Strength training

This article is about the basic principles to train muscular strength. For strength training using free weights or weight machines, see weight training.

Strength training is a type of physical exercise specializing in the use of resistance to induce muscular contraction which builds the strength, anaerobic endurance, and size of skeletal muscles.

When properly performed, strength training can provide significant functional benefits and improvement in overall health and well-being, including increased bone, muscle, tendon and ligament strength and toughness, improved joint function, reduced potential for injury, increased bone density, increased metabolism, increased fitness, improved cardiac function, and improved lipoprotein lipid profiles, including elevated HDL ("good") cholesterol. Training commonly uses the technique of progressively increasing the force output of the muscle through incremental weight increases and uses a variety of exercises and types of equipment to target specific muscle groups. Strength training is primarily an anaerobic activity, although some proponents have adapted it to provide the benefits of aerobic exercise through circuit training.

Sports where strength training is central are bodybuilding, weightlifting, powerlifting, strongman, Highland games, shotput, discus throw, and javelin throw. Many other sports use strength training as part of their training regimen, notably American football, wrestling, track and field, rowing, lacrosse, basketball, pole dancing, hockey, professional wrestling, and soccer. Strength training for other sports and physical activities is becoming increasingly popular.

Uses

The benefits of weight training include greater muscular strength, improved muscle tone and appearance, increased endurance and enhanced bone density.

Increased physical attractiveness

Many people take up weight training to improve their physical attractiveness. There is evidence that a body type consisting of broad shoulders and a narrow waist, attainable through strength training, is the most physically attractive male attribute according to women participating in the research. Most men can develop substantial muscles; most women lack the testosterone to do it, but they can develop a firm, "toned" (see below) physique, and they can increase their strength by the same proportion as that achieved by men (but usually from a significantly lower starting point). An individual's genetic make-up dictates the response to weight training stimuli to a significant extent.

Workouts elevate metabolism for several hours following the workout, which also promotes fat loss.

Increased general physical health

Strength training also provides functional benefits. Stronger muscles improve posture, provide better support for joints, and reduce the risk of injury from everyday activities. Older people who take up weight training can prevent some of the loss of muscle tissue that normally accompanies aging—and even regain some functional strength—and by doing so become less frail. They may be able to avoid some types of physical disability. Weight-bearing exercise also helps to prevent osteoporosis and to improve bone strength in those with osteoporosis. The benefits of weight training for older people have been confirmed by studies of people who began engaging in it even in their 80s and 90s.

Though strength training can stimulate the cardiovascular system, many exercise physiologists, based on their observation of maximal oxygen uptake, argue that aerobics training is a better cardiovascular stimulus. Central catheter monitoring during resistance training reveals increased cardiac output, suggesting that strength training shows potential for cardiovascular exercise. However, a 2007 meta-analysis found that, though aerobic training is an effective therapy for heart failure patients, combined aerobic and strength training is ineffective.

Strength training may be important to metabolic and cardiovascular health. Recent evidence suggests that resistance training may reduce metabolic and cardiovascular disease risk. Overweight individuals with high strength fitness exhibit metabolic/cardiovascular risk profiles similar to normal-weight, fit individuals rather than overweight unfit individuals.

For rehabilitation or to address an impairment

For many people in rehabilitation or with an acquired disability, such as following stroke or orthopaedic surgery, strength training for weak muscles is a key factor to optimise recovery. For people with such a health condition, their strength training is likely to need to be designed by an appropriate health professional, such as a physiotherapist.

Increased sports performance

Stronger muscles improve performance in a variety of sports. Sport-specific training routines are used by many competitors. These often specify that the speed of muscle contraction during weight training should be the same as that of the particular sport.

For the pleasure of the activity

One side effect of any intense exercise is increased levels of dopamine, serotonin, and norepinephrine, which can help to improve mood and counter feelings of depression.

Developing research has demonstrated that many of the benefits of exercise are mediated through the role of skeletal muscle as an endocrine organ. That is, contracting muscles release multiple substances known as myokines which promote the growth of new tissue, tissue repair, and various anti-inflammatory functions, which in turn reduce the risk of developing various inflammatory diseases.

