Resistance Exercise

Author: Richard Weil, MEd, CDE
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

What is resistance exercise?

Resistance exercise is any exercise where muscles contract against an external resistance with the objective of increasing strength, tone, mass, and/or muscular endurance. The resistance can come from dumbbells, weight machines, elastic tubing or bands, cinder blocks, cans of soup, your own body weight (for example, pushups), or any other object that forces your muscles to contract. Results occur when you train consistently over time.

What are types of resistance exercise?

There are several types or styles of resistance exercise. Power lifting (a weight-lifting competition in which participants compete in the squat, dead lift, and bench press), Olympic weight lifting (the type you see on TV where athletes lift the weight overhead), strength training (lifting weights to get stronger), and weight lifting (the sport of lifting heavy weight, typically fewer than six repetitions). Weight lifting should not be confused with "weight training," which is the general lifting that you do at the gym. I'll discuss the basic principles of all resistance exercise in this article.

What is progressive overload?

One of the fundamentals of resistance exercise is the principle of progressive overload. Progressive overload means that you increase the workload gradually over time as your muscles accommodate to the resistance with the objective of gaining strength and/or mass. For example, suppose that you've been lifting biceps curls for two weeks with 12 pounds, 10 repetitions, and then at week three, 12 pounds is easy and you can lift more. According to the principle of progressive overload, at this point, you would increase the weight if strength improvement is your goal. Your strength will remain the same if you keep the weight the same.

What is volitional fatigue?

Another fundamental of resistance exercise is to lift each set to volitional fatigue. Volitional fatigue is the point in the set where you can't lift one more rep without cheating it up (using momentum, leaning way back, etc.). Although there isn't a large body of research to prove that lifting every set to volitional fatigue is necessary for maximal benefit, most strength and fitness professionals agree that working to exhaustion changes muscle fibers in a way that leads to significant growth.

What are sets and repetitions (reps)?

Sets and reps are the terms used to describe the number of times you perform an exercise. A rep is the number of times you perform a specific exercise, and a set is the number of cycles of reps that you complete. For example, suppose you complete 15 reps of a bench press. You would say you've completed "one set of 15 reps." A set can be any number of reps, so if you complete 10 reps of a bench press, you would say you've completed "one set of 10 reps," and if you complete just five reps, then that would be "one set of five reps."

How many sets should I do?

Research is clear that beginners can develop as much strength performing one set per exercise as they can performing three sets. This is because beginners typically start off with a low level of strength which leaves room for improvement (called an "adaptive window"). Muscles respond quickly to resistance exercise in untrained individuals because the adaptive window is large. This is great news because the motivation to continue working out is reinforced by immediate and significant improvement. However, after three to four months, strength gains will level off and then multiple sets (three to five per exercise) are necessary if more improvement is desired.

How do I go about lifting for strength?

Muscular strength is gained when you lift heavy. For pure strength development, keep the resistance heavy enough so that you cannot lift more than eight reps, and then follow the progressive overload principle and increase the weight when you can lift more then eight. Expect your reps to drop whenever you increase the weight. For example, suppose you've been doing 10 reps of bench presses with 175 pounds and you increase the weight to 190 pounds. Because the weight is heavier, you will lift fewer reps, but as your muscles accommodate, you will again be able to lift more reps. When strength is your priority, you can experiment with heavy days. Heavy days are when you lift as much as you can one time. This is called a one-repetition maximum (a 10-rep maximum would be the weight you can lift 10 times to fatigue). Heavy days are challenging, so I don't recommend them more than once a week so that your muscles have time to recover and grow.

How do I go about lifting for tone and endurance?

Tone and endurance is maximized when you keep the weight light enough to lift 12-15 reps. Again, the principle of progressive overload applies. That is, increase the weight when 15 reps become easy.

