Flexibility Exercise: Three Purposes

 Flexibility can be defined as the ability of joints to move through a range of motion. The more flexible we are, the greater the range of motion. This joint flexibility depends on the connective tissue and muscles associated with the point. Connective tissue refers to the ligaments that bind bones together and tendons that bind muscle to bone. 

There is little flexibility to connective tissue. Tendons are the least flexible and will tear beyond 4% of stretching.  Ligaments have a bit more flexibility but will tear when stretched beyond 6%. Thus, flexibility exercises are primarily devoted to the muscles attached to the tendons. With stretching exercises, muscles can be stretched 50% or more without tearing.

The purpose of flexibility is threefold. 

First, by extending the range of joint motion, you reduce the potential of injury when that range is over extended. The ankle and the knee joint are particularly subject to joint injury. When running or just walking on rough ground, the foot can easily be turned by a hidden hole causing a bad sprain. Skiers suffer injury to knees when they fall awkwardly. When ligaments have some range of movement, damage can be avoided or minimized by accidental movement. 

Second, flexibility can reduce the stress on the vertebral column. Much of lower back pain can be caused by excessively tight quadriceps (quads) and hamstrings (hams). These are two of the most powerful muscles in the body, and they can exert powerful stresses on the spinal column. If these muscles are stretched, the level of stress on the back is also reduced. 

Back stress can also be caused by an imbalance between the quadriceps and the hamstrings. Generally the quadriceps are larger and the more powerful of the two. Quadriceps are used also (exercised) more often. Every time we raise ourselves from a chair we exercise the quadriceps. Most aerobic exercises utilize the quadriceps more than the hamstrings so balancing the strength is difficult. However, with power exercise, it is possible to set resistance to balance the quads and hams. Both weights and Human Isokinetics can achieve this balance.

Third, flexibility can reduce the internal resistance of the both the quads and hams. By stretching these muscles, their tension loosens. Not only will this lesson the stresses on back, but also reduce the resistance when running or cycling. This can improve both speed and resistance to fatigue. This is certainly a benefit for runners.

Many fitness books concentrate on the importance of flexibility and claim significant benefits from this exercise. Flexibility exercise improves flexibility--it does little for strength or aerobic fitness which for seniors, the most essential elements of fitness.