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Objective: Skeletal muscle function is vital for preventing injury during exercise. It has been reported that skeletal muscle function fluctuates with the menstrual cycle and is considered one of the causes of injury. This study aimed to clarify the relationship between muscle flexibility and muscle contraction characteristics and their changes with the menstrual cycle. Methods: The subjects were healthy women who voluntarily participated in the study through recruitment posters. Muscle flexibility was measured with the passive knee extension (PKE) test, isokinetic knee flexor strength, and the maximum muscle strength exertion angle under two conditions of 60°/s and 120°/s in dominant hamstrings. Additionally, their correlations were analyzed and compared between the menstrual and ovulatory phases. Results: Sixteen subjects (mean age: 20.56 ± 0.73 years; body mass index: 20.21 ± 1.60) participated in the study. Correlation analysis showed a significant negative correlation between PKE and the maximum muscle strength exertion angle under the condition of 60°/s during the menstrual phase (r = –0.54; p = 0.03). No significant difference was observed in the two-group comparison of the variables measured during the menstrual and ovulatory phases. Conclusion: This study confirmed that the more flexible muscles generate the maximum strength at a more contracted position during the menstrual phase in women. In the future, it is necessary to examine the relationship between the results of this study and exercise performance and injury occurrence.

Muscle architectural parameters play a crucial role in the rate of force development, strength, and sports performance. On the other hand, deteriorated muscle architectural parameters are associated with injuries, sarcopenia, mortality, falls, and fragility. With the development of technology, exergames have emerged as a complementary tool for physical therapy programs. The PRISMA 2020 statement was followed during the systematic review and meta-analysis. CENTRAL, CINAHL, PROQUEST, PubMed, and OpenGrey databases were searched last time on 22 September 2021. In total, five controlled trials were included in the systematic review. Twelve weeks of virtual dance exercise (Dance Central game for Xbox 360®) showed a medium effect on the improvement of hamstrings (g = 0.55, 95% CI (−0.03, 1.14), I2 = 0%) and the quadriceps femoris muscle cross-sectional area (g = 0.58, 95% CI (0.1, 1.00), I2 = 0%) in community-dwelling older women. Additionally, a four-week virtual balance-training program (the ProKin System) led to significant increments in the cross-sectional areas of individual paraspinal muscles (14.55–46.81%). However, previously investigated exergame programs did not show any medium or large effects on the architectural parameters of the medial gastrocnemius muscle in community-dwelling older women. Distinct exergame programs can be used as a complementary therapy for different prevention and rehabilitation programs.

In wheelchair basketball, the performance of a player is not only determined by his/her physical ability but also depending on the settings of the wheelchair such as the height and/or angle of its seat and the size and/or position of its wheels. However, these wheelchair settings are based on the rules of thumb of players and instructors, and there are no specific guidelines or rules regarding the settings of wheelchair according to the physical characteristics and/or types of disabilities of the athletes. This study, therefore, aims to provide the suggestions to improve the performance of the athletes by analyzing the wheelchair starting actions in comparison to the top players with the highest ability of wheelchair operation. We propose the method to measure the detailed behaviors of players during starting actions from video footages. Through the experimental verification, we successfully retrieved the detailed behaviors of players and wheelchairs. We also confirmed it is possible to measure the difference in the behaviors among multiple participants and different wheelchair settings, respectively.

Boccia is one of sports designed for the disabled. In boccia, to propel balls to the target, throwing, rolling, kicking and using tools such as a ramp are permitted. Therefore, a wide range of people with or without disabilities can participate in the game. However, at present, boccia games are classified according to the degree of disability. It is difficult that people with severe disability and people without disability participate in the same game together. Therefore, in this study, we propose “RoBoccia”, boccia using robotic throwing device that is shared by players and is connectable with various interfaces. We provided the robotic throwing device and an operational interface to operate it. In addition, we developed a throwing support interface using laser pointers to present the estimated lobbing and rolling distances to the operator intuitively. Finally, we verified the usefulness of the developed robot by carrying out the field experiments.