Can Skipping Cardio Make You Stronger Than Your Twin?

On Huberman Lab, the non-exercising twin was as strong as the endurance-training twin, and the measures often favored the non-exerciser. Grip strength stood out, and the vertical jump and leg extension power did too. Genetics give a clear starting place, and the strength measures are very responsive anyway. Distance running alone does not build them.

The non-exerciser was in his mid-fifties, did not exercise, and paid no real attention to his diet, and he was still in pretty good shape. It is unknown whether the endurance training reduced the other twin's strength. In both studies, the endurance-trained people were much better off on measures tied to how long a person lives, including VO2 max, and the training still did not reach strength. Aging selectively reduces fast-twitch fibers. Daily living keeps slow-twitch fibers active, while fast-twitch fibers need high-force work or they are not kept. Without fast-twitch fibers, there is no speed to get a foot out in front in time and no eccentric strength to stop a fall.

High functionality takes something besides distance running. Strength training alone has the mirror limit. Endurance training improved VO2 max and the other measures tied to how long a person lives, and it still left strength behind. The aging literature is clear about maintaining strength and fast-twitch fibers.