Non-Linear Relation Between Upper Arm Volume and Maximal Effort Force Production

The objective of the present study was to examine the relationship between maximal effort force production and anthropometric measures of upper arm volume. Thirty healthy young participants (15 women) performed five isokinetic concentric and eccentric maximal-effort elbow flexor/extensor contractions, on separate days. Measures of arm length, circumference, and skinfold/subcutaneous fat thickness were used to obtain a measure of arm volume, modeled as two separate right-angle frustra. Single variable regression analyses demonstrated significant (p<0.001) second-order polynomial relationships between maximal effort elbow flexor and extensor force with arm volume (r² = 0.63 - 0.86). The major findings demonstrated that strong and positive relations between maximal force production and estimates of limb volume can be observed using non-linear modeling and a closer geometric representation of the exercising limb.