Muscle contraction velocity, strength and power output changes following different degrees of hypohydration in competitive olympic combat sports

H2OAthletes study protocol: effects of hydration changes on neuromuscular function in athletes

We aim to understand the effects of hydration changes on athletes' neuromuscular performance, on body water compartments, fat-free mass hydration and hydration biomarkers and to test the effects of the intervention on the response of acute dehydration in the hydration indexes. The H2OAthletes study (clinicaltrials.gov ID: NCT05380089) is a randomised controlled trial in thirty-eight national/international athletes of both sexes with low total water intake (WI) (i.e. < 35·0 ml/kg/d). In the intervention, participants will be randomly assigned to the control (CG, n 19) or experimental group (EG, n 19). During the 4-day intervention, WI will be maintained in the CG and increased in the EG (i.e. > 45·0 ml/kg/d). Exercise-induced dehydration protocols with thermal stress will be performed before and after the intervention. Neuromuscular performance (knee extension/flexion with electromyography and handgrip), hydration indexes (serum, urine and saliva osmolality), body water compartments and water flux (dilution techniques, body composition (four-compartment model) and biochemical parameters (vasopressin and Na) will be evaluated. This trial will provide novel evidence about the effects of hydration changes on neuromuscular function and hydration status in athletes with low WI, providing useful information for athletes and sports-related professionals aiming to improve athletic performance.

Nutrient Intake, Performance, and Body Composition of Preseason Wrestlers

College athletes, especially in weight class sports, often experience energy deficits. Athletes competing in weight class sports such as wrestling are at greatest risk for deficiencies and little is known about the relationships between body composition, nutrient intake, and performance in these athletes. The purposes of this study were to (1) quantify macronutrient and micronutrient intake of pre-season male collegiate wrestlers and compare to estimated needs, and (2) examine relationships among nutritional intakes, body composition, and performance measurements of strength and anaerobic capacity. Male Division I wrestlers (n = 11, age: 21.3 ± 1.7 years, wrestling experience: 14.9 ± 2.5 years) were recruited during pre-season. Nutrient intake was collected from a 3-day food diary. A 7-site skinfold assessment determined fat-free mass (FFM) to estimate total daily energy expenditure (eTEE). Isokinetic and isometric strength were evaluated by a Biodex dynamometer. Anaerobic capacity was tested on a stationary cycle ergometer. Eight of eleven wrestlers were energy deficient based on estimated needs. Mean intake of four micronutrients fell below the Recommended Dietary Allowances (RDA). Significant correlations were found between dietary intake, strength and anaerobic performance variables (r = 0.603 - 0.902, p = 0.0001 - 0.05). However, after accounting for FFM, these relationships were no longer significant. Nutrient intake in tandem with body composition affects performance for weight class athletes. Achieving high FFM during the preseason may be advantageous for wrestling performance. Nutrient intake and body composition should be monitored so coaches and health professionals can create individualized recommendations to help athletes optimize performance.

Effects of unilateral, bilateral, and combined unilateral+bilateral complex resistance training on bench press and squat strength in adolescent boxers

Objective: To assess the effects of 8 weeks of unilateral (UNI), bilateral (BI), and combined unilateral + bilateral (UNI + BI) resistance training on bench press and squat strength in adolescent boxers. Methods: Using the Gym Aware linear accelerometer, free-weight squat and bench press strength exercises were evaluated after an 8-week training intervention. Thirty adolescent boxers were randomly assigned to three groups: UNI, height: 1.73 ± 0.08 m, weight: 55.42 ± 5.85 kg; UNI + BI, height: 1.7 ± 0.06 m, weight: 54.73 ± 5.33 kg; and BI, height: 1.74 ± 0.06 m, weight: 59.67 ± 8.39 kg. Each group followed their designated UNI/BI/UNI + BI compound resistance training protocols, and the effects of 8 weeks of single-sided and bilateral intervention training on the performance of free-weight squat and bench press exercises at 30%, 50%, and 80% of 1-repetition maximum (1RM) were evaluated. Results: Significant improvements were observed in the 30% 1RM, 50% 1RM, and 80% 1RM outcomes for both squat and bench press exercises before and after the interventions (p < 0.05, p < 0.01). In the intergroup comparison, GymAware measurements revealed that the UNI and UNI + BI groups exhibited superior peak power values for squat and bench press exercises at 30% 1RM compared to the BI group. Discussion: UNI and UNI + BI training led to significantly higher output power values in bench press and squat exercises at 30% 1RM compared to the BI training group.

