For weight loss, science has found that lifting between 60-80% of your 1 rep max is the best way to stimulate muscle growth, which is what helps you lose fat. The problem is that most of us don't think much about how much weight we need, much less going through the process of figuring out 1 rep max for every exercise we're doing. In fact, I see many gym-goers lifting the same weights week after week, which is just one way to keep your body from changing.
So how do you figure out how much to lift if you don't know your 1 rep max? Typically, if you lift 60%-80% of max, you could do anywhere from 10-20 reps. Lifting at 80% and above takes you down to the lower rep range, which is where you'll be if you're trying to gain size. That means keeping your reps somewhere between 8-16, if you're lifting for weight loss and fitness. Your weights are determined by the number of reps you're doing.
- Choose a weight you can only lift 16 times. You don't need to go to complete failure, but make sure you're challenging your body.
- Begin with 1 set of each exercise, slowly working your way up to 2-3 sets (i.e., adding a set each week)
- When you've added sets and have a solid foundation (after 6-8 weeks), add more weight so that you can ONLY do 8-12 reps.
- Continue to progress by adding a rep each week until you reach the max reps (no more than 16), increase your weight and drop your reps back down to 8-12.
For more on the specific guidelines of strength training, including choosing reps, sets and exercises, read Weight Training 101.
The important thing to remember when it comes to strength training is that you must give you your muscles more weight than they can handle--that's how muscles grow. The challenge of lifting heavy is just as much a mental game as it is a physical one and, if you haven't pushed your body's limits in a while, just the act of lifting weights may be all you can handle. If you're consistent with a basic program and build a solid foundation of strength, you'll be ready for the next step--lifting heavy and pushing your muscles to their limits. You'll be amazed at the changes in your body!