Journal of Human Kinetics最新文献

This study aimed to investigate the effects of lower limb muscular asymmetry on the bilateral variations observed in high platform drop jumps, with a particular emphasis on the side-to-side differences in both the initial and secondary ground contacts during these jumps. Seventy-one students from the Physical Education department were selected to perform countermovement jumps. Participants were further classified into two groups, strength symmetry and strength asymmetry groups, based on the asymmetry strength index calculated from data collected via the force plates. Drop jumps were performed from three designated heights, i.e., 30 cm, 40 cm and 50 cm (DJ30, DJ40 and DJ50, respectively). The mixed design two-way ANOVA revealed notable differences between the stronger and weaker legs. Significant differences were observed in the timing of the peak vertical ground reaction force at the first ground contact of the DJ30 (p < 0.05) and in the shape factor of the push-off phase of the DJ40 (p < 0.05). The unilateral preference might lead to an increased risk of lower limb injuries. Prolonged training may exacerbate the degree of lower limb asymmetry. Potentially these findings can provide valuable suggestions for athletes and coaches in their training.

The objective of this research was to examine the impact of conventional breathing versus apnoea technique on acid-base equilibrium, physiological reactions, and performance throughout high-intensity interval training sessions in swimming. Two groups of sixteen athletes completed 6 x 50-m intervals of freestyle swimming with normal breathing and apnoea at maximum intensity, with a 1-min rest interval. Capillary blood gasses (pH, PCO₂, PO₂, HCO₃, Hct, Hb) were collected at four measurement time points: 1) at rest, 2) at rest just after the 3^rd repetition, 3) at finish, and 4) at the 10^th min of recovery. Measured variables included the heart rate (HR) during swimming, lactate (La) concentration and swimming time (t₅₀). Uncompensated metabolic acidosis, exhibiting greater prominence during apnoea, was attributed to heightened lactic acidosis under both breathing conditions. Despite experiencing bradycardia, swimmers demonstrated faster completion times during apnoea. In conclusion, during repeated high-intensity short-distance swimming, specifically 50 m of freestyle, apnoea enhances sprint performance without compensating for metabolic acidosis.

Orthorexia Nervosa, although not recognized as an official mental disorder, is a behavior characterized by a pathological focus on healthy eating. The purpose of the study was to assess the risk of Orthorexia Nervosa and attitudes toward one's own body among amateur and professional soccer players. The survey was administered among 137 male soccer players, both amateur and professional, from different Polish leagues. A mixed method survey (direct and electronic) was applied, using the Düsseldorfer Orthorexia Scale and the Body Esteem Scale to assess Orthorexia Nervosa risk and attitudes towards one's own body. The survey was administered between February and April 2024. The results showed that professional soccer players had higher satisfaction with their bodies compared to amateurs. Approximately 27% of the participants were at risk of Orthorexia Nervosa, regardless of their sports level. The analysis showed a weak but statistically significant correlation between the risk of Orthorexia Nervosa and scores on the upper body strength subscale. The results suggest that professional athletes may have a better relationship with their bodies, which may result from a more systematic and conscious approach to training and diet. At the same time, it is confirmed that Orthorexia Nervosa is present among soccer players. The study underscores the need for awareness of the risk of Orthorexia Nervosa among soccer players and points to the importance of support at both the amateur and professional levels.

Wearable technology for running analysis is growing in both sports science research and applied fields. This study examined the reliability of some spatiotemporal and kinetic variables estimated from an inertial measurement unit (IMU) fastened over the lumbar spine. Eighteen recreational endurance runners performed two maximal incremental treadmill running tests during a 7-10 day period under standard conditions. Contact time (CT), stride time (ST), stride length (SL), stride frequency (SF), as well as anteroposterior (AP) impulses and vertical (VT) peak brake data were analysed at 9, 15 and 21 km•h^-1. Test-retest reliability was measured as the intraclass correlation coefficient (ICC), the coefficient of variation (CV) and minimal detectable change (MDC). No significant differences between tests were observed (p > 0.05; effect size (ES) < 0.28; trivial to small). Reliability increased from 9 to 21 km•h^-1 (ICC from 0.88 to 0.93; ES = 1.0; moderate) and was higher in spatiotemporal (CV < 2.3%) than kinetic variables (CV < 6.8%). This study adds novel data regarding the reliability of the MTw IMU. The results reported in this study enable researchers to determine whether the changes in IMU-derived data are outside of the measurement error following training and rehabilitation settings.

