Monitoring Training Loads in Judo Athletes: Different Time Courses of Physiological, Neuromuscular, and Perceptual Responses.

This study aims to elucidate the internal load, performance, physiological, and perceptual recovery responses during four weeks of traditional judo training. Ten cadet and junior judo athletes were evaluated daily for four weeks, in which their perception of recovery, heart rate variability, handgrip strength, and countermovement jump performance were assessed. A one-way repeated-measures ANOVA was performed to analyze the variables across the weeks. A significant time effect in internal load (F = 6.51; p = 0.001) has been observed. Handgrip test performance showed significantly higher values in the 3rd and 4th weeks (p <0.001), while countermovement jump performance was significantly higher in the 4th week (p =0.0007). The heart rate variability's coefficient of variation was lower in both the 3rd and 4th weeks (p =0.02). Regarding perceptual aspects, the Hooper Index showed a significant time effect (p =0.04), but pairwise comparison did not reveal differences between weeks. The present study indicates that neuromuscular, physiological, and perceptual responses to training load alterations present different time courses. This must be considered for the adequate monitoring of training programs.

Effects of lower-limb extensors' neuromuscular fatigue on the regularity of running movements: a crossover study.

Neuromuscular fatigue (NMF) reduces the musculoskeletal system's ability to produce force during activities like running. Analysis of motor behaviour's regularity may identify motor system deficits caused by fatigue. The present study investigated whether the NMF of lower limb extensors alters the regularity of running movement and whether this possible effect remains over time. Crossover study with two randomised conditions: NMF and control. Twelve healthy young males participated in this study. Hip, knee, and ankle angles (sagittal plane) and centre of mass (CoM) linear accelerations were assessed during treadmill running at self-selected speed in four assessment conditions: Baseline (pre-NMF), and after NMF (NMF condition) or after rest (control), at the 1st (Time_1), 10th (Time_10) and 20th (Time_20) minutes. Kinematics regularity was measured as Sample Entropy. Repeated measures ANOVAs were used (α = 0.05). NMF reduced regularity of lower limb joints during running, and these effects remained up to 20 minutes. No changes were observed in the CoM accelerations' regularity. The regularity reductions may be an adaptive solution for the motor system to maintain the task performance. The measure of regularity of the lower limb joints' motion is sensitive to NMF and can identify states with deficits in muscles' force production capacity in running.

Predicting the body core temperature of recreational athletes at the end of a 10 km self-paced run under environmental heat stress.

NEW FINDINGS: What is the central question of this study? The aim was to identify the factors predicting the body core temperature of athletes at the end of a 10 km self-paced run in a hot environment. What is the main finding and its importance? Hyperthermia in athletes subjected to self-paced running depends on several factors, highlighting the integrated control of core temperature during exercise under environmental heat stress. Five of the seven variables that significantly predicted core temperature are not invasive and, therefore, practical for use outside the laboratory environment: heart rate, sweat rate, wet-bulb globe temperature, running speed and maximal oxygen consumption. ABSTRACT: Measurement of body core temperature (Tcore ) is paramount to determining the thermoregulatory strain of athletes. However, standard measurement procedures of Tcore are not practical for extended use outside the laboratory environment. Therefore, determining the factors that predict Tcore during a self-paced run is crucial for creating more effective strategies to minimize the heat-induced impairment of endurance performance and reduce the occurrence of exertional heatstroke. The aim of this study was to identify the factors predicting Tcore values attained at the end of a 10 km time trial (end-Tcore ) under environmental heat stress. Initially, we extracted data obtained from 75 recordings of recreationally trained men and women. Next, we ran hierarchical multiple linear regression analyses to understand the predictive power of the following variables: wet-bulb globe temperature, average running speed, initial Tcore , body mass, differences between Tcore and skin temperature (Tskin ), sweat rate, maximal oxygen uptake, heart rate and change in body mass. Our data indicated that Tcore increased continuously during exercise, attaining 39.6 ± 0.5°C (mean ± SD) after 53.9 ± 7.5 min of treadmill running. This end-Tcore value was primarily predicted by heart rate, sweat rate, differences between Tcore and Tskin , wet-bulb globe temperature, initial Tcore , running speed and maximal oxygen uptake, in this order of importance (ß power values corresponded to 0.462, -0.395, 0.393, 0.327, 0.277, 0.244 and 0.228, respectively). In conclusion, several factors predict Tcore in athletes subjected to self-paced running under environmental heat stress. Moreover, considering the conditions investigated, heart rate and sweat rate, two practical (non-invasive) variables, have the highest predictive power.