Lifting for strength, tone, and endurance (general conditioning)

Keeping the reps in the eight-to-12 range emphasizes a combination of strength, tone, and endurance. This is a realistic quantity of training for most individuals. The recommendation in the American College of Sports Medicine Position Stand, "Progression Models in Resistance Training for Healthy Adults," is for beginners to lift eight to 12 reps, and for the range to widen to one to 12 reps for intermediate and advanced training. Although research supports the eight to 12 recommendation, I believe it's prudent for beginners to start with 12-15 reps to reduce the risk of injury, and then the weight can be increased after a few weeks when the muscles have accommodated. Keep in mind that strength, tone, and some mass still accrue by training with reps in the 12-15 range, and so you don't have to lift heavier than that if you prefer not to. You can read the entire ACSM position stand document here: www.acsm-msse.org/pt/pt-core/template-journal/msse/media/0202.pdf.

How many days should I lift?

Beginners, because of their wide adaptive window, will accrue significant benefits with two to three days of training. Advanced lifters need at least three days per week, and typically more for significant gains because they are already so strong (more benefit takes more effort). It's not uncommon for bodybuilders and other strength athletes to train four to five days per week.

How do I know how much weight to lift?

Trial and error is the way to determine how much weight to lift. Select a weight that looks close to what you think you can lift based on your goals. If general conditioning is your goal, then select a weight you think you can lift eight to 12 reps (or 12-15 reps for beginners). If you can lift it 25 times with ease, then it's too light, and if you can lift it only four times, then it's too heavy. There are no formulas to calculate this. Simply decide what your goal is so you know how many reps to lift, take a guess by looking at the weights, and then give it a try. You'll get good at this quickly.

How much do I increase?

Unlike aerobic conditioning where duration and intensity is increased by 10%, increases in the weight you lift aren't prescribed with such precision, partly because muscle groups vary so much in size and strength, and partly because of the practical matter of the weights available at the gym. Typically you increase to whatever dumbbell is next on the rack (or plate on a weight machine), and so if you're lifting 12 pounds with biceps curls, then the next dumbbell available is usually 15 pounds. There is an option to increase in smaller increments with dumbbells by using an accessory called a donut, a magnetic 1¼ pound weight that attaches to the end of the dumbbell (they come in other weights besides 1¼ pounds as well). Weight machines have half weights for the same purpose. Ask your gym manager to purchase donuts if they don't have them.

Free weights vs. machines

Dumbbells and barbells are free weights. They are "free," or untethered, unlike a weight machine where the weight stack is connected by cables to cams and pulleys and only move in one direction. There are advantages to both styles of lifting.

Weight machines:

1. Weight machines are easy to learn and use.

2. There are some exercises you can do with a machine that you can't do with a dumbbell. For instance, cable rows would be difficult to replicate with free weights. You could do bent over dumbbell rows, but they won't be quite the same. For my money, cable rows feel smoother than any exercise in the gym!

Free weights:

How important is the order in which I perform my exercises?

Research shows that the order of exercises can significantly affect strength development, and so it is standard practice to set up a resistance-training routine to work large muscle groups before smaller ones. The reason is that a small muscle group that fatigues first will be the weakest link in the chain and prevent large muscle groups from working to full capacity. For example, if you isolate and fatigue your biceps muscles with curls, and then try to do lat pull-downs (which use biceps, shoulders and back), you won't be able to do as much work for your shoulders and back because your biceps will already be fatigued. In the starter programs below, you will see examples of working large to small muscle groups.

What are weight-lifting splits?

A split refers to the practice of dividing workouts by muscle group. For example, you can work all upper body muscles on one day and lower body on another. Or you could work all the pushing muscles (triceps, pecs, anterior shoulder) on one day, and the pulling muscles (biceps, lats, rhomboids, posterior shoulder) on another. There are many possible combinations of splits, and I suggest that you experiment to find what works best for you. In the starter programs below, you will see examples of a split.

How much should I rest between sets and between days?

