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.
- Increased physical attractiveness
- Increased general physical health
- For rehabilitation or to address an impairment
- Increased sports performance
- For the pleasure of the activity
- Realization of training goals
- Progressive overload
- Split training
- Intensity volume and frequency
- Methods and equipment
- Aerobic exercise versus anaerobic exercise
- Exercises for specific muscle groups
- Advanced techniques
- Set structure
- Combined sets
- Beyond failure
- Other techniques
- Risks and concerns
- Sex differences in mass gains
- Muscle toning
- Weight loss
- Safety concerns related to children
- Australias stance on pre adolescence strength training
- For older adults
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.
Strength training is typically associated with the production of lactate, which is a limiting factor of exercise performance. Regular endurance exercise leads to adaptations in skeletal muscle which can prevent lactate levels from rising during strength training. This is mediated via activation of PGC-1alpha which alter the LDH (lactate dehydrogenase) isoenzyme complex composition and decreases the activity of the lactate generating enzyme LDHA, while increasing the activity of the lactate metabolizing enzyme LDHB.
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 tennis,American football, wrestling, track and field, rowing, lacrosse, basketball, pole dancing, hockey, professional wrestling, rugby union, rugby league and soccer. Strength training for other sports and physical activities is becoming increasingly popular.
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, training can not exceed a muscle's intrinsic genetically determined qualities, but clearly polymorphic expression of Myosin heavy chains is possible.
Workouts elevate metabolism for up to 14 hours following 45-minutes of vigorous exercise.
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 or an occupational therapist.
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.
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:
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.
Strength training has a variety of specialized terms used to describe parameters of strength training:
Realization of training goals
For developing endurance, gradual increases in volume and gradual decreases in intensity is the most effective program. Sets of thirteen to twenty repetitions develop anaerobic endurance, with some increases to muscle size and limited impact on strength.
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.
Weights for each exercise should be chosen so that the desired number of repetitions can just be achieved.
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 reaching a personal maximum at a given time. 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 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:
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.
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:
This is an example of periodization where the number of repetitions decreases while the weight increases.
Methods and equipment
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 barbells and dumbbells, 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
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.
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 stabilizing muscles in the waist should be trained last.
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.
A reverse pyramid is the opposite in which the heavier weights are used at the beginning and progressively lightened.
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 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.
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 which delivers 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.
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.
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.
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.
Safety concerns related to 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.
Australia's stance on pre-adolescence strength training
Strength training is the fourth most popular form of fitness in Australia. Due to its popularity amongst all ages, there is great scepticism on what the appropriate age to commence strength training in young athletes is. Some points of the opposing view of strength training in young adolescence are stunted growth, health and bone problems in later stages of life and unhealthy eating habits. Studies by Australian experts that have been recognised by the Australian Institute of Sport (AIS) have debunked these myths. There is no link between any prolonged health risks and strength training in pre-adolescence if the procedures of strength training are followed correctly and under suitable supervision. Strength training for pre-adolescents should focus on skills and techniques. Children should only work on strengthening all the big muscle groups, using free weight and body weight movements with relatively light loads. The benefits of these practices include increased strength performance, injury prevention and learning good training principles.
For older adults
Older adults are prone to loss of muscle strength. With more strength older adults have better health, better quality of life, better physical function 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.
Recommended training for older adults is three times a week of light strength training exercises. Exercise machines are a commonly used equipment in a gym setting, including treadmills with exercises such as walking or light jogging. Home-based exercises should usually consist of body weight or elastic band exercises that maintain a low level of impact on the muscles. Weights can also be used by older adults if they maintain a lighter weight load with an average amount of repetitions (10–12 REPS) with suitable supervision. It is important for older adults to maintain a light level of strength training with low levels of impact to avoid injuries.
Older people who exercise against a resistance or force become stronger . Progressive resistance training (PRT) also improves physical functioning in older people, including the performance of simple (e.g.: walking, climbing stairs, rising from a chair more quickly) and complex daily activities (e.g.: bathing, cooking). Caution is recommended when transferring PRT exercises for clinical populations,as adverse effects are unclear.