The effect of an inclined landing surface on biomechanical variables during a jumping task
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Effect of fatigue on single-leg hop landing biomechanics
by
Orishimo KF, Kremenic IJ.
—
last modified
2009-10-09 15:17
J Appl Biomech. 2006 Nov;22(4):245-54.
The objective of this study was to measure adaptations in landing strategy during
single-leg hops following thigh muscle fatigue. Kinetic, kinematic, and
electromyographic data were recorded as thirteen healthy male subjects performed
a single-leg hop in both the unfatigued and fatigued states. To sufficiently
fatigue the thigh muscles, subjects performed at least two sets of 50 step-ups.
Fatigue was assessed by measuring horizontal hopping ability following the
protocol. Joint motion and loading, as well as muscle activation patterns, were
compared between fatigued and unfatigued conditions. Fatigue significantly
increased knee motion (p = 0.012) and shifted the ankle into a more dorsiflexed
position (p = 0.029). Hip flexion was also reduced following fatigue (p = 0.042).
Peak extension moment tended to decrease at the knee and increase at the ankle
and hip (p = 0.014). Ankle plantar flexion moment at the time of peak total
support moment increased from 0.8 (N x m)/kg (SD, 0.6 [N x m]/kg) to 1.5 (N x
m)/kg (SD, 0.8 [N x m]/kg) (p = 0.006). Decreased knee moment and increased knee
flexion during landings following fatigue indicated that the control of knee
motion was compromised despite increased activation of the vastus medialis,
vastus lateralis, and rectus femoris (p = 0.014, p = 0.014, and p = 0.017,
respectively). Performance at the ankle increased to compensate for weakness in
the knee musculature and to maintain lower extremity stability during landing.
Investigating the biomechanical adaptations that occur in healthy subjects as a
result of muscle fatigue may give insight into the compensatory mechanisms and
loading patterns occurring in patients with knee pathology. Changes in single-leg
hop landing performance could be used to demonstrate functional improvement in
patients due to training or physical therapy.