Article

OBJECTIVE: To examine the dynamic modulation of the soleus H-reflex while walking
with a posterior leaf spring ankle foot orthosis (PAFO). METHODS: Soleus
H-reflexes were evoked on randomly chosen lower limb of fourteen healthy
individuals (age range of 22-36 years, 7 women) while walking on a treadmill with
and without a PAFO. In order to capture excitability across the duration of the
gait cycle, H-reflexes were evoked at heel strike (HS), HS+100ms, HS+200ms,
HS+300ms, HS+400ms in the stance phase and at toe-off (TO), TO+100ms, TO+200ms,
TO+300ms, TO+400ms in the swing phase respectively. RESULTS: H-reflex
excitability was significantly higher in the form of greater slope of the rise in
H-reflex amplitude across the swing phase (p=0.024) and greater mean H-reflex
amplitude (p=0.014) in the swing phase of walking with a PAFO. There was no
change in the slope (p=0.25) or the mean amplitude of H-reflexes (p=0.22) in the
stance phase of walking with a PAFO. Mean background EMG activity between the two
walking conditions was not significantly different for both the tibialis anterior
(p=0.69) and soleus muscles (p=0.59). CONCLUSION: PAFO increased reflex
excitability in the swing phase of walking in healthy individuals. Altered
sensory input originating from joint, muscle and cutaneous receptors may be the
underlying mechanism for greater reflex excitability. The neurophysiological
effect of PAFOs on reflex modulation during walking needs to be tested in persons
with neurological injury. The relationship between the sensory input and the
reflex output during walking may assist in determining if there exists a
neurological disadvantage of using a compensatory device such as a PAFO.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS