The effect of an inclined landing surface on biomechanical variables during a jumping task
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The role of exercising muscle length in the protective adaptation to a single bout of eccentric exercise
by
McHugh MP, Pasiakos S.
—
last modified
2009-10-09 15:16
Eur J Appl Physiol. 2004 Dec;93(3):286-93.
The purpose of this study was to determine if the protective adaptation to a
single bout of eccentric exercise (repeated bout effect) is dependent on the
muscle length at which the eccentric contractions are performed. Ten subjects
(six men, four women) performed two bouts of 120 isokinetic eccentric
contractions separated by 2 weeks (target intensity was 90% of maximum isometric
strength at 70 degrees). In the initial bout one limb exercised from 30 degrees
to 70 degrees of knee flexion (short initial bout; SIB) and the contralateral
limb exercised from 70 degrees to 110 degrees (long initial bout; LIB). For the
repeated bout 2 weeks later, the limb that initially exercised at a short length
now exercised at a long length (long repeated bout; LRB) and the limb that
initially exercised at a long length now exercised at a short length (short
repeated bout; SRB). Isometric strength and pain (scale 0-10) were assessed
immediately post exercise and on the next 3 days. Strength loss and pain were
greater following LIB versus SIB (strength loss P < 0.01; pain P < 0.001) and
following LRB versus SRB (strength loss P < 0.01; pain P < 0.001). Strength loss
and pain were not different between LIB and LRB. Pain was significantly greater
following SIB compared with SRB (P < 0.05). Strength loss was not different
between SIB and SRB. These results confirm that the symptoms of muscle damage are
highly dependent on exercising muscle length and also demonstrate that the
repeated bout effect is dependent on muscle length. Performing an initial bout of
eccentric exercise at a shortened muscle length did not protect against strength
loss and pain following a repeated bout at a longer muscle length. Data are given
as mean (SE) unless otherwise stated.