Post-activation performance enhancement (PAPE) is a phenomenon that can enhance muscle performance following maximal or near-maximal muscle actions. While the effects of concentric and isometric conditioning actions on PAPE have been studied, less is known about the influence of eccentric muscle actions. This study investigated the effects of a multi-joint eccentric overload (EOL) protocol on PAPE expressed through countermovement jump (CMJ) height and isokinetic peak force (PF) outcome measures. Twenty-eight recreationally trained participants (18-30 years) completed three visits in a randomized, counterbalanced design. Following familiarization, participants performed either an EOL protocol involving two sets of six maximal isokinetic eccentric actions or a control condition (CON) involving cycling. The CMJ and PF were assessed at baseline and 15 s, 5 min, and 10 min post-exercise. Results showed no significant condition × time interaction or main effect of condition for either CMJ or PF (p > 0.05). However, a significant main effect of time (collapsed across condition) was observed for CMJ (p = 0.019), with post hoc analyses revealing a significantly higher CMJ at 5 min post-exercise compared to 15 s post-exercise (p = 0.037). These findings suggest that this multi-joint eccentric protocol did not effectively elicit PAPE, and therefore may not be optimal for inducing acute performance enhancement. Future research should further elucidate the optimal eccentric loading parameters and muscle action types for inducing PAPE.

Reactive agility is one of the most important skills in basketball. However, the question remains to what extent the sensory and motor components of agility contribute to specific performance in the game. This study investigated the relationship between indicators of game-specific performance and perceptual-cognitive and physical aspects of agility performance in youth skilled basketball players. A group of 16 basketball players (age 15.5 ± 0.9 years) performed visual perception tasks, divided attention tasks, simple and choice reaction tests, along with Y-shaped and Lane agility tests. Their specific game performance was evaluated using the game statistics analysis. The visual perception score significantly correlated with assists (r = 0.850, p = 0.000), game efficiency (r = 0.760, p = 0.001) and total points scored (r = 0.715, p = 0.003). Coefficients of determination showed that visual perception explained 72.3% of the variance in assists, 57.8% in game efficiency and 51.1% in total points scored. These findings indicate that specific game performance in basketball is not associated with sensory and physical aspects of agility skills in youth players. An exception is visual perception, which plays a significant role in their performance. Players with better visual perception are able to dish out more assists, are more efficient in the game and score more points overall.

This study aimed to explore the impact of playing experience on vertical release velocity (VV) and horizontal release velocity (HV) during mid- and long-distance jump shots, and the relationships among VV, HV, and the contraction intensity levels of primary muscles. The study utilized a cross-sectional experimental design, with 30 participants completing three effective jump shots at distances of 4.8 m and 6.75 m. Data were collected using a 3D motion capture system and an electromyography (EMG) recording system, with velocity-time data extracted to determine VV and HV, and EMG data analyzed using wavelet analysis. A two-factor mixed ANOVA was used to compare differences in VV and HV under different conditions, and Spearman correlation analysis was employed to explore relationships among VV, HV, and the energy values of major muscle frequency bands. The results indicated that playing experience significantly improved VV (p < 0.001). At mid-range distances, experienced athletes' VV positively correlated with the low frequency band (r = 0.479, p = 0.048) and near frequency band (r = 0.539, p = 0.038) energy values of the triceps brachii (TB), as well as the high frequency band (r = 0.679, p = 0.005) and mid-high frequency band (r = 0.571, p = 0.026) energy values of the anterior deltoid (AD). At long-range distances, VV negatively correlated with the low frequency band energy values of the flexor carpi radialis (r = -0.5, p = 0.045), the high frequency band of TB (r = -0.564, p = 0.028), and the near frequency band of AD (r = -0.496, p = 0.046). These findings suggest that playing experience significantly alters VV during jump shots, and this alteration may be associated with the overall activity of the TB, the explosive activity of the AD, and the baseline activity of the rectus femoris.

