Relationship of aerobic and neuromuscular indexes with specific actions in judo

Strength and Conditioning (S&C) Practices of Judo Athletes and S&C Coaches: A Survey-Based Investigation

ABSTRACT

Weldon, A, Cloak, R, Kirk, C, Ruddock, A, Langan-Evans, C, Detanico, D, Loturco, I, and Kons, R. Strength and conditioning (S&C) practices of judo athletes and S&C coaches: A survey-based investigation. J Strength Cond Res 38(4): e160-e173, 2024-The benefits of strength and conditioning (S&C) for improving judo performance and reducing injuries have been widely studied. However, the S&C practices used and perspectives held by those delivering S&C have yet to be elucidated. Therefore, this study investigated the S&C practices and perspectives of judokas and S&C coaches working within judo. Forty-two judokas and 9 S&C coaches completed an online survey comprising 6 sections: (a) written informed consent; (b) background information; (c) education, qualifications, and prescription; (d) views on S&C; (e) exercise selection; and (f) issues and improvements. Frequency analysis was used to report responses to fixed-response questions and thematic analysis for open-ended questions. Results indicated that S&C coaches were primarily responsible for delivering S&C programs (60%), and S&C information was predominantly sourced from S&C coaches (43%). Strength and conditioning was deemed very important for randori (78-88%), overall judo performance (67-79%), and judo fitness (62-78%). Similarly, S&C was considered very important for the development of speed and power (76-89%), strength (71-89%), and injury reduction (69-78%). Novel findings were also observed, such as integrating judo-specific training within S&C practice, which may be partly explained by more S&C coaches holding judo belts (67%) than S&C qualifications (11%). This study supports practitioners delivering S&C in judo by offering a base of information to critique or align with their existing S&C practices and perspectives. Furthermore, our results may help identify potential gaps between methods used, proposed guidelines, and actual practice, facilitating the development of research and education resources tailored to the current climate.

Variability Analysis in Judo Para Athletes With Visual Impairments: Match-Outcome Performance in the Tokyo 2020 Paralympic Games With Evidence From the New Classification System

Match-related performance analysis in judo Para athletes with visual impairments is important to coaches and staff to identify technical-tactical profiles of their athletes and opponents but also to identify whether there are similar characteristics in each visual class. Thus, this study explores the match-related performance in judo Para athletes and verifies the relationship between performance using the old and new classification systems. The match-derived variables were analyzed using different statistical methods considering a total of 182 matches from the Tokyo 2020 Paralympic Games. The results indicated that performance was affected by sex and degree of impairment. The new classification system seems suitable for grouping Para judo athletes, as it differentiates performance between the two proposed classes (J1 and J2), since athletes from each group compete separately. Furthermore, different variability index measures were correlated with competitive performance, demonstrating a specific performance profile for each sport class in judo.

Effects of stretch-shortening cycle fatigue protocol on lower limb asymmetry and muscle soreness in judo athletes

This study aimed to analyse unilateral countermovement jumps (CMJ) performance and muscle soreness in lower limbs, as well as to compare lower limb asymmetry over 48h after a stretch-shortening cycle (SSC) fatigue protocol. Fourteen judo athletes performed unilateral CMJ on each leg before, and after the 5th and 10th sets over 24h and 48h of an SSC-fatigue protocol. The SSC protocol reduced CMJ performance after the 5th set and 10th sets, especially in the weaker limb (p < 0.05), but returned to the baseline values after 24h. Asymmetry increased for peak force, peak power, and mean power after the 5th set compared to the baseline (p < 0.05) and remained higher for peak force after the 10th set (p = 0.019), returning to the baseline values after 24h (p < 0.05). Soreness increased for the lower body at post, 24h, and 48h compared to the baseline (p < 0.05). In conclusion, a fatiguing SSC protocol can result in increased bilateral asymmetries in judo athletes, but after 24h and 48h of the protocol the bilateral asymmetry returned to the baseline values, with only muscle soreness still elevated.

Bilateral deficit in the countermovement jump and its associations with judo-specific performance

This study aimed to describe the bilateral deficit (BLD) during the countermovement jump (CMJ) in judo athletes and determine the relationship between the BLD and judo-specific performance. Fourteen male judo athletes participated. Athletes performed three specific judo tests, Maximal Sprint Speed Judo Test, Maximal Aerobic Speed Judo Test and Special Judo Fitness Test (SJFT), and double- and single-leg CMJ. The following CMJ variables were used: jump height (JH), mean (MPO) and peak (PPO) power output, peak force (PF), peak velocity (PV) and impulse (IMP). The Pearson's or Spearman's test were used (p < 0.05). The results show that the BLD is found in all CMJ parameters (20 to 31%). Negative correlations between first set of SJFTTT (total throws) and BLD in PF (r = -0.60; p= 0.022) and between the second set of SJFTTT and BLD in MPO (r= -0.74;p = 0.002), PV (r =-0.59;p = 0.025) and IMP (r =-0.55; p = 0.040) were found. Also, negative correlations between SJFTTT and the BLD in all CMJ parameters (r= -0.53 to -0.85; p < 0.05) were found. Higher values of BLD are related to poor SJFTTT performance.

