Muscle strength testing: use of normalisation for body size

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Muscle strength assessment is crucial in sports and movement sciences.
• The influence of body size on muscle strength is often overlooked or improperly handled in research.
• Inconsistent normalization methods hinder data comparison across studies.

Purpose of the Study:

• To address the challenges in muscle strength assessment related to body size.
• To propose a standardized allometric formula for body-size-independent muscle strength.
• To recommend the use of size-independent indices for accurate functional performance evaluation.

Main Methods:

• Review of existing muscle strength testing and normalization practices.
• Application of an allometric formula (S = m^b) to normalize muscle strength data.
• Determination of specific allometric parameters (b=0.67 for force, b=1 for torque).

Main Results:

• Identified two key issues: non-normalized data and inappropriate normalization methods.
• Demonstrated that body size significantly confounds muscle function and performance assessments.
• Proposed an allometric formula to derive body-size-independent muscle strength indices.

Conclusions:

• Recommends the routine use of the allometric formula for standardized muscle strength assessment.
• Advocates for body-size-independent indices to improve the accuracy of athletic profiling and functional movement analysis.
• Emphasizes the importance of consistent normalization for reliable cross-study comparisons.