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Resistance-Training Principles Part 1: The Basics

Author: Stan Reents, PharmD
Original Posting: 05/06/2007 01:05 PM
Last Revision: 01/15/2016 08:28 AM

This article will review weight-training, more accurately known as "resistance-training." Since there is so much information on this topic, the discussion will be divided into 2 separate parts: Part 1 will cover the basics. Part 2 will discuss more advanced theories and principles.

In these discussions, the term "strength-training" will not be used since working out with weights (or other forms of resistance) increases not only muscular strength, but improves muscular "endurance" and muscular "size" as well.

Also, note that weights (barbells, dumbells) and weight-machines are not the only way to provide resistance. Resistance can be generated from working out with springs, rubber bands, or exercise machines like Bow-Flex(tm). Resistance training can also be achieved by using your body weight as the source of the resistance (for example, pull-ups, push-ups, dips, squats, and sit-ups). Even isometric exercises produce increases in strength.

In fact, for some exercises, such as push-ups, pull-ups, sit-ups, dips, barbells aren't even an option. To add resistance to these exercises, consider using a weighted vest, such as the X-Vest(tm), a wearable vest that can hold anywhere from 1 to 84 pounds of weight.

Resistance can be added to running and biking, too. It just requires a little creativity. Everyone knows that running or biking uphill is a lot harder than the same activity on a level surface. Some athletes add resistance to their running program by pulling a parachute or a weight sled behind them.

But, before we review specific training principles, let's go over some definitions...


Intensity and Volume: "intensity" is the amount of weight lifted; "volume" is calculated from the amount of weight lifted and how many times that weight is lifted.

Muscular Endurance: generally reflects how long a muscle can work before becoming fatigued.

Muscular Strength: determined by the maximum amount of weight that can be lifted once. The 1-RM value is a measurement of muscular strength.

"1-RM": stands for "1 repetition maximum." The most weight you can lift one-time-only is your "1-RM" for that exercise. So, if you can only bench-press 120 lbs once, then your 1-RM for that exercise is 120 lbs. If you can bench-press a particular weight 8 times in a row (but no more than that), then that weight is known as your "8-RM.. Thus, as you progress from 8-RM to 6-RM to 4-RM, the amount of weight increases.


A "set" is one series of repetitions. If you bench-press a certain weight 12 times, rest 5 minutes, and then bench-press it again 12 more times, you have done 2 sets of 12 reps. Here are some terms for other types of sets:

Straight Sets: the "standard" weight-lifting workout: a number of reps followed by a rest period, then one or more sets of that same exercise.

Super Sets: a set of each of two different exercises performed back-to-back without resting between each one.

Tri-Sets: Three different exercises performed one after another, without any rest in between.

Drop Sets (aka, descending sets): Three or four sets of one exercise performed without rest, using a lighter weight with each successive set.

Circuit Sets: a series of exercises (usually 6) that are completed in succession without rest.

Next, let's discuss the concept of adaptation.


The concept of a "general adaptation" response as it pertains to human physiology was first proposed by Hans Selye, MD, PhD. During his second year of medical school (1926), he began developing his now-famous theory of the influence of physiologic stress on the body's ability to cope with and adapt to the pressures of injury and disease. He discovered that patients with a variety of ailments manifested many similar symptoms, which he ultimately attributed to their bodies' efforts to respond to the stresses of being ill. He called this collection of symptoms "stress syndrome," or the general adaptation syndrome (GAS).

Today, we know that the human body has an amazing capacity to adapt. And this can be demonstrated in terms of fitness, too. For example, when subjected repeatedly to strenuous aerobic exertion, a myriad of changes begin to occur in the cardiovascular system. Stroke volume increases tremendously and capillary growth is stimulated to help deliver more oxygen to muscles. These 2 factors in turn lead to a decrease in resting heart rate since the efficiency of oxygen uptake by skeletal muscle is improved.