Athletes with different habitual fluid intakes differ in hydration status but not in body water compartments

Physiological differences have been reported between individuals who have habitual low (LOW) and high (HIGH) water intake (WI). The aims of this study were to explore body water compartments, hydration status, and fat-free mass (FFM) hydration of elite athletes exposed to different habitual WI. A total of 68 athletes (20.6 ± 5.3 years, 23 females) participated in this observational cross-sectional study. Total WI was assessed by seven-day food diaries and through WI, athletes were categorized as HIGH (n = 28, WI≥40.0 mL/kg/d) and LOW (n = 40, WI≤35.0 mL/kg/d). Total body water (TBW) and extracellular water (ECW) were determined by dilution techniques and intracellular water (ICW) as TBW-ECW. Hydration status was assessed by urine-specific gravity (USG) using a refractometer. Fat (FM) and FFM were assessed by dual-energy X-ray absorptiometry (DXA). The FFM hydration was calculated by TBW/FFM. The USG was statistically different between groups for females (LOW: 1.024 ± 0.003; HIGH: 1.015 ± 0.006; p = 0.005) and males (LOW: 1.024 ± 0.002; HIGH: 1.018 ± 0.005; p < 0.001). No differences between groups were detected in body water compartments and FFM hydration in both sexes (p > 0.05). Multiple regression showed that WI remains a predictor of USG regardless of FFM, age, and sex (β = -0.0004, p < 0.01). We concluded that LOW athletes were classified as dehydrated through USG although their water compartments were not different from HIGH athletes. These results suggest that LOW athletes may expectedly maintain the body water compartments' homeostasis through endocrine mechanisms. Interventions should be taken to encourage athletes to have sufficient WI to maintain optimal hydration.

Effects of Different Rapid Weight Loss Strategies and Percentages on Performance-Related Parameters in Combat Sports: An Updated Systematic Review

Most combat sports (CS) are structured in weight categories, and it is very common to carry out body weight adjustment strategies in order to compete in lower weight categories. For this reason, different rapid weight loss (RWL) strategies are usually performed to pass the pre-competition weigh-in test, and then a replenishment of fluids and carbohydrate-rich foods is conducted in an attempt to recover the weight and avoid a performance loss. In this context, no clear references have been found on whether these types of strategies have negative effects, impairing the athlete's combat and/or physical performance. For this reason, the aim of this study was to review the scientific literature on the effect of rapid weight reduction strategies on the performance of CS athletes. A literature search was performed through four different databases (PubMed, SPORTDiscus, Web of Science and ScienceDirect). Four inclusion criteria were established as follows: (1) the subjects had to be competitors in the CS and carry out RWL strategies; (2) at least two measurement points, that is, normal conditions and dehydration condition; (3) measurements in a real competition or simulating the same conditions; (4) original research articles written in English or Spanish and available in full text. Finally, a total of 16 articles were finally included in this research. All subjects (n = 184) were athletes from combat disciplines, with a minimum of 3-4 years of practice, as well as with certain experience in RWL. Six of the studies reported that an RWL strategy of around 5% of body weight loss did not affect performance parameters. However, the other ten studies with RWL between 3 and 6% or even higher reported negative effects or impairments on different parameters related to performance and/or athlete's psychophysiology, such as perceived fatigue, mood states, strength and power production, as well as changes in hormonal, blood and urine parameters, body composition, or the kinematics of the technical gesture. Although there is still no clear answer to the issue approached in this research, in general terms, it seems that in order to guarantee an acceptable athletic performance of the competitor, the weight loss should not exceed 3% to ≤5% of body weight together with ≥24 h for adequate (or at least partial) recovery and rehydration processes. In addition, it is highly recommended to lose weight progressively over several weeks, especially focusing on competitions lasting several days, as well as multiple rounds or qualifying stages.

