Strength deficits of the shoulder complex during isokinetic testing in people with chronic stroke

OBJECTIVES:

To examine the strength deficits of the shoulder complex after stroke and tocharacterize the pattern of weakness according to type of movement and type ofisokinetic parameter.

METHOD:

Twelve chronic stroke survivors and 12 age-matched healthy controls had theirshoulder strength measured using a Biodex isokinetic dynamometer. Concentricmeasures of peak torque and work during shoulder movements were obtained in randomorder at speeds of 60°/s for both groups and sides. Type of movement was definedas scapulothoracic (protraction and retraction), glenohumeral (shoulder internaland external rotation) or combined (shoulder flexion and extension). Type ofisokinetic parameter was defined as maximum (peak torque) or sustained (work).Strength deficits were calculated using the control group as reference.

RESULTS:

The average strength deficit for the paretic upper limb was 52% for peak torqueand 56% for work. Decreases observed in the non-paretic shoulder were 21% and 22%,respectively. Strength deficit of the scapulothoracic muscles was similar to theglenohumeral muscles, with a mean difference of 6% (95% CI -5 to 17). Ability tosustain torque throughout a given range of motion was decreased as much as thepeak torque, with a mean difference of 4% (95% CI -2 to 10).

CONCLUSIONS:

The findings suggest that people after stroke might benefit from strengtheningexercises directed at the paretic scapulothoracic muscles in addition to exercisesof arm elevation. Clinicians should also prescribe different exercises to improvethe ability to generate force and the ability to sustain the torque during aspecific range of motion.