Mechanical parameters as predictors of performance in alpine World Cup slalom racing.

The aims of the present study were to develop a method for classifying slalom skiing performance and to examine differences in mechanical parameters. Eighteen elite skiers were recorded with three-dimensional kinematical measurements and thereafter divided into a higher (HP) and lower performance group, using the ratio between the difference in mechanical energy divided by the mass of the skier and section entrance velocity (Δe(mech)/v(in)). Moreover, the skiers' velocity (v), acceleration (a), center of mass turn radii (R(CM)) and skis' turn radii (R(AMS)), ground reaction forces (GRF) and differential specific mechanical energy [diff(e(mech))] were calculated. v and diff(e(mech)) were different between the performance groups (P<0.001 and <0.05), while no inter-group differences in R(CM), R(AMS), a and GRF were observed. A relationship between R(AMS) and diff(e(mech)) was demonstrated (r=0.58; P<0.001). The highest GRFs were related to the lowest diff(e(mech)) and a was related to GRF (r=-0.60; P<0.001). The Δe(mech)/v(in) predicted the performance over short course sections. The HP skiers skied with a higher v and a similar range of diff(e(mech)). We suggest that shortest R(AMS) and the highest GRFs should be reduced in elite slalom in order to increase performance.