Technique

The basic principles of strength training involve a manipulation of the number of repetitions (reps), sets, tempo, exercises and force to cause desired changes in strength, endurance or size by overloading of a group of muscles. The specific combinations of reps, sets, exercises, resistance and force depend on the purpose of the individual performing the exercise: to gain size and strength multiple (4+) sets with fewer reps must be performed using more force. A wide spectrum of regimens can be adopted to achieve different results, but the classic formula recommended by the American College of Sports Medicine reads as follows:

• 8 to 12 repetitions of a resistance training exercise for each major muscle group at an intensity of 40% to 80% of a one-repetition max (RM) depending on the training level of the participant.
• Two to three minutes of rest is recommended between exercise sets to allow for proper recovery.
• Two to four sets are recommended for each muscle group

Typically failure to use good form during a training set can result in injury or an inability to meet training goals – since the desired muscle group is not challenged sufficiently, the threshold of overload is never reached and the muscle does not gain in strength. There are cases when cheating is beneficial, as is the case where weaker groups become the weak link in the chain and the target muscles are never fully exercised as a result.

The benefits of strength training include increased muscle, tendon and ligament strength, bone density, flexibility, tone, metabolic rate and postural support.

Terminology

Strength training has a variety of specialized terms used to describe parameters of strength training:

• Exercise – different movements which involve rotating joints in specific patterns to challenge muscles in different ways.
• Form – each exercise has a specific form, a topography of movement designed to maximize safety and muscle strength gains.
• Rep – short for repetition, a rep is a single cycle of lifting and lowering a weight in a controlled manner, moving through the form of the exercise.
• Set – a set consists of several repetitions performed one after another with no break between them with the number of reps per set and sets per exercise depending on the goal of the individual. The number of repetitions one can perform at a certain weight is called the Rep Maximum (RM). For example, if one could perform ten reps at 75 lbs, then their RM for that weight would be 10RM. 1RM is therefore the maximum weight that someone can lift in a given exercise – i.e. a weight that they can only lift once without a break.
• Tempo – the speed with which an exercise is performed; the tempo of a movement has implications for the weight that can be moved and the effects on the muscle.

Realization of training goals

According to popular theory:

• Sets of one to five repetitions primarily develop strength, with more impact on muscle size and none on endurance.
• Sets of six to twelve repetitions develop a balance of strength, muscle size and anaerobic endurance.
• Sets of thirteen to twenty repetitions develop anaerobic endurance, with some increases to muscle size and limited impact on strength.
• Sets of more than twenty repetitions do still use the anaerobic system, but usually at a rate through which it can consistently remove the lactic acid generated from it.

Individuals typically perform one to six sets per exercise, and one to three exercises per muscle group, with short breaks between each set – the specific combinations of reps, exercises, sets and break duration depends on the goals of the individual program. The duration of these breaks determines which energy system the body utilizes. Performing a series of exercises with little or no rest between them, referred to as "circuit training", will draw energy mostly from the aerobic energy system. Brief bursts of exercise, separated by breaks, are fueled by anaerobic systems, which use either phosphagens or glycolysis.

For developing endurance, gradual increases in volume and gradual decreases in intensity is the most effective program.

It has been shown that for beginners, multiple-set training offers minimal benefits over single-set training with respect to either strength gain or muscle mass increase, but for the experienced athlete multiple-set systems are required for optimal progress. However, one study shows that for leg muscles, three sets are more effective than one set.

Beginning weight-trainers are in the process of training the neurological aspects of strength, the ability of the brain to generate a rate of neuronal action potentials that will produce a muscular contraction that is close to the maximum of the muscle's potential.

Variable	Training goal
	Strength	Power	Hypertrophy	Endurance	Speed
Load (% of 1RM)	90–80	60–45	80–60	60–40	30
Reps per set	1–5	1–5	6–12	13–60	1–5
Sets per exercise	4–7	3–5	4–8	2–4	3–5
Rest between sets (mins)	2–6	2–6	2–5	1–2	2–5
Duration (seconds per set)	5–10	4–8	20–60	80–150	20–40
Speed per rep (% of max)	60–100	90–100	60–90	60–80	100
Training sessions per week	3–6	3–6	5–7	8–14	3–6
Table reproduced from Siff, 2003

Weights for each exercise should be chosen so that the desired number of repetitions can just be achieved.

Progressive overload

In one common method, weight training uses the principle of progressive overload, in which the muscles are overloaded by attempting to lift at least as much weight as they are capable. They respond by growing larger and stronger. This procedure is repeated with progressively heavier weights as the practitioner gains strength and endurance.

