Heavier Weights or More Repetitions?

by: Dr. Gabe Mirkin, M.D.

Older people gain more muscle strength by spending more time lifting weights, whereas younger people gain more muscle strength by lifting heavier weights. In younger men, doubling exercise volume by spending more time lifting weights produced limited added muscle enlargement. In older men, it resulted in much larger muscles and far more strength (The Journals of Gerontology. August 2012).

EVERYONE LOSES MUSCLE WITH AGING

Everyone becomes weaker and loses muscles with aging. You can slow down this loss of progressive weakness and even enlarge muscles by exercising against resistance as you age (The Journals of Gerontology, August 2012), but not by eating more protein (Clin Interv Aging, July 2012 ;7:225 - 234).

Image from SweatLikeAPig.com

Expect to lose strength and muscle size as you age. Muscles are made up of thousands of individual fibers, like a rope that is made of many threads. Each muscle fiber is innervated by a single nerve. With aging you lose nerves, and each nerve that you lose also causes you to lose the muscle fiber that is innervated by that nerve. When you were 20 years old, the vastus medialis muscle in your thigh had 800,000 fibers. At age 60, it will have fewer than 250,000.

HOW YOU CAN MAKE MUSCLES LARGER

Just exercising does not make you stronger. You cannot grow a lot of new muscle fibers as you age. However, you can markedly enlarge the existing muscle fibers that you have by lifting heavy weights or pressing against progressively greater resistance. When you press against increasingly heavier weights, you damage your muscle fibers and feel sore on the next day. Then you lift very light weights for as many days as it takes for the muscles to heal and the soreness to go away. Only then do you lift heavy again.

OLDER PEOPLE SHOULD JOIN A GYM AND LEARN HOW TO USE STRENGTH TRAINING MACHINES

First check with your doctor to make sure you do not have a condition that will be harmed by vigorous exercise. Then join a gym and ask for instructions how to use the weight machines.

As a general rule, on each machine, you will try to lift a weight 10 times in a row, rest a minute, and then do two more sets of 10. In the beginning, you should lift very light weights and go home without your muscles feeling sore. However, after a few weeks of lifting weights three times a week (never on consecutive days), you should be able to add more weight to each lift. Eventually you should feel some muscle soreness during and after lifting, and the soreness should go away in 48 hours and before your next workout.