Association of in-competition injury risk and the degree of rapid weight cutting prior to competition in division I collegiate wrestlers

OBJECTIVES

Weight cutting is thought to offer a competitive advantage in wrestling. Dehydration has deleterious effects on physical and cognitive function, which may increase the risk of injury. The purpose of the study was to investigate whether the degree of weight cutting was associated with injury risk.

METHODS

Data were collected prospectively in a cohort of collegiate wrestlers over seven seasons. Changes in weight, body fat and lean mass were measured during the preseason, at midseason and before competition. Cox proportional-hazard ratios were calculated for risk of in-competition injury.

RESULTS

Among 67 unique division 1 collegiate wrestlers (163 athlete seasons), there were 53 unique injuries affecting 46 athletes. There was no difference in absolute weight change, per cent weight change, per cent body fat change or per cent lean mass change between injured and non-injured wrestlers from the preseason to midseason measurements. From midseason to competition weight, change in body weight was -7.0%±3.2% (-5.3 kg±2.6) in injured athletes compared with -5.7%±3.3% (-4.3 kg±2.5) in non-injured athletes. For every kilogram of body weight lost, wrestlers had a 14% increased hazard of injury (HR 1.14, 95% CI 1.04 to 1.25, p=0.004). For every 1% of body weight lost, wrestlers had an 11% increased hazard of injury (HR 1.11, 95% CI 1.03 to 1.19, p=0.005).

CONCLUSION

Rapid weight cutting was associated with a higher risk of in-competition injuries in division 1 collegiate wrestlers. For every per cent in body weight lost, wrestlers had an 11% increased hazard of injury during competition.

Rapid Weight Gain and Weight Differential Predict Competitive Success in 2100 Professional Combat-Sport Athletes

PURPOSE

Combat-sport athletes commonly undergo rapid weight loss prior to prebout weigh-in and subsequently rapid weight gain (RWG) prior to competition. This investigation aimed to evaluate the effect of RWG and weight differential (WD) between opponents on competitive success.

METHODS

A retrospective cohort study was performed using data from professional mixed martial arts (MMA) and boxing events held between 2015 and 2019. The primary outcome was RWG (relative and absolute) between weigh-in and competition stratified by bout winners and losers. Binary logistic regression was used to explore the relationships among bout outcome, RWG, and WD between competitors on the day of their bout.

RESULTS

Among 708 MMA athletes included, winners regained more relative body mass (8.7% [3.7%] vs 7.9% [3.8%], P < .01) than losers. In 1392 included male boxers, winners regained significantly more relative body mass (8.0% [3.0%] vs 6.9% [3.2%], P < .01) than losers. Each percentage body mass increase resulted in a 7% increased likelihood of victory in MMA and a 13% increase in boxing. The relationship between RWG and competitive success remained significant in regional and male international MMA athletes, as well as boxers. WD predicted victory in international mixed martial artists and boxers. WD predicted victory by knockout or technical knockout in international MMA athletes and regional boxers.

CONCLUSION

This analysis of combat-sport athletes indicates that RWG and WD influence competitive success. These findings raise fair-play and safety concerns in these popular sports and may help guide risk-mitigating regulation strategies.

