Weight training

Weight training can be the most effective technique for developing the strength and size of skeletal muscles. It provides functional benefits and may improve overall health and well-being.

Types of exercises

Isometric, isotonic, isokinetic, and plyometric exercises

These terms combine the prefix "iso", meaning same, with "metric" (distance), "tonic" (strength) and "kinetic" (speed). In "isometric" exercises the length of the muscle does not change, in "isotonic" exercises the force applied to the muscle is relatively unchanged, and in "isokinetic" exercises the speed of movement is constant.

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In isometric exercises the muscles flex and hold a stationary position. No movement of a load takes place, and the exercises require little in the way of equipment. An example of an isometric exercise is placing the palms of the hands against each other and pushing. Strength increases only occur at the angles the joints are held at during the exercise http://www.clearleadinc.com/site/exer_isometrics.html. Isometric exercises are primarily used in physiotherapy and injury rehabilitation because the intensity can be rapidly and precisely adjusted, which makes them very safe. They are now rarely used outside this context.

Related Topics:
Physiotherapy - Rehabilitation

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In isotonic exercises the muscles are used to push or pull a weight. Any object can be used for weight training, but dumbbells, barbells and other specialised equipment are normally used because they can be adjusted to specific weights, and are easily gripped. Elastic resistance bands are a cheap and portable alternative. Some exercises, such as the push-up, use the individual's body weight instead. Advanced practitioners often add weight to body-weight exercises such as the crunch by, in this case, holding a dumbbell on their chest.

Related Topics:
Dumbbell - Barbell - Elastic - Resistance band - Push-up - Crunch

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A third type of training, which is less common—except in sport-specific training or in rehabilitation—is isokinetic exercise. An exercise machine is used which registers the force applied to it by the user, and offers just that amount of resistance. (The rate of change of angle at the joints being utilised is kept constant.) This allows the user to exercise at the speed optimal for their needs, without the danger of being subjected to more weight than they can handle.

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Another form of training that often uses weights has a different goal. Plyometric exploits the stretch-shortening cycle of muscles to enhance the myotatic (stretch) reflex. This involves rapid alternation of lengthening and shortening of muscle fibers against a resistance. The resistance involved is often a weighted object such as a medicine ball, but can also be the body itself as in jumping exercises. Plyometrics is used to develop explosive speed, and focuses on power instead of maximal strength, and may be used to improve the effectiveness of a boxer's punch, for example, or to increase the vertical jumping ability of a basketball player.

Related Topics:
Plyometric - Medicine ball - Power - Boxer's - Basketball

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Isolation exercises vs compound exercises

An isolation exercise is one where the movement is restricted to one joint and one muscle group. For example, the leg extension is an isolation exercise for the quadriceps. No other muscle groups are involved, and movement occurs only around the knee joint.

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Compound exercises work several muscle groups at once, and include movement around two or more joints. For example, in the leg press movement occurs around the hip, knee and ankle joints. This exercise is primarily used to develop the quadriceps, but it also involves the hamstrings, glutes and calves.

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Compound exercises are generally similar to the ways that people naturally push, pull and lift objects, whereas isolation exercises often feel a little unnatural.

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Each type of exercise has its uses. Compound exercises build the basic strength that is needed to perform everyday pushing, pulling and lifting activities. Isolation exercises are useful for "rounding out" a routine, by directly exercising muscle groups that cannot be fully exercised in the compound exercises.

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Free weights vs exercise machines

Free weights are dumbbells and barbells. Unlike exercise machines, they do not constrain users to specific, fixed movements, and therefore require more effort from the individual's stabilizer muscles. It is often argued that free weights exercises are superior for precisely this reason. But because exercise machines largely prevent users from performing exercises with poor form, they are safer than free weights—particularly for beginners. Moreover, since users need not concentrate so much on maintaining good form, they can focus more on the effort they are putting into the exercise—which may lead to faster progress.

Related Topics:
Dumbbell - Barbell

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Some free weight exercises can be performed while sitting or lying on a Swiss ball. This makes it more difficult to maintain good form, which helps to exercise the deep torso muscles that are important for maintaining a good posture.

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There are a number of exercise machines that are commonly found in neighbourhood gyms. The Smith machine is a barbell that is constrained to move only vertically upwards and downwards. The cable machine consists of two weight stacks separated by 2.5 metres, with cables running through adjustable pulleys (that can be fixed at any height) to various types of handles. There are also exercise-specific machines such as the leg press. A multigym includes a variety of exercise-specific mechanisms in one apparatus.

Related Topics:
Smith machine - Cable machine - Metre - Leg press

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One limitation of many free weight exercises and exercise machines is that the muscle is working maximally against gravity during only a small portion of the lift. Some exercise-specific machines feature an oval cam (first introduced by Nautilus) which varies the resistance so that the resistance, and the muscle force required, remains constant throughout the full range of motion of the exercise.

Related Topics:
Cam - Nautilus

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Aerobic exercise vs anaerobic exercise

Weight training at high intensity (using a weight near the maximum the participant can lift for a given number of repetitions, or a lower weight and a sharp motion) is primarily anaerobic7, and at low intensity (low weight and slower, steady motion) is substantially aerobic.

Related Topics:
Anaerobic - 7 - Aerobic

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Except in the extremes, a muscle will fire fibers 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.7 Because the anaerobic muscle fiber 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.

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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.

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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 not the same as saying that a weight training set is itself an aerobic process.

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