Hemiparetic Knee Extensor Strength and Balance Function Are Predictors of Ambulatory Function in Subacute Stroke Patients

OBJECTIVE To identify the potential predictors of ambulatory function in subacute stroke patients, and to determine the contributing factors according to gait severity. METHODS Fifty-three subacute stroke patents were enrolled. Ambulatory function was assessed by gait speed and endurance. Balance function was evaluated by the Berg Balance Scale score (BBS) and the Timed Up and Go test (TUG). The isometric muscular strengths of bilateral knee extensors and flexors were measured using an isokinetic dynamometer. Cardiovascular fitness was evaluated using an expired gas analyzer. Participants were assigned into the household ambulator group (<0.4 m/s) or the community ambulator group (≥0.4 m/s) based on gait severity. RESULTS In the linear regression analyses of all patients, paretic knee isometric extensor strength (p=0.007) and BBS (p<0.001) were independent predictors of gait endurance (R(2)=0.668). TUG (p<0.001) and BBS (p=0.037) were independent predictors of gait speed (R(2)=0.671). Paretic isometric extensor strength was a predictor of gait endurance (R(2)=0.340, p=0.008). TUG was a predictor of gait speed (R(2)=0.404, p<0.001) in the household ambulator group, whereas BBS was a predictive factor of gait endurance (R(2)=0.598, p=0.008) and speed (R(2)=0.713, p=0.006). TUG was a predictor of gait speed (R(2)=0.713, p=0.004) in the community ambulator group. CONCLUSION Our results reveal that balance function and knee extensor isometric strength were strong predictors of ambulatory function in subacute stroke patients. However, they work differently according to gait severity. Therefore, a comprehensive functional assessment and a different therapeutic approach should be provided depending on gait severity in subacute stroke patients.