Muscle strength and leg asymmetries in elite runners and cyclists.

Background: Bilateral strength imbalance in the lower extremities has been studied in several sports as well as cycling and running. However, there has been little investigation of the differences in muscle strength and leg asymmetries in vertical jump between elite runners and cyclists. Research question: The primary purpose of this investigation was to determine the differences in vertical jump capacity between elite athletes (runners and cyclists). A secondary purpose was to describe single leg vertical jump capacity and leg asymmetries in elite athletes. Type of study: The evaluation sessions consisted of a different vertical jump tests. Methods: 27 elite male endurance athletes (endurance runners and road cyclists) performed a countermovement jump (CMJ), single leg CMJ, arm swing CMJ and a 10 s repeat jump (RJ) test. Results: The runners had a significantly greater (p < 0.01) jump performance in the double leg CMJ (19%), arm swing CMJ (27%) and RJ (16%) compared with cyclists. Similarly, single leg vertical jump performance was significantly better in runners compared with cyclists both with reference to the right leg CMJ (13.4%, p < 0.05), left leg CMJ (15.5%, p < 0.05), dominant leg CMJ (12.6%, p < 0.05) and non-dominant leg CMJ (16.4%, p < 0.01). Significant differences between dominant leg CMJ and non-dominant leg CMJ performance in jump height (leg asymmetry 5.5%) and power production (leg asymmetry 6.5%) were found in the runners' group. In the cyclists' group, significant differences were also found between dominant leg CMJ and non-dominant leg CMJ jump height (leg asymmetry 9.7%) and power production (leg asymmetry 14.6%). Conclusions: The present study demonstrated a markedly higher single and double leg vertical jump capacity in elite endurance runners compared with professional road cyclists. [ABSTRACT FROM AUTHOR]