European Journal of Sport Science最新文献

The aims of this study were to test the change and retention of player's overall tackling technique and technical components following a player-specific video-based technical feedback and instruction intervention on both their dominant and non-dominant shoulders. Twenty-four (n = 24) rugby union players participated in a non-randomized control-intervention, which consisted of a video-based technical feedback and instruction group (video-based technical feedback) and a no video-based technical feedback and instruction group (control). During 3 sessions (baseline, intervention, retention) separated by one week, participants in each group performed six tackles (3 tackles on each shoulder) on a tackle simulator. In total, 432 tackles (video-based technical feedback = 216, control = 216) were analysed. Each tackle was analysed using a standardized list of technical criteria (arbitrary units, AU). For the dominant shoulder, tackling technique scores significantly improved from baseline to intervention for both groups. For the non-dominant shoulder, only the video-based technical feedback group improved their tackling technique from baseline to intervention (baseline 6.89 [6.33-7.45] AU vs. intervention 7.72 [7.35-8.10] AU p = .001, ES = 0.60 moderate). For the retention session, the video-based technical feedback group scored significantly higher than the control group, for dominant (video-based technical feedback 8.00 [7.60-8.40] AU vs. control 7.22 [6.83-7.62] AU p = .014, ES = 0.66 moderate) and non-dominant (video-based technical feedback 8.11 [7.81-8.41] AU vs. control 7.22 [6.90-7.55] p = .004, ES = 0.96 moderate) tackles. This study demonstrates the efficacy of video-based technical feedback as a method to optimize tackle training for player safety and performance.HIGHLIGHTSVideo-based technical feedback can improve tackling technique in both dominant and non-dominant shoulders.Video-based technical feedback group continued to improve following a retention interval of one week.The video-based technical feedback group showed a significant (with a moderate effect size) improvement from baseline for two techniques - namely, "body position - upright to low" and "drive through contact with legs and shoulders".Video-based technical feedback can be used as a method to optimize tackle training for injury prevention and performance.

This study aimed to define, develop, and validate a subjective scale of training quality. Two related studies were used to 1) define training quality and 2) develop and validate a subjective scale. Part One: a purposive sample of 15 sub-elite (i.e. national) and elite (i.e. international) swimmers participated in one, 20-30-min semi-structured interview. Thematic analysis of interview responses established three constructs to define training quality. These were the physical, technical, and mental aspects of training. Part Two: development of the Subjective Training Quality (STQ) scale based on the three constructs identified in Part One. 252 sub-elite and elite athletes, across eight sports completed the STQ scale. Cronbach's alpha (α) assessed internal consistency, histogram plot analysis assessed face validity, and confirmatory factor analysis (CFA) compared physical, technical, and mental constructs with training quality. Root mean square error of approximation (RMSEA) and standardised root mean square residual (SRMR) evaluated CFA quality of fit. Physical, technical, and mental constructs demonstrated a high "acceptable" level of internal consistency (α = 0.85) and excellent face validity. Comparatively, the CFA quality of fit was "excellent" (RMSEA = <0.01 "good", SRMR = 0.00 "perfect"). The STQ scale demonstrated excellent internal consistency and face validity, establishing capacity to monitor training quality. The STQ scale could be used in conjunction with traditional training monitoring tools to provide additional insight into athlete's training quality. Further investigation is required to determine how the STQ scale may interact with subjective and objective training performance measures, and how it could be incorporated into daily training monitoring.HighlightsAthletes perceive the subjective training quality (STQ) scale adequately represents the physical, technical, and mental constructs of training quality.Excellent internal consistency and confirmatory factor analysis fit demonstrates the STQ scale is an effective tool to monitor training quality.With additional validation, the STQ scale could be used in conjunction with traditional load monitoring tools to provide greater insight to an athlete's training response, and subsequently inform training prescription.

