Strength, Flexibility, And Balance Asymmetries In Adolescent Long- and Short-track Speed Skaters

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Both long- (400m) and short-track (111.12m) speed skating are a racing competition on ice but their skating mechanics are different, especially on curves. Hence, skating types may have bilateral asymmetries in the lower extremity. PURPOSE: To examine bilateral asymmetries of strength, flexibility, and balance in the lower-extremity in long- and short-track speed skaters. METHODS: Adolescent long- (n=18) and short-track (n=20) speed skaters (age: 17.6±3.0 yrs; career: 9.1±3.8 yrs) underwent measurements of strength on a dynamometer (sampling rate: 100 Hz), joint flexibility using a smartphone goniometer, and one-leg balance using a digital balance system. To test strength, subjects performed maximal voluntary isometric contractions for 5s (knee extension at 60°, hip flexion/extension at 45°, and hip adduction/abduction at 15°). Sampled data from 2s through 4s were averaged, then normalised by each subject’s body mass (N·m/kg). For joint flexibility, end points of completed active range of motion were measured (ankle dorsi-/plantar-flexion, knee flexion, hip flexion/extension, and hip adduction/abduction). To test balance, Fall Risk Screening Programme was used for 20s. Three successful trials on both sides were recorded and averaged to quantify each measurement. To test bilateral symmetries across skating type, we performed 2×2 mixed model ANOVAs. RESULTS: We did not find any significant difference in all strength tests. Regardless of skating type, subjects had 3.9° less in the left side compared to the right side in hip abduction flexibility (48.4° vs. 52.3°; F1,36=6.65; p<0.01). Short-track speed skaters showed 2.5° greater hip adduction (23.3° vs. 20.8°; p<0.05) but 7.5° less hip abduction (45.3° vs. 52.8°; p<0.01) on the left side. Regardless of skating type, subjects had a better balance score on the left side compared to the right side (0.79 vs. 1.15; F1,36=15.66; p<0.001). CONCLUSION: Skating mechanics on curves are thought to cause bilateral differences in balance and hip joint flexibility which should be addressed when training and conditioning speed skaters. Future studies should attempt to test the relationship between the asymmetries and performance. Supported by the National Research Foundation of Korea funded by the Ministry of Science, ICT, and Future Planning (NRF-2014M3C1B1033324)