Optimal Joint Positions for Manual Isometric Muscle Testing

Abstract

Context Manual isometric muscle testing is a common clinical technique that is used to assess muscle strength. To provide the most accurate data for the test, the muscle being assessed should be at a length in which it produces maximum force. However there is tremendous variability in the recommended positions and joint angles used to conduct these tests, with little apparent objective data used to position the joint such that muscle force production is greatest. Objective To use validated anatomically and biomechanically-based musculoskeletal models to identify the optimal joint positions in which to perform manual isometric testing. Design In silico analysis. Main Outcome Measure The joint position which produces maximum muscle force for 49 major limb and trunk muscles. Results The optimal joint position for performing a manual isometric test was determined. Conclusion Using objective anatomical models that take into account the force-length properties of muscles, we identified joint positions in which net muscle force production was predicted to be maximal. This data can help health care providers to better assess muscle function when manual isometric strength tests are performed.

Maximum isometric torque at individually-adjusted joint angles exceeds eccentric and concentric torque in lower extremity joint actions

“…Indeed, the joint angles used closely resemble those used in other isometric strength assessment studies that were not designed to compare torque during different contraction types, including for hip flexion and extension [ 44 ], hip adduction and abduction [ 36 ], and knee flexion and extension [ 30 , 33 , 37 ]. By individually optimizing the joint angle to the point where the torque was highest, we maximized the torque-length relationship of the muscle by theoretically locating the point with the most filament overlap [ 18 , 19 , 45 ].…”

“…This leads to methodological constraints since the magnitude of peak joint torques is only reasonable to compare when the optimal joint torque angle is applied during isometric contractions [ 11 , 23 ]. Although some recommendations for an optimal joint angle for maximum torque are available [ 33 – 37 ], deviations through individuals anthropometry exist, and therefore optimal joint angles unique to each individual should be obtained beforehand in order to produce a true maximal isometric torque measurement [ 15 ]. However, this has not been included in previous studies comparing torque differences between contraction types.…”

Knee Extensor Strength Prediction Formula Using Modified Aneroid Sphygmomanometer in Healthy Female Adults

“…The maximum isometric knee extensor strength is peaked around 60 o of knee flexion. 2,15 This study is concerned more about the positioning to allow the recording of absolute maximum force output in the isometric knee extensor muscles while still preventing the subjects to overpower the examiner and also preventing difficulties in stabilizing equipment on subjects' legs. The previous studies stated that one of the problems found in isometric knee extensor muscle strength measurement is that the examiners were not able to give proper pressure against subjects' maximum force while stabilizing the equipment on the legs.…”

“…The measurements of muscle strength appropriate for application in clinical practices can be performed using a manual muscle testing (MMT) and hand-held dynamometer (HHD) . [1][2][3] Manual muscle testing is commonly used in clinical settings for screening muscle strength; however, it is subjective and less sensitive. On the other hand, HHD is able to give objective results and also more sensitive than the MMT; therefore, it is more suitable to be used for diagnosing weakness in quadriceps femoris muscle and for the post-treatment evaluation of the muscle.…”

“…Hence, this study was performed using 60 o knee flexed position. 2,15 Despite the fact that HHD has become the gold standard for evaluating muscle strength in clinical settings, its limited availability in developing country becomes a major limitation; while aneroid sphymomanometer is widely available and its modification is reversible and easy to do. This study aimed to explore knee extensor muscle strength prediction formula using HHD from measurement using MAS with bag method in healthy adult subjects.…”