Gait & posture
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Gait variability has been correlated with fall risk in the elderly. Older adults typically display greater variability than young adults, but the cause of this increase is unclear. Slower walking leads to greater variability in young adults, but slow speeds are also typical in older adults. ⋯ Step length (p=0.005), stride time (p=0.018), and trunk pitch (p=0.022) exhibited similar trends. This greater variability was explained by decreased leg strength and passive ranges of motion. Thus, the greater variability observed in the gait of older adults may result more from loss of strength and flexibility than from their slower speeds.
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The activity of descending stairs increases loading at the joints of the lower extremities as compared to walking, which may cause discomfort and or difficulties in completing the task. This study compared and contrasted the kinematics and kinetics of both forwards and backwards stair descent to those of level walking. We compared the support moments and moment powers of the lower limb joints while descending stairs forwards at a self-selected pace, backwards at a self-selected pace and forwards at the same pace as backwards. ⋯ The hip moments during stair descent were relatively small and highly variable. We observed significantly larger distances between the centres of pressure and the stair edges for backwards stair descent versus forwards stair descent. These results demonstrate that stair descent, even at a slower pace, requires greater power from the knee extensors than level walking but that backwards stair descent significantly reduced the peak knee power during midstance and provided a potentially safer means of descending stairs than forwards stair descent.
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This study investigated the reliability and validity of the Visual Gait Assessment Scale when used by experienced and inexperienced observers. Four experienced and six inexperienced observers viewed videotaped footage of four children with hemiplegic cerebral palsy on two separate occasions. Validity of the Scale was obtained by comparison with three-dimensional gait analysis (3DGA). ⋯ The experienced observers had slightly higher agreement with 3DGA than the inexperienced observers. The inexperienced observers showed a learning effect and had higher inter-observer agreement and higher agreement with 3DGA in the second assessment of the videotapes. This scale can be used by inexperienced observers but is limited to observations in the sagittal plane and by poor reliability at the knee and hip for experienced and inexperienced observers.
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In walking faster than 3 km/h, transverse pelvic rotation lengthens the step ("pelvic step"). It is often assumed that the thorax then starts to counter rotate to limit total body angular momentum around the vertical. But the relative timing of pelvis and thorax rotation during gait is insufficiently understood. ⋯ Moreover, pelvic and thoracic contributions to total body angular momentum were low (less than 10%), while contributions of the legs and arms were much larger (approximately 90%), suggesting that pelvis-thorax coordination is relatively unimportant to the organisation of total body angular momentum. Taken together, these results may imply that our understanding of the pelvic step need to be changed. Moreover, the alterations in pelvis-thorax relative phase that were reported for different locomotor pathologies may depend on different mechanisms.
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Randomized Controlled Trial
An exploration of the function of the triceps surae during normal gait using functional electrical stimulation.
Gastrocnemius and soleus have a common tendon and both are active during stance phase, where they are thought to arrest and control tibial advance. Soleus is associated with the production of an extending moment at the knee. The two-joint gastrocnemius, which crosses the knee joint, will have an additional contribution to the knee flexors. ⋯ The actions of both muscles at the knee confirm published IAA predictions. In vivo evidence such as this gives greater confidence when using model predictions. The approach adopted in this study could eventually be extended to other muscles and patient populations.