The study aimed (I) to quantify external and internal training loads during simulated 3x3 basketball games of 1, 2, 3, and 4 min, each followed by 1-min rest intervals; and (II) to assess the heart rate and muscle oxygen saturation recovery rates following, 1-, 2-, 3-, and 4-min periods of play. Twelve (n = 12) elite male 3x3 basketball players (age: 26.6 ± 5.6 years, body height: 196.8 ± 5.5 cm, body mass: 92.0 ± 9.5 kg, training experience: 15.4 ± 3.9 years, and 3x3 basketball training experience: 4.8 ± 1.6 years) from the Lithuanian national team participated in two controlled simulated games. Differences between playing intervals were analysed using a repeated-measures factorial analysis of variance. The results demonstrated that extended 3x3 basketball play duration led to significant increases in total distance covered, the sprint count, and the jump count, while diminishing dynamic responses in the deceleration rate, average speed, the jump rate, and high-intensity effort. Notably, SmO₂ levels exhibited stability during recovery intervals regardless of activity duration, whereas heart rate recovery improved markedly, particularly following extended play periods. This knowledge is instrumental in refining training protocols for 3x3 basketball, emphasizing the necessity of recovery strategies tailored to specific play duration.

The purposes of this study were to examine relationships between athlete self-report measures of wellness, mood, sleep, and performance indicators of a women's national basketball team during international competition (2023 FIBA Women's Asia Cup). Physical and psychological wellness were recorded using a cloud-based athlete management system, mood was assessed using the 24-item Brunel Mood Scale (BRUMS), and performance was evaluated by player self-assessment and the National Basketball Association's (NBA) player efficiency score. Wellness indicators were rated at or either side of a normal rating (i.e., 3 on a 1-5 scale), as was self-rated performance. Mean sleep duration was 8:13 hours (± 1:13), with large individual differences in retiring time and sleep duration. Mood scores showed a general pattern of declining tension and vigour over the 14-day assessment period. Mood subscales predicted 49.0% of variance in wellbeing scores, 46.8% of variance in preparedness scores, and 26.0% of variance in player efficiency scores. Wellbeing indicators predicted 34.9% of self-rated performance variance and mood subscale scores predicted 27.7% of variance. These findings suggest that female athletes may be particularly susceptible to mood disturbances impacting performance and highlight the potential for targeted interventions, including stress management and sleep optimization, to mitigate these stressors and support mental wellbeing. These strategies may enhance both psychological health and athletic performance during the high stress demands associated with international competition.

The primary purpose of this study was to identify exemplary basketball shooting mechanics to devise an effective and efficient training method for successful basketball shooting. Motion data of basketball shots by 10 recreational players and 10 college athletes at three different distances (3.2 m, 5 m, 6.8 m) were collected using 13 cameras (240 Hz). The present study quantified the upper extremity joint coordination using the vector-coded Coupled Angular Variability (CAV). Recreational players exhibited higher CAV at 6.8 m (Median P50 = 16.947), whereas college athletes exhibited higher CAV at 5 m (Median P50 = 18.487). The primary focus of arm coordination patterns was on shoulder joint coordination during the preparation phase, with higher coordination variability associated with greater shot accuracy. Recreational athletes straightened their shoulder and elbow joints simultaneously when performing a basketball shot. In contrast, collegiate athletes showed variations primarily resulting from proximal coordination patterns, leading to a larger range of motion (ROM) for elbow joint flexion and extension. This finding could fundamentally alter how shooting is practiced.