Maximum Voluntary Isometric Contraction: Investigation of Reliability and Learning Effect

Abstract

Maximum Voluntary Isometric Contraction (MVIC) is a standardised, objective and sensitive tool for the measurement of muscle strength. The purpose of this study was to investigate different aspects of reliability of MVIC and to determine if a learning effect existed in a relatively new user of the system. Two clinical investigators participated in the study. The inter- and intra-rater reliability of MVIC of 11 muscle groups was tested on healthy subjects (n=35). Intra-class correlation co-efficients (ICCs) were calculated and the statistical methods described by Bland and Altman were applied to the data. ICCs were higher for the more experienced investigator and a learning effect was demonstrated in a relatively new user of the system. Inter-rater reliability was acceptable but lower than intra-rater reliability. Upper limb tests generally yielded higher ICCs and lower ranges of error. The ICC was similar regardless of whether the maximum or average of the two values was taken in a single session. Utilising the statistical methods proposed by Bland and Altman allows estimation of the magnitude of error of MVIC and gives additional information to the ICC. These methods may be useful in the training of investigators and in clinical interpretation of MVIC values.

The Interday Reliability of Leg and Ankle Musculotendinous Stiffness Measures

“…Indeed, the execution of an isometric contraction is more common in trained and male subjects compared with the relatively untrained female subjects used in the current investigation. Other research has also shown that a learning effect is present for isometric force testing of relatively inexperienced subjects, with multiple trials required before a reliable result can be established (Bemben et al, 1992;Meldrum et al, 2003). This finding was confirmed in the variation of our MIF data between days (Table 1) and the higher reliability scores achieved after one session of testing (Table 2).…”

Stature is an essential predictor of muscle strength in children

“…Indeed, when normalized to the mean of the measurements, the relative SEMs for the two studies are similar (10% and 9%, respectively). Meldrum et al [25] used the same QMT measurement system with adults, and the standard error of the difference between test and retest reported can be used to compute the relative SEM: the relative SEM was between 3.9 and 12.8% in adults, to be compared to 9.8 to 15.1% for children in our study. This suggests lower reliability of strength measurement in children than adults possibly due to their poorer concentration or motivation through successive visits.…”

Standardized voluntary force measurement in a lower extremity rehabilitation robot

“…For instance, Scott et al demonstrated for hip flexion and extension fair to good (0.65 – 0.87) inter-rater reliability assessed with a handheld dynamometer and poor to good (0.48 – 0.91) inter-rater reliability assessed with a portable dynamometer anchoring station [ 19 ]. Also a fair to good intra-rater reliability (0.76 – 0.98) for hip and knee flexion and extension movement with a slightly lower inter-rater reliability (0.64 – 0.97) was reported using a strain gauge [ 2 ]. Using isokinetic dynamometry to measure isometric muscle force mainly results in good reliability.…”

“…Muscle force testing is a well established method of assessing muscle function in subjects with neurological movement disorder (NMD) [ 1 , 2 ], despite the fact that these tests are in generally not sensitive enough to assess the force of a single muscle. Isometric force measurements are widely used because walking ability has been shown to be related to muscle strength [ 3 - 6 ].…”