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Updated: Jun 21, 2026
Manual Muscle Testing: A Method of Measuring Extremity Muscle Strength Applied to Critically Ill Patients
Published on: April 12, 2011
Hand-held dynamometry for muscle strength measurement in children with cerebral palsy
Jodi Crompton1, Mary P Galea, Bev Phillips
1Rehabilitation Sciences Research Centre, School of Physiotherapy, The University of Melbourne, Parkville, Victoria, 3108 Australia.
Insights
Hand-held dynamometry shows reliable lower-limb muscle strength measurements in children with cerebral palsy (CP) for some muscle groups. However, reliability varies by muscle, position, and stabilization, requiring careful consideration of measurement error.
Area of Science:
- Pediatric Rehabilitation
- Neuromuscular Biomechanics
- Clinical Measurement Science
Background:
- Cerebral palsy (CP) significantly impacts motor function, necessitating reliable methods to assess muscle strength.
- Accurate measurement of lower-limb isometric strength is crucial for tracking progression and evaluating interventions in children with CP.
Purpose of the Study:
- To evaluate the reliability of hand-held dynamometry for measuring isometric lower-limb muscle strength in pediatric CP.
- To identify specific muscle groups and testing conditions that yield reliable strength measurements.
Main Methods:
- Twenty-three children with spastic diplegia (GMFCS Levels I-III) underwent two isometric strength testing sessions one week apart.
- A 'make' test protocol was used, with peak force normalized to body weight.
- Intraclass correlation coefficients (ICC) and measurement errors were calculated for within- and between-session reliability.
Main Results:
- High within-session reliability (ICC > 0.79) and acceptable between-session reliability (ICC > 0.70) were found for hip flexors/extensors (supine), knee flexors/extensors, and stabilized ankle dorsiflexors.
- Poor reliability (ICC < 0.70) was observed for hip extensors (prone), knee extensors (20° flexion), unstabilized ankle dorsiflexors, and ankle plantarflexors.
- Measurement error varied across muscle groups, limbs, and testing positions, with stabilization yielding inconsistent results.
Conclusions:
- Hand-held dynamometry can be reliable for specific lower-limb muscles in children with CP, but careful selection of testing positions and stabilization is critical.
- Measurement error must be considered when interpreting strength changes, with separate analyses for muscle groups and limbs.
- Further research may be needed to optimize testing protocols for comprehensive and reliable strength assessment in this population.
Abstract:
The aim of this study was to investigate the reliability of hand-held dynamometry for measuring isometric lower-limb muscle strength in children with cerebral palsy (CP). Twenty-three children (14 males, nine females) with CP (spastic diplegia; Gross Motor Function Classification System Levels I-III) aged 5 years 7 months to 14 years 5 months (mean 9 y 6 mo [SD 2 y 8 mo]) attended two test sessions 1 week apart. A 'make' test, using a gradual build-up of force to a maximum isometric contraction, was employed and peak values were normalized to body weight for analyses. Within-session reliability was high with an intraclass correlation coefficient (ICC) of 1,1>0.79 for all muscle groups, and there was acceptable between-session reliability ICC>0.70 and measurement errors for hip flexors and extensors (measured in supine), knee flexors and extensors, and ankle dorsiflexors (with stabilization). Within- and between-session reliability was poor (ICC<0.70) for hip extensors (in prone), knee extensors (20 degrees flexion), ankle dorsiflexors (without stabilization), and ankle plantarflexors. Measurement error differed in each test and across limbs, with stabilization producing inconsistent reliability outcomes. Changes in strength measurements in children with CP should take into account measurement error for particular muscle groups. Changes should be determined for separate muscle groups and limbs, and reported relative to body weight. Different testing positions may be required for greater reliability.
