Author(s): MURATOMI, K., FURUHASHI, Y., USHIROOKA, N., TANIGAWA, S., MAEMURA, H., Institution: UNIVERSITY OF TSUKUBA, Country: JAPAN, Abstract-ID: 494

INTRODUCTION:
Unlike the short sprint, in the 400 m race it is well known that the body cannot complete the event at maximum effort. This compels even the elite athlete to compromise in the areas of speed and energy expenditure. Reis and Miguel [1] found that the 400 m performance improvement was matched by significant decreases in the oxygen uptake during the run. Mann and Murphy [2] reported that the most successful long sprinter is the one who is able to produce the most economical mechanics performance. However, few studies have examined in detail changes in metabolic and mechanical variables within individuals. Therefore, the aim of this study was to assess metabolic and mechanical energy costs during a supramaximal running test and to comprehensively examine the components that determine to improved performance in long sprinters.
METHODS:
Five trained 400 m or 400 m hurdles runners performed a supramaximal constant load test for 50 seconds on a treadmill (ORK-7000, Ohtake Root Kogyo, Japan). During the constant load were determined the metabolic responses (i.e., gas exchange and blood lactate) to estimate the energetic contribution. The mechanical variables were calculated by the kinematic responses. The test was conducted two times for all participants, and the two tests were classified into high-performance condition (HPC) and low-performance condition (LPC) according to the result in most recent competition. The velocity was chosen based on mean velocity during 400 m run so that the participants could run for 50 seconds, and the same velocity was used in the two tests for each participant. A paired samples t-test was used to detect differences between the variable values in the two moments of assessment.
RESULTS:
The oxidative, glycolytic, and phosphagen metabolisms were no significant differences between HPC and LPC respectively. Additionally, there were no significant differences in stride parameters. However, whole body mechanical work per unit distance was significantly lower in HPC than in LPC.
CONCLUSION:
The findings suggest that the running technique of lower mechanical work per unit distance is an important component of long sprint performance.

1. Reis, V. M. and Miguel, P. P. (2007) Changes in the accumulated oxygen deficit and energy cost of running 400 metres. New Studies in Athletics, 22(2): 49-56.
2. Mann, R. V. and Murphy, A. (2022) The mechanics of sprinting and hurdling. CreateSpace Independent Publishing Platform.