However, performing exercises at the absolute limit of one's strength (known as one rep max lifts) is considered too risky for all but the most experienced practitioners. Moreover, most individuals wish to develop a combination of strength, endurance and muscle size. One repetition sets are not well suited to these aims. Practitioners therefore lift lighter (sub-maximal) weights, with more repetitions, to fatigue the muscle and all fibres within that muscle as required by the progressive overload principle.

Commonly, each exercise is continued to the point of momentary muscular failure. Contrary to widespread belief, this is not the point at which the individual thinks they cannot complete any more repetitions, but rather the first repetition that fails due to inadequate muscular strength. Training to failure is a controversial topic with some advocating training to failure on all sets while others believe that this will lead to overtraining, and suggest training to failure only on the last set of an exercise. Some practitioners recommend finishing a set of repetitions just before the point of failure; e.g. if you can do a maximum of 12 reps with a given weight, perform only 11. Adrenaline and other hormones may promote additional intensity by stimulating the body to lift additional weight (as well as the neuro-muscular stimulations that happen when in “fight-or-flight” mode, as the body activates more muscle fibres), so getting "psyched up" before a workout can increase the maximum weight lifted.

Weight training can be a very effective form of strength training because exercises can be chosen, and weights precisely adjusted, to safely exhaust each individual muscle group after the specific numbers of sets and repetitions that have been found to be the most effective for the individual. Other strength training exercises lack the flexibility and precision that weights offer.

Split training

Split training involves working no more than three muscle groups or body parts per day, instead spreading the training of specific body parts throughout a training cycle of several days. It is commonly used by more advanced practitioners due to the logistics involved in training all muscle groups maximally. Training all the muscles in the body individually through their full range of motion in a single day is generally not considered possible due to caloric and time constraints. Split training involves fully exhausting individual muscle groups during a workout, then allowing several days for the muscle to fully recover. Muscles are worked roughly twice per week and allowed roughly 72 hours to recover. Recovery of certain muscle groups is usually achieved on days while training other groups, i.e. a 7-day week can consist of a practitioner training trapezius, side shoulders and upper shoulders to exhaustion on one day, the following day the arms to exhaustion, the day after that the rear, front shoulders and back, the day after that the chest. In this way all mentioned muscle groups are allowed the necessary recovery.

Intensity, volume, and frequency

Three important variables of strength training are intensity, volume, and frequency. Intensity refers to the amount of work required to achieve the activity, and is proportional to the mass of the weights being lifted. Volume refers to the number of muscles worked, exercises, sets and reps during a single session. Frequency refers to how many training sessions are performed per week.

These variables are important because they are all mutually conflicting, as the muscle only has so much strength and endurance, and takes time to recover due to microtrauma. Increasing one by any significant amount necessitates the decrease of the other two, e.g. increasing weight means a reduction of reps, and will require more recovery time and therefore fewer workouts per week. Trying to push too much intensity, volume and frequency will result in overtraining, and eventually lead to injury and other health issues such as chronic soreness and general lethargy, illness or even acute trauma such as avulsion fractures. A high-medium-low formula can be used to avoid overtraining, with either intensity, volume, or frequency being high, one of the others being medium, and the other being low. One example of this training strategy can be found in the following chart:

Type	High	Med	Low
Intensity (% of 1RM)	80–100%	50–70%	10–40%
Volume (per muscle)	1 exercise	2 exercises	3+ exercises
Sets	1 set	2–3 sets	4+ sets
Reps	1–6 reps	8–15 reps	20+ reps
Session frequency	1 p/w	2–3 p/w	4+ p/w

A common training strategy is to set the volume and frequency the same each week (e.g. training 3 times per week, with 2 sets of 12 reps each workout), and steadily increase the intensity (weight) on a weekly basis. However, to maximize progress to specific goals, individual programs may require different manipulations, such as decreasing the weight, and increase volume or frequency.

Making program alterations on a daily basis (daily undulating periodization) seems to be more efficient in eliciting strength gains than doing so every 4 weeks (linear periodization), but for beginners there are no differences between different periodization models.

Periodization

There are many complicated definitions for periodization, but the term simply means the division of the overall training program into periods which accomplish different goals.

Periodization is the modulating of volume, intensity, and frequency over time, to both stimulate gains and allow recovery.

In some programs for example; volume is decreased during a training cycle while intensity is increased. In this template, a lifter would begin a training cycle with a higher rep range than he will finish with.

