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Updated: Jun 13, 2026
Manual Muscle Testing: A Method of Measuring Extremity Muscle Strength Applied to Critically Ill Patients
Published on: April 12, 2011
Measurement of muscle strength with a handheld dynamometer in patients with chronic spinal muscular atrophy
Anna Febrer1, Natalia Rodriguez, Laura Alias
1Service of Physical Medicine and Rehabilitation, University Hospital Sant Joan de Deu, Barcelona, Spain. afebrer@hsjdbcn.org
Objective:
To measure muscle strength in patients with spinal muscular atrophy using a handheld dynamometer as an objective tool to evaluate the progression of disease and the outcome of therapeutic trials.
Design:
Maximum voluntary isometric contraction was measured in a group of 24 patients aged 5-38 years with types II and III spinal muscular atrophy. Four muscle groups were examined. Data were grouped according to age and sex. Comparison was made between spinal muscular atrophy types; ambulatory vs non-ambulatory, and survival motor neuron (SMN)2 copies. The results were compared with those of a healthy reference population.
Results:
Muscle strength was much lower in patients with spinal muscular atrophy than in the healthy population. The walkers group yielded higher values than patients who were non-walkers. Knee extensors were the weakest muscles in both groups, regardless of the ability to walk. The greatest differences were found between ambulatory and non-ambulatory patients. Non-walkers type III patients showed lower values, similar to those for type II patients. Patients with 3 and 4 SMN2 copies showed higher strength with respect to those with 2 SMN2 copies, although not statistically significant.
Conclusion:
The handheld dynamometer is a valid tool for measuring muscle strength in patients with spinal muscular atrophy. It can be used to measure disease progression and to evaluate changes in therapeutic trials.
