Visual symptoms and G-induced loss of consciousness in 594 Chinese Air Force aircrew--a questionnaire survey.

A questionnaire survey was performed for the first time to assess the prevalence of visual symptoms and G-induced loss of consciousness (G-LOC) due to +Gz exposure in the Chinese Air Force (CAF) to determine the effectiveness of current G tolerance training. Responses were received from 594 individuals. Among them, 302 reported at least one episode of some sort of symptoms related to +Gz, including 110 (18.5%) with visual blurring, 231 (38.9%) with greyout, 111 (18.7%) with blackout, and 49 (8.2%) with G-LOC. Incidences were most common in aircrew with 250-1,000 flying hours (53.6%) and were more prevalent in those with fewer on type flying hours (p < 0.001). The most common situation was reported between +5 and 5.9 Gz. The results indicate a fairly high prevalence of visual symptoms and G-LOC among Chinese Air Force aircrew. There remains considerable scope for +Gz education, particularly in the early centrifuge training and selection of rational physical exercises.

The effects of low-impact dance on knee torque and lower extremity mobility in middle-aged and older women.

BACKGROUND: Although low-impact dance is one of the most prevalent exercises in older persons, little is known about its effects on knee torque and range of motion (ROM) in lower extremity joints. PURPOSE: The aim of this study was to examine the effects of low-impact dance on knee torque and lower extremity joint ROM in older women. METHODS: Twenty-six low-impact dancers and 12 physically inactive individuals comprised the dance group (DG) and the control group (CG), respectively. The knee extension torque, knee and ankle ROMs, and bone mineral density in calcanei were measured for all participants. RESULTS: Several ROMs of the lower extremity joints in the dominant leg, ankle inversion, plantarflexion, and dorsiflexion were significantly higher in the DG than in the CG (p < .05). In addition, the ankle inversion of the nondominant leg in the DG was also significantly higher than that in the CG. The knee extension torque of the nondominant leg in the DG was significantly higher than that in the CG (p < .05). CONCLUSION: Although this study did not focus on the efficacy of a particular intervention type, the results showed that low-impact dance can help achieve higher lower extremity ROM and knee torque values than attained by inactive individuals. It is hoped that this exposition of positive benefits will encourage further studies related to the effect of low-impact dance intervention on reducing fall risk.