A well-balanced fitness programme includes cardiovascular (aerobic) activity, strength and flexibility training. Aerobic training such as jogging is great for your heart and improving cardiovascular fitness, but does little for muscular strength, especially upper body. A certain amount of muscular strength and endurance is necessary for everyday activities such as lifting.
Research has shown that resistance training to improve muscular fitness also improves bone density, metabolism and body composition. Group strength training classes are not new - they were offered in the early 1980s (mainly in the US), but as other classes, such as step and indoor cycling, took off resistance training classes dropped in popularity.
Today, as more people understand that strength training helps to build lean muscle mass and develop a stronger, shapelier physique faster than a cardio workout, classes like body pump and sculpt bar have become very popular.
Muscular fitness includes both muscular endurance and strength. Strength refers to the maximum amount of force that can be generated by a specific muscle or group of muscles. Endurance is the ability to exert less than maximal force for several repetitions. Both of these are developed by overloading the muscle through resistance, duration and frequency. This is accomplished by varying the amount of weight, amount of rest and sets of exercises in a strength training programme.
In a body pump or sculpt bar class, the emphasis is on muscular endurance or high repetitions, so the amount of weight should be below an individual's maximum weight. The basic muscle actions are isometric, eccentric and concentric contractions. Isometric occurs when there's no joint movement, eccentric and concentric contractions occur when there is joint motion. Concentric occurs when the muscle is shortened and eccentric when the muscle is lengthened, like the lowering phase of a bicep curl.
Research has shown individuals increased their muscle tone, bone density and metabolic rate after doing a strength training class such as body pump or sculpt bar twice a week for at least six weeks.