For this example, the lifter has a 1 rep max of 225 lb:

Week	Set 1	Set 2	Set 3	Set 4	Set 5	Volume Lbs.	% Exertion(Last Set)	% of 1 Rep Max(Last Set)
1	125 lb x 8reps	130 lb x 8reps	135 lb x 8reps	140 lb x 8reps	145 lb x 8reps	5,400	78%	64%
2	135 lb x 7reps	140 lb x 7reps	145 lb x 7reps	150 lb x 7reps	155 lb x 7reps	5,075	81%	69%
3	145 lb x 6reps	150 lb x 6reps	155 lb x 6reps	160 lb x 6reps	165 lb x 6reps	4,650	84%	73%
4	155 lb x 5reps	160 lb x 5reps	165 lb x 5reps	170 lb x 5reps	175 lb x 5reps	4,125	87%	78%
5	165 lb x 4reps	170 lb x 4reps	175 lb x 4reps	180 lb x 4reps	185 lb x 4reps	3,500	90%	82%
6	175 lb x 3reps	180 lb x 3reps	185 lb x 3reps	190 lb x 3reps	195 lb x 3reps	2,775	92%	87%

This is an example of periodization where the number of repetitions decreases while the weight increases.

Practice of weight training

Methods and equipment

See also: Weight training: Types of exercises

There are many methods of strength training. Examples include weight training, circuit training, isometric exercise, gymnastics, plyometrics, Parkour, yoga, Pilates, Super Slow.

Strength training may be done with minimal or no equipment, for instance bodyweight exercises. Equipment used for strength training includes weight machines and other exercise machines, weighted clothing, resistance bands, gymnastics apparatus, Swiss balls, wobble boards, indian clubs, pneumatic exercise equipment, hydraulic exercise equipment.

Aerobic exercise versus anaerobic exercise

Strength training exercise is primarily anaerobic. Even while training at a lower intensity (training loads of ~20-RM), anaerobic glycolysis is still the major source of power, although aerobic metabolism makes a small contribution. Weight training is commonly perceived as anaerobic exercise, because one of the more common goals is to increase strength by lifting heavy weights. Other goals such as rehabilitation, weight loss, body shaping, and bodybuilding often use lower weights, adding aerobic character to the exercise.

Except in the extremes, a muscle will fire fibres of both the aerobic or anaerobic types on any given exercise, in varying ratio depending on the load on the intensity of the contraction. This is known as the energy system continuum. At higher loads, the muscle will recruit all muscle fibres possible, both anaerobic ("fast-twitch") and aerobic ("slow-twitch"), in order to generate the most force. However, at maximum load, the anaerobic processes contract so forcefully that the aerobic fibers are completely shut out, and all work is done by the anaerobic processes. Because the anaerobic muscle fibre uses its fuel faster than the blood and intracellular restorative cycles can resupply it, the maximum number of repetitions is limited. In the aerobic regime, the blood and intracellular processes can maintain a supply of fuel and oxygen, and continual repetition of the motion will not cause the muscle to fail.

Circuit weight training is a form of exercise that uses a number of weight training exercise sets separated by short intervals. The cardiovascular effort to recover from each set serves a function similar to an aerobic exercise, but this is not the same as saying that a weight training set is itself an aerobic process.

Exercises for specific muscle groups

Main article: Weight training exercises

A back extension.

Weight trainers commonly divide the body's individual muscles into ten major muscle groups. These do not include the hip, neck and forearm muscles, which are rarely trained in isolation. The most common exercises for these muscle groups are listed below. (Videos of these and other exercises are available at exrx.net and from the University of Wisconsin-La Crosse.)

The sequence shown below is one possible way to order the exercises. The large muscles of the lower body are normally trained before the smaller muscles of the upper body, because these first exercises require more mental and physical energy. The core muscles of the torso are trained before the shoulder and arm muscles that assist them. Exercises often alternate between "pushing" and "pulling" movements to allow their specific supporting muscles time to recover. The stabilising muscles in the waist should be trained last.

Advanced techniques

A number of techniques have been developed to make weight training exercises more intense, and thereby potentially increase the rate of progress. Many weight lifters use these techniques to bring themselves past a plateau, a duration where a weightlifter may be unable to do more lifting repetitions, sets, or use higher weight resistance.

Set structure

Drop sets

Drop sets do not end at the point of momentary muscular failure, but continue with progressively lighter weights.

Pyramid sets

Pyramid sets are weight training sets in which the progression is from lighter weights with a greater number of repetitions in the first set, to heavier weights with fewer repetitions in subsequent sets.

