The purpose of this investigation was to quantify the magnitude of change in maximal strength and jumping abilities over approximately one, two, and three years of supervised sport and resistance training in NCAA Division I women's volleyball athletes. This was an exploratory study on a cohort of women's volleyball athletes (n=29) split into three groups based on length of time spent in a supervised resistance training program: group 1 (n=11): 0.7+/-0.3 yrs, group 2 (n=9): 1.6+/-0.2 yrs, and group 3 (n=9): 2.4+/-0.6 yrs. Monitoring tests consisted of standing height (cm), body mass (kg), body fat (%), static (SJH) and countermovement jump heights (CMJH) with 0, 11, and 20kg loads (cm), and isometric mid-thigh clean pull peak force (IPF) and allometrically scaled peak force (IPFa) (N[middle dot]kg-0.67). Increasing trends were observed for all variable from groups 1 to 2 to 3. Statistically greater improvements (p<0.05) with moderate to large effect sizes were found between groups 1 and 3 for SJH 0 (19.7%, d=1.35), SJH 11 (23.8%, d=1.23), SJH 20 (30.6%, d=1.20), CMJH 11 (22.6%, d=1.18), IPF (44.4%, d=1.22,), and IPFa (41.2%, d=1.32). A combination of traditional resistance training exercises and weightlifting variations at various loads, in addition to volleyball practice, appear to be effective at increasing maximal strength by 44% and vertical jump height by 20-30% in NCAA Division I women's volleyball athletes after about two and half years of training. Furthermore, these characteristics can be improved in the absence of additional plyometric training outside of normal volleyball-specific practice.
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