We studied 16 women 21-23 years old with regular menstrual cycles (28±4 days) and no history of knee injury. From their basal body temperatures and the serum concentrations of estradiol and progesterone, the follicular, ovulatory, and luteal phases were delineated. Using a KT-2000 arthrometer, anterior displacement at 89 N and 134 N and anterior terminal stiffness (N/mm) at 134 N were measured two or three times every week over a 4-week period. Eight men 21-23 years old were also measured. In women the anterior displacement at 89 N varied between the follicular and the ovulatory phase and between the follicular and the luteal phase (P<0.05) and at 134 N between the follicular and the luteal phase (P<0.05). There were no statistical differences in the anterior displacement with time in men, nor in anterior terminal stiffness in either sex. We conclude that anterior cruciate ligament laxity in women might be dependent on the concentrations of hormones. et à 134 N entre la phase folliculaire et lutéale (p<0,05). Il n'y avait pas de différences statistiques dans le déplace-ment antérieur chez les hommes, ni dans la raideur terminale antérieure dans l'un et l'autre sexe. Nous concluons que la laxité du ligament croisé antérieur chez la femme peut être dépendante des concentrations hormonales. Résumé

Psychological distress caused by decreased physical activity (PA) is a growing concern among the elderly due to public health measures since the coronavirus disease (COVID-19). We aimed to (1) assess how public health restrictions impact PA, subjective well-being (SWB), and health-related quality of life (HRQoL) of community-dwelling elderly, and (2) investigate risk factors that lead to a decline in PA. Self-administered questionnaires assessed the changes in PA, SWB, HRQoL. Multivariate logistic regression analysis was performed to identify significant associated risk factors for decreased PA. Of 165 participants (valid response rate, 41.3%; mean age, 78.5 ± 8.0 years), 47.3% became less active, 23.0% became more active, and 29.7% maintained PA levels. There was a significant decrease in SWB at baseline and follow-up after COVID-19 restrictions in the less active group (p < 0.01). Higher levels of moderate or strenuous exercise/sports activity at baseline (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.01–1.24), and lower mental component HRQoL scores at baseline (OR, 0.96; 95% CI, 0.93–0.99) were associated with an increased risk of decreased PA. Public health restrictions impact the PA of the elderly, especially those who had higher levels of exercise/sports activity and lower HRQoL before COVID-19. Decreased PA was strongly associated with lower SWB.

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This research received no external funding. Acknowledgments:We would like to thank Toshihide Seto and Sachiko Okuda in the Department of General Affairs and staff in the Department of Rehabilitation for their great contribution to the mailing of the questionnaire and the compilation of the survey data.