Effects of initial foot position on neuromuscular and biomechanical control during the stand-to-sit movement: Implications for rehabilitation strategies

• DOI: 10.1371/journal.pone.0315738
• Publication Date: 2025-02-14T18:27:28Z
• Authors: Woohyoung Jeon; Ashley Dalby; Xuanliang Neil Dong; Chung-Hyun Goh

Background Initial foot position (IFP) is one of the important movement strategies that influence neuromuscular and biomechanical control during sit-to-stand (STS) movements. Similarly, stand-to-sit (StandTS) vital in rehabilitation settings for evaluating strength balance descending Understanding how IFP impacts changes factors StandTS can provide valuable insights designing effective programs. Methods Twelve healthy young adults participated this study, examining three symmetric IFPs: (1) REF (reference); (2) wide: each was shifted outwards by 30% from REF; (3) TO (toes-out): toes-out angle 30° REF. Kinematic kinetic differences among IFPs were analyzed, along with characteristics muscle activation patterns using synergy analysis. Results In wide IFP, trunk flexion reduced, valgus greater than other IFPs. The resulted dorsiflexion knee angles compared to Compared both showed eccentric work at hip joint anterior-posterior (power absorption) vertical direction (gravitational force control) demonstrated reduced postural sway medio-lateral directions. Muscle analysis EMG activity revealed increased back plantar flexor contribution muscles IFP. Conclusion angle, leading activation. enabled angular displacement ankle joints, enhancing involvement control. Both facilitated work, improving descent phase StandTS. These findings tailored specific patient needs.