Influence of Lower-Leg muscle spindle function in irregular surface walking

Walking is one of basic motion of human. However, walking has risk of falling accident. Falling accident is large problem for elderly people. One of the causes of falling for elderly people is reduced sensation. The purpose of this study was to investigate difference of walking on irregular surface made from some blocks between health and reduced muscle spindle functional condition. 10 healthy young adult males (age: 21.5 ± 0.92 year) were recruited in this research. Normal and high-speed walking motion ware measured on two surfaces: an even surface and an uneven surface. Healthy and reduced muscle spindle function conditions were compared. The ice immersion approach was applied on the lower-leg muscles as a method of reducing muscle spindle function. To create an irregular surface, a thin cloth carpet was modified by many blocks under the carpet. During normal walking, the step length and the rate of upper-body acceleration were significantly increased by icing and/or the uneven surface (p<0.01). The step length and the rate of upper-body acceleration during high-speed walking even and uneven surface were significantly decreased compared with walking on even surface under icing (p<0.05). During high-speed walking, the walking velocity was significantly decreased by icing and/or the uneven surface (p<0.01). These changes in walking show that the muscle spindle function is related to walking. However, standard deviations for all walking parameters were not significantly difference between not only even and uneven surface, but also between healthy and reduced muscle spindle functional condition. The experimental results suggest that muscle spindle function is not important to walk on the irregular surface.