In-season resistance training intervention improves strength and power characteristics in academy freestyle freeski athletes – a quasi-experimental study

Resistance training (RT) is recognized for enhancing strength and power in athletes, yet its application and effects in freestyle freeski athletes remain underexplored. This study examined the impact of an in-season RT intervention on lower-body strength and power characteristics in freeski athletes. Twenty-four male athletes (mean ± SD; age 17.5 ± 1.3 years, height 177.2 ± 3.9 cm, mass 71.9 ± 4.4 kg) participated in a nonrandomized controlled study. Participants were assigned to two groups: 13 freeski athletes formed the RT group, 11 sports athletes served as historical control. A repetitions in reserve RT approach (including knee and hip dominant exercises) were performed twice per week. Assessments, CMJ height, drop jump (DJ) height, DJ contact time, reactive strength index (RSI), absolute peak force (PF abs ), and relative PF, were conducted pre-and post-intervention. Differences were analysed using repeated measures MANOVA Wilks’ lambda (Λ), magnitude of effect with partial-eta squared (ηp2), and pairwise comparisons with Cohen's d. Within-group pre-to-post changes were assessed using paired sample t-tests. A significant effect between timepoint and group was found (Wilks’ Λ=0.3, F(8,15) = 4.33, p < 0.007, ηp 2 =0.7), indicating changes over time (pre vs. post) differed significantly between the RT intervention and control groups. There was a significant main effect of group (Wilks’ Λ=0.4, F(8,15) = 2.65, p = 0.049, ηp 2 =0.6), highlighting differences across all dependent variables. Timepoint effect was significant (Wilks’ Λ=0.15, F(8,15) = 10.3, p < 0.001, ηp 2 =0.8), reflecting considerable changes across dependent variables. The RT group demonstrated significant improvements in all dependent variables (p < 0.05). A 10-week in-season RT intervention twice per week elicited significant improvements in lower-body strength and power characteristics in freeski athletes.