European Journal of Applied Physiology

, Volume 111, Issue 1, pp 125–134

Changes in spring-mass model characteristics during repeated running sprints

  • Olivier Girard
  • Jean-Paul Micallef
  • Grégoire P. Millet
Original Article

DOI: 10.1007/s00421-010-1638-9

Cite this article as:
Girard, O., Micallef, JP. & Millet, G.P. Eur J Appl Physiol (2011) 111: 125. doi:10.1007/s00421-010-1638-9

Abstract

This study investigated fatigue-induced changes in spring-mass model characteristics during repeated running sprints. Sixteen active subjects performed 12 × 40 m sprints interspersed with 30 s of passive recovery. Vertical and anterior–posterior ground reaction forces were measured at 5–10 m and 30–35 m and used to determine spring-mass model characteristics. Contact (P < 0.001), flight (P < 0.05) and swing times (P < 0.001) together with braking, push-off and total stride durations (P < 0.001) lengthened across repetitions. Stride frequency (P < 0.001) and push-off forces (P < 0.05) decreased with fatigue, whereas stride length (P = 0.06), braking (P = 0.08) and peak vertical forces (P = 0.17) changes approached significance. Center of mass vertical displacement (P < 0.001) but not leg compression (P > 0.05) increased with time. As a result, vertical stiffness decreased (P < 0.001) from the first to the last repetition, whereas leg stiffness changes across sprint trials were not significant (P > 0.05). Changes in vertical stiffness were correlated (r > 0.7; P < 0.001) with changes in stride frequency. When compared to 5–10 m, most of ground reaction force-related parameters were higher (P < 0.05) at 30–35 m, whereas contact time, stride frequency, vertical and leg stiffness were lower (P < 0.05). Vertical stiffness deteriorates when 40 m run-based sprints are repeated, which alters impact parameters. Maintaining faster stride frequencies through retaining higher vertical stiffness is a prerequisite to improve performance during repeated sprinting.

Keywords

Repeated sprint abilityLeg spring behaviorMechanical stiffnessFatigue

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Olivier Girard
    • 1
  • Jean-Paul Micallef
    • 2
  • Grégoire P. Millet
    • 3
  1. 1.Research and Education CentreASPETAR, Qatar Orthopaedic and Sports Medicine HospitalDohaQatar
  2. 2.M2H, Faculty of Sport SciencesUniversity of Montpellier 1MontpellierFrance
  3. 3.ISSULUniversity of LausanneLausanneSwitzerland