Min-Hao Hung

Backpacks are commonly worn by many people for multiple purposes. This study investigated the effects of habitual wearing of backpacks on lower limb kinematics and kinetics. Fourteen participants were recruited for analysis. All participants performed four randomly assigned scenarios, including running and walking at speeds of 3.5 and 1.5m/s, respectively, with and without load carriage. The motion analysis system and force plate were used to investigate the lower limb kinematics and kinetics. A paired sample t-test was performed for statistical measurement with a significance level of α.05. The results indicated that active force, breaking force, impact peak, loading rate, active peak, maximum braking, hip flexion, and hip range of motion were substantially higher under load carriage conditions than under walking condition, however, time to peak was lower. Conversely, during load carriage running, active force, braking impulse, time to peak, ankle plantarflexion, and ankle range of motion were all higher than those during running. Carrying a backpack weighing 10 of the body weight induced different foot strike patterns at both speeds; during load carriage walking, the hip tended to flex more; whereas, during load carriage running, the ankle tended to flex more. In conclusion, human body seems to adopt different gait strategies during load carriage walking and running. That is, the hip strategy is used during walking, while the ankle strategy is used during running.

The purpose of this study was to investigate the receiving ability and efficacy of volleyball players, which can be effectively improved after practicing with volleyballs of different weights. In this study, 36 elite male volleyball players were recruited and participated in a four-week training program in four groups: a lighter-ball training group (LBTG), a heavier-ball training group (HBTG), a normal-ball training group (NBTG), and a control group (CG). All subjects were required to evaluate their receiving ability during the initial training (week-0) and then to reevaluate it after two (week-2) and four (week-4) weeks of training. The statistical analysis revealed that the time factor (F_{2, 64} = 209.346, p < 0.001) and the time × group factor (F_{6, 64} = 17.463, p < 0.001) were significant but the group factor (F_{3, 32} = 0.340, p = 0.797) was not. The results revealed that the LBTG experienced a significant positive effect on the receiving test after four weeks of training, with an 8.6% improvement in skill performance after two weeks and a 16.4% improvement after four weeks. The HBTG, NBTG, and CG improved by 2.6%, 5.3%, and 3.8% after two weeks and by 6.3%, 9.3%, and 4.3% after four weeks, respectively. The main findings were that four weeks of volleyball training with a lighter ball resulted in significant improvements in player performance. In contrast, training with a ball with 70 g of added mass did not effectively enhance motor ability development.

The aim of this study was to examine the effects of different agility training methods on skill-related physical capabilities in young volleyball players. Twenty-seven young female volleyball players were randomly assigned to a shuttle-run training group (STG, n = 9), an agility-ladder training group (ATG, n = 9), and a control group (CG, n = 9). The intervention program was carried out three times a week for six weeks. Before and after the training period, participants’ 10 m sprint (10 MS), agility T-test, and digging agility test (DAT) performances were assessed. Within-group analysis showed significant improvements (p < 0.05) in the DAT, agility T-test, and 10 MS performance from pre- to post-test for the STG (6.08%, 2.64%, and 5.68%, respectively) and ATG (4.05%, 3.28%, and 3.27%, respectively). In the group analysis, there were significant differences (p < 0.05) between the STG and CG in the DAT and agility T-test. The STG and ATG were significantly superior to the CG in the 10 MS (p < 0.05). In conclusion, the results indicate that appropriate agility training can enhance the agility of lateral movements and speed of sprinting, as well as enable players to rapidly complete movements during a moving defense.

