Resistance bands have been around since the 1960s, but were mainly used in rehabilitation. But they are becoming popular with athletes looking to gain a competitive edge and those looking for alternative workouts.
While the early bands were basically surgical tubing that used a loop and knot at the ends as handles, today's bands are made of hi-tech polymers. They also offer more resistance options and come with extras such as leg straps and lifting bars. Training with the bands alone won't be enough to make you look like Arnold Schwarzenegger, but many athletes who do train heavily with weights use band work as a supplement. If you're a beginner in the gym or can't always get to a gym and are looking for a complete strength workout, then this training tool may work for you.
One of the major drawbacks to using typical weight machines found in gyms is they don't allow you to work in the three planes of motion the human body operates in. The coronal or frontal plane divides the body's movement into front and back (anterior and posterior), the sagittal plane divides movement into side to side, and the transverse or axial plane dissects the body into top and bottom portions. Within each plane are specific actions that don't happen individually but as part of an entire movement. Weight machines typically focus on one or two motions (flexion and extension or side to side, for example) in one plane instead of the entire movement (swinging a golf club or throwing a cricket ball). With resistance bands you can move in any or all planes of motion so you're not just training one isolated action within one plane.
Because the resistance band can stress stability, flexion, extension, and rotation in more than one plane, athletes are able to train specifically for their particular sport.
Another benefit of using resistance bands is that they offer continuous tension. When a weight is lifted, there is an arch of resistance. The peak of the resistance or workload is just past the half-way point in the concentric contraction (lifting phase) with a decline in the workload afterwards. With the band, this doesn't happen because the resistance keeps increasing the further it is stretched.
Resistance bands can also be adjusted in intensity by changing their length. So you can work both core (quads and back, for example) and assisting muscle groups using the same band. However, most experts advise using a thicker band for the large muscle groups and a thinner one for small muscles such as the biceps and triceps. By being able to work through a full range of motion with continuous tension, muscles are worked in balance and it's easier on the joints.