Journal of Human Kinetics最新文献

This study aimed to present an updated version of VO₂FITTING software, where it is possible to dynamically edit, process, filter and model $\dot{V}$ O₂ post-exercise data and to characterize the $\dot{V}$ O₂ on/off symmetry along different exercise intensity domains. Validation datasets were developed and applied to four widely used models for describing low, moderate, heavy and severe intensity transitions. Perfect fits were observed and parameter estimates perfectly matched the known inputted values for all available models (standard error = 0; p < 0.001). In addition, an experiment with 10 trained swimmers performing a 5 x 200 m front crawl protocol (with 0.05 m•s^-1 velocity step increments and 3-min passive rest intervals) was conducted. The on- and off-transient phases were symmetrical in their shape since they were both adequately fitted by a mono-exponential regression model and no slow component was observed independently of the intensity domain. Furthermore, the mono-exponential model without time delay best fitted the $\dot{V}$ O₂ off-transient data. The mean time constant of the on-transient period value was lower than the respective off-transient for all the intensities (15.8 ± 11.4 vs. 30.8 ± 10.4, 11.3 ± 2.3 vs. 29.7 ± 8.4, 13.9 ± 7.0 vs. 28.7 ± 10.8 and 10.3 ± 4.6 vs. 37.0 ± 9.2 s; p < 0.05). VO₂FITTING is valid, free and open-source software for characterizing $\dot{V}$ O₂ kinetics during both the exercise and recovery periods, helping researchers to give rapid feedback also about the off-transient kinetic parameters.

This study investigated the relationship between force-power-velocity (F-P-V) mechanical variables measured during the ballistic bench press throw (BPT), shoulder isokinetic rotation strength, and the throwing velocity in handball players. Twenty-seven experienced male handball players (age: 20.0 ± 3.2 yrs, body height: 180.5 ± 6.3 cm, body mass: 73.9 ± 7.9 kg) volunteered for the investigation. F-P-V mechanical variables (i.e., theoretical maximal force [F0], velocity [V0], power [P_max]) were obtained during the single-arm BPT and an isokinetic shoulder isokinetic internal rotation test. Throwing performance was assessed for the standing and 3-step throwing velocity. Participants were divided into a "High/Fast" and a "Low/Slow" group considering their throwing performance based on a median split analysis. A strong correlation was found between V₀ obtained from the BPT and maximal throwing velocity for standing throwing (r² = 0.51, f² = 1.04) and three-step throwing (r² = 0.46, f² = 0.85). At the same time, P_max obtained from the BPT had a weak association with three-step throwing performance (r² = 0.18, f² = 0.22). Furthermore, no significant correlation was found between all the mechanical variables obtained from the isokinetic rotation and throwing performance (all p-values > 0.05). The High/Fast group showed that only V₀ and P_max obtained from the ballistic BPT had a small to moderate effect size (ES [0.06 0.23]) compared to the Low/Slow group. This finding indicates the importance of measuring the upper limb F-P-V profile obtained from the BPT in predicting throwing performance. Thus, training programs should focus on F-P-V mechanical properties to design specific training methods to optimize throwing performance in handball players.

This study aimed to 1) investigate and compare physiological and neuromuscular fatigue after a 3-min lateral shuffle movement (LSM) at different speeds and distances, and 2) examine the relationship between the number of changes of direction (CODs) during LSM and fatigue-related variables. Twenty male college athletes (age: 20.9 ± 1.7 yrs, body mass: 72.8 ± 8.6 kg, body height: 177.9 ± 5.6 cm; mean ± SD) performed six LSM protocols at two speeds (1.8 and 2.0 m/s) and three distances (2.5, 5 and 10 m) in random order and on separate days. The heart rate (HR), blood lactate (BLa) concentration, the rating of perceived exertion (RPE) and the countermovement jump (CMJ) were assessed and recorded before and immediately after exercise. Neuromuscular fatigue was assessed with the decline in CMJ performance (CMJ_decline). Results showed no interaction effect (speed*distance) for all variables. The distance was a significant factor influencing the HR (F = 12.663, p = 0.000, η_p ² = 0.25), BLa concentration (F = 15.357, p = 0.000, η_p ² = 0.288), CMJ_decline (F = 19.496, p = 0.000, η_p ² = 0.339), and the RPE (F = 20.149, p = 0.000, η_p ² = 0.347). Speed was also a significant factor influencing the HR (F = 6.367, p = 0.016, η_p ² = 0.144), BLa concentration (F = 10.292, p = 0.000, η_p ² = 0.213), CMJ_decline (F = 9.014, p = 0.005, η_p ² = 0.192), and the RPE (F = 9.539, p = 0.004, η_p ² = 0.201). CODs displayed moderate correlations with BLa concentration (r = 0.331, p < 0.001), CMJ_decline (r = -0.415, p < 0.001), and the RPE (r = 0.318, p < 0.001). These results suggest that physiological and neuromuscular fatigue would be greater with higher speed and shorter distance of LSM.

