Isokinetic knee strength across physical activity levels: A gender-based comparison in young adults

Background While isokinetic knee strength profiles have been widely studied in athletes, data based on physical activity levels in young adult men and women remain limited. Objective This study aimed to determine knee isokinetic strength values according to physical activity level, with a focus on inactive (sedentary) individuals. Methods A total of 84 participants (42 females, 42 males) were divided three groups based on the International Physical Activity Questionnaire-Short Form (IPAQ-SF): inactive, minimally active, and active (12-15 per subgroup). Unilateral knee strength was assessed using isokinetic dynamometry at 60 degrees/s and 180 degrees/s. Two-way ANOVA was used to evaluate differences across groups, and gender comparisons were analysed using a t-test. Results Men demonstrated higher absolute strength values than women in all activity levels. In inactive and minimally active groups, there were no significant gender differences in extensor relative peak moment (PM/kg), peak work (PW/kg), or peak power (PPw/kg) (p > 0.05). However, flexor values showed significant gender differences (p < 0.05). In the active group, all relative strength values differed significantly between genders. Conclusion The absence of gender difference in extensor strength of inactive individuals suggests their use as a normative references for this cohort. Gender differences became more pronounced with increased physical activity.