Active warm-up and time-of-day effects on repeated-sprint performance and post-exercise recovery.

PURPOSE: This study investigated the effects of both an active warm-up and the time-of-day variation on repeated-sprint performance. A second objective was to compare the post-exercise recovery between the experimental conditions. METHODS: Eleven male participants performed ten maximal cycling sprints (6 s each, with a 30-s interval between them) in the morning and late afternoon, either after a warm-up or control condition. The warm-up consisted of cycling for 10 min at 50% of the peak aerobic power. RESULTS: Rest measurements of rectal, muscle, and skin temperatures were higher in the afternoon compared to the morning (p < 0.05), with no significant differences in heart rate (p = 0.079) and blood lactate concentration (p = 0.300). Warm-up increased muscle temperature, heart rate, and lactate, and reduced skin temperature (all p < 0.001), though no significant differences were observed for rectal temperature (p = 0.410). The number of revolutions (p = 0.034, ηp2 = 0.375), peak (p = 0.034, ηp2 = 0.375), and mean (p = 0.037, ηp2 = 0.365) power of the first sprint (not the average of ten sprints) were higher in the afternoon compared to the morning, regardless of warm-up. However, beneficial performance effects of warming up were evident for the first (p < 0.001) and the average of ten sprints (p < 0.05), regardless of time of day. More remarkable changes during the 60-min post-exercise were observed for rectal temperature (p = 0.005) and heart rate (p = 0.010) in the afternoon than in the morning. CONCLUSION: Warming-up and time-of-day effects in enhancing muscular power are independent. Although warm-up ensured further beneficial effects on performance than the time-of-day variation, a faster post-exercise recovery was observed in the late afternoon.

Influence of Mental Fatigue on Physical Performance, and Physiological and Perceptual Responses of Judokas Submitted to the Special Judo Fitness Test.

ABSTRACT: Campos, BT, Penna, EM, Rodrigues, JGS, Mendes, TT, Maia-Lima, A, Nakamura, FY, Vieira, ÉLM, Wanner, SP, and Prado, LS. Influence of mental fatigue on physical performance, and physiological and perceptual responses of judokas submitted to the Special Judo Fitness Test. J Strength Cond Res 36(2): 461-468, 2022-Mentally fatigued athletes present impaired aerobic performance, strength endurance, and manual dexterity, despite no changes in anaerobic performance and maximal muscle strength and power. Noteworthy, the effect of mental fatigue on physical performance during high-intensity intermittent tests that require specific motor skills of fighting sports has not been investigated. Therefore, this study aimed to verify whether mental fatigue influences performance and physiological and perceptual responses of judokas subjected to a high-intensity intermittent test designed specifically and validated for judo. Each judoka performed 2 experimental trials-a control trial one and the other one after the induction of mental fatigue. These trials were scheduled in a random and balanced order. In both trials, lactate, glucose, and cortisol concentrations, the heart rate variability, and perceptual variables were collected after the initial treatment and after the Special Judo Fitness Test (SJFT). The initial treatment consisted of a 30-minute cognitive demanding task (Stroop Color test) or watching a movie (control) and was followed by the SJFT. The Stroop Color test increased the perceptions of mental fatigue and effort, without affecting motivation for subsequent testing. Unexpectedly, mentally fatigued athletes did not show reduced performance during the SJFT. Regarding the physiological variables, no significant differences were identified between the 2 experimental conditions. We conclude that physical performance measured during a specific test for judokas is not impaired by a previous 30-minute cognitive task that causes mental fatigue. In addition, this cognitive task did not influence the physiological changes induced by the specific physical test.

