EFFECTIVENESS AND ECONOMY IN RUNNING
Keywords: effectiveness, running economy, training, 3D-kinematography
AbstractINTRODUCTION: The present study aims at the assessment of the effectiveness of running movements by a combination of approaches. For this purpose ‘inefficient mechanical work’ in the vertical and lateral directions was determined, as well as ‘conservation of mechanical energy’ by inter- and intra-segmental energy transfer. These parameters were related to total mechanical power, to physiological indicators of energy expenditure and to the state of physical training. METHODS: Ten untrained physical education students and 10 highly-trained runners (specialists) ran 2000m 3-5 times with different running speeds on a 200m indoor track. Before and after each 2000m-run their heart rate and blood lactate were recorded. In 4 subjects wearing a portable spirometer, O2 consumption and respiratory quotient were determined. One step cycle was filmed by two highspeed cameras (LOCAM) (150 frames/sec) in the 1., 9. and 10. round of each 2000m run. Three-dimensional coordinates of 21 points defining a 15-segment HANAVAN model were constructed using the DLT technique. The data were smoothed using a low pass filter with a cut-off frequency of 15 Hz. Mechanical power outputs were calculated by the changing of the translational, rotational and potential energy of each segment. The energy transfer within and between the segments was calculated using the method of Winter (1979). To describe the effectiveness of the running movement we calculated segmental work in lateral and vertical directions and energy transfer in relation to total mechanical power (Ptot). To determine the differences between students and specialists we computed a one-way analysis of variance (ANOVA) with running velocity as a covariate. RESULTS: Table 1 Group differences of physiological parameters, training and effectiveness mean ±std.-dev. [table] CONCLUSIONS: The results of this study indicate an inverse relationship between metabolic energy expenditure during running and the effectiveness of the running technique. The more economical running technique is characterized by a smaller transfer of segmental power in the vertical and transversal directions and a higher degree of inter- and intra-segmental energy transfer.
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