Getting started

If you have a chronic condition, or if you're older than age 40 and you haven't been active recently, check with your doctor before beginning a strength training or aerobic fitness program.

Before beginning strength training, consider warming up with brisk walking or another aerobic activity for five or 10 minutes. Cold muscles are more prone to injury than are warm muscles.

Choose a weight or resistance level heavy enough to tire your muscles after about 12 to 15 repetitions. When you can easily do more repetitions of a certain exercise, gradually increase the weight or resistance.

Research shows that a single set of 12 repetitions with the proper weight can build muscle efficiently in most people and can be as effective as three sets of the same exercise.

To give your muscles time to recover, rest one full day between exercising each specific muscle group.

Also be careful to listen to your body. If a strength training exercise causes pain, stop the exercise. Consider trying a lower weight or trying it again in a few days.

It's important to use proper technique in strength training to avoid injuries. If you're new to weight training, work with a trainer or other fitness specialist to learn correct form and technique.

When to expect results

You don't need to spend hours a day lifting weights to benefit from strength training. You can see significant improvement in your strength with just two or three 20- or 30-minute weight training sessions a week.

The Department of Health and Human Services recommends incorporating strength training exercises of all the major muscle groups into a fitness routine at least two times a week.

As you incorporate strength training exercises into your fitness routine, you may notice improvement in your strength over time. As your muscle mass increases, you'll likely be able to lift weight more easily and for longer periods of time. If you keep it up, you can continue to increase your strength, even if you're not in shape when you begin.

April 22, 2016 See more In-depth