How much does lower body strength impact Paralympic running performance?

Objectives: Development of evidence-based methods of Paralympic classification requires research quantifying the relative strength of association between ratio-scaled measures of impairment and athletic performance. The purpose of this study was to quantify the extent to which muscle strength affects running performance in runners with and without brain impairment. Design: Cross-sectional study. Methods: Participants were 41 male runners: 13 with brain impairments (RBI) and 28 non-disabled (NDR). All participants completed a maximal 60-m sprint and a novel battery of three lower limb isometric strength tests. Results: RBI showed significantly lower strength scores compared with NDR on the more affected side in leg flexion (176 vs. 243N), leg extension (993 vs. 1661N) and plantarflexion (824 vs. 1457N). Significant differences were also seen on the less affected side in plantarflexion (1072 vs. 1508N). RBI were significantly slower in the acceleration phase (0-15m) (3.2s +/- 0.3vs. 2.8s +/- 0.2) and top speed phase (30-60m) (4.3s +/- 0.6vs. 3.8s +/- 0.3). Correlation analysis showed stronger relationships between strength and running performance in RBI than NDR; however, the correlations were not significant. Conclusions: This study evaluated measures to assess strength for the purposes of classification and found that the measures were significantly different in RBI compared with NDR indicating the tests were able to capture strength impairment in this population. This study indicates that strength may be an important impairment type to assess in this population, as impairments of muscle strength may influence the outcome of running performance in athletes with more severe impairments.