Physical performance and somatic maturity in male and female judo athletes: An analysis in different age categories

BACKGROUND

Maturity status is an important parameter to understand physical performance in young judo athletes, especially considering different age categories.

OBJECTIVES

The aim of this study was to investigate the role of each age category (U13, U15, and U18) on physical performance between and within the age groups.

METHODS

Sixty-five male athletes from the U13 (n = 17), U15 (n = 30), and U18 categories (n = 18), and 28 female from the U13 (n = 9), U15 (n = 15), and U18 categories (n = 4) participated in this study. The assessments were performed at two moments separated by 48 h and included anthropometric measurements and physical tests (standing long jump, medicine ball throw, handgrip strength, Special Judo Fitness Test, and Judogi Grip Strength Test). The athletes also provided their date of birth and judo experience. One-way analysis of variance and Pearson correlation were used with significant level set at 5%.

RESULTS

The main results showed higher values of somatic variables (maturity status and body size) and physical performance in the U18 compared to U15 and U13 in male and female (p < 0.05), but no differences between U15 and U13 (p > 0.05). In general, training experience, chronological age, and somatic variables were correlated (moderate to very large magnitude) with physical performance in all age categories for male (r = 0.40-0.66, p < 0.05) and female groups (r = 0.49-0.73, p < 0.05).

CONCLUSION

We concluded that U18 athletes showed higher values of somatic maturity, training experience, and physical performance compared to U13 and U15 categories, with no differences between U13 and U15. In general, training experience, chronological age, and somatic variables were correlated with physical performance in all age categories.

Relation between VT1, VT2, and VO2max with the Special Wrestling Fitness Test in Youth Wrestlers: A Short Report

This study investigated the relationship between peak oxygen uptake and ventilatory threshold 1 (VT1) and 2 (VT2) with the Special Wrestling Fitness Test variables. Thirteen wrestlers (male: six; female: seven) of Olympic freestyle wrestling were assessed. The Pearson's correlation coefficient (p < 0.05) was used to establish the relationship between variables. A positive correlation was found between VT1 with throws in set B (r = 0.77; p = 0.002; 95%CI = 0.37-0.93), total throws (r = 0.73; p = 0.004; 95%CI = 0.30-0.91), heart rate recovery (r = 0.58; p = 0.036; 95%CI = 0.05-0.86), and test index (r = -0.60; p = 0.031; 95%CI = -0.86-0.07); between VT2 and throws in set B (r = 0.57; p = 0.043; 95%CI = 0.01-0.86); and between peak oxygen uptake with throws in set B (r = 0.77; p = 0.002; 95%CI = 0.39-0.93), throws in set C (r = 0.64; p = 0.02; 95%CI = 0.12-0.89), and total throws (r = 0.72; p = 0.006; 95%CI = 0.28-0.91). In conclusion, the peak oxygen uptake and ventilatory thresholds correlated with specific Special Wrestling Fitness Test variables.

Biomechanical and Anthropometric Factors That Differentiate National- and Regional-Level Judo Players

PURPOSE

The study aimed to identify the variables that differentiate judo athletes at national and regional levels. Multivariable analysis was applied to biomechanical, anthropometric, and Special Judo Fitness Test (SJFT) data.

METHOD

Forty-two male judo athletes from 2 competitive groups (14 national and 28 state levels) performed the following measurements and tests: (1) skinfold thickness, (2) circumference, (3) bone width, (4) longitudinal length, (5) stabilometric tests, (6) dynamometric tests, and (7) SJFT. The variables with significant differences in the Wilcoxon rank-sum test were used in stepwise logistic regression to select those that better separate the groups. The authors considered models with a maximum of 3 variables to avoid overfitting. They used 7-fold cross validation to calculate optimism-corrected measures of model performance.

RESULTS

The 3 variables that best differentiated the groups were the epicondylar humerus width, the total number of throws on the SJFT, and the stabilometric mean velocity of the center of pressure in the mediolateral direction. The area under the receiver-operating-characteristic curve for the model (based on 7-fold cross validation) was 0.95.

CONCLUSION

This study suggests that a reduced set of anthropometric, biomechanical, and SJFT variables can differentiate judo athlete's levels.

Diurnal variation in Uchikomi fitness test performance: Influence of warm-up protocols

Performance is judged using a variety of methods to ensure uniformity between competitions. Uchikomi Fitness Test (UFT) could accomplished between morning qualifying and evening finals. The purpose of this study is to investigate the impact of different warm-up protocols on UFT at different times of the day in female judokas. Ten volunteer women who had been practising judo on a regular basis for more than 5 years and actively competed in international tournaments took part in this study. Judokas completed UFT, either after no-warm-up (NWU), specific warm-up (SWU), and linear+lateral warm-up (FWU) protocols for two times a day in the morning: 09:00-11:00 and in the evening: 16:00-18:00, on non-consecutive days. In conclusion, there was a significant increase in UFT scores (F = 9.89; p = 0.002), a + b (F = 4.42; p = 0.04) and heart rate (F = 28.99; p < 0.001) in the early evening compared to the morning. Increases in UFT performance were observed in the SWU protocol compared to the NWU and FWU protocols (p < 0.05). However, the interaction between time of day and warm protocol was not significant (p > 0.05). The UFT performance revealed diurnal variation, and the judokas' performances may be favourably affected more in the late hours, particularly following SWU procedures.

