Upper Limb Isokinetic Muscle Strength Predicts the Performance in Cross-Country Sit-Skiing

Abstract

Understanding the physical fitness attributes in a sport-specific technical skill is a key to improve the action economy, and thus aerobic endurance performance. The present study was designed to investigate how upper limb muscle strength predicts double poling (DP) power performance in cross-country sit-skiing. A total of 19 female able-bodied college students (age 23.2±0.8 years, BMI 20.4±2.2) were subjected to a 30-s and 3-min DP performance tests using a sit-skiing ergometer. Isokinetic muscle strength by the angular velocity of 30 °/second, 60 °/second, and 120 °/second of the shoulder and elbow extensor/flexor were measured with an ISOMED2000 isokinetic system. A medium correlation was found between DP output power and isokinetic upper limb muscle strength (shoulder strength at all speed, r = 0.39-0.74, p < 0.1). Multiple regressions, which were employed to predict power production in the 30-s and 3-min tests, showed that shoulder extension strength at 60 °/second accounted for 34% of the variation in the 30-s test, and 40% of the variance in the 3-min test.