The purpose of this research was to study the effects of complex functional strength training (whole-body vibration + unstable surface training) on overall shooting performance, including the shooters’ stability of hold, time on target, and the body sway. We compared the shooters’ performances at three time intervals: (a) pretraining, (b) 6 weeks post-WBV+UST, and (c) 6 weeks detraining. The study participants were eight rifle shooters. Training was c on an unstable surface with vibration frequency of 30 Hz and amplitude of 2 mm. Six weeks after complex training, participants’ shooting performance and body sway significantly improved. Specifically, shooting scores and total time improved by 5.50% and 7.34%, respectively, as did the DevTotal values between performances at different times: 10 ms (p = 0.01), 20 ms (p = 0.04), 30 ms (p = 0.02), and 40 ms (p = 0.02). The DevY values also showed significant differences between performances at different times: 10 ms (p < 0.01), 20 ms (p < 0.01), 30 ms (p < 0.01), 40 ms (p < 0.01), and 50 ms (p < 0.01). A 6 week complex training method can effectively improve shooting stability, fluency, and scores.

In volleyball matches, there are three minute intervals between sets. Therefore, the improvement of the muscle output ratio is one of the most import foundational physical elements for the players. The purpose of this study was to investigate the effects of plyometric training on the changes in electrical signals in the lower limb muscles of male college volleyball players during continuous blocking and to examine the benefits of plyometric training on blocking agility and maximum vertical jump height. In this study, twenty elite male college volleyball players were recruited and divided into a plyometric training group (PTG) and a control group (CG). The wireless electromyography was used for data acquisition, and the electrodes were applied to the left and right rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius. The median frequency was used as the measurement of the electromyographic signals during the jumping blocks. This study used covariate analysis methods, with previously measured results used as covariates to perform a two-way analysis of covariance for the independent samples. Based on the results of this study, after 6 weeks of training, the median frequency of the rectus femoris (2.13% to 4.75% improved) and that of the tibialis anterior muscles (4.14% to 7.71% improved) were significantly lower in the PTG than in the CG. Additionally, the blocking agility increased by 6.26% and the maximum vertical jump height increased by 3.33% in the PTG compared to the CG. The findings provide important insights on the neuromuscular status for volleyball players during continuous blocking jumps. Six weeks of appropriate plyometric training can facilitate the performance of volleyball players.

Badminton atypical actions and hitting movements often occur during the game; therefore, many special footwork methods have been developed to facilitate the rapid movements required to hit the shuttlecock, including quick turning and jumping and quick directional change movements. Studies have shown that the majority of badminton sport injuries occur in the lower extremity joints of athletes. The purpose of this study was to investigate the influences of hitting motion and unanticipated hitting direction on landing mechanics after backhand lateral jump smashing and landing to analyze joint stiffness and torque changes in three lower extremity joints. Recruited sixteen badminton athletes.The capture frequency of the Vicon Motion System (300Hz), Kistler force platform (1500Hz) and Vicon Nexus Version 1.8.5 software were used simultaneously to capture the kinematic and kinetic parameter of backhand side lateral jump smash footwork. The swing actions were divided into two situations, shadow (footwork and racket swinging practice without targets) and hitting (footwork and stroke shuttlecock) actions, whereas the directions were divided into directional and non-directional. Two-way repeated measures ANOVA with the LSD correction was used to compare the differences among the four conditions. The significance level was set to a = 0.05. Results shown that, at the peak of torque, the ankle plantar flexion of the non-directional shadow (p < 0.05) were greater than that of directional shadow (p < 0.05); meantime, ankle torque change of non-directional shadow (p < 0.05) and directional hitting (p < 0.05) was lower than that of non-directional hitting, but the non-directional hitting was larger compared to non-directional shadow (p < 0.05) at the maximum vertical GRF. The hip extension at peak of torque of directional hitting were larger than that of non-directional shadow (p < 0.05). The shadow actions hip flexion angle was larger than that of directional hitting at initial contact, but the non-directional hitting hip abduction was has the significant difference among all the conditioning. The hip flexion angle of non-directional shadow was larger than that of directional hitting (p < 0.05), the hip abduction angle of the nondirectional hitting was greater than that of non-directional shadow (p < 0.05) at the peak VGRF. Elite badminton players execute different training movements; the joint stiffness was in the same state. In the hitting actions has greater ankle and hip joint torque than shadow actions. The badminton player was change joint range of motion to adjust lower limbs stiffness.