Differences in Body Segment Energy Utilization between World-Class and Recreational Cross-Country Skiers

Abstract

Differences in the utilization of body segment movements between world-class and recreational cross-country skiers which result in a longer stride of the elite were studied using mechanical energy analyses. Nine world-class racers and six recreational skiers (novices) were filmed, the latter while they executed their fastest possible stable diagonal stride on a level track, and the former during competition. A 15-member linked segment model was digitized, the coordinate data filtered at 4.5 Hz and body segment energy curves; mechanical work output and mechanical energy transfers were calculated using the method described by Pierrynowski, Winter, and Norman (1980). The elite skiers exhibited larger exchanges between potential and kinetic energy in all segments during swing phases and all but the upper arm segment during pushing phases. Step-wise discriminant function analysis showed significant differences in the swinging foot, pushing foot, and pushing shank. The differences appear to be largely attributable to the higher leg swings of the experts, who prolong the glide and enhance step length, probably at a relatively lower metabolic cost by exploiting gravity to augment muscular force by generating pendulum-like movements.