Abstract
This study investigated the effects of a six-week strength training intervention on the physical fitness of female high school athletes, with a focus on training frequency. Twenty-three female high school basketball athletes were recruited and split into two groups: one group participated in strength training once per week (S1), while the other participated in two training sessions per week (S2). The groups were not random as training sessions were voluntary, and some participants were only able to train once per week. Participants were tested before and after the intervention, and the data included: age, body height, body mass, body fat percentage, grip strength, leg/back dynamometer (LBD) strength, a seated medicine ball throw (MBT), a vertical jump (VJ), 505 tests from each foot, 0–5, 0–10, and 0–20 sprint times, and multistage fitness test shuttles. Data were analyzed by a two (time) x two (group) repeated measures analysis of variance (ANOVA; p < 0.05). When significant F ratios were detected in any ANOVA calculations, post hoc pairwise comparisons were conducted using the Bonferroni adjustment procedure. There were significant main effects for time that indicated the following: increased body height, body mass, grip strength, LBD strength, MBT distance, and VJ height, faster 505 times, and slower 0–5 and 0–10 m sprint times (p ≤ 0.021). There were no significant time by group ANOVAs or between-group main effects. These performance changes occurred irrespective of training frequency. High school girls who participate in at least one strength training session per week can improve their strength (grip, LBD), power (MBT, VJ), and change-of-direction speed (505).