THE EFFECTS OF SHOE TYPE ON BIOMECHANICAL AND PHYSIOLOGICAL RESPONSES TO STEPPING AND INCLINED WALKING

The purpose of this study was to examine the effect of hiking shoes and hiking boots on the biomechanical responses to a stepping task and physiological responses to an inclined walking task. Participants (n = 16) performed six two minute stepping trials at a stepping rate of 72 bpm; three trials in hiking boots and three trials in hiking shoes. Following the stepping task, participants (n = 19) walked at 3.0 mph and 10% grade for five minutes in hiking shoes and hiking boots. Lower limb joint angles and moments were calculated using Visual 3D. Physiological data was averaged over the last three minutes of the stepping task to determine mean variables during steady state exercise. Results showed that during the lowering phase of the stepping cycle, ankle ROM and ankle and knee moments were significantly greater in hiking shoes than hiking boots, indicating that no compensatory mechanisms of the knee and hip were implemented due to restricted ankle ROM. Additionally, VO2 and VE were significantly greater in the hiking shoe condition during the inclined walking task. While these variables are statistically significant, they may not be practically significant in an actual hiking scenario, as the magnitudes of differences observed in variables were minimal. Use of either shoe or boot may not result in an increased risk of injury, therefore leaving the choice of footwear up to the hiker’s personal preference

Influence of the Lower Body on Seated Arm Cranking Performance

© Georg Thieme Verlag KG Stuttgart New York. During upper-body tasks, use of the lower body is important for minimizing physiological strain and maximizing performance. The lower body has an integral role during standing upper-body tasks, however, it is less clear if it is also important during seated upper-body tasks. We determined the extent to which the lower body influenced seated arm cranking performance. Eleven males performed incremental (40+20 W·3 min -1) and short-duration maximal effort (5 s, 120 rpm) arm cranking trials with and without lower-body restriction. The lower body was restricted by securing the legs to the seat and suspending them off the floor. Upper-body peak oxygen consumption (VO 2peak) and maximal power were determined. At the end of the incremental protocol, lower-body restriction reduced VO 2peak by 14±12% (P \u3c 0.01) compared to normal arm cranking. At greater submaximal stages (60-100% isotime) heart rate, ventilation, RER, and arm-specific exertion increased to a greater extent (all P \u3c 0.05) with lower-body restriction. During short duration maximal arm cranking, lower-body restriction decreased maximal power by 23±9% (P \u3c 0.01). Results indicated that lower-body restriction limited aerobic capacity, increased physiological strain during high-intensity submaximal exercise, and compromised maximal power generating capacity. These results imply that use of the lower body is critical when performing seated arm cranking. Our findings have implications for exercise testing, training and rehabilitation