Abstract
Isokinetic trunk muscle strength of 36 postpartum women was evaluated using the Kin-Com dynamometer at 24 and 25 weeks following vaginal delivery of a healthy infant. Test-retest reproducibility of a standardised isokinetic testing protocol was evaluated in concentric and eccentric muscle actions through a 50° range of motion at velocities of 20 deg/s and 40 deg/s for the trunk flexors and extensors.
Moderate agreement was found for inter-test reproducibility (ICCs from 0.67 to 0.85; CVs from 8.8% to 15.9%). Intratest reproducibility was high (ICCs from 0.90 to 0.95). The ratio of trunk extensor to flexor strength was similar in both concentric and eccentric action at both velocities (p>0.05). The ratio of strength at the two velocities was similar for both muscle groups in both actions (p>0.05). Eccentric strength was significantly higher than concentric strength. Eccentric strength did not vary with velocity while concentric strength displayed an inverse relationship with velocity (p<0.05).