Using Inertial and Physiological Sensors to Investigate the Effects of a High-Intensity Interval Training and Plyometric Program on the Performance of Young Judokas

The use of inertial and physiological sensors in a sport such as judo is scarce to date. The information provided by these sensors would allow practitioners to have a better understanding of sports performance, which is necessary for an accurate training prescription. The purpose of this study was to use inertial and physiological sensors in order to investigate the effect of a plyometric and high-intensity interval training (HIIT) training program on Special Judo Fitness Test (SJFT) performance and speed of execution of throws in young judokas. A total of 32 participants were divided into two groups: experimental and control. The intervention consisted of six sessions with a duration of 60 min for 3 weeks. Physiological sensors collected heart rate data to assess the Special Judo Fitness Test, and inertial sensors collected angular velocity. The results show a significant decrease in the SJFT index (Score pre: 22.27 ± 2.73; Score post: 19.65 ± 1.70; p ≤ 0.05; d = 0.61) and a significant increase in the angular velocity of the X-axis (Pre: 320.87 ± 51.15°/s; Post: 356.50 ± 40.47°/s; p ≤ 0.05; d = 0.45) and Y-axis (Pre: 259.40 ± 41.99°/s; Post: 288.02 ± 65.12°/s; p ≤ 0.05; d = 0.31) in the experimental group. In conclusion, this study demonstrates that using inertial and physiological sensors allowed us to analyze the effect that a high-intensity interval training program and plyometrics had on the performance of young judokas. Strength and conditioning coaches should consider these results because including plyometric training and HIIT in judokas' workout programming can be especially positive for eliciting increases in performance. However, future training interventions should investigate the training adaptations to longer interventions.

Aerobic Capacity and Restitution Efficiency Level in Relation to the Training Experience and Weekly Training Volume of Male and Female Judo National Team Members in the Cadet Age Group (U18) during the Preparatory Period

This study aims to analyze the relationship between the level of aerobic capacity and post-exercise restitution during the preparation period, with training experience and weekly training volume. All (12) athletes (six women; six men) participating in the training camp of the Polish national judo team in the cadet age group were tested. The Maximal Multistage 20-m Shuttle Run Test was used to investigate the level of aerobic capacity, and the Klonowicz coefficient of restitution (COR) 3 min after exercise (COR 3') and 5 min after exercise (COR 5') was used to determine the level of post-exercise restitution efficiency. The results showed that higher training experience significantly affected the deterioration of COR 3' in female athletes and improved the results in the capacity test of male athletes. Female and male athletes with a higher weekly training volume had a higher HR at the end of the performance test. Considering the demonstrated correlations, special attention should be paid to matching the loads in training programs to the age of the athletes, introducing into training programs the teaching of body management during fatigue. Failing to adjust this may make participation impossible in competitions at the international level for older age groups.

Judo specific fitness test performance variation from morning to evening: specific warm-ups impacts performance and its diurnal amplitude in female judokas

BACKGROUND

A number of specific tests are used to standardize competition performance. Specific Judo fitness test (SJFT) can be applied by considering the start of the competition qualifiers in the morning and the continuation of the final competitions in the evening. The improvement of test performances can be achieved with warm-up for elevating heart rate (HR) and muscle temperature such as raise, activate, mobilise, potentiate (RAMP) protocols.

PURPOSE

The aim of this study is to evaluate the effects of different warm-up protocols on SJFT at different times of the day in female judokas.

METHODS

Ten volunteer women participated in this study, who regularly participated in judo training for more than 5 years and actively competed in international competitions. Judokas completed SJFT, either after no warm-up, or RAMP protocols like specific warm-up (SWU), and dynamic warm-up for two times a day in the morning: 09:00-10:00 and in the evening: 16:00-17:00, with at least 2 days between test sessions. The following variables were recorded: throws performed during series A, B, and C; the total number of throws; HR immediately and 1 min after the test, and test index after different warm-ups.

RESULTS

When analyzed evening compared to the morning without discriminating three warm-up protocols, evening results statistically significant number of total throws performed during series A, B, and C, the total number of throws; HR immediately and 1 min after the test, and test index than morning results (p < 0.01). Moreover, RAMP protocols interaction with time have demonstrated an impact on SJFT for index [F₍₂₎ = 4.15, p = 0.024, η_p²: 0.19] and changes after 1 min HR [F_(1.370)= 7.16, p = 0.008, η_p²: 0.29]. HR after 1 min and test index results were statistically significant in favor of SWU (p < 0.05).

CONCLUSIONS

In conclusion, SJFT performance showed diurnal variation and judo performances of the judokas can be affected more positively in the evening hours especially after RAMP protocols.