Sex differences in wrist torque and endurance-Biomechanical factors associated with developing lateral epicondylitis of the humerus

Since eccentric contractions contribute to the development of tendinopathy, sex differences in wrist torque and endurance may be involved in the pathophysiology of lateral epicondylitis and its refractoriness. Therefore, the present study investigated sex differences in wrist torque and endurance. The wrist extension and flexion torques of the 100 wrists of 25 males and 25 females were measured. The following parameters were assessed: muscle strength at the starting- and end point for the measurement, Δ muscle strength, that is, the amount of a loss over time, and the muscle endurance ratio, that is, the decrease rate over time. Each parameter in males and females was statistically analyzed. In wrist extension, muscle strength at the starting point was 6.1 Nm for males and 3.3 Nm for females (p < 0.001); Δ Muscle strength was -0.052 Nm/s for males and -0.038 Nm/s for females (p = 0.036); The muscle endurance ratio was 99.1%/s for males and 98.8%/s for females (p = 0.015). In wrist flexion, muscle strength at the starting point and absolute value of Δ muscle strength were significantly larger in males than in females; No significant difference was observed in the muscle endurance ratio in wrist flexion between males and females. These results revealed sex differences in wrist torque and endurance. The muscle endurance ratio of the wrist extensors was lower in females than in males, which suggests that females need to exert more effort to maintain the wrist extension position under resistance. This may predispose the wrist extensor muscles in females to eccentric contractions.

A Survey of Combat Athletes' Rapid Weight Loss Practices and Evaluation of the Relationship With Concussion Symptom Recall

OBJECTIVE

There is a high incidence of concussion and frequent utilization of rapid weight loss (RWL) methods among combat sport athletes, yet the apparent similarity in symptoms experienced as a result of a concussion or RWL has not been investigated. This study surveyed combat sports athletes to investigate the differences in symptom onset and recovery between combat sports and evaluated the relationships between concussion and RWL symptoms.

DESIGN

Cross-sectional study.

SETTING

Data were collected through an online survey.

PARTICIPANTS

One hundred thirty-two (115 male athletes and 17 female athletes) combat sport athletes.

INTERVENTIONS

Modified Sport Concussion Assessment Tool (SCAT) symptom checklist and weight-cutting questionnaire.

MAIN OUTCOME MEASURES

Survey items included combat sport discipline, weight loss, medical history, weight-cutting questionnaire, and concussion and weight-cutting symptom checklists.

RESULTS

Strong associations ( rs = 0.6-0.7, P < 0.05) were observed between concussion and RWL symptoms. The most frequently reported symptom resolution times were 24 to 48 hours for a weight cut (WC; 59%) and 3 to 5 days for a concussion (43%), with 60% to 70% of athletes reporting a deterioration and lengthening of concussion symptoms when undergoing a WC. Most of the athletes (65%) also reported at least one WC in their career to " not go according to plan ," resulting in a lack of energy (83%) and strength/power (70%).

CONCLUSIONS

Rapid weight loss and concussion symptoms are strongly associated, with most of the athletes reporting a deterioration of concussion symptoms during a WC. The results indicate that concussion symptoms should be monitored alongside hydration status to avoid any compound effects of prior RWL on the interpretation of concussion assessments and to avoid potential misdiagnoses among combat athletes.

Nutritional Considerations for the Power Athlete

ABSTRACT

Nutrition is a significant factor in a power athlete's ability to achieve hypertrophy, strength, lean body mass, and overall performance goals. Optimizing an athlete's macronutrient balance, timing of intake, and hydration is essential for advancing performance and should be fluid as the athlete transitions between cycles of training, matching nutrient requirements to intensity of training throughout periodization. Supplement use can help athletes meet their performance and nutrition goals when used as an adjunct to a well-chosen diet, both by direct ergogenic effect and by reducing risk of illness or injury. Educating athletes and coaches on an optimal nutrition plan to support training, performance, and health is critical to prevent the negative effects that may come from poor diet, dangerous weight cutting practices, and relative energy deficiency in sport.

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.

