Biomechanics of simulated versus natural cross-country sit skiing.

The purpose of this study was to investigate the biomechanics of cross-country sit-skiing in simulated and natural skiing. Thirteen international level athletes participated in a ski ergometer test (simulated conditions) and a test on snow in a ski-tunnel (natural conditions) using their personal sit-ski. Tests in both conditions were performed at individual maximal speed. When comparing the two conditions the main results were: (1) maximal speed in simulated conditions was lower (p<0.05) but correlated well with the natural condition (r=0.79, p<0.001); (2) no differences in pole force variables were found; peak force (r=0.77, p<0.01) and average force (r=0.78, p<0.01) correlated well; (3) recovery time and time to peak did not differ and time to impact correlated with each other (r=0.88, p<0.01); (4) no differences were found in peak electromyography (EMG) and average EMG for Triceps, Pectoralis, and Erector Spinae; Rectus Abdominis did not differ in peak. EMG peak and average EMG of all muscles were correlated between the two conditions (r=0.65-0.94; p<0.05-0.01). Although some differences were observed, this study demonstrated that technical skill proficiency in natural and simulated cross-country skiing is comparable from a force production and muscle activation perspective.