Identifying the Effects of Sex on Reactive Strength Scores using Receiver Operating Characteristic (ROC) Curves: 1848 Board #109 May 31 3

Receiver operating characteristic curves are used as a technique to evaluate the sensitivity and specificity of a continuous variable to discrete, categorical variables. It is known that post-pubescent females tend to diverge from males in neuromuscular performance. Measures of reactive strength attempt to model lower extremity neuromuscular reactivity in agile movement tasks. It is likely that constructing ROC curves would reveal that reactive strength scores are sensitive and specific to the effects of sex on neuromuscular reactivity. PURPOSE: The purpose of this study was to construct ROC curves to evaluate the sensitivity and specificity of the Reactive Strength Kinetic (RSK), Reactive Strength Index (RSI), and the Coefficient of Reactivity (CoR) to the effects of sex on neuromuscular reactivity. METHODS: Fifty-nine young adults from the general community and 21 NCAA Division I basketball players performed depth jumps from heights of 0.51 m, 0.66 m, and 0.81 m. The RSK, RSI, and CoR were computed using tri-axial force platform data and two-dimensional videography. Multiple paired t-tests, Cohen’s d effect sizes, and ROC curve analysis were used evaluate sex differences and the extent that reactive strength scores are sensitive and specific to sex (α=0.05). RESULTS: RSK, RSI, and CoR scores were greater in males versus females across all depth jump conditions (p < 0.000 - 0.002). ROC areas under the curve were larger for CoR (0.78 - 0.87) versus RSI (0.73 - 0.77) and RSK (0.69 - 0.77) across all three depth jump heights. Average sensitivity of all measures was largest in the 0.81 m condition (0.80 versus 0.73 (0.66 m) and 0.76 (0.51 m)). CONCLUSION: Results suggest that all measures evaluated in this study were sensitive to differences in neuromuscular reactivity across sexes. ROC analyses suggested that the CoR may be the most sensitive measure of sex effects on lower extremity neuromuscular reactivity in depth jumping. Additional research using higher depth heights may confirm this. Additionally, the CoR is a field-test that may be easy to implement by strength and conditioning and clinical professionals.