Scaling of Maximal Strength Scores in Physically Active College Females

Peter D. Hart^{1, 2,}

¹Health Promotion Research, Havre, Montana, USA

²Kinesmetrics Lab, Tallahassee, Florida, USA

Cite this paper:
Peter D. Hart. Scaling of Maximal Strength Scores in Physically Active College Females. Journal of Physical Activity Research. 2024; 9(1):20-23. doi: 10.12691/jpar-9-1-4

Abstract

Background: When an exercise scientist assesses an individual’s muscular strength, the measurement and evaluation should not be impacted by the participant’s body weight (BW). The purpose of this study was to compare the effectiveness of different scaling techniques in normalizing maximal strength scores for BW in college-aged females. Methods: Complete data for 37 traditional aged (18 to 24 years) females were used. Maximal strength tests included grip strength (GS), 1RM bench press (BP), 1RM leg press (LP), and vertical jump (VJ). Anthropometric measures of height, BW, BMI, and WC were also objectively measured. Two scaling techniques were used with the following calculation: MS/BW^b. Ratio scaling was simply the strength score (MS) divided by BW (i.e., b = 1.0). Allometric scaling used the fit BW coefficient (b) from log-log regression models. Pearson correlation coefficients determined the extent of influence of BW on unscaled and scaled strength scores. ANOVA determined the extent of influence of BW on group means of allometric-scaled strength scores. Results: Mean age of the sample was 20.7 ± 1.6 yr with mean BMI, GS, BP, LP, and VJ of 23.8 ± 3.1 kg/m², 34.3 ± 7.8 kg, 97.4 ± 23.5 lb, 316.5 ± 105.0 lb, and 15.7 ± 3.5 in, respectively. BW was significantly related to GS, BP, and LP but not VJ. Ratio scaling removed the influence of BW from all strength scores less VJ. Allometric scaling adequately removed the influence of BW from all strength scores. ANOVA models for each of the strength tests showed that allometric scaling for BW also removed its influence from group means. Conclusion: These results indicate that ratio scaling for BW was a sufficient technique for removing BW effects from low-speed strength tests in college-aged females. However, allometric scaling for BW adequately removed the influence of BW from all maximal strength scores in this population.

Keywords:
Allometry Scaling measurement evaluation muscular strength

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