A reverse pyramid is the opposite in which the heavier weights are used at the beginning and progressively lightened.

Burnouts

Burnouts combine pyramids and drop sets, working up to higher weights with low reps and then back down to lower weights and high reps.

Diminishing set

The diminishing set method is where a weight is chosen that can be lifted for 20 reps in one set, and then 70 repetitions are performed in as few sets as possible.

Rest-pause (heavy singles)

Rest-pause heavy singles are performed at or near 1RM, with ten to twenty seconds of rest between each lift. The lift is repeated six to eight times. It is generally recommended to use this method infrequently.

Giant set

The Giant set, is a form of training that targets one muscle group (e.g. the triceps) with four separate exercises performed in quick succession, often to failure and sometimes with the reduction of weight halfway through a set once muscle fatigue sets in. This form of intense training 'shocks' the muscles and as such, is usually performed by experienced trainers and should be used infrequently.

Combined sets

Supersets

Supersets combine two or more exercises with similar motions to maximize the amount of work of an individual muscle or group of muscles. The exercises are performed with no rest period between the exercises. An example would be doing bench press, which predominantly works the pectoralis and triceps muscles, and then moving to an exercise that works just the triceps such as the triceps extension or the pushdown.

Push-pull supersets

Push-pull supersets are similar to regular supersets, but exercises are chosen which work opposing muscle groups. This is especially popular when applied to arm exercises, for example by combining biceps curls with the triceps pushdown. Other examples include the shoulder press and lat pulldown combination, and the bench press and wide grip row combination.

Pre-exhaustion

Pre-exhaustion combines an isolation exercise with a compound exercise for the same muscle group. The isolation exercise first exhausts the muscle group, and then the compound exercise uses the muscle group's supporting muscles to push it further than would otherwise be possible. For example, the triceps muscles normally help the pectorals perform their function. But in the "bench press" the weaker triceps often fails first, which limits the impact on the pectorals. By preceding the bench press with the pec fly, the pectorals can be pre-exhausted so that both muscles fail at the same time, and both benefit equally from the exercise.

Breakdowns

Breakdowns were developed by Fredrick Hatfield and Mike Quinn to work the different types of muscle fibers for maximum stimulation. Three different exercises that work the same muscle group are selected, and used for a superset. The first exercise uses a heavy weight (~85% of 1 rep max) for around five reps, the second a medium weight (~70% of 1 rep max) for around twelve reps, and finally the third exercise is performed with a light weight (~50% of 1 rep max) for twenty to thirty reps, or even lighter (~40% of 1 rep max) for forty or more reps. (Going to failure is discouraged.) The entire superset is performed three times.

Beyond failure

Forced reps

Forced reps occur after momentary muscular failure. An assistant provides just enough help to get the weight trainer past the sticking point of the exercise, and allow further repetitions to be completed. Weight trainers often do this when they are spotting their exercise partner. With some exercises forced reps can be done without a training partner. For example, with one-arm biceps curls the other arm can be used to assist the arm that is being trained.

Cheat reps

Cheating is a deliberate compromise of form to maximize reps. Cheating has the advantage that it can be done without a training partner, but compromises safety. A typical example of cheat reps occurs during biceps curls when, beginning with the load at the waist, the exerciser swings the barbell or dumbbell forward and up during the concentric phase utilizing momentum to assist their bicep muscles in moving the load to a shortened muscle position. Momentum assistance during the concentric phase allows them to move greater loads during the more difficult concentric phase. The objective can be to position greater loads of resistance to the biceps in preparation of performing the eccentric phase than the more difficult concentric phase would otherwise allow. Replacing a typical function of a training partner with a solo exerciser performing cheat reps facilitates forced reps or negative reps when training alone.

Rest-pause (post-failure)

After a normal set of 6–8 reps (to failure), the weight is re-racked and the trainer takes 10–15 deep breaths, and then performs one more repetition. This process can be repeated for two further repetitions. The twenty-rep squat is another, similar approach, in that it follows a 12–15 rep set of squats with individual rest-pause reps, up to a total of 20 reps.

Weight stripping a.k.a. Number Setting

Weight stripping is a technique used after failure with a normal resistance in certain exercises, particularly with easily adjustable machines, whereby the weight trainer or a partner gradually reduces the resistance after a full set is taken to failure. With each reduction in resistance, as many possible reps are completed and the resistance is then reduced again. This is continued until the resistance is approximately half the original resistance.