High-Intensity Interval Exercise Performance in Judo Athletes: Physiological, Perceptual, and Pacing Responses

This study aimed to verify the behavior of physiological, perceptual, and performance responses during a high-intensity exercise in judo athletes and to identify if this protocol is able to discriminate athletes from different levels (national vs. state). Forty-five male judo athletes participated and were divided into two groups: state (age 24.2 ± 3.7 years) and national (22.1 ± 3.3 years). Judo athletes performed a judo-specific protocol contained high-intensity intermittent exercise consisted of 12 sets of 20 s in all-out intensity. During the protocol, the repetitions and heart rate were assessed over the sets, and at the end of the protocol, the rate of perceived exertion was measured. The results showed that the national group presented higher repetitions (29 ± 4 repetitions) during the high-intensity intermittent exercise compared with state (22 ± 2 repetitions). However, the national group showed a progressive decrease of repetitions up to the middle of the protocol, which coincided with higher values of heart rate compared with state (first and second sets). There was a decrease of repetitions from the first set (p < .001) and similar values of heart rate from the third set in the state. In conclusion, the performance (in repetitions) during the high-intensity intermittent exercise was able to discriminate athletes from different competitive levels. National athletes presented better performance, but worse pacing strategy compared with state.

Body Size Measurements and Physical Performance of Youth Female Judo Athletes with Differing Menarcheal Status

Purpose: To compare body size measurements and physical performance among female youth judo athletes with differing menarcheal status and to identify indicators of physical performance in post-menarcheal girls. Methods: Nineteen young female judo athletes (age 13.9 ± 2.3 years) were divided into a pre-menarche (n = 7) and a post-menarche (n = 12) group. The athletes were evaluated through neuromuscular tests, including standing long jump (SLJ), medicine ball throw (MBT), and handgrip strength (HGS), and judo-specific assessments, including the Special Judo Fitness Test (SJFT) and the Judogi Grip Strength Test (JGST_ISO). Furthermore, years of experience in judo and the age at menarche were determined. Results: The main results showed higher performance for the post-menarche group for most variables (p < 0.05) compared to the pre-menarche group. A multiple linear regression analysis demonstrated that age at menarche, chronological age, and body mass explained close to 70% of JGST_ISO, while training experience, chronological age, and age at menarche explained close to 59% of SLJ. Additionally, chronological age and age at menarche explained 40% of MBT, and chronological age and height explained 52% of HGS. Conclusions: Age at menarche and somatic growth variables explained moderate proportions of the variance of physical performance, thereby providing evidence that these parameters are the primary indicators of physical performance in young female judo athletes.

Influence of Physical Fitness on Special Judo Fitness Test Performance: A Multiple Linear Regression Analysis

ABSTRACT

Lopes-Silva, JP, Panissa, VLG, Julio, UF, and Franchini, E. Influence of physical fitness on Special Judo Fitness Test performance: a multiple linear regression analysis. J Strength Cond Res 35(6): 1732-1738, 2021-The purpose of this study was to identify the physical fitness variables that best predict Special Judo Fitness Test (SJFT) performance. Thirty-five male experienced judo athletes took part in this study. All athletes performed 5 tests: upper- and lower-body cycle ergometer graded exercise tests; upper- and lower-body Wingate tests; and SJFT. The peak oxygen consumption (V̇o2peak), maximum heart rate (HRmax), maximum aerobic power, and the variables corresponding to onset blood lactate accumulation (OBLA) were determined during the graded exercise tests. For the Wingate tests, peak power (PP) and mean power were used. Furthermore, the total number of throws, heart rate (HR) immediately and 1 minute after, and SJFT index were calculated. Four separated forward multiple linear regressions (forward model) were used to identify the physical fitness variables that best explained the SJFT variables. Upper-body V̇o2peak (ml·min-1·kg-1) explained 27% of variance in the total number of throws, whereas an additional 7% was explained by upper-body PP. Upper-body HRmax explained 46% of the variance in the HR immediately after the SJFT, whereas lower-body HR at OBLA accounted for an additional 8%. Lower-body HRmax explained 21% of the variance in the HR 1 minute after the SJFT, whereas peak lactate ([La-]peak) after the lower-body graded exercise test accounted for an additional 12%. Upper-body V̇o2peak (ml·min-1·kg-1) alone accounted for 15% of the variance in the SJFT index. Based on these results, the data suggest that physical fitness variables, derived from upper- and lower-body aerobic and anaerobic tests, have a small ability to predict the SJFT variables.

Different Training Methods Cause Similar Muscle Damage in Youth Judo Athletes

It is well known that different factors can contribute to muscle damage in judo matches or training. Previous research analyzed only the effects of simulated judo combat or judo training on biochemical markers of muscle damage without determining its specific causes. Our objective was to identify possible differences in biochemical markers of muscular damage in response to different training methods in youth judo athletes. Twelve high-level male judo athletes were randomly assigned to a standing (SP, n = 6, age = 16.6 ± 1.1 years) or a groundwork (GP, n = 6, age = 17.8 ± 0.8 years) position combat practice group. Both groups had the same protocol of four 4-minute combat practice bouts separated by 1-minute rest intervals. Before and immediately after combat practice blood samples were taken to assess muscle damage markers: creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). There were significant increases in AST, LDH, and CK after the standing and groundwork training sessions compared with resting values in both groups. Additionally, no significant differences in the enzyme's activity between SP and GP groups were found. These results showed that standing and groundwork randori training (free sparring or free practice) causes similar muscle damage in adolescent judo athletes. Future research should assess the effects of the same damage mechanisms over a longer period of time.

