Dynamic strength index (DSI) is an indicator showing the relationship between an athlete`s relative strength and power production capacity. This metric is calculated by dividing the peak propulsive force of an athletes` countermovement vertical jump (CMVJ) by the peak force generated during an isometric mid-thigh pull (IMTP). The resulting ratio shows whether an athlete is relatively more strength- or power-dominant, with some researchers suggesting that scores between 0.6 - 0.8 represent athletes with a well-balanced lower-body strength and power profile. However, there have been no published studies reporting cross-sectional or longitudinal DSI data in collegiate Olympic weightlifters. PURPOSE: To characterize DSI scores and evaluate longitudinal changes in DSI and its constituent variables in collegiate Olympic weightlifters. METHODS: Male (n = 10) and female (n = 12) collegiate Olympic weightlifters performed three trials each of CMVJ and IMTP once per week during the final eight-week peaking period prior to a major national competition. All tests occurred following a 12h abstention from exercise and a standardized warmup. Mixed effects models with random intercept for subject ID were computed to identify week-to-week differences in DSI, CMVJ, and IMTP performance (a = 0.05). Cohen`s d effect sizes were calculated comparing between each week and baseline. RESULTS: Mean DSI across the entire testing period was 0.725 ± 0.133. Significant changes in CMVJ peak propulsive force (p = 0.057), IMTP peak force (p = 0.066), and DSI (p = 0.855) were not detected throughout the testing period. Effect sizes showing the magnitude of changes in IMTP and CMVJ compared to Week 1 were negligible (d < 0.10). Effect sizes were slightly larger for between-week comparisons in DSI, which decreased from baseline in Weeks 3 (d = 0.21), 5 (d = 0.19), and 7 (d = 0.22). CONCLUSION: The average DSI for collegiate Olympic weightlifters fell within the ideal range hypothesized by previous investigators (0.6 - 0.8). DSI and its component variables did not significantly change across the eight-week period, although small magnitudes of between-week change were detected. These results suggest practitioners can perform less frequent DSI tests and still capture a relevant strength and power profile of their athletes.
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