Negative reps

Negative reps are performed with much heavier weights. Assistants lift the weight, and then the weight trainer attempts to resist its downward progress through an eccentric contraction. Alternatively, an individual can use an exercise machine for negatives by lifting the weight with both arms or legs, and then lowering it with only one. Or they can simply lower weights more slowly than they lift them: for example, by taking two seconds to lift each weight and four seconds to lower it.

Partial reps

Partial reps, as the name implies, involves movement through only part of the normal path of an exercise. Partial reps can be performed with heavier weights. Usually, only the easiest part of the repetition is attempted.

Burns

Burns involve mixing partial reps into a set of full range reps in order to increase intensity. The partials can be performed at any part of the exercise movement, depending on what works best for the particular exercise. Also, the partials can either be added after the end of a set or in some alternating fashion with the full range reps. For example, after performing a set of biceps curls to failure, an individual would cheat the bar back to the most contracted position, and then perform several partial reps.

Other techniques

Progressive movement training

Progressive movement training attempts to gradually increase the range of motion throughout a training cycle. The lifter will start with a much heavier weight than they could handle in the full range of motion, only moving through the last 3–5” of the movement. Throughout the training cycle, the lifter will gradually increase the range of motion until the joint moves through the full range of the exercise. This is a style that was made popular by Paul Anderson.

Super slow

Super slow repetitions are performed with lighter weights. The lifting and lowering phases of each repetition take 10 seconds or more.

Timed rests

By strictly controlling the rest periods between reps and sets a trainer can reduce their level of blood oxygenation, which helps to increase the stress on the muscles.

Using a wrist strap.

Wrist straps

Wrist straps (lifting straps) are sometimes used to assist in gripping very heavy weights by applying the opposite torque that you create with your grip from your hands. Wrist straps can be used to isolate muscle groups like in "lat pull-downs", where you primarily will work your latissimus dorsi muscles of your back and not use your biceps which is the secondary muscle worked during the lift. They are particularly useful for the deadlift. Some lifters avoid using wrist straps in order to develop their grip strength, just as some go further by using thick bars. Wrist straps can allow a lifter initially to use more weight than they might be able to handle safely for an entire set, as unlike simply holding a weight, if it is dropped then the lifter must descend with it or be pulled down. Straps place stress on the bones of the wrist which can be potentially harmful if excessive.

Risks and concerns

Strength training is a safe form of exercise when the movements are controlled, and carefully defined. Or some safety measures can also be taken before the training. However, as with any form of exercise, improper execution and the failure to take appropriate precautions can result in injury. A helmet, boots, gloves, and back belt can aide in injury prevention. Principles of weight training safety apply to strength training.

Bodybuilding

Main article: Bodybuilding

Bodybuilding is a sport in which the goal is to increase muscle size and definition. Bodybuilding increases the endurance of muscles, as well as strength, though not as much as if it were the primary goal. Bodybuilders compete in bodybuilding competitions, and use specific principles and methods of strength training to maximize muscular size and develop extremely low levels of body fat. In contrast, most strength trainers train to improve their strength and endurance while not giving special attention to reducing body fat below normal. Strength trainers tend to focus on compound exercises to build basic strength, whereas bodybuilders often use isolation exercises to visually separate their muscles, and to improve muscular symmetry. Pre-contest training for bodybuilders is different again, in that they attempt to retain as much muscular tissue as possible while undergoing severe dieting. However, the bodybuilding community has been the source of many strength training principles, techniques, vocabulary, and customs.

Nutrition

It is widely accepted that strength training must be matched by changes in diet in order to be effective. Although aerobic exercise has been proven to have an effect on the dietary intake of macronutrients, strength training has not and an increase in dietary protein is generally believed to be required for building skeletal muscle with popular sources advising weight trainers to consume a high-protein diet with from 1.4 to 1.8 g of protein per kg of body weight per day (0.6 to 0.8 g per pound). Protein that is neither needed for cell growth and repair nor consumed for energy is converted into urea mainly through the deamination process and is excreted by the kidneys. It was once thought that a high-protein diet entails risk of kidney damage, but studies have shown that kidney problems only occur in people with previous kidney disease. However failure to properly hydrate can put an increased strain on the kidney's ability to function. An adequate supply of carbohydrates (5–7 g per kg) is also needed as a source of energy and for the body to restore glycogen levels in muscles.