Head pre-cooling improves 5-km time-trial performance in male amateur runners in the heat.

This study aimed to evaluate the effect of head pre-cooling on the 5-km time-trial performance of amateur runners in the heat. In a counterbalanced design, 15 male amateur runners (22.6 ± 3.5 y; VO2 max in heat 42.3 ± 4.4 mLO2 /kg/min) completed two 5-km time trials performed in the heat (35°C, 50% relative humidity). In one trial (HCOOL), participants underwent 20 min of head cooling in a temperate environment (23°C, 70% relative humidity) prior to exercise. In another trial (CON), exercise was preceded by 20 min of rest under the same temperature conditions. Exercise time was shorter in HCOOL (25 min and 36 s ± 3 min) compared to CON (27 ± 3 min; p = 0.02). Rectal temperature was reduced during the pre-exercise intervention in HCOOL (p < 0.001), but not in CON (p = 0.55). Relative changes in rectal temperature and mean head temperature were lower throughout HCOOL when compared with CON condition (p = 0.005 and p = 0.022, respectively). Mean skin temperature, heart rate, and rating of perceived exertion did not differ between HCOOL and CON conditions throughout exercise (p = 0.20, p = 0.52 and 0.31, respectively). Thermal comfort was lower in HCOOL condition in pre-exercise (p = 0.014) with no differences observed throughout exercise (p = 0.61). 5-km running performance in a hot environment was improved after a 20-min head cooling intervention, suggesting that this method may be practical as pre-cooling strategy and easily administered to both professional and amateur runners alike.

Comparison of Physical Fitness and Anthropometrical Profiles Among Brazilian Female Soccer National Teams From U15 to Senior Categories.

ABSTRACT: Ramos, GP, Nakamura, FY, Penna, EM, Mendes, TT, Mahseredjian, F, Lima, AM, Garcia, ES, Prado, LS, and Coimbra, CC. Comparison of physical fitness and anthropometrical profiles among Brazilian female soccer national teams from U15 to senior categories. J Strength Cond Res 35(8): 2302-2308, 2021-This study aimed to compare anthropometric and physical fitness of Brazilian female national team soccer players from the U15 to senior categories, and to compare the physical performance between selected and nonselected players. Subjects included 231 athletes (U15, n = 46, U17, n = 49, U20, n = 98, and Senior, n = 38). Body mass, height, sum of skinfolds, squat jump (SJ), countermovement jump (CMJ), 20-m linear sprint, and Yo-Yo IR1 were assessed. The U15 players were shorter than all other groups (p < 0.01) and lighter than U20 players (p < 0.01). Regarding physical tests, Senior athletes presented higher SJ compared with U20, and both showed higher CMJ and SJ compared with the U15 and U17 (p < 0.05). Senior athletes were also faster than players of all other categories in 20-m sprint (p < 0.01) and covered the greatest distance in the Yo-Yo IR1 (p < 0.05). U20 were better in the Yo-Yo IR1 than the younger groups (p < 0.05). When comparing selected and nonselected players, no differences were identified in anthropometric measures (p > 0.05). However, selected players from U17, U20, and Senior teams showed better performance in Yo-Yo IR1 than nonselected ones (p < 0.05). Finally, selected senior athletes also presented higher CMJ and SJ than nonselected players (p < 0.05). These results suggest that, although there is a tendency for maintenance in anthropometric measures from the age of 15 years, there are substantial improvements in speed, lower-body power, and aerobic capacity from U20 age group. In addition, it seems that intermittent aerobic fitness contributes to the selection of players to international tournaments in national teams.

