Purpose:The purpose of this study was to compare the spatiotemporal and kinematic gait parameters and muscle activity of the lower extremities between forward walking on sand (FWS) and backward walking on sand (BWS) in normal adults. Methods: This study was conducted on 13 healthy adults. Subjects performed FWS and BWS and the spatiotemporal and kinematic gait parameters of stride time, stride length, velocity, cadence, step length, stance, swing, double support, and hip range of motion (ROM), knee ROM were measured by a wearable inertial measurement unit system. In addition, the muscle activity of the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GA) was measured. Results: The stride length, stride velocity, cadence, and step length in the BWS were significantly lower than FWS (p< 0.05), and stride time was significantly greater (p< 0.05). However, there was no significant difference in the ratio of stance, swing, and double support between the two (p> 0.05). The kinematic gait parameters, including hip and knee joint range of motion in BWS, were significantly lower than FWS (p< 0.05). The muscle activity of the RF in BWS was significantly higher than FWS (p< 0.05), but the muscle activity of the BF, TA, GA did not show any significant differences between the two movements (p> 0.05). Conclusion:A strategy to increase stability by changing the gait parameters is used in BWS, and this study confirmed that BWS was a safe and effective movement to increase RF muscle activity without straining the joints. Therefore, BWS can be recommended for effective activation of the RF.

Purpose: Gait termination (GT) is the transition from steady-state walking to a complete stop, occurring under planned gait termination (PGT) or unplanned gait termination (UGT) conditions. This study aimed to investigate the biomechanical differences between PGT and UGT, which could help develop therapeutic interventions for individuals experiencing difficulty with GT. Methods: Twenty healthy adults performed three walking trials, followed by PGT and UGT trials. Gait termination was analyzed in three phases as follows: Phase 1 (pre-stopping), Phase 2 (initial stopping phase), and Phase 3 (terminal stopping phase). Spatiotemporal, kinematic, and kinetic data during each phase were compared between conditions. Results: The GT time and GT step length were significantly different between the PGT and UGT trials. Ankle range of motion (ROM) demonstrated significant differences in Phase 1, with the PGT having a slightly lower ankle ROM than the UGT. In Phase 2, the hip, knee, and ankle ROM exhibited significant differences between the conditions. Finally, in Phase 3, UGT showed reduced hip ROM but increased knee ROM and kinetic parameters compared to PGT. Conclusion: Our results indicate that the ankle joint primarily contributes to deceleration during the initial preparation for generating braking force during PGT. Conversely, UGT reveals disrupted kinesthetic control due to instability, leading to a preference for a hip and knee strategy to absorb force and control the center of mass for a safe and rapid GT in response to unexpected stimuli. These findings provide valuable insights into the biomechanical mechanisms underlying body stability during GT and may contribute to the development of effective rehabilitation strategies for individuals with gait impairment.