Determination of Muscle Strength in Parkinsonian Patients Through the Use of an Isokinetic Dynamometer

An isokinetic muscle action is defined by its performance at a constant speed or velocity. The laboratory measurements of isokinetic strength provides torque measurements throughout the active range of motion during a maximal effort. Torque is the force rotating about an axis and is produced and recorded from the angular motion. Consequently, the peak torque is an index of the muscular strength. Isokinetic testing was introduced as a quantitative measurement of both statistic and dynamic muscular contraction in which all variables involved (resistance, limb velocity, joint position) are under control. This is because isokinetic muscle testing allows objective, valid, and reliable measurement of the force produced by skeletal muscle during exercise at constant velocity and accommodating resistance and it is appropriate for measuring muscle strength and muscle endurance across the disability spectrum.

Decreased muscle strength has been reported to be a factor contributing to increased incidences of falling in the elderly patients causing fractures, joint dislocations, severe soft tissue lesions and head trauma. Parkinson's Disease (PD) patients often complain of weakness and it has been reported that they have reduced muscle strength, decreased rate of force development, impaired ability to maintain constant force, and increased muscle coactivation during balance perturbation tasks. The specific cause of this weakness is not known, and in this study the investigators have analyzed and measured isokinetic muscle strength in PD patients to clarify this issue. the investigators have compared the data obtained with those of age-matched controls.