Resistance training exercises strengthen muscles by forcing the muscles to contract against the weight or resistance of an exterior object such as dumbbells, barbells, or resistance bands. A person performing these exercises will be looking to improve muscle strength and mobility, and this can be done through many methods. Weight training is perhaps the most common of resistance training exercises, and the person will use weights or weight machines to develop strength. Resistance bands can also be used to improve strength and mobility without the use of bulky weights or weight machines.
Resistance bands are lengths of elastic material that allow the user to loop the band around a fixed object to provide resistance; the band can also be used by looping it around certain parts of the body such as the foot to provide resistance for resistance training exercises. Different thicknesses of resistance band will provide more or less resistance, and the bands are very often color coded for quick reference. A person starting out with resistance band training will usually start with thinner resistance bands that offer less resistance for muscle workouts; this is akin to using lighter dumbbells during weight training exercises.
Weight training involves the use of heavy weights attached to a bar. The person doing the resistance training exercises will pick up the weights with one hand or both hands; in other cases, the resistance training exercises can be done with the lower body on specially designed machines that are operated with the legs or feet. Such machines can also be designed for the upper body, eliminating the need for free weights altogether. In either case, the weights are used as the resistance device to make the muscles work harder and consequently become stronger. Sometimes a medicine ball is used in place of weights. This is a heavy ball, often made from leather or a synthetic material that mimics leather, that can be used for a variety of resistance exercises.
Some weight training machines are designed to be set up in a circuit, or specific order, and when the person doing the training uses the machines in order, he or she is said to be doing circuit training. During circuit training, weight training is often combined with aerobic workouts to provide a whole-body workout that is high-intensity and efficient. Many gyms and fitness centers feature a circuit training room in which a circuit trainer can use all the machines in order quickly and easily.