A light, balanced meal prior to the workout (usually one to two hours beforehand) ensures that adequate energy and amino acids are available for the intense bout of exercise. The type of nutrients consumed affects the response of the body, and nutrient timing whereby protein and carbohydrates are consumed prior to and after workout has a beneficial impact on muscle growth. Water is consumed throughout the course of the workout to prevent poor performance due to dehydration. A protein shake is often consumed immediately following the workout, because both protein uptake and protein usage are increased at this time. Glucose (or another simple sugar) is often consumed as well since this quickly replenishes any glycogen lost during the exercise period. To maximise muscle protein anabolism, recovery drink should contain glucose (dextrose), protein (usually whey) hydrosylate containing mainly dipeptides and tripeptides, and leucine. Some weight trainers also take ergogenic aids such as creatine or steroids to aid muscle growth. However, the effectiveness of some products is disputed and others are potentially harmful.

Sex differences in mass gains

Due to the androgenic hormonal differences between males and females, the latter are generally unable to develop large muscles regardless of the training program used. Normally the most that can be achieved is a look similar to that of a fitness model. Muscle is denser than fat, so someone who builds muscle while keeping the same body weight will occupy less volume; if two people weigh the same (and are the same height) but have different lean body mass percentages, the one with more muscle will appear thinner.

In addition, though bodybuilding uses the same principles as strength training, it is with a goal of gaining muscle bulk. Strength trainers with different goals and programs will not gain the same mass as a professional bodybuilder.

Muscle toning

Some weight trainers perform light, high-repetition exercises in an attempt to "tone" their muscles without increasing their size.

The word tone derives from the Latin "tonus" (meaning "tension"). In anatomy and physiology, as well as medicine, the term "muscle tone" refers to the continuous and passive partial contraction of the muscles, or the muscles' resistance to passive stretching during resting state as determined by a deep tendon reflex. Muscle tonus is dependent on neurological input into the muscle. In medicine, observations of changes in muscle tonus can be used to determine normal or abnormal states which can be indicative of pathology. The common strength training term "tone" is derived from this use.

What muscle builders refer to as a toned physique or "muscle firmness" is one that combines reasonable muscular size with moderate levels of body fat, qualities that may result from a combination of diet and exercise.

Muscle tone or firmness is derived from the increase in actin and myosin cross filaments in the sarcomere. When this occurs the same amount of neurological input creates a greater firmness or tone in the resting continuous and passive partial contraction in the muscle.

Exercises of 6–12 reps cause hypertrophy of the sarcoplasm in slow-twitch and high-twitch muscle fibers, contributing to overall increased muscle bulk. This is not to be confused with myofibril hypertrophy which leads to strength gains. Both however can occur to an extent during this rep range. Even though most are of the opinion that higher repetitions are best for producing the desired effect of muscle firmness or tone, it is not. Low volume strength training of 5 repetitions or fewer will increase strength by increasing actin and myosin cross filaments thereby increasing muscle firmness or tone. The low volume of this training will inhibit the hypertrophy effect.

Lowered-calorie diets have no positive effect on muscle hypertrophy for muscle of any fiber type. They may, however, decrease the thickness of subcutaneous fat (fat between muscle and skin), through an overall reduction in body fat, thus making muscle striations more visible.

Weight loss

Exercises like sit-ups, or abdominal crunches, performs less work than whole-body aerobic exercises thereby expending fewer calories during exercise than jogging, for example.

Hypertrophy serves to maintain muscle mass, for an elevated basal metabolic rate, which has the potential to burn more calories in a given period compared to aerobics. This helps to maintain a higher metabolic rate which would otherwise diminish after metabolic adaption to dieting, or upon completion of an aerobic routine.

Weight loss also depends on the type of strength training used. Weight training is generally used for bulking, but the bulking method will more than likely not increase weight because of the diet involved. However, when resistance or circuit training is used, because they are not geared towards bulking, women tend to lose weight more quickly. Lean muscles require calories to maintain themselves at rest, which will help reduce fat through an increase in the basal metabolic rate.

History

Arthur Saxon performing a Two Hands Anyhow with an early kettlebell and plate-loaded barbell.

Until the 20th century, the history of strength training was very similar to the history of weight training. With the advent of modern technology, materials and knowledge, the methods that can be used for strength training have multiplied significantly.