The biarticular triceps brachii long head (TB_Long) is lengthened more in the overhead than neutral arm position. We compared triceps brachii hypertrophy after elbow extension training performed in the overhead vs. neutral arm position. Using a cable machine, 21 adults conducted elbow extensions (90-0°) with one arm in the overhead (Overhead-Arm) and the other arm in the neutral (Neutral-Arm) position at 70% one-repetition maximum (1RM), 10 reps/set, 5 sets/session, 2 sessions/week for 12 weeks. Training load was gradually increased (+5% 1RM/session) when the preceding session was completed without repetition failure. 1RM of the assigned condition and MRI-measured muscle volume of the TB_Long, monoarticular lateral and medial heads (TB_Lat+Med), and whole triceps brachii (Whole-TB) were assessed pre- and post-training. Training load and 1RM increased in both arms similarly (+62-71% at post, P = 0.285), while their absolute values/weights were always lower in Overhead-Arm (-34-39%, P < 0.001). Changes in muscle volume in Overhead-Arm compared to Neutral-Arm were 1.5-fold greater for the TB_Long (+28.5% vs. +19.6%, Cohen's d = 0.61, P < 0.001), 1.4-fold greater for the TB_Lat+Med (+14.6% vs. +10.5%, d = 0.39, P = 0.002), and 1.4-fold greater for the Whole-TB (+19.9% vs. +13.9%, d = 0.54, P < 0.001). In conclusion, triceps brachii hypertrophy was substantially greater after elbow extension training performed in the overhead versus neutral arm position, even with lower absolute loads used during the training.HighlightsGrowing evidence suggests that resistance training at long muscle lengths promotes muscle hypertrophy, but its practical applications are yet to be explored.Triceps brachii muscle hypertrophy was substantially greater after cable elbow extension training performed in the overhead than neutral arm position, particularly in the biarticular triceps brachii long head, even with lower absolute loads lifted (i.e. lower mechanical stress to muscles/joints).Cable elbow extension training should be performed in the overhead rather than neutral arm position if one aims to maximise muscle hypertrophy of the triceps brachii or to prevent atrophy of this muscle.

The objective of this study was to examine the association between time engaged in moderate (MPA), vigorous (VPA), and moderate-to-vigorous (MVPA) physical activity (PA) and indicators of lipid profile in adolescents. This longitudinal study with a four-year follow-up, and three collection points (2014, 2015 and 2017) analyzed the data of 136 adolescents (10-13 years old; 53.7% girls), in João Pessoa, Brazil. The time in MPA, VPA and MVPA times was measured by accelerometers. The lipid profile indicators analyzed were total cholesterol (TC), low-density (LDL-C) and high-density lipoproteins cholesterol (HDL-C), triglycerides (TG), non-HDL-C, TC/HDL-C and TG/HDL-c ratios. There was an inverse association between MPA time and TC values (ß = -0.560; 95%CI: -1.116; -0.004); VPA and LDL-C (ß = -0.962; 95%CI: -1.678; -0.246) and non-HDL-C (ß = -0.955; 95%CI: -1.708; -0.201); and MVPA and TC (ß = -0.436; 95%CI: -0.816; -0.055), TG (ß = -0.415; 95%CI: -0.712; -0.118), LDL-C (ß = -0.460; 95%CI: -0.823; -0.096), non-HDL-C (ß = -0.522; 95%CI: -0.908; -0.136) and TC/HDL-C (ß = -0.472; 95%CI: -0.889; -0.055). Adolescents more engaged in PA, especially in MVPA, exhibited better levels of TC, TG, LDL-C, non-HDL-C and TC/HDL-C; and AFV exerted a greater influence on LDL-c and non-HDL-c levels.HighlightsThis study is one of the first observational longitudinal studies to analyze the association between different PA intensities, measured by accelerometer, and lipid profile indicators, with a 4-year follow-up and 3 collection points in adolescents from a low-to-middle income country;Adolescents engaged in PA, especially MVPA intensity, obtained better TC, TG, LDL-c, non-HDL-C and TC/HDL-C levels;VPA was more strongly associated with LDL-C and non-HDL-C levels compared to MVPA.

