Allometric Grip Strength Norms for American Children

Area of Science:

• Pediatric Exercise Science
• Human Performance Measurement
• Biostatistics

Background:

• Establishing normative data for physical performance metrics like handgrip strength is crucial for assessing child development.
• Existing handgrip strength data may be confounded by body size (body mass [BM] and stature [Ht]), impacting accurate comparisons.
• Allometric scaling is a statistical method used to normalize measurements by body size.

Purpose of the Study:

• To create normative data for unscaled and allometrically scaled handgrip strength in American children (ages 6-18).
• To determine if allometric scaling effectively removes the influence of body size (BM and Ht) on handgrip strength.
• To develop reliable handgrip strength benchmarks for pediatric populations.

Main Methods:

• Utilized data from 4,665 American children (ages 6-18) from the National Health and Nutrition Examination Survey (2011-2014).
• Employed multiple log-linear regressions to calculate allometric exponents for BM and Ht, separately for age and sex.
• Assessed model appropriateness using regression diagnostics and correlated scaled/unscaled grip strength with BM and Ht.

Main Results:

• Allometric scaling successfully rendered handgrip strength correlations with BM and Ht non-significant (p ≤ 0.479), approaching zero.
• Unscaled handgrip strength showed significant correlations with BM and Ht (p < 0.001), indicating body size influence.
• A common allometric exponent across age and sex was not feasible without violating established principles.

Conclusions:

• Allometric scaling effectively controls for body size (Ht and BM) and potentially maturation in handgrip strength measurements.
• The developed allometric exponents and normative values enable size-independent comparisons of handgrip strength within age and sex groups.
• This method provides a more accurate assessment of handgrip strength relative to expected values for American children.