The goal of this research was to evaluate whether there are relationships between parenting styles, mental toughness, and sportsmanship in athletes. The sample was made up of 201 Spanish adolescent athletes (Mage = 15.30; SD = 1.82; 110 men and 91 women) who completed the Child-Parental Acceptance-Rejection Questionnaire, the Mental Toughness Inventory, and the Spanish version of the Multidimensional Sportsmanship Questionnaire. Structural equation modeling was used to examine the relationships among the studied variables. The results revealed that maternal and paternal love/affection significantly positively predicted mental toughness. Likewise, the results showed that paternal hostility/aggression and indifference/neglect significantly positively predicted fair play. In conclusion, given the connection between perceived parental education, psychological variables (mental toughness), and sports ethics principles (sportsmanship) of athletes, programs that train athletes' cognitive and axiological skills should not ignore the parental role. Hence, an attempt could be made to encourage athletes to compete when feeling mentally strong and respecting the ethical values of sportsmanship.

Ischemic preconditioning (IPC) is a promising strategy to enhance athletic performance and recovery by improving local muscle oxygen saturation. This study aimed to investigate the effects of different IPC protocols on muscle oxygenation in physically active healthy men. Thirty-four subjects were randomized into three groups and underwent four occlusion cycles of duration of three (IPC-3), five (IPC-5) or seven (IPC-7) min in only one limb. Near-infrared spectroscopy was used to assess oxygenated and deoxygenated hemoglobin levels, calculating total hemoglobin and oxygen saturation percentage (TSI%). Results showed significant improvements in muscle oxygenation following IPC, with variations in minimum, peak, and mean values across protocols. IPC-5 demonstrated the most consistent enhancements in oxygen saturation levels, with statistically significant differences observed in TSI% values during occlusion and reperfusion phases compared to IPC-3 (p < 0.05) and IPC-7 (p < 0.05), without supercompensation of TSI% during reperfusion phases compared to baseline. Specifically, IPC-5 induced the greatest increase in oxygenation in the contralateral limb compared to IPC-3 and IPC-7. These findings suggest that IPC, particularly the five-min protocol, effectively enhances local muscle oxygenation in non-occluded limbs, which may contribute to improved athletic performance and recovery, mainly under conditions where the exercise or testing does not directly involve cuffed limbs.

This study aimed to (1) assess the test-retest reliability and sensitivity of kinematic and kinetic metrics from 5-m, 10-m, and 20-m horizontal deceleration ability (HDA) tests; (2) explore the relationships of those metrics from HDA5m, HDA10m and HDA20m tests. Eighteen college athletes completed one familiarization session and two test sessions separated by 48 hours. Test sessions consisted of three 5-m, 10-m, and two 20-m maximal sprints, along with HDA tests conducted at the same sprinting distances. The deceleration-related metrics measured from HDA5m, HDA10m and HDA20m tests showed good-to-excellent overall reliability (ICC > 0.75, CV < 5.81%) and were efficiently sensitive in detecting moderate changes in deceleration performance (SEM < SWC0.5), except for the DTS and TTS of the HDA20m test (ICC: 0.44-0.57, CV: 5.15-6.37%, SEM > SWC0.5). DTS and TTS of the HDA5m test showed non-significant and small to moderate relationships with the HDA10m and HDA20m tests, while all kinetic metrics displayed significant and large to very large correlations among three tests. This suggests that short-distance HDA tests are reliable and sensitive for assessing deceleration performance, and further research is needed to explore the biomechanical and physiological factors influencing this unique ability.

