EFFECTS OF A SUPRAMAXUMAL RUN TO EXHAUSTION ON RUNNING ECONOMY AND RUNNING KINEMATICS

Abstract

The purpose of this study was to quantify total intra-individual variability in running economy (RE), Stride kinematics after a supramaximal run to exhaustion in French elite 400m runners. Ten runners took part in this study. All subjects had been following a training program for a minimum of 4 years and were experienced treadmill runners. They were selected after a maximal protocol to be homogeneous on V 02 max (63,5 * 2,l ml.kg-l.min -1 ) and on the speed reached with V02max (Vmax: 19 km.h-I). After completing a 15 rnin accommodation run, each subject performed a submaximal run, 6 rnin in length and 0% grade at 75% Vmax (14,5km.h-1). Following this run subjects completed a supramaximal run to exhaustion at 22 km.h-1 and 7% grade according to the protocol described by Schnabel and Kindermann (1983). Half an hour and one hour after this run, each subject repeated the 6 min submaximal run. During supramaximal run physiological parameters were continuously recorded. During each submaximal run, physiological parameters were recorded during the last 3 rnin and subjects were filmed between the second and the third minute. Stride rate was continuously recorded by an impact monitor fixed on the runner's right shoe. Results of physiological impact of the supramaximal run were in accordance with those found by Schnabel and Kindermann (1983) with the same population. Mean time to exhaustion was 98,2 * 16 sec and mean post exercise blood lactate peak was 16,71 * 2,31. No significant differences were found, after the supamaximal test, in running economy (39,8 vs 39,6 ml.kg-l.min-1, P>.05), and most of the stride kinematics with exception with plantar flexion at toe-off ( 70,9 vs 65,7 deg, P<.005). Furthermore stability of stride phase recorded on 30 strides was the same after the test. (0,6 % vs 0,7%, P>.05). The results of this study are in agreement with the study of Morgan et al. (1990) for a 30 rnin maximal run and moderately trained runners. It demonstrates that acute fatigue following a suparamaximal run to exhaustion does not increase the oxygen cost of submaximal running or alter stride kinematics over the short terzn. These results indicate, for elite runners and after a supramaximal run, the general stability of metabolic and kinematics parameters during a submaximal run. Key Words. Running economy, Stride Kinematics, Variability, Running.