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ALLOMETRY & A 70-LB BENCH PRESS TASK CREATE A FAIR MUSCULAR STRENGTH-ENDURANCE TEST FOR COLLEGE-AGE WOMEN

Crowder, T A.1

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Medicine & Science in Sports & Exercise: May 2002 - Volume 34 - Issue 5 - p S35
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We have reported that a specific muscular strength-endurance test for college-age men (175-lb bench press) is not biased due to body mass only when one utilizes allometry to determine the appropriate exponent (1.62 with our data). Unfortunately, for men the procedure of utilizing 1 as an exponent (within 95% CI) is simpler to use (divide by body mass) but most importantly, this procedure does not statistically remove the influence of body mass. We questioned if a specific muscular strength-endurance test for college-age women could be utilized to overcome some of the aforementioned problems.

PURPOSE:

To validate via allometry that a specific task (70-lb bench press) is a user-friendly, fair, upper body muscular strength-endurance test for college-age women.

METHODS:

Fifty-one college-age, female subjects performed a 70-lb bench press to momentary muscular concentric failure. This test was part of a larger comprehensive 4-month physical assessment protocol conducted for an academic grade.

RESULTS:

Performances included: (70-lb) mean = 15.4 reps, 0–21 reps range, .67 SEE; body mass = mean 65.3 kg, 49–84 kg range, 1.02 SEE. Allometry was used to determine the exponent for body mass such that 70-lb reps X BMûα creates a muscular strength-endurance index free of any confounding influence of body mass. Data indicated the exponent to be 1.23 (.33–2.13 = 95% CI). In theory, because 1 is included in the 95% CI, dividing 70-lb reps by body mass is a legitimate method in creating a ôfair muscular strength-endurance index.ö One of the basic tenets of allometry is that the newly scaled variable should have zero correlation with body mass. Correlation between 70-lb reps X BMû1.23 and body mass is −.04 (essentially 0). The correlation between 70-lb reps X BMû1.0 (Reps/BM; within the 95% CI, convenient for the professional) and body mass is .02. Thus the influence of body mass has been removed by a simple procedure (70-lb reps/BM).

CONCLUSIONS:

We conclude that 70-lb reps X BMû1.23 and 70-lb reps X BMû1.0 are both statistically correct for removing the influence of BM in a muscular strength-endurance test for women. Because 70-lb reps X BMû1.0 (Reps/BM) is simpler to calculate, we recommend the 70-lb bench press test and the index (Reps/BM) be utilized when assessing upper-body muscular strength-endurance in college-age women.

©2002The American College of Sports Medicine