The optimization of descending motor commands from the central nervous system is essential for maximizing performance during short-distance running. Recent studies have shown that transcranial direct current stimulation (tDCS) can modulate central nervous system excitability and enhance exercise performance. Additionally, plyometric exercise is known to enhance instantaneous motor performance. However, the combined effects of tDCS and plyometric exercise remain poorly understood. Therefore, we investigated the combined effects of anodal tDCS and plyometric conditioning exercises on short-distance sprint running. Eleven university athletes were asked to perform a 20-meter sprint test both before (pre-test) and after tDCS (post-test). Before the pre-test, the participants engaged in jogging, stretching, and incremental 20-meter sprint exercises. After the pre-test, anodal tDCS was applied to the cortical leg area. Following tDCS, plyometric hopping exercises were performed, and a post-test was conducted. The intensity and duration of the stimulation were 2 mA and 15 min, respectively. Sham stimulations were performed on different days using the same experimental procedure. The post-test time was significantly shorter than the pre-test time in both the anodal and sham tDCS conditions. Further, the improvement rate in the post-test was significantly higher in the anodal tDCS condition than in the sham tDCS condition. These findings indicate that combined anodal tDCS and prior plyometric exercise can optimize descending motor commands and peripheral motor function, thereby improving short-sprint running performance.

Falls after total knee arthroplasty are common in knee osteoarthritis patients due to advanced age and implant-induced sensory function changes. We reported the influence of toe grip strength on falls in knee osteoarthritis patients. This study aimed to determine whether toe grip strength training after total knee arthroplasty is related to screening assessment and incidence of falls. Elderly patients undergoing unilateral total knee arthroplasty were divided into toe grip strength training group and control group. Six types of training were conducted on bilateral toes. The primary outcomes were changes in toe grip strength and timed up and go test (TUG) time from pre-intervention to 12 weeks post-intervention. Secondary outcomes involved several factors, including the occurrence of falls. The analysis included 37 participants in both groups. The toe grip strength training group had a shorter timed up and go test (TUG) and stronger bilateral toe grip strength than control group. The changes in timed up and go test time were significantly correlated with the changes of toe grip strength on the affected side. There were significantly fewer falls in the toe grip strength training group than in control group between 3 and 12 months after total knee arthroplasty. Toe grip strength training was useful in improving walking ability and preventing falls in postoperative total knee arthroplasty patients. The advantage of toe grip strength training is that it is non-invasive (a muscle function not requiring an operation), so the intervention can be conducted safely without specialist supervision unless the toes are impaired.

This study investigated the changes in the physical activity of Japanese breast cancer survivors during and after the state of emergency declaration (SOED) due to the spread of COVID-19. Participants were survivors of stage I-IIa breast cancer diagnosed between the ages of 18 and 60 years who wore a wearable device (Fitbit Versa) before and after the SOED period. Outcomes included steps per day on weekdays and weekend days and holidays, sedentary time, and time spent engaged in various levels of physical activity. Seventeen participants were included in the analysis. Steps per day decreased significantly from 8450 ± 905 steps before the SOED to 6085 ± 526 steps during, and 6871 ± 776 steps after the SOED on weekdays (p < 0.05). No difference in sedentary time was observed before, during or after the SOED period on weekdays or weekend days, or holidays. Time spent engaged in light physical activity was significantly shorter on weekdays, decreasing from 251 ± 15 minutes before the SOED to 216 ± 15 minutes during, and 223 ± 16 minutes after the SOED (p < 0.05). Time spent engaged in moderate to vigorous physical activity was significantly shorter on weekdays before the SOED at 154 ± 39 minutes, dropping to 101 ± 29 minutes during, and increasing to 136 ± 38 minutes after the SOED (p < 0.05). It was concluded that participants spent less time engaged in all levels of physical activity on weekdays during the SOED. Therefore, during lockdowns, it is important to maintain higher intensities of physical activity on weekdays. Because steps and time spent engaged in light physical activity did not recover after the SOED period, breast cancer survivors need to focus on these parameters after lockdowns while also paying attention to infection prevention.

Few studies have compared the impact characteristics of modern American football helmet types. The purpose of this study was to measure and compare the collision biomechanics of the common Vicis Zero1 (2.27 kg) and Riddell Speedflex (2.09 kg) helmets. Linear drop tests were conducted from 1.52, 1.98, 2.59, and 3.05 m with a Hybrid III headform. The helmets were positioned crown-down and dropped in a manner that resulted in minimal pre-collision rotation. An 8-camera motion capture system recording at 300 Hz was used to verify that contact occurred to the region of the helmet immediately superior to the top of the facemask for each trial. Impact kinetics were recorded via a force plate sampling at 1800 Hz. Peak and mean accelerations (g) were calculated from initial contact until peak vertical ground reaction force (VGRF) was reached. Independent t-tests and effect sizes (Hedge’s g) were performed. The Speedflex helmet resulted in greater peak VGRF, peak acceleration, and mean acceleration (p = 0.045, <0.001, and <0.001, respectively). Effect sizes were medium for VGRF (0.73) and large for peak (48.07) and mean (2.28) accelerations. These data indicate that the Zero1 helmet, which has a compliant outer shell, may lead to greater athlete safety by resulting in peak forces and accelerations of less magnitude as compared to helmets with rigid shell designs.