Neuromuscular and physiological responses to different training loads in Randori of elite judo athletes

Abstract Aim: To compare two different randori structure (high volume and short pauses - TRAD training vs low volume with long pauses - COMP training) in the neuromuscular and metabolic responses of elite judo athletes. Methods: The first situation (TRAD) consisted of 12 randoris of 5 minutes with 45 seconds rest, and the other situation (COMP), consisted of 6 randoris of 5 minutes with 10 minutes between them. Physiological (Blood Lactate and Creatine Kinase), neuromuscular (Countermovement Jump and Medicine Ball Throws) and perceptive variables (Rating Perceived Exertion) were measured before and at the end of the sessions. Results: The subjective perception of effort at the end of the training was significantly higher in the TRAD training type (TRADpost: 8.1 ± 0.9 AU; COMPpost: 6.6 ± 1.5 AU, p <0.001). Blood lactate concentration (TRADpost: 6.4 ± 2.2 mmol/L; COMPpost: 8.1 ± 2.9 mmol/L; p <0.001), CMJ height (TRADpost: 36.2 ± 4.6 cm; COMPpost: 35.9 ± 4.3 cm, p = 0.012) and upper limb power performance (TRADpost: 6.4 ± 0.9 m; COMPpost: 6.3 ± 0.9 m p = 0.03) were significantly higher at the end of the two training sessions compared to their start, but there are no group effect. There is group effect in CK (TRADpost: 490.7 ± 273.5 U/L; COMPpost: 357.4 ± 203.8 U/L; p <0.001). Conclusions: This study demonstrated that TRAD and COMP Judo training induced similar physical demands, and both seem to not be enough to reach higher intensities, which made them distant methods of competitive reality.

Influence of Autonomic Control on the Specific Intermittent Performance of Judo Athletes.

Judo is a high-intensity intermittent combat sport which causes cardiac adaptations both morphologically and related to the autonomic nervous system (ANS). Therefore, this study aims to verify the correlation between heart rate variability (HRV) at rest with performance in the Special Judo Fitness Test (SJFT) and whether groups with different RR values at rest show different performance in the SJFT and during post-test recovery. Sixteen judo athletes with 7.2 ± 3.9 years of training experience participated in the study. Before and after the SJFT execution HRV and lactate measurements were conducted. For HRV analysis, we used the mean interval RR, the standard deviation of the RR interval (SDNN), the root mean square of successive differences in RR intervals (RMSSD), the low frequency (LF) and high frequency (HF) in normalized and absolute units. The sample was split into two groups (low RR and high RR) to verify if this variable could differentiate between specific performance. For the SDNN, a significant and moderate correlation (r = 0.53) was found with the total number of throws and throws in the series A (r = 0.56) and B (r = 0.54) and for the RMSSD a correlation with throws during series B (r = 0.59) in the SJFT. However, the groups did not differ in performance and recovery. Therefore, HRV is related to intermittent judo performance; however, it cannot differentiate between judokas at different levels of performance.

Evaluation of hydration status by urine, body mass variation and plasma parameters during an official half-marathon.

