By definition, a stretch is a specific position sustained to increase and maintain the length of a muscle or muscle group. It lengthens tendons, warms up ligaments, and prepares joints for work.
As a result, there is:
- Additional flexibility throughout the body.
- Increased awareness of muscles and their capabilities during any daily activity or sport.
- Increased coordination or agility.
- Quicker removal of waste products.
- Better posture.
- Increased range of motion available at a joints or joints.
- The development of functional or “usable” flexibility.
- Injury prevention.
- Increased blood supply, nutrients, and joint fluid.
- Reduced muscular soreness, stiffness, tightness and inflammation.
- Personal enjoyment, relaxation and reduced stress.
What Happens In A Stretch?
As you increase tension in a stretch, within a few milliseconds, the spinal cord reflexively tells the muscle to shorten in order to protect the muscle from being overstretched. It takes 6-10 seconds for the brain and spinal cord to perceive that the stretch is safe and, suddenly, the mild pulling sensation you feel of the muscle shortening to resist the stretch is gone. It is in the next 20-24 seconds that the stretch has the beneficial effects. That is a why a stretch must be held at least 30 seconds.
When Should You Stretch?
Ideally, stretching should be done when the body is warm. A warm-up of at least 2-5 mins. of movement is necessary to get the blood flowing and the muscles, tendons, and ligaments warmed up. After every activity, especially taxing ones, you should do a cool-down stretch routine, similar to a warm-up stretch, to relax the muscles that were just exercised. This helps eliminate the metabolic build-up of waste, such as lactic acid, nitrogen, and carbon dioxide, from the muscles to enhance muscle repair and recovery. Otherwise the metabolic waste will cause muscle stiffness, which affects the movement of the joints.
The Anatomy of Flexibility
Flexibility is most easily introduce by defining it as the range of motion (ROM) available to a joint or joints. Healthy or desired flexibility should be viewed as a capacity to move freely in every intended direction. The movement should not be confined to the joint’s functional range of motion (FROM) or intended movement capabilities.
Connective tissues of the joint include: cartilage, ligaments, tendons and muscle fascia or fascial sheath. The physical properties of connective tissue determine flexibility at the joint.
Cartilage is often present between bony surfaces to present a degree of protection for bone surfaces by providing “padding” and shock absorption capabilities.
Ligaments connect bone to bone and offer stability and integrity to joint areas. Tendons connect muscles to bone. The force of muscle contraction is transferred via the tend nous attachment of the muscles to the skeletal system.
Muscle fascia is represented by 3 “layers” of fascia that wrap the muscle:
- Endomysium- wraps individual muscle fibers or cells.
- Perimysium- wraps around groups or bundles of muscle fibers.
- Epimysium- wraps the entire muscle.
These various “layers” of fascia culminate in the tendons of the muscle.
* Flexibility is joint specific. The degree of movement is specific to each joint. Joint shape (joint capsule) effectively limits motion by 47%. The joint cannot be altered unless injury occurs. The tendon limits motion by 10%, the muscle fascia limits it by 41%, and the skin by 2%. However, connective or “soft” tissue can be altered long term. It is elasticity, which means a measure of a soft tissue’s resistance to stretch or lack of elasticity, that allows improvement in range of motion, or predisposes a client to injury if he engages in improper flexibility training.
Flexibility is influenced by a variety of factors, some of which may be changed, while others are unable to be altered, or if altered could lead to injury. These include:
- genetic inheritance
- the joint structure itself
- tension (partial contraction) in the muscle
- connective tissue elasticity within the muscles
- skin surrounding the joint
- neuromuscular influence (from sensory organs such as the muscle
- spindle and Golgi tendon organ (GTO)
Flexibility is generally limited by 4 important factors:
- The elastic limits of the ligaments and tendons crossing the joint.
- The elasticity of the muscle fibers themselves as muscle fascia which “encases” single muscle fibers, groups of muscle fibers and the entire muscle.
- The bone and joint structure.
- The skin.
What Is Being Stretched During Flexibility Training?
Muscle fascia’s lack of resistance to stretch makes it the most significant, changeable, limiting factor for gains in flexibility. Muscle fascia gives muscle the ability to change length. Muscle itself can be stretched to 150% of it’s length if relaxed and uninhibited by muscle fascia. Muscle fascia’s physical properties are not unlike that of candy taffy. When it’s warm, it is “stretchable”. When it’s cold, it is brittle and breakable. Because of these physical characteristics, a participant should warm the body first and hold sustained stretches so the muscle fascia can literally cool in a new and lengthened position.
Types of Stretching
There are 5 types of stretching techniques available:
- Static Stretching- a controlled stretch, held at the point of mild tension for about 10-60 seconds.
- Dynamic or Ballistic Stretching- Uses bouncing, jerking or abrupt movements to gain momentum into the posture to facilitate overstretching.
- Active Stretching- Voluntary, unassisted movement which requires strength and muscular contraction of the agonist (prime mover).
- Passive Stretching- Movements are accomplished through the use of an outside (external) force such as that provided by a partner, exerting pull on your own body part with another limb, gravity or momentum.
- PNF Stretching- PNF stretching works by first putting the targeted muscle on stretch and then generating maximal force in the muscle being stretched.
* As a result of static stretching being performed in a slow and controlled manner, it is the recommended and sometimes most effective stretch for individuals.