Improving on Half-Lightweight Male Judokas' High Performance by the Application of the Analytic Network Process

Judo is a multifactorial sport where many variables or key performance indicators (KPIs) such as force-velocity profile, bioenergetic capacity, technical and tactical skills, and cognitive and emotional competence play a role and influence the final result. While there have been many academic studies of these variables, usually in isolation, none have examined KPIs holistically or analyzed their impact on strategic performance. The main objective of the present study, therefore, is to apply a novel and easily replicable methodology to identify and prioritize the main KPIs affecting performance in professional judo. Such a methodology was applied to the High-Performance Judo Centre of Valencia, using a multi-criteria decision aid technique: the analytic network process (ANP). The ANP is used to identify and quantify cause and effect relationships not only between KPIs but also between KPIs and performance objectives. Further, the ANP offers effective results when there is a lack of historical KPI data, because it is based on experts' opinions and judgments. A judo expert group (JEG) comprising elite judo coaches and half-lightweight (under 66 kg) male judokas applied the methodology to discriminate between the characteristics required when aiming to reach high-level strategic objectives (such as participating in the Olympic Games or winning a medal in a Grand Slam/Gran Prix). The JEG, which consisted of five elite judokas, national and international champions, and three Olympic coaches-including a former European champion and silver medalist in a world championship-provided high added value to the study. The main findings were that the KPIs that made the most difference were mostly psychological, specifically motivation, stress, and team cohesion. Of these, motivation was by far the most important KPI for success in our case study, so judokas should make sure that they analyze it properly. Motivation is usually intrinsic to the competitor and should be maintained at a high level, not only during tournaments but also during daily training and lifestyle activities. Physical and other specific forms of training, as well as lifestyle KPIs, are very important for the elite competitor but are not sufficient to reach high-level objectives. The most important of these KPIs were Kumi-Kata (grip work), dual career, focus and concentration level, scouting, nutrition, and basic technique. Power and strength were the most important physical KPIs. In general, these are essential for meeting strategic objectives, but they do not make the crucial difference. This suggests that professional psychological support should be provided in daily training and that international team composition and internships should be fostered.

Significant Predictors of Sports Performance in Elite Men Judo Athletes Based on Multidimensional Regression Models

BACKGROUND

This research aimed to identify the most significant predictors of sports level using regression modeling.

METHODS

This study examined 16 judokas (aged 23 (±2.5)) from four weight categories, with four athletes in each category (66 kg, 73 kg, 81 kg and 90 kg). Each athlete was a member of the Polish National Team, an international master class (IM) or national master class (M). The tests were carried out twice (every two weeks) during the pre-competitive season in the morning, after a 10-min warm-up. The tests were performed according to the following protocol: Explosive Strength Lower Limbs (ExSLL) [W], Strength Endurance Lower Limbs (SELL) [%], Explosive Strength Upper Limbs (ExSUL) [W], Strength Endurance Upper Limbs (SEUL) [%]. The relationships between the dependent variable (ranking score) and the other analyzed variables (predictors) were estimated using the one-factor ridge regression analysis.

RESULTS

There were significant intergroup and intragroup differences in the results of explosive strength and strength endurance of the lower and upper limbs. The best predictors were identified using regression modeling: ExSLL, SELL, and SEUL.

CONCLUSIONS

Increasing the value of these predictors by a unit should significantly affect the scores in the ranking table. Correlation analysis showed that all variables that are strongly correlated with the Polish Judo Association (PJA) ranking table scores may have an effect on the sports performance.

Meta-Analysis to Determine Normative Values for the Special Judo Fitness Test in Male Athletes: 20+ Years of Sport-Specific Data and the Lasting Legacy of Stanisław Sterkowicz

The aim of this study was to evaluate Special Judo Fitness Test (SJFT) results specific to the population of male judoka and to develop age category norms for junior and senior athletes. A systematic review of the existing literature was conducted to identify 281 publications reporting SJFT results between 1995 and 2018. The final meta-analysis included data from 37 relevant studies that reported SJFT results from 51 individual samples of 515 senior and 209 junior male athletes. The combined mean and SD for SJFT variables were calculated, and the Cohen’s d effect size with 95% confidence intervals (CI) for the senior and junior age classifications were compared. Senior athletes demonstrated higher total number of throws (d = 0.41, CI = 0.25–0.57, p <0.001) and heart rate (HR) immediately after the SJFT (d = 0.18, CI = 0.02–0.35, p = 0.025) with limited differences for HR one minute after the SJFT between groups. The SJFT index was lower for seniors compared to juniors (d = 0.38, CI = 0.22–0.54, p <0.001) indicating better overall performance by the more advanced athletes. Percentile rankings were used to develop SJFT classificatory tables for male senior and junior judo athletes. Training staff can use the age group classifications in the evaluation process of their athletes and for the purpose of monitoring training.