We conducted a systematic review and meta-analysis to investigate the effect of sleep deprivation on endurance performance, as well as possible effect-modifying factors. Searches were done in Pubmed, Web of Science, Embase, and Scopus on 12 July 2022. We additionally searched the bibliographic references and citations on Google Scholar of the papers whose full text was analyzed. Eligible studies were randomized and non-randomized controlled trials that compared sleep deprivation and habitual-sleep night effects on endurance performance in healthy humans. The studies' quality was examined by the Cochrane Collaboration's risk of bias tool. We calculated the pooled standardized mean differences (pooled SMD) and 95% confidence interval (95%CI) by a random-effects model. A mixed-effects model analyzed subgroups. Thirty-one studies were analyzed (n = 478), generating 38 effect sizes in full. The overall risk of bias was low in 8% of the studies, unclear in 74%, and high in 18%. Sleep deprivation in general had a moderate negative effect on endurance performance (polled SMD [95%CI] = -0.52 [-0.67; -0.38]). Training status, sleep deprivation magnitude, assessment time, exercise mode, and endpoint type did not influence the sleep deprivation effect, whereas longer exercises (>30 min) were more affected by sleep deprivation than shorter ones (P = 0.035). Therefore, the available evidence supports that sleep deprivation's deleterious effect on endurance performance is of moderate size and depends on exercise duration. This information can be useful to estimate the performance decrement of endurance exercise practitioners under sleep deprivation in training routines and competitions.PROSPERO registration number CRD42021229717.

This study investigated whether skilled batsmen in a state cricket pathway could anticipate ball types when congruency of field-placings was manipulated with a bowler's action. Twenty-four male cricket batsmen were recruited who had played either first-class cricket (n = 6), were part of under 17 (n = 8) or under 19 (n = 10) state cricket squads. Participants completed a video-based temporal occlusion test where they were required to anticipate ball types from a swing bowler. In condition one, contextual field-placing information was presented to be congruent with the delivery type and bowler's action, whilst in condition two it was incongruent. Results did not reveal skill level differences across conditions for anticipation. In the congruent condition, all skill groups predicted above the chance level at the beginning and end of the bowler's delivery stride. In the incongruent condition, first-class players predicted above chance at the beginning of the bowler's delivery stride, and to a higher magnitude above chance compared to other skill groups at ball release. Under 17 and 19 players could not predict above chance at the start of the bowler's delivery stride with their magnitude of prediction lower than first-class players at ball release. Results indicate skilled batsmen find it challenging to integrate contextual and kinematic information to anticipate. This is likely due to greater emphasis placed upon contextual information in part supplied by data analysts. Findings have theoretical and practical implications respectively for lower body positioning for bat-ball interception and perceptual training to improve pick-up of kinematic cues.HIGHLIGHTSSkilled batsmen in a high-performance state cricket pathway could integrate congruent field-placings and bowler kinematics to anticipate ball types.First-class batsmen could integrate incongruent field-placing information to the start, but not the end, of the bowler's delivery action to anticipate ball types.Under 17 and 19 batsmen could not integrate incongruent field-placings to bowler kinematics to anticipate ball types.Skilled batsmen who cannot use kinematic information to anticipate ball types should be given visual-perceptual simulation training to accelerate performance.

Clarifying the muscular factors that contribute to performance improvement can be beneficial for athletes and coaches. The present study examined the relationships between the resting muscle shear modulus and dynamic performance during the stretch-shortening cycle (SSC) and explosive exercises. To this end, we measured the jump height during three types of vertical jumps (squat jump [SJ], countermovement jump [CMJ], and rebound jump [RJ]) and the multi-joint leg extension power at three velocities (low, moderate, and high) of 30 healthy women. Using ultrasound elastography, the resting shear modulus of the vastus lateralis was assessed in the sitting position as an index of passive muscle mechanical properties. The results showed that the shear modulus was positively correlated with RJ height and multi-joint leg extension power at moderate and high velocities (r = 0.435-0.563, P < 0.05). There was no significant correlation between the shear modulus and SJ height, CMJ height, and multi-joint leg extension power at low velocity. Contact time (i.e. the time under force exertion against the ground) during RJ (161 ± 19 ms) was 19% of that during CMJ (869 ± 171 ms). The results suggest that passive muscle mechanical properties play an important role in high-speed SSCs and dynamic explosive performance.HighlightsThe resting shear modulus was related to performance in stretch-shortening cycle (SSC) exercise involving a series of rapidly performed SSCs.The resting shear modulus was associated with muscular power in high-velocity conditions but not in low-velocity conditions.This study suggests that the passive mechanical properties of an agonist muscle play an important role in high-speed dynamic performance.

