Asymmetry in strength training: Investigating the Impact of offset training on the deep stabilisation system, strength/performance, and maximal power in Female Softball Players

Purpose This study aims to fill a significant gap in sports science research by examining the underexplored effects of asymmetric load training on the deep stabilisation system (DSS), strength, and maximal power in female softball players. Methods Fourteen participants were divided into two groups: a control group (CON), which exercised with a symmetrically weighted bar, and an experimental group (EXP), which used a bar with asymmetrically distributed weight. The asymmetric load with a distribution of weight that was gradually increased during the 8-week intervention program. The assessment included a 1 repetition maximum (1RM) test for deadlift, flat bench press, front squat, and 4RM tests for single-leg leg press for both legs, along with evaluations of DSS and strength/performance, before and after a resistance training program. A two-way ANOVA was used to compare pre- and post-intervention performance on the DSS and 1RM strength tests. Results The results showed significant improvements in all 1RM and 4RM tests for both groups in all exercises (<i>p</i> > 0.001), with no significant differences between the groups (<i>p</i> < 0.05). However, a dependent <i>t</i>-test in the EXP group revealed significant improvements in DSS strength/performance from pre- to post-measurements in all tests, with large effect sizes. In contrast, the CON group showed significant improvements only in trunk extension, side plank, and prone tests. Conclusions These findings indicate that asymmetric training may provide superior benefits in strengthening the DSS, while still achieving comparable gains in maximal strength.