No abstract

Aims: This study examined how vision, base of support (BOS) and surface compliance affected postural sway and electromyography (EMG) activity of hip and ankle muscles during eight balance training tasks in young adults. Methods: Postural sway and EMG activity of gluteus maximus (GMAX), gluteus medius (GMED), tibialis anterior (TA), and medial gastrocnemius (GAST) were measured during eight balance tasks with eyes open or closed, feet in tandem or apart, and on foam or a firm surface. Results: Postural sway and EMG activity of hip and ankle muscles were significantly affected by the alteration of vision, surface compliance or BOS during eight balance tasks (P<0.05). There was more postural sway when the number of sensory factors altered in the balance tasks increased. GMED and TA EMG activity increased significantly in tasks with tandem standing; GMAX was recruited significantly only when vision was excluded in tasks with tandem standing; and GAST EMG activity was significantly higher in tasks on the foam and in tandem standing. Conclusions: Balance exercises may be progressed according to the rank of the task’s difficulty by increasing the number of sensory factors altered in a balance task. There was significant recruitment of hip and ankle muscles in the balance tasks indicating the importance of these muscles in postural control.

Objective:To assess the effect of vitamin D administration on the skin blood flow response to occlusion and heat. Design: Cross-sectional study. Methods: Twenty age matched subjects; 10 who had diabetes and 10 who were controls were administered 4,000 IU of vitamin D3 for 3 weeks at breakfast. The function of the endothelial cells was evaluated in 2 ways; first, the response to 4 minutes of vascular occlusion of the skin was measured with a laser Doppler flow meter. Second, the skin blood flow response to local heat at 42 degrees C for 6 minutes was examined. Results:The results of the experiments showed that the blood flow response to heat was reduced after 3 weeks administration of vitamin D in the subjects with diabetes and in the control subjects (p<0.05). The response to occlusion was not significantly different within each group before and after vitamin D administration, but the group with diabetes had a significantly lower blood flow response to occlusion than did the controls (p<0.05). Conclusions: Acute doses of vitamin D may impair nitric oxide production and reduce blood flow to tissue during stressors in people with diabetes.