. Based on the studies analyzed in this review, several limitations were reported. First, the subjects in each paper were limited in number, as is MMA literature itself, and it is impossible to make a generalization regarding the anthropometric and physiological profile for male athletes. Second, no studies included female MMA athletes; therefore, there was no evidence for what their profiles might be. Last, the majority of the above-mentioned studies used different tests, or the same tests with different protocols, and as a result, it is difficult to compare their results. The similarity observed between the levels of the athletes might be a result of the different tests and protocols used by the researchers or might be evidence that the anthropometric and physiological profile of an MMA athlete did not vary among high-level athletes. Considering the increasing number of those engaging in MMA training and sport events, the findings of the present study provided strength and conditioning trainers working with MMA athletes a valuable tool for monitoring training and performance.

The Current State of Weight-Cutting in Combat Sports-Weight-Cutting in Combat Sports

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.

Considerations When Assessing Endurance in Combat Sport Athletes

Combat sports encompass a range of sports, each involving physical combat between participants. Such sports are unique, with competitive success influenced by a diverse range of physical characteristics. Effectively identifying and evaluating each characteristic is essential for athletes and support staff alike. Previous research investigating the relationship between combat sports performance and measures of strength and power is robust. However, research investigating the relationship between combat sports performance and assessments of endurance is less conclusive. As a physical characteristic, endurance is complex and influenced by multiple factors including mechanical efficiency, maximal aerobic capacity, metabolic thresholds, and anaerobic capacities. To assess endurance of combat sports athletes, previous research has employed methods ranging from incremental exercise tests to circuits involving sports-specific techniques. These tests range in their ability to discern various physiological attributes or performance characteristics, with varying levels of accuracy and ecological validity. In fact, it is unclear how various physiological attributes influence combat sport endurance performance. Further, the sensitivity of sports specific skills in performance based tests is also unclear. When developing or utilizing tests to better understand an athletes' combat sports-specific endurance characteristic, it is important to consider what information the test will and will not provide. Additionally, it is important to determine which combination of performance and physiological assessments will provide the most comprehensive picture. Strengthening the understanding of assessing combat sport-specific endurance as a physiological process and as a performance metric will improve the quality of future research and help support staff effectively monitor their athlete's characteristics.

Acute Dehydration Impairs Endurance Without Modulating Neuromuscular Function

Introduction/Purpose: This study examined the influence of acute dehydration on neuromuscular function.

Methods: On separate days, combat sports athletes experienced in acute dehydration practices (n = 14) completed a 3 h passive heating intervention (40°C, 63% relative humidity) to induce dehydration (DHY) or a thermoneutral euhydration control (25°C, 50% relative humidity: CON). In the ensuing 3 h ad libitum fluid and food intake was allowed, after which participants performed fatiguing exercise consisting of repeated unilateral knee extensions at 85% of their maximal voluntary isometric contraction (MVIC) torque until task failure. Both before and after the fatiguing protocol participants performed six MVICs during which measures of central and peripheral neuromuscular function were made. Urine and whole blood samples to assess urine specific gravity, urine osmolality, haematocrit and serum osmolality were collected before, immediately and 3 h after intervention.

Results: Body mass was reduced by 3.2 ± 1.1% immediately after DHY (P < 0.001) but recovered by 3 h. Urine and whole blood markers indicated dehydration immediately after DHY, although blood markers were not different to CON at 3 h. Participants completed 28% fewer knee extensions at 85% MVIC (P < 0.001, g = 0.775) and reported a greater perception of fatigue (P = 0.012) 3 h after DHY than CON despite peak torque results being unaffected. No between-condition differences were observed in central or peripheral indicators of neuromuscular function at any timepoint.

Conclusion: Results indicate that acute dehydration of 3.2% body mass followed by 3 h of recovery impairs muscular strength-endurance and increases fatigue perception without changes in markers of central or peripheral function. These findings suggest that altered fatigue perception underpins muscular performance decrements in recovery from acute dehydration.