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Indexed/Abstracted in: Chemical Abstracts, CINAHL, Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 1,111
Online ISSN 1827-1928
EXERCISE PHYSIOLOGY AND BIOMECHANICS
Le Bris R. 1, Billat V. 2, Auvinet B. 1, Chaleil D. 3, Hamard L. 2, Barrey E. 4
1 Pégase-Mayenne Association, Hospital of Laval, France
2 Laboratory of Studies of the Exercise Physiology University of Evry, Evry, France
3 Service of Clinical Pharmacy Faculty of Pharmacy, Angers, France
4 INRA-Laboratory of Studies of the Exercise Physiology University of Evry, Evry, France
Aim. The purpose of this study was to analyze the continuous changes in stride patterns of athletes running at speed elicited V.O2max.
Methods. Six male sub-elite middle-distance runners carried out a constant track running test to exhaustion (time to exhaustion: 409±71 s) at their maximal aerobic speed (17.4±1.1 km.h-1). The body accelerations were measured with a triaxial accelerometer fixed at the low back. A set of variables was computed from the accelerometer output: stride frequency, stride symmetry and regularity, signal energies and impulses in each axis and the integral of the total acceleration vector. An ANOVA with repeated measures was performed to test the changes of these variables during the three times: the onset point, midway point and end point of exercise.
Results. The following changes were observed: the regularity index which describes the similarity of crania-caudal movements over successive strides, decreased significantly between the start and the end of the test (309.9 to 274.5; P<0.05). During the same time, the media-lateral impulse (4.69%BW.s to 5.71%BW.s; P<0.001; BW: body weight) and signal energy (1.40 G2.s to 2.06 G2.s; P<0.001; G=9.81 m.s-2) increased significantly.
Conclusion. The changes in medio-lateral axis (increase of energy expenditure which is not useful for propulsion) and in the regularity index (modifications in the temporal-spatial periodicity of the running cycle) could be considered as early alterations of running pattern when the athletes got fatigued.