Photobiomodulation Therapy Does Not Attenuate Fatigue and Muscle Damage in Judo Athletes: A Randomized, Triple-Blind, Placebo-Controlled Trial

Fatigue and muscle damage negatively affect performance in lower limb exercises involving the stretch-shortening cycle in judo athletes during competition and training sessions. Photobiomodulation therapy has emerged as an effective non-invasive strategy to attenuate fatigue and muscle damage when applied before different types of exercises. Our objective was to investigate the effects of photobiomodulation therapy on fatigue and muscle damage in judo athletes. Sixteen judo athletes participated in the study (23.1 ± 3.8 years, 77.9 ± 14.9 kg, 173.1 ± 8.9 cm, 17.5 ± 7.3 body fat%, 12.9 ± 5.0 years of practice). Each participant received, in a randomized manner, photobiomodulation in one limb and placebo in the contralateral limb on the same day. Thereafter, subjects performed a stretch-shortening cycle protocol to induce muscle fatigue and damage. Countermovement jump (impulse, peak power, peak velocity, and peak force), echo intensity (rectus femoris and vastus lateralis), and muscle soreness were assessed at different time points before, during, immediately post, and 24 and 48 h after the protocol. Muscle fatigue was detected due to reductions in countermovement jump impulse (14.7 ± 9.8 and 15.9 ± 15.5%), peak power (12.9 ± 8.5 and 11.9 ± 6.9%), peak velocity (8.6 ± 8.1 and 6.5 ± 6.0%), and peak force (7.0 ± 5.3 and 8.0 ± 6.1%) after the protocol (p < 0.001), for placebo and photobiomodulation therapy, respectively. Muscle damage was detected due to reductions in countermovement jump impulse (−6.1 ± 19.2% and −4.5 ± 9.2%, p < 0.05), increases in echo intensity (rectus femoris, 21.0 ± 11.9 and 20.8 ± 9.0%; and vastus lateralis, 22.4 ± 23.2%; and 16.7 ± 23.8%; p < 0.001), and quadriceps muscle soreness (3.6 ± 1.6 and 3.5 ± 1.7 a.u; p < 0.011), 48 h after the protocol, for placebo and photobiomodulation therapy, respectively. No differences were observed between photobiomodulation therapy and placebo at any time points for any variables (p > 0.05), indicating no positive effect favoring photobiomodulation therapy. In conclusion, our findings suggest no effect of photobiomodulation therapy applied before exercise to reduce lower limb muscle fatigue and damage during and following a stretch-shortening cycle protocol in judo athletes.

Criterion Validity, Reliability and Usefulness of a Judo-Specific Maximal Aerobic Power Test

PURPOSE

To evaluate criterion validity, reliability and usefulness of a test to measure maximal aerobic power using judo-specific movements (UK_test).

METHODS

12 judokas performed five graded exercise tests (GETs) in 4 sessions. In sessions 1 and 2, upper-body (UB_test), lower-body (LB_test) and familiarization UK_test. GETs were randomly performed and separated by at least 48 hours. In sessions 3 and 4, test and retest UK_test were performed (7-day apart). For all GETs, peak oxygen consumption (V̇O_2peak), maximal heart rate (HR_max), peak blood lactate concentration ([Lapeak]), maximal aerobic intensity and rating of perceived exertion (RPE) were determined. Another group of 12 judokas performed the UK_test and one confirmation test (20-min after the UK_test), at 105% of maximal aerobic speed (MAS) until exhaustion, to confirm if maximal responses were achieved.

RESULTS

V̇O_2peak did not differ (P>.05) between UK_test (46.04±5.34 mL.kg^-1.min^-1) and LB_test (44.78±5.98 mL.kg^-1.min^-1), but was higher (P<.05) than UB_test (37.03±7.16 mL.kg^-1.min^-1). Total duration (551±60s) and [Lapeak] (7.10±1.76 mmol.L^-1) in the UK_test were different (P<.05) from UB_test (416±47s, 9.93±2.15 mmol.L^-1, respectively) and LB_test (433±54s, 10.29±2.23 mmol.L^-1, respectively). Very large relationships between V̇O_2peak in UK_test with UB_test (r=0.78, P=.003) and LB_test (r=0.87, P<.001) were found. Maximal values were achieved for the UK_test V̇O_2peak, HR_max, [Lapeak], RPE and MAS, with no difference between test and retest (P>.05). In addition, very large intraclass correlation coefficients (ICC) for the V̇O_2peak (ICC=0.86), HR_max (ICC=0.90) and MAS (ICC=0.81) were found.

CONCLUSIONS

UK_test can be considered a valid, reliable and useful test to measure maximal aerobic power using judo-specific movements.

Neuromuscular and postural control in visually and nonvisually impaired judo athletes: case study

This study aimed to analyze neuromuscular and postural control in visually and nonvisually impaired judo athletes. Two judo athletes, one visually impaired and the other nonvisually impaired, participated in the study. The athletes presented similar demographic, anthropometric, and judo-technical characteristics. They performed maximal isometric handgrip strength (dominant and nondominant hand), vertical jumps (countermovement jump [CMJ] and squat jump [SJ]), and center of pressure assessment in three positions: neutral, anteroposterior, and judo combat base (Migi-shizentai). The main findings showed that the visually impaired athlete presented higher standing balance in the neutral and anteroposterior positions than non-visually impaired athlete (effect size [ES]>2.0). In the Migi-shizentai position, the disparity between both athletes was reduced, particularly in the displacement area (ES=0.52). The visually impaired athlete showed higher performance in the SJ but lesser performance in CMJ and handgrip strength tests than nonimpaired athlete (ES>2.0). We concluded that the postural stability was higher in the visually impaired athlete in the neutral and anteroposterior position, but similar to the nonvisually impaired athlete in Migi-shizentai position, possible due to the influence of judo practice. Moreover, the visually impaired athlete showed higher performance in the SJ than nonvisually impaired.

