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 3-D kinematical measurements and thereafter divided into a higher (HP) and lower performance (LP) 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), centre 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 P < 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 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.