The amount of time you rest between sets can significantly affect your results. Rest up to three minutes between sets if pure strength development is your priority, and one to two minutes if muscular endurance and tone is your priority. Three minutes permits the muscles to recover from fatigue so that you can generate enough energy to perform another maximal lift on the next set. Benefits are not discreet. That is, there is carryover from one style to another, so that if you rest just one minute between sets, you will still increase endurance and tone, and if you rest three minutes between sets, you will still gain endurance and tone. The number of days that you rest between workouts can also affect your results. The standard advice is to rest two days between workouts. This makes sense if you push hard, since the muscles need time to recover and grow. In fact, it can take up to five days for muscles to fully recover from a tough workout, and if you push too hard, you might experience symptoms of overtraining (fatigue, loss of strength, inability to lift 100%, chronic soreness, and persistent injuries). It's okay to lift two days in a row. Experienced lifters do it all the time by splitting their workout so that they work one muscle group per day. For example, they might work their upper body on one day, and legs on another, or back muscles on one day, and chest muscles on the next. Experiment with different splits until you find what works best for you.

The golden rule is to remember that muscles recover and grow during downtime, not when you train, and so it's important to take time off. You know you need more rest if you have any symptoms of overtraining.

I wrote a response to this question in the Ask the Experts section that you can find here: www.medicinenet.com/script/main/art.asp?articlekey=77873. I mentioned in my response that there is no research to show the proper form for any resistance exercise. People are built and move differently, and so you need to listen to your body when you perform resistance exercises and make sure that you feel it in the muscles that you want to work. The basics rules I propose in my response are (1) take your time and lift mindfully, (2) feel it in the belly of the muscle you're trying to work, and not in the joints, and (3) select weights that your body can handle without having to cheat or force the weight up (leaning way back, using momentum, etc.).

What are the benefits of weight lifting? Is it ever too late to start?

New benefits of resistance exercise seem to be discovered all the time. Research to date shows that resistance exercise is associated with improvements in all of the following:

• muscular strength and endurance
• functional capacity and ability (falling, climbing stairs)
• blood pressure
• osteoporosis
• sarcopenia (loss of muscle as we age)
• low back pain
• insulin resistance and glucose metabolism
• resting metabolic rate
• body fat
• psychological well-being

Is it ever too late?

It's never too late to start a resistance-exercise program. In a classic study in a Boston nursing home, 100 residents ranging from 72 to 98 years of age performed resistance exercise three times a week for 10 weeks. Muscle strength increased 113%, walking speed increased by almost 12%, and thigh-muscle area increased 2.7%!

Weight-lifting programs

You'll find two starter programs below. They are broken up by muscle group and are three days per week. You can experiment with splits, exercises, and the number of days per week. I suggest 12-15 repetitions and one to three sets per exercise for beginners (remember, you can gain significant strength with just one set). I've included more than one exercise for each muscle group. You can stick with one exercise if you like, or experiment with more than one. Use the principle of progressive overload and increase the weight when you can perform 15 reps easily. If you're using elastic tubing, start with the tube that you can lift 12-15 times to fatigue, and then increase when you get stronger.

Day 1: Chest (bench press with bar or dumbbell press, flies, pushups), triceps (bench dips, kickbacks)

Day 2: Back (bent-over rows), biceps (curls, standing or seated)

Day 3: Shoulders (lateral raises, front raises), legs (squats, lunges)

Here's a different split.

Day 1: Chest (bench press with bar or dumbbell press, flies, pushups), back (bent-over rows, pull-downs)

Day 2: Biceps (curls, standing or seated), triceps (bench dips, kickbacks)

Day 3: Shoulders (lateral raises, front raises), legs (squats, lunges)

It's worth it!

Resistance exercise is worth it. You'll gain strength, endurance, and confidence. It's feels great to feel strong, and I encourage you to give it a try! Remember, it's never too late to start!

Last Editorial Review: 4/19/2007