Eccentric Versus Concentric Training in Old Adults

PURPOSE: We compared training with eccentric (i.e. lengthening) versus concentric (i.e. shortening) muscle contractions (hand gripping) for increasing muscle size and strength in the forearms of 25 older individuals (10 males, 15 females, mean age 63y). METHODS: We used a within-subjects design where each arm was randomized to a different training mode. Training was progressive up to 6 sets of 8 maximal repetitions on a Norm dynamometer, 3 times per week for 6 months. Forearm muscle size was assessed by ultrasound and peripheral quantitative computed tomography. Isometric, concentric, and eccentric grip torque was assessed on the Norm dynamometer. RESULTS: Eccentric training increased muscle thickness from a mean (SD) of 3.99 (0.51) to 4.19 (0.56) cm (+4.9%), which was greater than the concentric training increase from 3.99 (0.56) to 4.04 (0.58) cm (+1.6%) (p<0.01). Eccentric training increased muscle cross-sectional area from 3687 (1084) to 3787 (1090) mm2 (+3.0%), which was greater than the concentric training increase from 3691 (996) to 3739 (997) mm2 (+1.4%) (p=0.017). There was a contraction-type by time interaction for strength, where eccentric strength increased more (+30%) than concentric (+22%) and isometric (+17%) strength across arms (p<0.05). CONCLUSIONS: Eccentric training is more effective than concentric training for increasing muscle size in older individuals. Eccentric strength increased to a greater extent than other contraction types with eccentric or concentric training. Supported by the Canadian Institutes of Health Research