Validity of judo-specific tests to assess neuromuscular performance of judo athletes

Uchi-komi Fitness Test (UFT) is a specific judo test that evaluates physiological fitness of judo athletes in similar conditions to judo matches. Neuromuscular parameters obtained by generic and judo-specific tests would aid to get more information about its criterion validity. This study aimed to analyse the relationship between UFT and shoulder external (PT_EX) and internal (PT_INT) rotation torque, handgrip strength (HGS) and vertical jumps (VJs) performance. The relationship between UFT and Judogi grip strength test (JGST) was also investigated. Eighteen male judo athletes participated in this study. Athletes performed neuromuscular tests (VJ, PT_EX, PT_INT and HGS) and judo-specific tests (JGST and UFT). Pearson's correlation was used with the level set at p < 0.05. Significant correlation was found between UFT and all VJ variables (r = 0.50-0.72, p < 0.004), UFT a + b (two first series of UFT) and PT_EX (r = 0.49, p = 0.033), UFT and PT_INT (r = 0.47, p = 0.044). Also, UFT was correlated to JGST (r = 0.50-0.72, p < 0.044, respectively). We conclude that muscle power of lower limbs, PT_EX and PT_INT was related to UFT. Strength-endurance in the upper limbs (JGST) was also related to the UFT performance.

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.

Physical fitness predicts technical-tactical and time-motion profile in simulated Judo and Brazilian Jiu-Jitsu matches

Background

Among combat sports, Judo and Brazilian Jiu-Jitsu (BJJ) present elevated physical fitness demands from the high-intensity intermittent efforts. However, information regarding how metabolic and neuromuscular physical fitness is associated with technical-tactical performance in Judo and BJJ fights is not available. This study aimed to relate indicators of physical fitness with combat performance variables in Judo and BJJ.

Methods

The sample consisted of Judo (n = 16) and BJJ (n = 24) male athletes. At the first meeting, the physical tests were applied and, in the second, simulated fights were performed for later notational analysis.

Results

The main findings indicate: (i) high reproducibility of the proposed instrument and protocol used for notational analysis in a mobile device; (ii) differences in the technical-tactical and time-motion patterns between modalities; (iii) performance-related variables are different in Judo and BJJ; and (iv) regression models based on metabolic fitness variables may account for up to 53% of the variances in technical-tactical and/or time-motion variables in Judo and up to 31% in BJJ, whereas neuromuscular fitness models can reach values up to 44 and 73% of prediction in Judo and BJJ, respectively. When all components are combined, they can explain up to 90% of high intensity actions in Judo.

Discussion

In conclusion, performance prediction models in simulated combat indicate that anaerobic, aerobic and neuromuscular fitness variables contribute to explain time-motion variables associated with high intensity and technical-tactical variables in Judo and BJJ fights.

Female Judo Athletes' Physical Test Performances Are Unrelated to Technical-Tactical Competition Skills

This study analyzed the relationship between generic and judo-specific physical test performances and technical-tactical competition performances among 19 female judo athletes. Participant data were gathered in two stages: (a) physical tests-countermovement jump (CMJ), handgrip strength, Special Judo Fitness Test and Judogi Grip Strength Test; and (b) match performances recorded for technical-tactical analysis. Pearson's linear correlation and multiple linear regression analysis showed no significant correlations between any technical-tactical parameter and judo-specific physical tests. However, the number of attacks during matches was significantly positively correlated with countermovement jump height (CMJ_JH; r = 0.69, p = .002), peak power output (CMJ_PPO; r = 0.53, p = .002), and peak velocity (CMJ_PV; r = 0.62, p = .001). Effective time during matches was significantly correlated with all CMJ parameters (except maximum force; r = 0.65-0.76, p ≤ .01) and with right hand grip strength ( r = 0.48, p = .037). Match effectiveness was correlated with CMJ_PPO ( r = -0.67, p = .001), mean power output (CMJ_MPO; r = -0.54, p = .017), and CMJ_PV ( r = -0.54, p = .004). The explained power of variance was low for all variables at 45-54%. We conclude that judo-specific performance tests do not seem to be related to female judo athletes' technical-tactical skills in official competition, though athletes with higher lower limb muscle power and higher handgrip strength showed higher time effectiveness during matches.

Effects of a 10-Week Introductory Judo Course on Postural Control During a Bilateral Reactionary Gripping Task

This study examined the effect of a 10-week introductory judo course on postural control during a bilateral reactionary gripping task using different stance conditions. A total of 20 volunteers were divided into experimental (JDO) and control (CON) groups. Countermovement jump was measured and center of pressure variables were evaluated while performing a bilateral reactionary gripping task under different stance conditions during pre- and posttesting. No interactions were observed for the center of pressure variables (p > .05), while both countermovement jump power (+165.4 W; p = .036) and height (+3.5 cm; p = .018) significantly improved in the JDO group following the 10-week course. Results indicate that 10 weeks of an introductory judo course has no effect on postural control while performing a bilateral reactionary gripping task using different stance conditions.

