Kinematics variations of gait from two 5 Km cross-country races

We have analysed the kinematics of gait during the same 5-km cross-country race run in two consecutive years. The aim of this study was to determine that these patterns of running gait are robust in a race situation across a variety of standards of athlete and in different climatic conditions. Video footage was recorded for eight (2001) and thirteen (2002) competitors running on a hard surfaced section of the course that was 500 m (lap 1) and 3000 m (lap2) from the start. Average race speed (ARS) was calculated for the entire race, instantaneous velocity (IV), stride rate (SR) and step length (SL) were measured using Silicon CoachPro TM software for video analyses. ARS of runners sampled in the 2002 race was 13% faster (p 0.05) than that recorded in 2001. IV of running for lap 1 was 11% (2001) and 15% (2002) faster (p 0.05) than for lap 2. Consistent with this finding, SL was significantly longer (9 % in 2001; 7 % in 2002), for lap 1 than for lap 2, (p 0.05) but stride rates were similar between laps for both years. These data suggest that running velocity changes may be accounted for principally by a decrease in step length that is similar for runners of different standards, consistent over time and relatively unaffected by climatic conditions.