Although investigations have been performed establishing the reliability of portable instruments designed to measure upper extremity strength, little research exists concerning the reliability of portable back and lower extremity dynamome ters. Therefore, the purpose of this study was to establish the intrarater reliability of one commercially available isometric dynamometer: the TEC isometric back, leg, and chest dynamometer. Subjects consisted of 27 volunteers (14 males and 13 females), with a mean age of 26.3 ± 4.5 years, who reported no back or lower extremity pathologies. Back and leg strength were measured standing in three positions: (1) knees extended, hips flexed, maintaining lumbar lordosis; (2) knees extended, hips flexed, spine flexed; (3) knees flexed, hips flexed, maintaining lumbar lordosis. The testing occurred on two occasions, separated by 1 week. Data analysis using intraclass correlations indicated reliability coefficients for all positions were over 0.97. These results indicate excellent intrarater reliability in each of the three testing positions using the TEC isometric back, leg, and chest dynamometer to evaluate healthy individuals.