Impact of time-of-day and chronotype on neuromuscular performance in semi-professional female volleyball players

This study aimed to determine if time-of-day could influence physical volleyball performance in females and to explore the relationship between chronotype and volleyball-specific performance. Fifteen young female athletes participated in a randomized counterbalanced trial, performing a neuromuscular test battery in the morning (9:00 h) and the evening (19:00 h) that consisted of volleyball standing spike, straight leg raise, dynamic balance, vertical jump, modified agility T-test and isometric handgrip tests. Chronotype was determined by the morningness-eveningness questionnaire. Compared to the morning, an increased performance was found in the standing spike (4.5%, p = .002, ES = 0.59), straight leg raise test (dominant-limb) (6.5%, p = .012, ES = 0.40), dynamic balance (non-dominant-limb) (5.0%, p = .010, ES = 0.57) and modified T-test (2.1%, p = .049, ES = 0.45) performance in the evening; while no statistical differences were reported in vertical jump tests or isometric handgrip strength. Moreover, no associations were found between chronotype and neuromuscular performance (r = -0.368-0.435, p = .052-0.439). Time-of-day affected spike ball velocity, flexibility in the dominant-limb, dynamic balance in the non-dominant-limb and agility tests. However, no association was reported among these improvements and the chronotype. Therefore, although the chronotype may not play critical role in volleyball-specific performance, evening training/matches schedules could benefit performance in semi-professional female volleyball players.

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.

Changes in body mass and hydration status in judo athletes before and after a top-level competition: a descriptive case study

OBJECTIVES

The International Judo Federation (IJF) implemented new regulations in an attempt to regulate rapid weight loss in 2013. The body weight of the athletes cannot be more than 5% higher than the upper limits of their weight categories at the weight check for randomly selected athletes from each weight category before the competition. However, therea lack of studies demonstrating rapid weight loss and hydration status of elite judo athletes in a real match atmosphere under the current refereeing rules. Thus, this study aimed to examine the body mass and hydration changes of elite judo athletes a week before the competition, official weigh-in, and 24 hours after competition.

METHODS

Eight high-level male judo athletes voluntarily participated in this study. Body mass and urinary measures of hydration status were collected a week before, at the official weigh-in and 24-hour post-weigh-in.

RESULTS

The one-way repeated-measures ANOVA showed a significant main effect of time on body mass (p < 0.001). Body mass decreased by 5.4 ± 0.7 kg or 6.8% from a week before the competition to official weigh-in (p < 0.001) and increased by 3.0 ± 1.1 kg or 4.2% from official weigh-in to 24-h post-competition (p < 0.001). A significant effect of time was also found in both urine-specific gravity (USG) (p < 0.001) and urine color (UC) among the measurements (p = 0.001). Athletes' USG values were at the highest level (USG = 1.030 ± 0.001) at the official weigh-in, while they decreased significantly at 24-hour post-competition (USG = 1.017 ± 0.007).

CONCLUSION

The results showed that elite judo athletes resort to rapid weight loss and present dehydration despite established regulations by the IJF.

Are the Parameters of Novel Two-Point Force-Velocity Model Generalizable in Leg Muscles?

The two-point force-velocity model allows the assessment of the muscle mechanical capacities in fast, almost fatigue-free conditions. The aim of this study was to investigate the concurrent validity of the two-point parameters with directly measured force and power and to examine the generalization of the two-point parameters across the different functional movement tests of leg muscles. Twelve physically active participants were tested performing three functional lower limb maximal tests under two different magnitudes of loads: countermovement jumps, maximal cycling sprint, and maximal force under isokinetic conditions of the knee extensors. The results showed that all values from the two-point model were higher than the values from the standard tests (p < 0.05). We also found strong correlations between the same variables from different tests (r ≥ 0.84; p < 0.01), except for force in maximal cycling sprint, where it was low and negligible (r = −0.24). The results regarding our second aim showed that the correlation coefficients between the same two-point parameters of different lower limb tests ranged from moderate to strong (r −0.47 to 0.72). In particular, the relationships were stronger between power variables than between force variables and somewhat stronger between standard tests and two-point parameters. We can conclude that mechanical capacities of the leg muscles can be partially generalized between different functional tests.

