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Musculoskeletal stiffness during hopping and running does not change following downhill backwards walking

journal contribution
posted on 01.09.2014, 00:00 authored by Corey W Joseph, Liz BradshawLiz Bradshaw, Justin Kemp, Ross A Clark
Eccentric contractions that provide spring energy can also cause muscle damage. The aim of this study was to explore leg and vertical stiffness following muscle damage induced by an eccentric exercise protocol. Twenty active males completed 60 minutes of backward-walking on a treadmill at 0.67 m/s and a gradient of - 8.5° to induce muscle damage. Tests were performed immediately before; immediately post; and 24, 48, and 168 hours post eccentric exercise. Tests included running at 3.35 m/s and hopping at 2.2 Hz using single- and double-legged actions. Leg and vertical stiffness were measured from kinetic and kinematic data, and electromyography (EMG) of five muscles of the preferred limb were recorded during hopping. Increases in pain scores (over 37%) occurred post-exercise and 24 and 48 hours later (p < 0.001). A 7% decrease in maximal voluntary contraction occurred immediately post-exercise (p = 0.019). Changes in knee kinematics during single-legged hopping were observed 168 hours post (p < 0.05). No significant changes were observed in EMG, creatine kinase activity, leg, or vertical stiffness. Results indicate that knee mechanics may be altered to maintain consistent levels of leg and vertical stiffness when eccentric exercise-induced muscle damage is present in the lower legs.

History

Journal

Sports biomechanics

Volume

13

Issue

3

Pagination

241 - 258

Publisher

Taylor & Francis

Location

Abingdon, Eng.

ISSN

1476-3141

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2014, Taylor & Francis