The Impact of Unipedal and Bipedal Stance on Reach and Lumbosacral Torque

The objective of this study was to investigate the effects of standing on one leg versus two legs on reach and torque at the lumbosacral joint. Our participant, a ۲۴-year-old individual weighing ۶۸ kilograms, had no history of surgery or serious musculoskeletal injuries. The participant performed reach tests in two positions: Single Leg Stance: Standing on one leg. Bipedal Stance: Standing on both legs. During each test, the participant reached as far as possible in various directions (anterior, posteromedial, and posterolateral) for ۳ seconds. Each position was repeated five times. Body weight distribution was determined using imaging and the Eshel geometry method, with reference to anthropometric data. Static interaction analysis allowed us to calculate forces, torques, and testable reach settings. Reach Accessibility: Unipedal stance (single leg) resulted in a marginal increase (less than half a percent) in reach accessibility compared to bipedal stance. Lumbosacral Torque: Remarkably, the torque on the lumbosacral joint increased significantly by ۸۵.۰۵% during unipedal stance. Discussion: The biomechanical implications of these findings warrant further exploration. Does the increased torque have practical significance or potential health implications? Future research could delve into muscle activation patterns and stability mechanisms during unipedal versus bipedal tasks. In summary, our study sheds light on the trade-offs between stability and reach in different stances, providing valuable insights for clinicians, athletes, and individuals seeking to optimize their movement patterns.