Different Waters for Different Performances: Can We Imagine Sport-Related Natural Mineral Spring Waters?

Preserving the hydration status means to balance daily fluids and salt losses with gains, where the losses depend on several physiological and environmental factors. Especially for athletes, these losses could be relevant and negatively influence the performance: therefore, their hydro-saline status must be preserved with personalized pre- and rehydration plans all along the performance period. Scientific literature in this field is mainly dedicated to artificial sport drinks. Different territories in most world areas are rich in drinking natural mineral spring waters with saline compositions that reflect their geological origin and that are used for human health (often under medical prescription). However, scarce scientific attention has been dedicated to the use of these waters for athletes. We therefore reviewed the existing literature from the innovative viewpoint of matching spring water mineral compositions with different athletic performances and their hydro-saline requirements.

FLUID BALANCE DURING TAEKWONDO TRAINING

ABSTRACT Introduction Dehydration has been described as one of the main factors of reduced performance in combat sports activities, leading to death in extreme cases. Objective To investigate the pre-training hydration status and changes in fluid homeostasis during two taekwondo training sessions. Methods Eighteen male college athletes (age 22.6 ± 3.37 years) were assessed. The study design aimed to reproduce the conditions of a 90-minute taekwondo training session, divided into three stages: a) warm-up exercises (20 min); b) poomsae (30 min) and c) technical training (40 min). The athletes had ad libitum water intake during training. To assess the hydration status we considered body mass (BM), the amount of liquid consumed and urine output, which enabled us to establish absolute and relative fluid loss in kg and percentage as well as the sweating rate. We also considered urine specific gravity (USG), urine color (U-COL), and subjective sensation of thirst (Sthirst) before and after the training session. Pre- and post-training results were compared separately in each session and between sessions. Results There was a significant difference (P<0.05) in pre-training BM between the two days of training. There was a significant difference (P<0.05) in the final BM on both days of the experiment. Most subjects had relative dehydration below 2%. A significant difference (P<0.05) was recorded pre and post training for U-COL and Sthirst, with the highest rates obtained at the end of each session. Participants always started training at a low dehydration status (USG >1,020g.ml-1). Conclusions The athletes tended to start the training sessions in dehydration status, which increases over the course of the training. Ad libitum water intake was not sufficient to balance fluid loss. Changes in fluid levels between sessions were similar. Level of Evidence II; Therapeutic Studies Investigating the Results Level of Treatment.

Evidence-based post exercise recovery in combat sports: a narrative review

INTRODUCTION

Some methods such as ergo nutritional aids, cooling or massage among others could improve recovery in combat sports (CS). The effects, doses, duration, and timing of these methods remains unknown. Nowadays, there is no clear consensus regarding the recovery strategies and it is necessary to understand the type of fatigue induced in CS and its underlying mechanisms. The main aim of this article is to review the update literature related to recovery strategies in CS.

EVIDENCE ACQUISITION

A literature search was conducted following preferred reporting items for review statement on the topic of: "combat sports," "recovery," "nutrition," "fatigue," "ergogenic aids," "weight cutting" and "hydration."

EVIDENCE SYNTHESIS

The initial search of the literature detected 369 articles about CS. Later, 307 were excluded after being determined unrelated to recovery or after failure to fulfill the inclusion criteria. Of the 80 included articles, 19 satisfied the final inclusion criteria.

CONCLUSIONS

To optimize CS performance, adequate recovery is required during training and competition processes. Traditional ergo nutritional supplementation of carbohydrates and proteins combined. Besides, the consumption of evidence supported supplementation (green tea, beetroot gels, creatine or alkaline water) improve recovery processes. Further methods of recovery including physical (cold water immersion, massage or photobiomodulation) and physiological (types of active recovery, sleep and rest) therapies have also been shown useful. This narrative review elucidates the important role of recovery techniques in CS.