Metabolic adaptations occur, too. The body gets more efficient at utilizing not only oxygen, but also, carbohydrates and fats for energy. The sweating reflex becomes more efficient if you train in hot/humid conditions. Training at an elevated altitude stimulates red blood cell production to compensate for the lower amount of oxygen in the air.

Each of the above examples qualifies as "physiologic stress." These changes take several weeks to months to develop. It is important to think of stress in this case as neither positive or negative, but, rather, as simply a "challenge" to the status quo of a particular system in the body.


The "general adaptation response" also applies to resistance training. It seems like such a simple concept: Muscles get stronger as a result of being forced to contract against higher amounts of resistance.

However, when weights are used to produce increases in strength, variables such as how much weight you lift and how many repetitions you do can yield vastly different results.

Consider the following theoretical example:

A 17-year-old, 180-lb high-school football player can bench-press more than a 44-year-old 200-lb full-time carpenter. How is it possible that a teenager is actually stronger than a grown man who does physical labor all week long?

The answer lies in 2 explanations: (a) specificity and (b) the amount of weight each person "works out" with.

Even though both men are doing exercises that challenge their shoulders and upper arms, and, even though the carpenter may swing that hammer 1000 times per week, the hammer weighs less than 2 pounds. The high-school football player, however, regularly performs bench press exercise with 150 lbs on the barbell. So, in this case, the "intensity" of exercise for the carpenter is extremely low.

Second, muscles respond in a very specific way. The motion of swinging a hammer is much different than the motion of the bench press. Yes, both "exercises" require contraction of the triceps muscle, but that's where the similarity ends. Pounding nails with a hammer involves movement more like a triceps extension, whereas the bench press requires substantial contribution from the deltoids and pectorals as well as the triceps. Thus, if we put both men on the bench-press and assessed their 1-RM, the high school football player would likely record a higher value (assuming the high-schooler had been practicing the bench press for at least several weeks prior to the test).

If, however, we measured forearm (grip) strength, we might find that this muscle group is much stronger in the carpenter than the same muscle group for the high-school football player. Here again, the explanation is specificity of exercise. Swinging a hammer requires a tremendous amount of forearm strength (and muscle endurance). The bench press does not really challenge the forearm muscles in the same manner.


So, specificity of exercise is important for building muscle strength. This brings us back to Hans Selye's concept of overload. Regardless of whether we are talking about males vs. females, old subjects vs. young, endogenous testosterone levels, or grams of protein in the daily diet, the #1 most important factor in developing muscular strength is the amount of resistance (ie., the amount of weight lifted). When a muscle is repeatedly forced to contract against resistance, it responds by getting stronger.

An almost unbelievable example of the capacity of the muscular system to adapt is represented by Gene Rychlak: In November 2003, at the International Powerlifting Assoc. championships in Harrisburg, PA, 35-year-old Rychlak bench-pressed...900 pounds!

So, somewhere between a 2-lb hammer, and a 900-lb barbell, is the "magic" weight that stimulates muscle strength to increase. According to William Kraemer, PhD, that magic weight lies between 50% and 100% of the 1-RM for a given muscle group (Kraemer WJ. 2003).


So, how are 1-RM values determined? One method that is NOT endorsed is to load up a barbell with the most weight you have ever lifted and see if you can lift that weight once. Not only do some health clubs prohibit this, but you can get injured.

Instead, use a weight that you know you can lift 4-10 times in a row. (Collegiate and NFL football players are typically tested using a standard 225-lb bench press test.) Do as many reps with that weight as you can. Then, plug the weight and the number of reps into this equation:

Weight / [1.0278 - (0.0278 x no. of reps)] = 1-RM

For example, if you can bench-press 120 lbs five times in a row, then your 1-RM for the bench-press is 135 pounds.

This formula is known as the Brzycki equation (Brzycki M. 1993). At least 11 different equations have been derived to calculate 1-RM, but the Brzycki equation is regarded as very accurate (Mayhew JL, et al. 1995). Other equations are also good, however the validity of all of these equations (for predicting 1-RM) is best when the number of repetitions is kept low (Mayhew JL, et al. 1995) (Whisenant MJ, et al. 2003).

