No abstract

This study was conducted to determine and compare the kinetics during step forward lunge (SFL) and jump forward lunge (JFL) in badminton. Fifteen university badminton players (mean age = 22.07 ± 1.39 years old) were recruited and were assigned to perform SFL and JFL while holding a badminton racquet using their dominant hand. For both dominant and non-dominant leg, all the force variables during JFL were significantly higher compared to SFL. Results also showed that time to peak force and stance time was significantly shorter during SFL compared to JFL. Besides that, all the forces variables were greater in the dominant limb compared to the non-dominant limb. Time to peak force and stance time were also shorter in dominant limb compared to the non-dominant limb. To conclude, coaches and athletes need to be aware of the mechanical demands during both lunge method and the assymetries that exist in terms of force production between both sites of limbs.

This paper focuses on current harmonics mitigation at the Permanent magnet Synchronous Generator (PMSG) wind turbine system using a Variable Frequency Active Power Filter (VF-APF) harmonic mitigation technique. Mitigation of current harmonics in the PMSG reduces harmonic losses, thus reducing the heating effect on the PMSG cause by the current harmonic components and extends the lifespan of the PMSG. The current harmonics in the wind turbine system is mainly caused by non-linear loading effect from the AC-DC converter in the Wind Energy Conversion System (WECS). Therefore, to filter current harmonics component in the PMSG, a conventional fixed frequency grid connected 3-phase-shunt APF is applied to compensate the current harmonics in the WECS PMSG generator. The conventional APF is coupled with a phaselock-loop (PLL) synchronizer to facilitate variable frequency functionality. The simulation results shown in this paper is conducted at PMSG WECS maximum power point conditions.The demonstrated results show that the designed VF-APF successfully mitigates the PMSG current harmonic over a wide range of wind speed.

This study was conducted to examine the lower limb kinematics during roundhouse kick in MuayThai. Fifteen MuayThai novices (mean age = 21.52 ± 1.09 years old) with 2-3 months experiences in MuayThai training were recruited and were asked to perform roundhouse kick for each side of legs (dominant and non-dominant). Joint angles and velocity between the dominant and non-dominant lower limb were compared during both strikes. Dominant lower limb were shown to have greater hip flexion velocity, knee flexion velocity, ankle upward and lateral velocity compared to the non-dominant lower limb. Results demonstrated the asymmetries between dominant and non-dominant sides of lower limbs existed during roundhouse kick among novices in MuayThai.

This study was conducted to determine the effect of different stance-width; i) narrow, ii) shoulder and iii) wide, on muscle activation and performance during Romanian deadlift (RDL) exercise. Thirty recreationally resistance trained men aged of 19-23 years old (22.20±1.13) were involved in this study. The participants need to perform RDL with 80% of their 1RM in three sessions with three difference stances in randomized order. To measure the muscle activation level during performing the exercise, the electromyogram (EMG) marker was placed on vastus lateralis, biceps femoris, gluteus maximus and multifidus muscles. The number of repetitions completed during each sets was recorded as indicator for performance. The mean EMG value during concentric and eccentric movement along with the number of repetitions completed were analysed using one way repeated measure analysis of variances (ANOVA). The result showed no significant differences were found on EMG reading of vastus lateralis and bicep femoris during eccentric and concentric phase of RDL when three different stances were used. However, when wide stances were used, a significant difference was observed on gluteus maximus whilst significant differences on multifidus were obviously seen when narrow stance were used. Higher number of repetition completed was significantly found when wide and shoulder width stances were used compared to narrow stance. The results of this study revealed the importance to choose correct stance width (depending on training objective) while performing RDL due to its effects on the muscle activation and performance.