Differences in the Bodyweight, Hydration Levels, Lean Mass, and Fat Mass in Spanish Junior Elite Judokas

Combat sports have a great interest in society and among professional sports. They are an important group of sports in the Olympic Games, but the strategies carried out by athletes to reduce body weight for weighing day, is famously known, suffering the adverse physical and psychological effects of rapid weight loss. This could compromise not only the performance, but the health and development of young athletes. A total of 22 elite male judokas (18.05 ± 1.05 years old) were evaluated during four different competitions in one season; the variables of body weight, water levels, and lean and fat mass were measured by bioimpedance (BIA), (Tanita BC545N) during one season. Using the linear mixed model test, we found significant differences in bodyweight variable during the competitions 3-4. The water level variable showed significant differences in all competitions, except for 2-4. Body mass index was significantly different in all competitions, being higher in the later competitions, except between competitions 1-2 and 2-3. Judokas participate in weight loss methods for their weigh-in days. Furthermore, the age at which the athletes reduced their water levels are worrisome. These results could be used to create healthy programs, especially in elite judokas, in order to carry out strategies before, during, and after competitions with weight loss and controlled water levels increasing future performance and health.

The Effects of Dehydration on Metabolic and Neuromuscular Functionality During Cycling

This study aimed to determine the effects of dehydration on metabolic and neuromuscular functionality performance during a cycling exercise. Ten male subjects (age 23.4 ± 2.7 years; body weight 74.6 ± 10.4 kg; height 177.3 ± 4.6 cm) cycled at 65% VO_2max for 60 min followed by a time-to-trial (TT) at 95% VO_2max, in two different conditions: dehydration (DEH) and hydration (HYD). The bioelectrical impedance vector analysis (BIVA) and body weight measurements were performed to assess body fluid changes. Heart rate (HR), energy cost, minute ventilation, oxygen uptake, and metabolic power were evaluated during the experiments. In addition, neuromuscular activity of the vastus medialis and biceps femoris muscles were assessed by surface electromyography. After exercise induced dehydration, the bioimpedance vector significantly lengthens along the major axis of the BIVA graph, in conformity with the body weight change (-2%), that indicates a fluid loss. Metabolic and neuromuscular parameters significantly increased during TT at 95% VO_2max with respect to constant workload at 65% of VO_2max. Dehydration during a one-hour cycling test and subsequent TT caused a significant increase in HR, while neuromuscular function showed a lower muscle activation in dehydration conditions on both constant workload and on TT. Furthermore, a significant difference between HYD and DEH for TT duration was found.

Effects of Rapid Weight Loss on Balance and Reaction Time in Elite Judo Athletes

Balance, reaction time, and strength are key factors affecting judo performance. Although ample research has been done examining potential strength changes caused by weight loss prior to competition, changes in balance and reaction time have been overlooked.

PURPOSE

To examine the effects of rapid and progressive weight loss (RWL and PWL) on balance, reaction time, and strength in a group of elite judo athletes.

METHODS

A total of 38 female and male judo athletes (age = 20.6 [2.6] y) completed balance, reaction-time, and strength assessments 1 wk prior to an official weigh-in (pretest) and immediately after the weigh-in (posttest). The athletes were divided into 3 groups, 1 control group who maintained regular training and eating habits, 1 experimental group who engaged in PWL (<3% reductions in body mass), and a second experimental group who used RWL techniques (>3% reductions in body mass).

RESULTS

The RWL group showed significant decreases (P < .05) in balance performance (ellipse area: 4.83 [0.87] vs 6.31 [1.39] mm2 with eyes closed; mean mediolateral velocity: 2.07 [0.2] vs 2.52 [0.45] mm·s-1 with eyes closed; and mean anteroposterior velocity: 2.25 [0.20] vs 2.51 [0.32] mm·s-1 with eyes open and 2.44 [0.26] vs 3.06 [0.56] mm·s-1 with eyes closed) and reaction time (0.38 [0.04] vs 0.42 [0.06] s) with no changes in strength from pretesting to posttesting. The athletes in the PWL and control groups maintained performance in all variables.

