Does slow, no-relaxation lifting at 50% 1RM build muscle after 60?

Watanabe and colleagues tested whether the slow, no-relaxation lifting style (LST) developed in young men also grows muscle in older people when the load is held constant.

Thirty-five men and women aged 59-76 were randomly assigned to knee extension and knee flexion at 50% of 1RM, either LST (3 s eccentric, 3 s concentric, 1 s isometric, no rest between repetitions) or normal speed (1 s concentric, 1 s eccentric, 1 s rest between repetitions), twice a week for 12 weeks (2 weeks of preparation and 10 weeks of intervention).

LST significantly increased thigh muscle thickness and isometric knee extension and flexion strength. Normal-speed training also improved strength significantly but had only a limited effect on muscle size. The authors conclude that LST is effective for gaining muscle mass and strength even in older people.

How this relates to the Russian static-dynamic method: the closest tested form in older adults: the load is fixed at 50% 1RM in both groups, so the comparison isolates the slow, no-relaxation style (with whatever change in effort it brings) against intermittent normal-speed lifting. Sets, repetitions, rest between sets, range and failure are not in the abstract. No oxidative, mitochondrial or capillary outcome.