The purpose of this study was to investigate the effects of transcranial magnetic stimulation (TMS) over the cerebellum on the triphasic electromyographic (EMG) pattern. Eight healthy subjects extended the left wrist as fast as possible in response to a start cue. TMS was delivered over the cerebellum 50 ms after the start cue. TMS over the cerebellum produced shortening of the latency in the first agonist burst, and an increase in the EMG activity of the antagonist burst. The triphasic EMG pattern may be partially under the control of the cerebellum.

Background Sports injuries are strongly associated with the impact loading at landing. The abilities to produce force and adjust timing are simultaneously required to absorb impact loading. Aims Hence, we aimed to examine the hypothesis that the ability to produce an explosive force at the right timing is related to the ability to absorb the impact loading at landing. Methods Twenty-nine healthy young men volunteered to participate in the study. We proposed a new test to measure the rate of force development (RFD) in accordance with the countdown signal. To evaluate the ability to produce explosive force at the right time, we measured the rate of change between the RFD at the standard start signal and the RFD at the countdown signal. Furthermore, to evaluate the ability to land from a jump, we measured the loading rate at single-leg drop landing (20 cm). Results We divided the participants into two groups based on the timing effect: the positive group (participants with increased RFD at the countdown signal, n = 11) and the negative group (participants with decreased RFD at the countdown signal, n = 18). The loading rate was significantly greater (P < .01) in the negative group (47.4 ± 11.2 body weight (BW)/s) than in the positive group (34.7 ± 7.1 BW/s). Conclusions Participants with increased RFD at the countdown signal had a lower loading rate at landing. Our results suggest that the ability to produce a timely explosive force may be a determinant of safe landing ability.

Background: Arch support has the effect of maintaining arch and correcting alignment, and it is broadly used for the prevention of sports impediment and treatment of athletes with lowered MLA and foot problems. The fact that the morphological change of MLA damages balance sense and postural control, it was reported that the insole supporting the arch of MLA improved postural balance. There are several studies regarding the effects of arch support; however, its effects on landing control have not been clarified. Therefore, in our research, we discussed the effect of MLA support for landing control, using lower limb dynamic alignment and the moment during landing as indexes. Methods: This study measured the landing motion to be evaluated was to jump from a platform with a height of 30 cm by taking-off with a single foot, and landing on a single foot on a floor reaction force gauge placed ahead and stay still for three seconds for the subjects were 13 healthy females. A soft 6 mm Boron sheet cut in the size of 9 × 3.5 cm, applied with double-sided tape (MLA pad) was used for arch support (hereafter referred to as "pad"). For the lower limb evaluation, an 8-camera with a three-dimensional behavioral analyzer (CORTEX, NAC product, sampling frequency: 120 Hz) and a floor reaction force gauge (AMTI product, sampling frequency: 1000 Hz) were used. Ten successful jump-landing tests for each limb were used for further analyses using Visual 3D software (Cmotion Inc., Kingston, Canada). Analysis objects were knee joint bending angle and valgus angle during landing; knee joint maximum bending angle; bending knee joint valgus angle, hip joint bending angle, adduction angle, ankle joint plantar flexion angle, varus angle at the time of knee joint maximum bending angle;

Background Sports injuries are strongly associated with the impact loading at landing. The ability to produce force and adjust the timing are simultaneously required for absorbing the impact loading. Aims Hence, we aimed to examine the hypothesis that the ability to produce explosive force at the right timing is related to the ability to absorb the impact loading at landing. Methods Twenty-nine healthy young men volunteered to participate in the study. We proposed a new test to measure the rate of force development (RFD) in accordance with the countdown signal. To evaluate the ability to produce explosive force at the right time, we measured the rate of change between the RFD at the standard start signal and the RFD at the countdown signal. Furthermore, to evaluate the ability to land from a jump, we measured the loading rate at single-leg drop landing (20 cm). Results We divided the participants into two groups based on the timing effect: the positive group (participants with increased RFD at the countdown signal, n = 11) and the negative group (participants with decreased RFD at the countdown signal, n = 18). The loading rate was significantly greater (P < .01) in the negative group (47.4 ± 11.2 body weight (BW)/s) than in the positive group (34.7 ± 7.1 BW/s). Conclusions Participants with increased RFD at the countdown signal had a lower loading rate at landing. Our results suggest that the ability to produce a timely explosive force may be a determinant of safe landing ability.