Decision trees of peak torque reference values and methodological quality considerations for assessment of muscle strength in isokinetic dynamometry: a systematic review

OBJECTIVES: Isokinetic dynamometers are the gold standard for muscle strength assessment, yet no systematic review has compiled Biodex-specific reference values or practical tools for their use. We aim to provide an overview of available Biodex isokinetic dynamometer peak torque reference values in healthy populations, assess methodological quality and offer recommendations for clinical and research use.

METHODS: MEDLINE/PUBMED, EMBASE, SCOPUS and WEB OF SCIENCE were systematically searched for studies establishing Biodex Dynamometer reference values. Data on study characteristics and protocols were extracted. Methodological quality was assessed with a 17-point checklist.

RESULTS: Ten studies were included from 1044 records screened. Population and protocol differences made meta-analysis unfeasible. The most predominant protocol assessed knee strength at 60°/s with 4-10 repetitions. Two studies had low methodological quality, six moderate, and two high. Studies lost points due to insufficient reporting rather than flaws in procedures. We created decision trees to facilitate readers in selecting appropriate reference values.

CONCLUSIONS: Reporting quality of Biodex reference values studies needs improvement. By integrating methodological quality, population characteristics, and protocols in decision trees, this review provides practical guidance to select appropriate reference values and improve muscle strength assessments in clinical and research settings.