Comparative Assessment of Knee Strength Using Hand-Held Myometry and Isometric Dynamometry in Patients with Inflammatory Myopathy

Abstract

Inflammatory myopathy is a group of disorders with progressive muscle weakness being the major symptom. Quantitative assessment of muscle function is important when evaluating the response of these conditions to treatment and various methods, including manual muscle testing, myometry and isokinetic dynamometry, have been used for the assessment of muscle strength. T h e aims of this study were to compare, in patients with inflammatory myopathy, the maximum isometric quadriceps and hamstrings torques using a hand-held myometer and a dynamometer (Kin-Com), and to compare make and break tests using myometry. T h e results showed that in stronger quadriceps the myometer tests underestimated maximum torque as measured with the dynamometer, and that in weaker quadriceps there was no difference in torque with the different methods. There was n o difference in hamstrings make torques for the two instruments. T h e break myometer torques were greater than the make torques for both muscle groups. These findings indicate that when using myometry, break tests measure maximum torque more accurately than make tests, and that isometric dynamometry is preferable to myometry when testing maximum strength of large muscles of near normal strength.

Analysis of Knee Strength Measurements Performed by a Hand-Held Multicomponent Dynamometer and Optoelectronic System

“…This finding can be interpreted by observing that the forceF and the momentM values exerted by the subjects involved in this paper were higher during the extension trial than the flexion one implying a greater difficulty for the operator to maintain still the participant's limb. This finding is in agreement with the results in [26] that showed higher quality of the trials achieved by fixing the HHD in contrast to HHD freely held by the operator.…”

Validation of Ankle Strength Measurements by Means of a Hand-Held Dynamometer in Adult Healthy Subjects

“…Both methods were proved reliable and repeatable only if the examiner had enough force to contrast the force exerted by the patient [19]. Other studies provided similar results, by showing that strength measurements performed through HHD are operator-dependent and the "break test" requires a larger force exerted by the examiner [20,21]. The influence of the operator was tested by Kim et al [9] by comparing three setups: (i) with the HHD fixed to the distal tibia by a Velcro strap; (ii) with the HHD held by the operator; and, finally, (iii) with an isokinetic dynamometer, assumed as a reference.…”

“…Strength of the ankle dorsiflexor and plantarflexor muscles has been measured by applying a validated clinical protocol [32], consisting in a "make test" method [19,21]. In both ankle plantarflexion and dorsiflexion movements, the subject was lying on the bed with ankle in neutral position (Figure 2).…”