Background Experiencing perimenstrual symptoms is a major health concern for young women. Women in the reproductive age experience menstruation about once a month, and many experience perimenstrual symptoms. Drug therapies such as painkillers (commonly used) and hormonal medications help to achieve symptomatic relief from perimenstrual symptoms. However, many women are concerned about tolerance and compliance of the drugs used to treat perimenstrual symptoms and lack awareness on how to cope with perimenstrual symptoms. If the association between exercise habits and the severity of symptoms is emphasized in young women, methods for coping with perimenstrual symptoms can be established, not relying only on pharmaceuticals. The objective of this study was to determine the differences in the severity of perimenstrual symptoms in young Japanese women with and without a regular exercise habit. Methods A cross-sectional study using an online survey was sent among 500 Japanese women aged 18–25 years. The severity of perimenstrual symptoms was assessed using the Menstrual Distress Questionnaire (MDQ). The differences in MDQ scores between those with and without exercise habits (exercise for more than 30 min for 2 days a week) were compared using the chi-square test and Mann–Whitney U test. The logistic regression analysis detected subscales of the premenstrual and menstrual symptoms affected by an exercise habit. Results 282 (56.4%) young Japanese women were answered this survey. Respondents were divided into the exercise group (n = 157) and the non-exercise group (n = 125). The exercise group had significantly low premenstrual and menstrual MDQ scores. The results of the logistic regression analysis stated that the subscale related to negative emotion before menstruation was associated with an exercise habit. In the analysis performed during menstruation, a statistically significant association was detected between an exercise habit and a behavioral change such as avoiding interaction with others. Conclusions This study suggested that exercise habits may reduce the severity of perimenstrual symptoms and could help to develop a non-pharmacological coping strategy. In addition, this study provides useful information for young women who want to prevent perimenstrual symptoms but do not have an exercise habit. Further, it may encourage young women to start exercising.

BACKGROUND: Intrinsic foot muscle (IFM) dysfunction and poor foot arch are associated with various foot conditions. Toe flexor exercise (TFE) has been used to improve it; however, the immediate effects of TFE on each IFM and how it relates to changes in navicular bone height (NH) are unclear. OBJECTIVE: This study aimed to investigate acute muscle swelling in the IFM after TFE and the association between changes in NH and IFM size. METHODS: Fourteen adults participated in this study. NH and cross-sectional area (CSA) of the IFM were acquired pre and post- TFE. The CSA of the IFM, including the abductor hallucis (AbH), flexor hallucis brevis, flexor digitorum brevis, and quadratus plantae, was acquired with ultrasonography. In the TFE, each participant completed five sets of eight repetitions with maximum strength. RESULTS: The NH and CSA of all IFM significantly increased significantly post-TFE (p< 0.01). Only the increase in AbH was moderately and positively correlated with the change in NH (r= 0.54, p< 0.01). CONCLUSION: This study suggests that the acute swelling of AbH after TFE is associated with an immediate increase in NH, supporting the important role of AbH in the formation of foot arch.

Background: Because the worldwide spread of coronavirus disease 2019 has forced a moratorium on student sports activity in Japan, reports on its impact on sports injuries are limited given its novelty. This study aimed to determine the characteristics and gender differences of injuries in adolescent athletes after returning to sport following restriction of club activities due to the coronavirus pandemic. Methods: An online retrospective questionnaire was distributed to 500 adolescent athletes who belong to school sports clubs in Japan from March 1-19, 2021. An anonymous questionnaire was created before and after the restriction of sports activities following the declaration of the first state of emergency of the COVID-19 pandemic in Japan. Subsequently, 258 valid responses were obtained, and injury-related characteristics were compared between injured and non-injured athletes after returning to sports and between genders for injured athletes. There were no differences in the body areas of sports injuries between males and females. Result: We found that injury experience before club activity restriction was significantly associated with injury after returning to sports (p < 0.001). Moreover, practice time increased before and after the restriction in the injury group (p = 0.038). The injury rate was higher in females (p < 0.024), and the trauma rate was higher among males (p = 0.016). There were no differences in the body areas of sports injuries between males and females. Conclusions: Our results provide gender-differentiated ideas and suggestions as they relate to injury prevention once in adolescent athletes returning to sports after the coronavirus disease 2019 induced restriction of club activities. We show the need for injury rehabilitation and practice time control in adolescent athletes in the coronavirus disease 2019 setting.

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BACKGROUND: Those undergoing pelvic floor muscle training (PFMT) often experience difficulty in perception; therefore, an easier PFMT method should be devised. OBJECTIVE: To determine the effectiveness of combining PFMT with either vibration stimulation or visual feedback provided by a branded cushion (not a prototype) in increasing PFM muscle activity. Since PFM does not involve large joint movements, muscle activity was a suitable indicator. METHODS: Twenty healthy adults were included in this study. All participants performed PFMT under three conditions using a branded cushion: vibration stimulation, visual feedback, and a control. All three conditions were provided separately. PFM activity of the midline of the perineum at two points was recorded as the root mean square measured using PFM electromyography, measured twice for each condition. Muscle activity ratio was obtained by calculating maximum voluntary contraction of PFM in pre- and post-PFMT conditions. RESULTS: PFM activity and muscle activity ratio were both significantly higher following PFMT under vibration stimulation and visual feedback conditions (p< 0.01, p< 0.01, respectively). CONCLUSIONS: PFMT accompanied by vibration stimulation or visual feedback could immediately raise PFM muscle activity. We believe this study contributes to improving PFMT efficiency by suggesting more suitable PFMT methods.