While your personal 1-RM values might be worth bragging rights, the real purpose for knowing these limits for each exercise is to have a basis for designing your training regimen (see below). There is more to lifting weights than simply picking up a barbell and trying to lift it as many times as you can. Serious body-builders and weight-lifters often have elaborate regimens that they follow.

Now we can discuss how the 1-RM value is used to design a specific resistance-training program....


The 2 main points required to design a resistance-training regimen are:

a) know your 1-RM value for each exercise.

b) decide whether you want to build maximum strength and power, strength and size, or muscular endurance.

To maximize increases in strength, use higher weights (eg., 8-RM to 4-RM) and perform fewer repetitions. To increase muscular endurance, generally you would do the opposite.

Here is an example of how different weight-repetition combinations can achieve different results:

Resistance exercise for the back: Stuart McGill, PhD, a professor at University of Waterloo in Ontario, and a leading authority on back pain and rehabilitation, points out that, to rehab the back muscles, the best strategy is to use a low amount of weight and a relatively high number of repetitions. For example, in a Norwegian study, the exercise program had subjects perform 2-3 sets of 20-30 reps for each back exercise (Torstensen TA, 1998).

Resistance exercise for cycling: Conversely, in a recent study of resistance-training to improve performance in cyclists (Loveless DJ, et al. 2005), the following formula was used to build leg strength:

  • squats performed at 85% of 1-RM
  • 5 reps per set
  • 4 sets on each exercise day
  • 3 days per week for 8 weeks

In the back exercise study, subjects performed as many as 90 reps per exercise. But, in the cycling study, subjects performed no more than 20 reps per exercise. This illustrates how resistance-training programs can be designed to develop muscle endurance (eg., low weight with high number of reps) or muscle strength and power (eg., heavy amounts of weight with a low number of reps).

• F (frequency) 2-3 days/week
(rest each muscle group
for 48 hrs after training)
2-3 days/week
(rest each muscle group
for 48 hrs after training)
• I (intensity) use a weight that causes
muscle "failure" after 8-12 reps
use a weight that causes
muscle "failure" after 20-30 reps
• T (time) perform 1-3 sets
of each exercise
perform 1-3 sets
of each exercise
• T (type) • free weights
• weight machines
• resistance bands
• push-ups
• pull-ups
• dips
• crunches, etc.
• free weights
• weight machines
• resistance bands


In Part 2, I will review more sophisticated concepts that have been employed in designing resistance-training regimens. But, for beginners, the following guidelines should be kept in mind:

• Never attempt to lift heavy weights over your head, or bench-press without a spotter.

• A good starting weight is one that allows you to do 12-20 repetitions. You can then build up from there. With each exercise, you should attain momentary muscle failure after about 30-90 seconds.

• Emphasize slow speed (about 4-5 seconds per repetition) and proper form over trying to lift higher amounts of weight.

• Work the larger muscle groups (back, chest, thighs) first, then progress outward to smaller muscle groups (biceps, forearms, calves).

• Alternate "pushing" exercises with "pulling" exercises in each session. For example, combine hamstring curls with squats; combine barbell rows with the bench press.

• Weight-training for strength: Increase the weight of each lift and decrease number of repetitions. Begin with a weight that brings you to momentary muscle failure after 8-12 repetitions.

• Weight-training for muscle endurance: Decrease the weight and perform a higher number of repetitions (ie., 12-20 reps).

• Protect your knees: Do not do squats or leg-press exercises where you allow the knee joint to go past 90-degrees. When doing lunges, do not let your knee extend forward farther than the foot (on the same leg).

• Protect your shoulders: Do not do flye exercises where you let your elbows drop below the level of your chest.