This study aimed to assess the validity of three commercial devices in recording mean velocity (MV) and peak velocity (PV) during a unilateral resistance exercise. Eighteen strength-trained and healthy males performed repetitions of Bulgarian split squats at loads ranging from 40% to 90% of their one-repetition maximum. MV and PV were simultaneously recorded by GymAware, PUSH, My Lift and compared to Vicon for all repetitions. Concurrent validity was assessed through a linear mixed model, as well as mean difference (MD), mean absolute error (MAE) and Hedge's g effect sizes. GymAware was found to be valid in MV (MD = -0.02 to -0.01 m/s, MAE = 0.02 to 0.03 m/s, g = -0.08 to -0.19) and PV (MD = 0.01 to 0.05 m/s, MAE = 0.05 to 0.07 m/s, g = -0.06 to -0.22) recordings. Significant differences were identified between GymAware, PUSH, My Lift and Vicon for both MV (p < 0.01) and PV (p < 0.01) assessments. Moreover, when comparing MV and PV recorded by PUSH and My Lift to Vicon, larger MD and MAE, and trivial to moderate effects were also evident. Therefore, our findings suggest that GymAware could be an alternative for recording MV and PV during unilateral resistance exercises.

Resistance training has been shown to be a stressor factor on the autonomic nervous system, and these changes can be detected by heart rate variability (HRV) analysis. The aim of the present study was to evaluate the delayed effects of velocity loss-based resistance training strategies on heart rate variability (HRV), the sleep quality index (SQI) and delayed onset muscle soreness (DOMS). Fourteen men performed daily recordings. After a baseline period of 14 days of no training, they performed one session per week of resistance training focused on lower body exercise (squats) based on movement velocity. Three resistance training sessions composed of four sets up to 10%, 20% and 40% of velocity loss were performed each week of the study. Statistically significant changes (p < 0.05) after 24 hours of training were found in DOMS, and HRV variables, specifically in RR intervals (RR), root mean square of successive differences of RR intervals (RMSSD), and the percentage of successive RR intervals that differed by more than 50 ms (pNN50), between 40% of velocity movement loss and the rest of conditions. We can conclude that greater losses of execution velocity may result in greater internal load stimuli according to the autonomic modulation measured by HRV. RR, RMSSD and pNN50 seem to be the most sensitive indicators of HRV to fatigue produced by resistance training. This research opens the door to the study of HRV behavior related to resistance training. New research possibilities are raised by measuring the effect of guiding resistance training by means of HRV behavior.

The objective of this study was to evaluate the impact of augmenting the foot area (by wearing fins) on the load-velocity relationship of the underwater dolphin kick (UDK) and to investigate the optimal loading zone of resistance training for the UDK. Seventeen swimmers underwent a semi-tethered swimming test and a 15-m maximum swim velocity test, both with and without fins (FINS and WF, respectively). The study revealed that the UDK's load-velocity relationship, when using semi-tethered swimming, displayed a robust linear correlation (R² = 0.88 ± 0.15). The FINS condition enhanced the optimization of the load-velocity relationship, resulting in a substantial rightward shift (R², AIC, BIC optimized by 15%-65%) and elevating the UDK velocity by 10%-22% across seven load levels. The effective load level rose from 57 N to 69 N (R = 0.70-0.85, p < 0.05); however, the FINS condition altered the original UDK technique, leading to a 7% decrease in the stroke rate (SR) and a 19% increase in stroke length (SL). Consequently, wearing fins modified the load-velocity relationship of the UDK and augmented the power output level. We recommend that athletes use semi-traction swimming to improve UDK performance with a maximum load of no more than 57 N or a velocity of no less than 73% of maximum velocity; wearing fins allows this range to be extended to 69 N and 71% of maximum velocity.

The purpose of this study was to compare the effects of on-court tennis training (OTT) combined with high-intensity interval training (HIIT) or repeated sprint training (RST) on the physiological, kinematic, kinetic, and perceptual responses of young tennis players. Twenty-four male tennis players (age 13.6 ± 0.3 years) were randomly assigned to either the OTT + HIIT group (n = 12) or the OTT + RST group (n = 12) three times per week for six weeks. Both groups trained for the same total training time with passive rest in each session. A number of physiological, performance and perceptual responses were measured before and after the 6-week training intervention. All variables showed a significant improvement over time, with maximal oxygen uptake showing the greatest improvement (p < 0.001, η² = 0.97). The 5-m sprint (p = 0.044, η² = 0.17), repeated sprint ability (p = 0.021, η² = 0.22), and T-drill agility (p = 0.048, η² = 0.17) showed a significant group effect. The OTT + RST group had a lower internal training load (better scores), a lower rate of perceived exertion (better scores), and higher scores in the Physical Activity Enjoyment Scale (PACES) at both times compared to the OTT + HITT group. These results demonstrate that OTT + RST appears to be a more effective training approach to improve speed and agility-based performance responses with more enjoyment in young tennis players.