Rlative shoulder fexor and handgrip strength is related to upper limb function after stroke

Abstract

Objective: To compare the relative strength of different muscle groups of the paretic upper limb and assess the relationship with motor performance. Design: Descriptive study. Setting: Secondary care rehabilitation centre. Subjects: A convenience sample of 13 chronic hemiparetic stroke subjects. Main outcome measures: The maximal active torques of fivemuscle groups were measured in both upper limbs (UL) and converted into relative strength (paretic/nonparetic). The UL function was assessed using the Box and Block Test, the Finger-to-Nose Test, the Fugl-Meyer Test and the TEMPA (Test Evaluant les Membres supérieurs des Personnes Agées). Results: The Friedman two-way analysis of variance shows a significant difference across the relative strength of the different muscle groups ( p = 0.017), but subsequent multiple comparisons indicate a significant difference between handgrip and elbow extension only (relative strength of 0.52 ± 0.27 and 0.73 ± 0.23 respectively). However, data show the presence of large intra-subject imbalances between muscle groups. The relative forces for shoulder flexion and handgrip are the best predictors of the UL function, the higher Spearman's rho correlation coefficients for each clinical test ranging from 0.70 to 0.81. Conclusions: These results do not confirm classical clinical teaching regarding the distribution of weakness following stroke (e.g., proximal to distal gradient; extensors more affected than flexors) but support the hypothesis that strength is related to the function of the paretic upper limb.