CONCLUSION

These findings demonstrate negative effects on perceptual motor-skill performance in judo athletes engaging in RWL strategies prior to competition.

Urine specific gravity as an indicator of dehydration in Olympic combat sport athletes; considerations for research and practice

Urine specific gravity (U_SG) is the most commonly reported biochemical marker used in research and applied settings to detect fluid deficits in athletes, including those participating in combat sports. Despite the popularity of its use, there has been a growing debate regarding the diagnostic accuracy and the applicability of U_SG in characterizing whole-body fluid status and fluctuations. Moreover, recent investigations report universally high prevalence of hypohydration (∼90%) via U_SG assessment in combat sport athletes, often in spite of stable body-mass. Given the widespread use in both research and practice, and its use in a regulatory sense as a 'hydration test' in combat sports as a means to detect dehydration at the time of weigh-in; understanding the limitations and applicability of U_SG assessment is of paramount importance. Inconsistencies in findings of U_SG readings, possibly as a consequence of diverse methodological research approaches and/or overlooked confounding factors, preclude a conclusive position stand within current combat sports research and practice. Thus the primary aim of this paper is to critically review the literature regarding U_SG assessment of hydration status in combat sports research and practice. When taken on balance, the existing literature suggests: the use of laboratory derived benchmarks in applied settings, inconsistent sampling methodologies, the incomplete picture of how various confounding factors affect end-point readings, and the still poorly understood potential of renal adaptation to dehydration in combat athletes; make the utility of hydration assessment via U_SG measurement quite problematic, particularly when diet and training is not controlled.

Effect of 10% weight loss on simulated taekwondo match performance: a randomized trial

The objective of the present study was to analyze the effect of 10% body mass reduction on simulated taekwondo match performance. Thirty-one male taekwondo athletes were randomly distributed in two groups: weight loss group (n= 15) - athletes in this group reduced 5% body mass per week during two successive weeks, totaling 10% body mass reduction; control group (n= 16) - athletes in this group kept their body mass constant during the 2-week period. Twenty-four hours before and after this period, athletes performed a simulated 3-round taekwondo match (6 min). Athletes wore body protectors to validate the scores during the match according to the official taekwondo rules. Match was filmed and actions were categorized using the Game Performance Assessment Instrument. There was a group and time interaction (P< 0.001) for body mass, with decrease only for the weight loss group (P= 0.001). A group and time interaction was also observed for the taekwondo match performance (P< 0.001), with performance increase being found only for the control group (P= 0.01). Thus, the 10% weight loss was not a good strategy to improve taekwondo skills' performance.

Food restriction alters salivary cortisol and α-amylase responses to a simulated weightlifting competition without significant performance modification

The aim of this investigation was to evaluate the effect of a 6-day food restriction period on the physiological responses and performance of 11 high-level weightlifters. After a period of weight maintenance (T₂), they were assigned into two groups depending on whether they lost (Diet group, n = 6) or maintained their body weight (Control group, n = 5) during the course of those 6 days. An evaluation of performance and the measurement of salivary cortisol concentrations and salivary α-amylase (sAA) activity were performed during a simulated weightlifting competition which took place at T₂, after a 6-day period of food restriction (T₃). Dietary data were collected using a 6-day diet record. We noted a 41.8% decrease in mean energy intake during the dietary restriction period, leading to a 4.34% weight loss for the Diet group. Dietary restriction did not modify absolute performance levels, whilst a significant improvement was noted for the Control group. Furthermore, we noted a response of decreased salivary cortisol and increased sAA activity to the simulated competition stress at T₃ for the Diet group. These results may indicate that dietary reduction led to a dissociation of the hypothalamo-pituitary-adrenal axis and the sympatho-adreno-medullary system, which could impair training adaptations and absolute performance development.