Abstract
Monitoring neuromuscular fatigue in collegiate athletes is challenging because force plate testing produces numerous biomechanical variables that are difficult to interpret collectively. PURPOSE: To develop the CMJ Overuse Risk Index (CORI), a composite measure of countermovement jump (CMJ) performance, and preliminarily evaluate its ability to characterize longitudinal neuromuscular changes among Division I female soccer athletes. METHODS: Twenty-eight athletes participated in CMJ testing (three jumps averaged per session) using VALD ForceDecks from July 30 through October 6, 2026 (IRB #2113291-7). Across 20 testing dates, 234 test records represented 230 unique athlete-days. Six phase-specific variables were examined: modified reactive strength index (RSI-mod), eccentric peak force, force at zero velocity, concentric impulse, peak landing force, and concentric impulse asymmetry, with relevant force measures normalized to body mass. Within-athlete correlations assessed redundancy. CORI combined RSI-mod, concentric impulse, and force at zero velocity, standardized to each athlete's first three testing days and weighted using principal component analysis of reference data. Change in asymmetry magnitude was evaluated separately using a four-quadrant monitoring framework. RESULTS: Twenty-six athletes had at least four testing days, contributing 150 post-reference athlete-days. Force at zero velocity and eccentric peak force were highly correlated within athletes (r=0.995), supporting exclusion of one redundant measure. The three retained performance variables shared substantial variation, with the first principal component explaining approximately 82% of reference-data variance. The quadrant framework characterized combinations of increased or decreased CORI and asymmetry relative to individual reference values. CONCLUSION: CORI consolidates related CMJ performance characteristics into a single individualized monitoring metric. Preliminary application demonstrated feasibility for characterizing athlete-specific trajectories, while asymmetry provided complementary mechanical context. Validation against training exposure, wellness, and injury outcomes is needed before CORI can be interpreted as an indicator of fatigue or overuse risk.
Recommended Citation
Fischer, William; Brady, Travis; Marmor, Alyson; Amitrano, Joseph; Whitney, Hayley; and Seshadri, Dhruv
(2026)
"Development and Preliminary Longitudinal Evaluation of a Composite Countermovement Jump Index in Division I Female Soccer Athletes,"
International Journal of Exercise Science: Conference Proceedings: Vol. 15:
Iss.
9, Article 4.
Available at:
https://digitalcommons.wku.edu/ijesab/vol15/iss9/4