• Protect your back at all times: Refrain from lifting any amount of weight by bending at the waist and lifting with your back muscles. When doing bent-over rows, use a dumbell instead of a barbell and exercise one side at a time. For example, if you are lifting with your right arm, support your spine by placing your left hand and left knee on a bench.


Everyone, including the elderly, should incorporate some type of resistance exercise into their weekly fitness plan. Resistance exercise is beneficial for conditions such as:

  • improving bone density
  • improving cardiovascular health
  • improving balance and stability
  • reducing low back pain

These issues are covered in detail in other reviews (see Articles).

While some beginners may find the formulas discussed above to be far too complex for their exercise and/or training plan, the concepts are really quite simple:

• If you want to build strength, first determine your 1-RM and calculate a training regimen from that value. Reassess your 1-RM periodically and adjust your training regimen accordingly.

• If you want to improve your muscular endurance (cyclists, rowers, tennis players, etc.), then use less weight and more repetitions.

• Use good form, protect your back and your knees, use a spotter when necessary, and don't ignore rest periods.


Human Kinetics ( is the world's leading publisher of exercise, fitness, and sports resources. The following books are good sources of information for resistance-training athletes:

Building Strength & Stamina (Human Kinetics, 2003) by Wayne Wescott. Wayne Wescott has been publishing quality texts on strength-training for over 20 years.

Fitness Weight Training (Human Kinetics, 2005) by Baechle and Earle.

Men's Body Sculpting (Human Kinetics, 2004) by Nick Evans, MD.

Strength Training For Women (Human Kinetics), by Lori Incledon, may be helpful to women who are less experienced with resistance training.

The X-Vest(tm) can be ordered at:

To learn more about the benefits of resistance-training on health and various disease states, see:


Stan Reents, PharmD, is available to speak on a variety of exercise-related topics. (Here is a downloadable recording of one of his Health Talks.) He also provides a one-on-one Health Coaching Service. Contact him through the Contact Us page.


Baechle T, Groves B. Weight Training: Steps to Success, 2nd ed., 1999, Human Kinetics, Champaign, IL.

Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. JOHPERD 1993;64:88-90. (no abstract)

Kraemer WJ. Strength training basics. Phys Sportsmed 2003;31:39-45. (no abstract)

Kraemer WJ, Ratamess NA. Fundamentals of resistance training: progression and exercise prescription. Med Sci Sports Exerc 2004;36:674-688. Abstract

Loveless DJ, Weber CL, Haseler LJ, et al. Maximal leg-strength training improves cycling economy in previously untrained men. Med Sci Sports Exerc 2005;37:1231-1236. Abstract

Mayhew JL, Prinster JL, Ware JS, et al. Muscular endurance repetitions to predict bench press strength in men of different training levels. J Sports Med Phys Fitness 1995;35:108-113. Abstract

Quill S. Get Sets, Grow. Men's Health, May 2004, pp. 120-123. (no abstract)

Torstensen TA, Ljunggren AE, Meen HD, et al. Efficiency and costs of medical exercise therapy, conventional physiotherapy, and self-exercise in patients with chronic low back pain: a pragmatic, randomized, single-blinded, controlled trial with 1-year follow-up. Spine 1998;23:2616-2624. Abstract

Whisenant MJ, Panton LB, East WB, et al. Validation of submaximal prediction equations for the 1 repetition maximum bench press test on a group of collegiate football players. J Strength Cond Res 2003;17:221-227. Abstract


Stan Reents, PharmD, is a former healthcare professional. He is a member of the American College of Sports Medicine (ACSM) and holds current certifications from ACSM (Health & Fitness Specialist), ACE (Health Coach) and has been certified as a tennis coach by USTA. He is the author of Sport and Exercise Pharmacology (published by Human Kinetics) and has written for Runner's World magazine, Training and Conditioning, Club Solutions, and other fitness publications.

DISCLOSURE: Neither the author, nor AthleteInMe, LLC, has any financial relationships with any of the corporations or products mentioned in this review.

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