Hippocrates explained the principle behind strength training when he wrote "that which is used develops, and that which is not used wastes away", referring to muscular hypertrophy and atrophy. Progressive resistance training dates back at least to Ancient Greece, when legend has it that wrestler Milo of Croton trained by carrying a newborn calf on his back every day until it was fully grown. Another Greek, the physician Galen, described strength training exercises using the halteres (an early form of dumbbell) in the 2nd century. Ancient Persians used the meels, which became popular during the 19th century as the Indian club, and has recently made a comeback in the form of the clubbell.

The dumbbell was joined by the barbell in the latter half of the 19th century. Early barbells had hollow globes that could be filled with sand or lead shot, but by the end of the century these were replaced by the plate-loading barbell commonly used today.

Strength training with isometric exercise was popularised by Charles Atlas from the 1930s onwards. The 1960s saw the gradual introduction of exercise machines into the still-rare strength training gyms of the time. Strength training became increasingly popular in the 1980s following the release of the bodybuilding movie Pumping Iron and the subsequent popularity of Arnold Schwarzenegger.

Special populations

Safety concerns related to children

Properly supervised strength training for children.

Orthopaedic specialists used to recommend that children avoid weight training because the growth plates on their bones might be at risk. The very rare reports of growth plate fractures in children who trained with weights occurred as a result of inadequate supervision, improper form or excess weight, and there have been no reports of injuries to growth plates in youth training programs that followed established guidelines. The position of the National Strength and Conditioning Association is that strength training is safe for children if properly designed and supervised.

Younger children are at greater risk of injury than adults if they drop a weight on themselves or perform an exercise incorrectly; further, they may lack understanding of, or ignore the safety precautions around weight training equipment. As a result, supervision of minors is considered vital to ensuring the safety of any youth engaging in strength training.

For older adults

Older adults with more strength have better health, better quality of life, and fewer falls. In cases in which an older person begins strength training, their doctor or health care provider may neglect to emphasize a strength training program which results in muscle gains. Under-dosed strength training programs should be avoided in favor of a program which matches the abilities and goals of the person exercising.

In setting up an exercise program for an older adult, they should go through a baseline fitness assessment to determine their current limits. Any exercise program for older adults should match the intensity, frequency, and duration of exercise that the person can perform. The program should have a goal of increased strength as compared to the baseline measurement.

See also

• Body image
• Bodybuilding supplement
• Exercise physiology
• General fitness training
• Gym
• Health club
• List of health and fitness magazines
• Metabolic window
• Mixed martial arts
• Muscle dysmorphia
• Overtraining
• Personal trainer
• Physical culture
• Physical exercise
• Physical fitness
• Sports medicine
• Super Slow
• Supercompensation
• Supination
• Weight training bench

Bibliography

Many of the most useful books about weight training contain the word "bodybuilding" in the title, but they should not be overlooked just for this reason. Weight trainers who are not interested in bodybuilding can ignore the material devoted to contest preparation, and still obtain much valuable information.

• Delavier, Frederic (2001). Strength Training Anatomy. Human Kinetics Publishers. ISBN 0-7360-4185-0.
• DeLee, J. MD and Drez, D. MD, Eds. (2003). DeLee & Drez's Orthopaedic Sports Medicine; Principles and Practice (vols 1 & 2). ISBN 0-7216-8845-4.
• Hatfield, Frederick (1993). Hardcore Bodybuilding: A Scientific Approach. McGraw-Hill. ISBN 0-8092-3728-8.
• Legeard, Emmanuel (2008). Musculation. Amphora. ISBN 2851807420.
• Issurin, Vladimir and Yessis, Michael, PhD. (2008). "Block Periodization: Breakthrough In Sports Training". Ultimate Athlete Concepts. ISBN 0-9817180-0-0.
• Lombardi, V. Patteson (1989). Beginning Weight Training. Wm. C. Brown Publishers. ISBN 0-697-10696-9.
• Powers, Scott and Howley, Edward (2003), Exercise Physiology. McGraw Hill. ISBN 0-07-255728-1.
• Rippetoe, Mark and Kilgore, Lon (2007) "Starting Strength (2nd Edition)". The Aasgaard Company. ISBN 0-9768054-2-1
• Schoenfeld, Brad (2002). Sculpting Her Body Perfect. Human Kinetics Publishers. ISBN 0-7360-4469-8.
• Schwarzenegger, Arnold (1999). The New Encyclopedia of Modern Bodybuilding. Simon & Schuster. ISBN 0-684-85721-9.