Cross-cultural Validation Of Isokinetic Peak Torque Prediction Equations On Young American Wrestlers

Abstract

PURPOSE: To determine the validity of fat-free weight equations derived on Saudi children and adolescents for predicting isokinetic peak torque in young American wrestlers. METHODS: One-hundred and eight males (x age ± SD= 11.3 ± 1.5y) volunteered to perform isokinetic leg extensions at 180 and 300°·s−1 on a Cybex II dynamometer to measure isokinetic peak torque (Nm) and underwater weighing to determine fat-free weight (FFW). Predicted peak torque values at 180 and 300°·s−1 were also calculated from FFW using the following formulas: EQ1: Extension Peak Torque at 180°·s−1 = 3.3(FFW) - 54.4 EQ2: Extension Peak Torque at 300°·s−1 = 2.4(FFW) - 38.5 The validity of EQ1 and EQ2 were determined by examining the constant error (CE), r, standard error of estimate (SEE), and total error (TE) values. RESULTS: There were significant (p<0.05) mean differences (CE) between the measured peak torque (x ± SD: 180°·s−1 = 54.9 ± 2.2 Nm; 300°·s−1 = 35.8 ± 1.5 Nm) and predicted peak torque (180°·s−1 = 62.0 ± 3.0 Nm; 300°·s−1 = 46.2 ± 2.2 Nm) at 180 and 300°·s−1. The CE, SEE, and TE values at 180°·s−1 were 7.1, 8.9, and 14.9 Nm, respectively. The CE, SEE, and TE values at 300°·s−1 were 10.4, 6.3, and 14.4 Nm, respectively. In addition, measured peak torque and predicted peak torque were correlated at r = 0.92 for both 180 and 300°·s−1. CONCLUSIONS: Although measured peak torque and predicted peak torque were highly correlated at both 180 and 300°·s−1, the TE values associated with EQ1 and EQ2 ranged from 27 to 40% of the mean measured peak torque values. Thus, EQ1 and EQ2 that were derived on Saudi children and adolescents resulted in error values that were too large to be used to predict isokinetic peak torque in young American wrestlers.