Resistance training, also called strength training or muscle-strengthening activity, is any exercise that makes your muscles work harder than they are used to. According to the U.S. Department of Health and Human Services (HHS), muscle-strengthening activities provide health benefits beyond what aerobic activity alone can offer, including increased bone strength and muscular fitness. The American Council on Exercise (ACE) notes that a well-designed strength-training program can also increase muscle mass, strengthen connective tissues, and make daily tasks like carrying groceries feel less taxing.
What Is Resistance Training?
HHS defines muscle-strengthening activities as those that overload the muscles, making them do more work than they are accustomed to. Examples include lifting weights, working with resistance bands, doing calisthenics that use body weight for resistance (such as push-ups, pull-ups, and planks), carrying heavy loads, and heavy gardening. The National Institute on Aging (NIA) explains that these exercises require the muscles to contract, often to lift a heavy object against the pull of gravity. Over time, gradual increases in the amount of weight, the number of sets or repetitions, or the number of days a week of exercise will result in stronger muscles.
ACE adds that a balanced strength-training program can increase the strength of bones, muscles, and connective tissues (tendons and ligaments), increase muscle mass, and enhance quality of life.
How Much Resistance Training Do You Need?
HHS recommends that adults do muscle-strengthening activities of moderate or greater intensity that involve all major muscle groups on 2 or more days a week. The major muscle groups are the legs, hips, back, chest, abdomen, shoulders, and arms. No specific amount of time is recommended, but exercises should be performed to the point at which it would be difficult to do another repetition. When using resistance training to enhance muscle strength, one set of 8 to 12 repetitions of each exercise is effective, although 2 or 3 sets may be more effective.
ACE echoes this guidance, stating that one set of 8 to 12 repetitions, working the muscle to the point of fatigue, is usually sufficient. Training each muscle group at least two times per week is recommended, with a minimum of two days of rest between workouts for the same muscle group. The NIA also advises avoiding work on the same muscle group on any two days in a row to allow for muscle recovery.
To continue making progress, ACE suggests increasing the resistance by 5 percent to 10 percent once you can perform 12 repetitions of an exercise correctly and without cheating. The HHS guidelines confirm that improvements in muscle strength and endurance are progressive over time, and increases in the amount of weight or the days a week of exercising will result in stronger muscles.
Choosing Your Equipment: Weights, Bands, and Bodyweight
Resistance training can be done with a variety of tools. HHS lists lifting weights, resistance bands, and bodyweight exercises as effective options. ACE notes that both machines and free weights are effective tools, and using a combination of the two provides variety that reduces boredom and the risk of overuse injury.
If you are using resistance bands, safety is essential. The THERABAND care and safety instructions emphasize inspecting the band for damage before and after each use. Do not use a band that is torn, punctured, or nicked; discard it immediately. Avoid sharp objects such as jewelry, rings, or fingernails that may puncture the band. Use the band only in an open area free of tripping hazards and never on wet or slippery floors. Wear eye protection, and do not over-stretch the product beyond three times its length at rest. Perform all exercises in a slow, controlled manner, and never let go of the band while it is under tension. Stop exercising if you experience dizziness, trouble breathing, increased pain, or begin to feel sick, and contact your healthcare provider immediately.
For free weights, the CDC and Tufts University’s Growing Stronger program advises starting with 2- to 3-pound dumbbells and ankle weights to reduce the risk of injury. After completing one week (or three sessions), reassess the intensity: if any exercise feels easy and you can complete more than 10 repetitions with proper form, start using heavier weights. The program also cautions never to wear ankle weights or hold dumbbells while walking or doing other aerobic exercises such as biking or jogging.
Bodyweight exercises require no equipment and can be done almost anywhere. HHS and the NIA both include push-ups, pull-ups, planks, squats, and lunges as examples of muscle-strengthening activities. The NIA suggests that beginners try exercises without weights or resistance bands until they are comfortable with the movements.
How to Perform Resistance Exercises Safely
Proper technique helps you get the most from your training while reducing the risk of injury. ACE recommends lifting the weight to a count of two and lowering it to a count of three or four, moving through the full range of motion in a slow, controlled cadence. The Growing Stronger program similarly instructs that exercises should be done in a slow, controlled motion, without letting momentum do the work. The NIA adds that you should breathe out during the effort and breathe in as you relax, and avoid holding your breath. It also advises against locking your arm and leg joints in a straight position.
A warm-up for muscle-strengthening activity commonly involves doing exercises with lighter weight, according to HHS and the NIA. If you are unsure about a particular movement, ACE recommends consulting a certified fitness professional to learn safe technique before beginning a strength-training program.
Rest between sets is important. The Growing Stronger program includes rest periods of about 1 minute between sets for exercises like the biceps curl and step-ups, and 1 to 2 minutes for exercises such as the knee extension and knee curl. These rest intervals allow muscles to recover enough to perform the next set with good form.
Putting It All Together: A Simple Checklist
Use this checklist to build a safe and effective resistance training habit.
- Check with a healthcare provider if you have a chronic condition, are pregnant, or have been inactive. HHS notes that healthy adults who plan gradual increases generally do not need to consult a provider, but the THERABAND instructions and NIA both recommend seeking approval if you have a medical condition.
- Choose exercises that target all major muscle groups. Include movements for the legs, hips, back, chest, abdomen, shoulders, and arms.
- Warm up by performing the exercises with lighter weight or easier variations.
- Perform 1 to 3 sets of 8 to 12 repetitions of each exercise, working to the point where another repetition would be difficult.
- Move slowly and with control, breathing out during the effort and never holding your breath.
- Rest about 1 to 2 minutes between sets.
- Increase the resistance by 5 to 10 percent when you can complete 12 repetitions with proper form.
- Allow at least two days of rest before working the same muscle group again (ACE), and avoid working the same muscle group two days in a row (NIA).
- Stop and seek help if you feel dizziness, chest pain, or severe shortness of breath.
Frequently asked questions
How often should I do resistance training?
HHS recommends muscle-strengthening activities on 2 or more days a week. ACE advises training each muscle group at least two times per week, with a minimum of two days of rest between sessions for the same muscle group. The NIA also suggests avoiding work on the same muscle group on consecutive days.
Can I use resistance bands instead of weights?
Yes. Resistance bands provide an effective way to overload muscles, and HHS lists them as a muscle-strengthening option. Follow the safety instructions provided with your bands: inspect them before each use, avoid over-stretching, wear eye protection, and never let go while the band is under tension.
What if I have a health condition or am pregnant?
The HHS guidelines state that women who are pregnant and adults with chronic conditions or disabilities are discussed separately and should consult a health care provider. The THERABAND safety information also advises consulting your healthcare provider before starting any exercise program if you have a medical condition.
For more detailed guidance on building a resistance training routine, visit our Resistance Training category page. You can also explore our Strength Training section and the Strength Training Basics article for foundational advice on sets, reps, and progression. To learn more about safe movement patterns, see our Exercise Form guide. If you are using bands, check the Resistance Bands equipment page for additional tips.