Strength-Power Performance of Visually Impaired Paralympic and Olympic Judo Athletes From the Brazilian National Team: A Comparative Study

Loturco, I, Nakamura, FY, Winckler, C, Bragança, JR, da Fonseca, RA, Filho, JM, Zaccani, WA, Kobal, R, Cal Abad, CC, Kitamura, K, Pereira, LA, and Franchini, E. Strength-power performance of visually impaired paralympic and olympic judo athletes from the brazilian national team: a comparative study. J Strength Cond Res 31(3): 743-749, 2017-The aim of this study was to compare the muscle power and maximal isometric strength capacities of Olympic and visually impaired Paralympic judo athletes. Twenty-eight elite judo athletes (7 men and 7 women per group) from the permanent Brazilian National Paralympic and Olympic teams took part in this study. After a specific warm-up, the athletes performed loaded jump squat (JS), bench press (BP), and standing barbell row (SBR) exercises to determine their values of maximum mean propulsive power (MPP) in these respective exercises. The maximal isometric strength (MIS) was also determined for both upper and lower limbs, through the use of BP and half-squat (HS) exercises. Finally, the jumping ability was assessed using unloaded squat jump (SJ). The magnitude-based inference was used to compare the groups. The Olympic judo athletes presented a likely higher SJ height than the Paralympic athletes. The Olympic group presented almost certainly higher MPP in the loaded JS and in the SBR exercises and likely higher MPP in the BP exercise. Importantly, in the MIS assessments the differences between groups in the HS and BP exercises were rated as unclear. In conclusion, our results showed that both Olympic and Paralympic judo athletes present similar levels of maximal isometric strength, but muscle power performance is superior in Olympic athletes.

Sex differences and the effects of modified combat regulations on endurance capacity in judo athletes: A meta-analytic approach

Judo requires endurance capacity to recover from its high-intensity intermittent actions. This systematic review aimed to evaluate VO2max and the anaerobic threshold in competitive male and female judo athletes. Twelve eligible studies were chosen for quantitative meta-analysis, including results for 188 male and 159 female athletes. Combined values were calculated and compared by gender prior to and following altered combat regulations in 2003. No significant differences in VO2max were noted following the rule changes, but female athletes’ values increased to a level comparable to those reported in male athletes prior to the alterations. VO2max in male judo athletes was higher (54.8±1.9 ml·kg^-1·min^-1) than in female athletes (48.7±2.2 ml·kg^-1·min^-1). The effect size of gender was large (d = 1.30) for VO2max and negligible for the anaerobic threshold. Sexual dimorphism exists in VO2max of judo athletes and changes in combat duration did not affect these differences.

Effects of successive judo matches on fatigue and muscle damage markers

This study aimed to investigate the acute effects of simulated judo matches on fatigue and muscle damage markers. Twenty male judo athletes participated in this study. The athletes performed three 5-minute judo matches separated by 15 minutes of passive rest between each match. The following measurements were performed before and after each match: shoulder external/internal rotation isokinetic torque and countermovement jump (CMJ). Blood samples were taken before the first match and after the third match for serum creatine kinase (CK) and lactate dehydrogenase (LDH) analysis. T-tests for dependent samples and analysis of variance for repeated measures were used to compare the variables over the time; the level of significance was set at 0.05. An overall effect of the successive matches on shoulder internal (PTIN) and external (PTEX) rotation peak torque and CMJ performance was observed. PTIN and PTEX showed significant decreases in postmatch 2 and postmatch 3 when compared with the baseline (p < 0.01). Also, CMJ height declined in postmatch 2 and postmatch 3 (p < 0.01) when compared with the baseline. Serum CK and LDH activity increased significantly after the third match (p < 0.01). It was concluded that 3 successive judo matches induced a decline of peak torque and muscle power in the upper and lower limbs, respectively, and also provoked an increase of muscle damage markers. These findings may provide important knowledge for coaches and physical trainers to improve judo-specific strength training in both the upper and lower limbs.

Establishing normative data for the special judo fitness test in female athletes using systematic review and meta-analysis

Conflicting results have been documented in the Special Judo Fitness Test (SJFT) for mean parameters of performance between male and female judo athletes matched by age and competitive level. Therefore, it is debatable whether previously established norms for the SJFT prepared for men, should be adopted for use in women. The goal of this investigation was to prepare standards to allow coaches and researchers to control and evaluate training effects in female judoka. Systematic review was used to compile previously published scientific studies containing information on female judo athletes who were tested using the SJFT. The results were derived using meta-analysis and included data obtained from 11 relevant studies published between January 1997 and December 2013. Combined mean and SDs were computed based on studies containing 161 individual results from the SJFT. A 5° scale was adopted as follows: Excellent = highest 5%, Good = next highest 15%, Regular = middle 60%, Poor = next lowest 15%, and Very poor = lowest 5%. The results of the current investigation provide normative data for the SJFT for junior and senior female judoka. Classification for each of the parameters of the SJFT, including number of throws completed during the test, heart rate (HR) measured immediately after the effort, HR after a 1-minute recovery period and SJFT index, were established. This normative data can be used in the design of training programs for female judoka, as well as evaluation after training, and in preparation for competition.