BACKGROUND: The aim of this study was to verify the agreement of urine, body mass variations and plasma parameters to determine the hydration status of 14 male runners (29±4 years and 54.3±5.5 mLO2/kg/min) in an official 21.1 km road race. METHODS: The mean dry-bulb temperature and air relative humidity during the road race were 25.1±2.1 °C and 54.7±2.2%, respectively. The volume of water ingested by the runners was monitored using marked volumetric plastic bottles provided at the hydration stations located at 0, 2.5, 5.0, 7.5, 10.5, 14.0, 16.0 and 18.5 km from the starting line. Hydration status was assessed using urine specific gravity (USG), urine osmolality (UOSM) and plasma osmolality (POSM). Furthermore, body mass variation (∆BM) was assessed by comparing body mass (BM) immediately prior and after the race. Total sweat was estimated by ∆BM, added water volume ingested and deducted blood volume collected. The sweat rate was calculated through total sweat and total exercise time. RESULTS: The mean water intake was 0.82±0.40 L, and the mean sweat rate and total sweating were 1440.11±182.13 mL/h and 2.67±0.23 L. After the race, the BM reduced by 1.7±0.4 kg. The ∆BM was -2.41±0.47%, and the plasma volume variation was -9.79±4.6% between pre- and post-running measurements. Despite the POSM increased post-race compared to pre-race, the UOSM and USG did not change. No significant correlations were found between POSM variation with UOSM variation (r=-0.08; P=0.71), USG variation (r=-0.11; P=0.78) or ∆BM (r=0.09; P=0.77). CONCLUSIONS: In conclusion, this study shows that both ∆BM and ∆POSM indicated a hypohydration state after exercise even though the ∆BM did not correlate significantly with ∆POSM. These results demonstrate that ∆BM is a practical method and can be sufficiently sensitive to evaluate the hydration state, but it should be utilized with caution.

T-Shirt fabric and color affect the physiological strain but not 10 km outdoor running performance.

BACKGROUND: The aim of the present study was to evaluate the effects of T-Shirt fabric and color on the 10 km outdoor running performance. METHODS: Six men and six women (mean±SD: age: 27±5 years; height: 1.70±0.13 m; weight: 64.0±12.7 kg; body surface area: 1.73±0.29 m2; Σskinfolds: 107±24 mm; VO2max: 40.2±8.4 mL.kg-1.min-1) took part in five experimental trials, during each of which they wore: 1) no T-shirt (CON); 2) white polyester T-shirt (WP); 3) black polyester T-shirt (BP); 4) white cotton T-shirt (WC); and 5) black cotton T-shirt (BC). Average running velocity (pace) was calculated from each 2 km running time. Rectal, skin and T-shirt temperatures, heart rates and Physiological Strain Index (PSI) were measured before and after the 10 km runs and at the end of each 2 km. RESULTS: There were no differences in pace, heart rate, rectal and skin temperatures among conditions (P>0.05). PSI was higher in BC and WC conditions when compared to BP and WP conditions. T-shirt temperature was higher for the BC when compared to WP, BP and WC conditions. Rectal temperature and heart rate increased simultaneously with reduced pace throughout self-paced running (P<0.05). CONCLUSIONS: Despite fabric type T-shirt altered PSI, running performance in the 10 km run was not affected by T-shirt type or color.

Acute heat exposure increases high-intensity performance during sprint cycle exercise.

The purpose of this study was to investigate the effects of acute heat exposure at thermal balance on high-intensity performance during sprint cycle exercise. Nine healthy male subjects were tested in three different, well-controlled environments in an environmental chamber: T (22 degrees C, 65% RH), H1 (30 degrees C, 55% RH) and H2 (35 degrees C, 62% RH), each test being carried out on a different day following a randomized sequence. After 30 min of exposure to the set environment, subjects performed the 30-s sprint cycle exercise. Heart rate, rectal and skin temperatures were measured prior to exercise, at rest, before and after environmental exposure, and after exercise. There were no differences in subjects' core temperature or heart rate prior to exercise. However, skin temperature was significantly higher in hot trials compared with the control throughout the experimental session (P < 0.05). Peak power was significantly higher in the hot environments compared with the control. Mean power was higher only in H2 compared with T (P < 0.05). This difference in power output was the consequence of a faster pedaling cadence in the hot trials (P < 0.05). Plasma ammonia was higher in the hot trials versus control at 4 min post-sprint. No differences in blood lactate levels at 3 min post-sprint were observed between tests. The results of this study suggest that the exposure to hot environment caused an improvement in power output for a single 30-s sprint. This increase in power output was associated with an elevation in plasma ammonia suggestive of an increase in adenine nucleotide loss.