Effects of eccentrically biased versus conventional weight training in older adults.

INTRODUCTION We compared the effects of eccentrically biased (EB) and conventional (CONV) resistance training on muscle architecture, one-repetition maximum (1RM), isometric strength, isokinetic force-velocity characteristics, functional capacity, and pulse wave velocity in older men and women. METHODS Twenty-eight older adults participated in the study (mean ± SD: age = 68 ± 5 yr). Of these, 13 were allocated to a waitlist control, 10 of whom progressed to training (CONV, n = 12; EB, n = 13). Training was twice a week for 16 wk. EB involved three sets of 10 concentric lifts at 50% of 1RM with the eccentric portion of repetitions performed unilaterally, alternating between limbs with each repetition. CONV involved two sets of 10 repetitions at 75% of 1RM. EB and CONV were matched for total work. Isokinetic knee extensor strength was assessed across a range of velocities (0-360°·s(-1)). Functional capacity was assessed via a 6-m fast walk test, a timed up and go test, stair climb and descent power test, and vertical jump test. Vastus lateralis and gastrocnemius medialis architecture were assessed using ultrasonography. RESULTS Both EB and CONV improved 1RM (Δ 23%-35%, P < 0.01). Compared to the control group, both training regimens improved 6-m fast walk (Δ 5%-7%, P < 0.01) and concentric torque at 60 and 120°·s(-1) (Δ 6%-8%, P < 0.05). Significant improvements were evident in EB for isometric and concentric torque at 240 and 360°·s(-1) (Δ 6%-11%, P < 0.05), vastus lateralis thickness (Δ 5%, P < 0.05), and stair climb (Δ 5%, P < 0.01). Timed up and go (Δ 5%, P < 0.01), stair descent (Δ 4%, P < 0.05), and vertical jump (Δ 7%, P < 0.01) improved in CONV. Pulse wave velocity, pennation angle, and fascicle length remained unchanged in both training groups. CONCLUSIONS EB seems superior to CONV at increasing torque at high contraction velocities, whereas CONV seems more effective at improving some functional performance measures and vertical jump. This has important implications for preserving functional capacity.