Weerawat Limroongreungrat

Objective: This study investigated the effects of hopping speed and distance on ankle joint moments, power, and muscle activation during repeated lateral hopping tasks. Methods: Twelve trained male athletes involved in team sports performed repeated lateral hop tasks at varying speeds (slow and fast) and hop widths (30 and 45 cm). Kinematics, kinetics, and muscle activation were recorded using ten optoelectronic cameras, two force platforms, and four channels of electromyography at the peroneus longus, tibialis anterior, lateral gastrocnemius, and soleus muscles. A two-way repeated-measures ANOVA assessed the effects of speed and distance, and secondary outcomes were adjusted for multiple comparison using the false discover rate procedure. Result: Hopping speed significantly influenced ankle joint moment (p < 0.05) and produced selective altered joint power and muscle activation (p < 0.05), while distance affected ankle joint moment and range of motion in the frontal plane (p < 0.05), but not muscle activation. Several of these effects remained significant after correction for multiple comparisons. A significant speed × distance interaction was observed for frontal plane peak ankle moment (p < 0.05). Conclusions: Hopping speed modulates ankle joint moment most consistently, with more variable changes in joint power and relative muscle activation, while distance manipulation selectively affects mechanical loading without altering muscle activation. Faster hopping increased ankle joint loading and altered relative muscle activation, while wider hopping distances could progressively load frontal plane structures. The results may inform progressive loading strategies for multidirectional sport training in healthy athletes, though clinical applicability remains to be confirmed.

This study aimed to investigate the relationship between the break-point angle (BPA) measured with the Nordic Angle app and absolute and relative eccentric knee flexion peak torques. Twenty-one male participants performed Nordic hamstring exercise (NHE) trials to determine their BPA, followed by absolute eccentric knee flexion strength testing. Absolute eccentric knee flexion peak torque was divided by body weight to calculate relative eccentric knee flexion peak torque. No Pearson correlation was observed between BPA and absolute eccentric knee flexion peak torque ( r _p = −0.05, p = 0.85). Conversely, the Pearson correlation between BPA and relative eccentric knee flexion peak torque was significant ( r _p = −0.54, p < 0.05). BPA measured with the Nordic Angle application was associated with relative eccentric knee flexor peak torque. As this study did not include a clinical population nor investigate hamstring injury incidence, clinical implications should be interpreted cautiously, and future research is required to determine whether BPA can predict hamstring injury risk.

Objective: This study aimed to investigate the effects of power and power endurance training on upper extremity muscle function and athletic performance in Thai wheelchair basketball (WB) athletes. Methods: Twenty-four WB athletes were divided into power (PO) and power endurance (PE) groups. All athletes were engaged in six weeks of upper extremities resistance training, twice weekly. The one-repetition maximum (1RM), maximum number of repetitions to failure (RTF) of the YMCA bench press test, prone bench pull (PBP) test, 20-metre sprint test, and maximal medicine ball throw were measured before and after. The PO training was at 70–80% of the 1RM, 5 sets of 4 repetitions, while the PE training was at 30–40% of the 1RM, 3 sets of 24 repetitions. The training load was set to increase by 5% of the 1RM every two weeks. Results: Bench press, shoulder press, lat pulldown, and shoulder internal and external rotation 1RM values all increased in PO training, while shoulder internal and external rotation 1RM values increased in PE training. The RTF for the PBP test was significantly improved in both groups. Only the PE training significantly improved the RTF for the YMCA bench press test. There was no statistically significant difference between groups on athletic performance after training. Conclusions: WB athletes benefit from power and power endurance training in a comparable manner to athletic performance. Power training significantly improves maximum strength, while power endurance significantly enhances muscular endurance, resulting in the ability to perform subsequent repetitive movements with adequate speed.

Nordic hamstring exercise (NHex) is well-known to reduce hamstring injury risk. However, the semitendinosus (ST) muscle is more activated than the biceps femoris long head (BFlh) muscle during NHex, though the BFlh muscle is more vulnerable to injury. It is important to investigate different NHex settings that may increase its effectiveness. This study aimed to examine the electromyographic (EMG) activity of the hamstring muscles and the break-point angle (BPA) during the NHex with the ankle joint positioned in plantar flexion (PF), dorsiflexion (DF) (neutral), and DF (neutral) with support. Twelve male volunteers without hamstring injuries in the four years preceding the experiment (age: 20.58 ± 0.9 years; body height: 171.1 ± 7.8 cm; body mass: 66.9 ± 12.2 kg) took part in the experiment. Participants randomly performed two sessions of the following exercise tests: NHex with ankle DF, NHex with ankle DF with sole support (DFS), and NHex with ankle PF. The EMG activity of the hamstring, BFlh, and ST muscles was measured for both the dominant and non-dominant limbs. The BPA was recorded using an IMU sensor. A repeated measures analysis of variance was conducted to assess hamstring muscle activity and the BPA. There was a significant main effect of EMG activity (p < 0.05) during the NHex under different ankle joint conditions for the BFlh in both the dominant and non-dominant legs. The findings indicated that EMG activity significantly increased during PF (p < 0.05) relative to DF and DFS for the BFlh in the dominant leg. Additionally, there were no significant differences in the BPA across different ankle positions (p > 0.05). This study demonstrated that the NHex elicited greater BFlh activity in PF than in DF and DFS.