The aim of this study was to determine if residual neuromuscular fatigue influenced subsequent match and training activity in professional women's basketball. Prior to matches and training sessions throughout a season, players performed countermovement jumps while wearing a magnetic, angular rate and gravity (acceleration) sensor on their upper back. Flight time to contraction time ratio was used to determine neuromuscular performance and to identify neuromuscular fatigue. Average session intensity and volume, the proportion of live time spent in different intensity bands (matches), and absolute and relative time spent in different intensity bands (training) were quantified using accelerometry. Residual neuromuscular fatigue was deemed to be present when the decrement in neuromuscular performance relative to pre-season baseline was greater than the smallest worthwhile change. Players displayed residual neuromuscular fatigue before 16% of matches and 33% of training sessions. When players were fatigued prior to matches, the proportion of live time undertaking supramaximal activity was 5.7% less (p = 0.02) and moderate-vigorous activity was 3.7% more than when not fatigued (p = 0.02). When fatigued prior to training, the players displayed a 2.6% decrement in average intensity (p = 0.02), 2.8% decrement in absolute (p = 0.01) and 5.0% decrement in relative (p = 0.01) maximal activity, as well as 13.3% decrement in absolute (p < 0.01) and 6.8% decrement in relative (p < 0.01) supramaximal activity when compared to not being fatigued. These findings suggest that residual neuromuscular fatigue influences players' ability to perform supramaximal activity, which highlights the importance of monitoring neuromuscular performance throughout a professional season.Highlights Residual neuromuscular fatigue can influence the amount of supramaximal activity players perform in a subsequent training session or match.Practices should be implemented to minimise residual neuromuscular fatigue carried into matches while maintaining a sufficient training volume to elicit physiological adaptations.MARG sensors can be used as an affordable and time-efficient tool for regularly monitoring countermovement jump-derived neuromuscular fatigue.

The assessment of the chronotropic response during acute physical exertion can allow the discovery of many cardiovascular diseases even at a young age. However, the increase in heart rate (HR) depends on the age and sex of the subject and the modality of the graded exercise test. This study aims to provide sex- and age-related normative values for heart rate performance in young athletes aged 10-18. A retrospective study was carried out on 7896 young athletes (5356 males and 2540 females) aged between 10 and 18 who underwent pre-participation screening to obtain eligibility for competitive sport. First, anthropometric parameters, performance data, and HR are reported. Thus, each age calculated third, tenth, twenty-fifth, fiftieth, seventy-fifth, ninetieth, and ninety-seventh percentiles for the stage-by-stage HR response, according to sex and graded exercise test modality category. Young female athletes of all ages showed lower performance with fewer stages performed on the cycle ergometer and the treadmill. Young male athletes on treadmill and cycle ergometers show lower HR values at submaximal intensities. The treadmill allows a longer duration than the cycle ergometer for males and females. Sex, age, and the specificity of the movement performed must be considered in assessing the chronotropic response in the young population, particularly for those who carry out a training program. In addition, providing reference values of HR response to acute physical exertion may allow for a better functional assessment of the young athletes.HighlightsGrowth and physical training induce continuous changes in the cardiovascular system. However, each young athlete shows individual features. The chronotropic response to incremental load is a common method for assessing health and fitness.Comparing the heart rate data obtained from the incremental effort with the reference percentiles can provide information in a short time in the evaluation of young athletes and the general youth population. Therefore, this methodology is regularly performed in the evaluation of anthropometric growth.In evaluating the chronotropic response to physical exertion, in addition to age and sex, should take the specificity of the movement performed during the test into account.