Pelvis-dominant coordination strategies in stroke patients with hemiplegia during sit-to-stand and stand-to-sit transitions: a cyclogram analysis.

OBJECTIVE

This study investigated inter-joint coordination between pelvis and lower limb joints in stroke patients during sit-to-stand (St-Si) and stand-to-sit (St-Si) transitions using cyclograms.

METHODS

Thirteen stroke patients and thirteen age-matched healthy controls performed St-Si and St-Si tasks while pelvis and lower limb joint angles were recorded using a three-dimensional motion capture system. Inter-joint coordination, specifically pelvis-hip, pelvis-knee, and pelvis-ankle, was assessed using cyclograms and quantified by geometric parameters: perimeter, area, and dimensionless ratio (DR).

RESULTS

Compared with healthy controls, the stroke group exhibited significantly lower DR values for the pelvis-hip and pelvis-knee joints bilaterally during the St-Si task (p < 0.01), and lower pelvis-knee DR values during St-Si (p < 0.01). Pelvis-ankle coordination showed task-dependent differences: during St-Si, the affected side showed a lower DR and a larger area than the unaffected side (p < 0.05); however, during St-Si, the stroke group showed increased DR (p < 0.01) but significantly smaller area values compared with controls (p < 0.05).

CONCLUSION

Stroke patients adopt simplified, pelvis-dominant patterns and task-dependent compensatory strategies, particularly at the ankle. Cyclogram-based measures may provide an intuitive approach for identifying joint-specific deficits and may inform rehabilitation strategies.