Muscle Stretching Techniques – Ballistic Stretching

Ballistic stretching involves a bouncing movement in which repetitive contractions of the agonist muscle are used, to produce quick stretches of the antagonist muscle. The ballistic stretching technique, although apparently effective in improving range of motion, has been criticized because increased range of motion is achieved through a series of jerks or pulls on the resistant muscle tissue. If the forces generated by the jerks are greater than the tissues' extensibility, muscle injury may result.

Successive forceful contractions of the agonist that results in stretching of the antagonist may cause muscle soreness. For example, forcefully kicking a soccer ball 50 times may result in muscular soreness of the hamstrings (antagonist muscle) as a result of eccentric contraction of the hamstrings to control the dynamic movement of the quadriceps (agonist muscle). Ballistic stretching that is controlled usually does not cause muscle soreness. 

Muscle Stretching Techniques - Agonist Versos Antagonist Muscles

The maintenance of a full, non-restricted range of motion has long been recognized as critical to injury prevention and as an essential component of a conditioning program.

The goal of any effective flexibility program should be to improve the range of motion at a given articulation by altering the extensibility of the musculotendinous units that produce movement at that joint. It is well documented that exercises that stretch these musculotendinous units over a period of time increase the range of movement possible about a given joint.

Stretching techniques for improving flexibility have evolved over the years. The oldest technique for stretching is called ballistic stretching, which makes use of repetitive bouncing motions. A second technique, known as static stretching, involves stretching a muscle to the point of discomfort and then holding it at the point for an extended time, this technique has been used for many years. Recently another group of stretching techniques known collectively as proprioceptive neuromuscular facilitation (PNF), involving alternating contractions and stretches, has been recommended.

Before discussing the three different stretching techniques it is essential to define the terms agonist and antagonist muscles. Most joints in the body are capable of more than one movement. The knee joint, for example, is capable of flexion and extension. Contraction of the quadriceps group of muscles on the front of the thigh causes knee extension, whereas contraction of the hamstring muscles on the back of the thigh produces knee flexion.

To achieve knee extension, the quadriceps group contracts while the hamstring muscles relax and stretch. The muscle that contracts to produce a movement, in this case the quadriceps, is referred to as the agonist muscle. The muscle being stretched in response to contraction of the agonist muscle is called the antagonist muscle. In knee extension, the antagonist muscle would be the hamstring group. Some degree of balance in strength between agonist and antagonist muscle groups is necessary for normal smooth coordinated movement and for reducing the likelihood of muscle strain caused by muscular imbalance.

Muscle Soreness and Dynamic Muscle Flexibility

Muscular overexertion may present as muscle soreness, muscle stiffness, and muscle spasm. According to the muscle spasm hypothesis of muscle soreness, ischemia to the muscles release pain substances from the muscle fibers and stimulate the pain receptors, resulting in reflex spastic contractions and a continued cycle of ischemia and pain, Stretching the muscles helps reduce the spasms and associated pain. According it) the tissue damage hypothesis, micro-tears occur and pain/soreness results from the nerve - endings being stimulated by muscle tissue swelling. Proper massage aid in reducing tissue edema, and decreasing accompanying muscle spasm. Ice applications or other forms of cryotherapy, and pool training, may facilitate the body's healing response. Appropriate rest will allow microscopic damage of the tissue to heal.

Active range of motion, also called dynamic flexibility, refers to the degree to which a joint can be moved by a muscle contraction, usually through the mid-range of movement. Dynamic flexibility is not necessarily a good indicator of the stiffness or looseness of a joint because it applies to the ability to move a joint efficiently, with little resistance to motion.

Passive range of motion, sometimes called static flexibility, refers to the degree to which a joint may be passively moved to the endpoints in the range of motion. No muscle contraction is involved to move a joint through a passive range.

When a muscle actively contracts, it produces a joint movement through a specific range of motion. However, if passive pressure is applied to an extremity, it is capable of moving farther in the range of motion. It is essential in sport activities that an extremity is capable of moving through a non-restricted range of motion. For example, a hurdler who cannot fully extend the knee joint in a normal stride is at considerable disadvantage because stride length and thus speed will be reduced significantly.

Passive range of motion is important for injury prevention. There are many situations in sport in which a muscle is forced to stretch beyond its normal active limits. If the muscle does not have enough elasticity to compensate for this additional stretch, it is likely that the musculotendinous unit will be injured.