Muscle cells strengthen in response to intense exercise - whether you're 18 or 88. But the intensity is what's lacking in most people's workouts. And there are doctors who'll give you the advice, "Well, don't push it."
Jack LaLanneI'm always asking people to do something in their mind [first]. So if they're gonna do one exercise, it would be to ask themselves what they want to change about themselves in the next 12 weeks. Once they solve that, the body will follow.
Jack LaLanneDevelop a positive attitude. Think and picture how amazing you are going to be. Visualize it!
Jack LaLanne