Flexibility can be defined as the ability of a joint to move through an optimum Range of Motion (ROM). Not only do flexibility exercises such as stretching help combat stiff muscles and joints, they also help to increase ROM. Stretching is especially important with high-intensity exercise or when repetitious movements are used during the activity. When the same muscles are used over and over again, such as with running, cycling and swimming, they gradually become stiffer. The increased tightness could result in a possible injury to muscles, tendons and ligaments. Many injuries can occur from a lack of proper stretching, and incorporating stretch training into your clients' exercise programs can help them improve their overall levels of fitness.

Benefits of Stretching
1. Reduction of low-back pain and injury
2. Reduction in the incidence and severity of injury
3. Improvement in posture and muscle symmetry
4. Delay in the onset of muscular fatigue
5. Prevention and alleviation of muscle soreness after exercise
6. Increase in the level of certain skills and muscular efficiency
7. Promotion of mental relaxation
8. Personal enjoyment and gratification

When to Stretch
All of the muscle groups that are going to be used in a workout should be stretched prior to the exercise, following a thorough warm-up to slightly increase muscle temperature. Stretching can also be done after the workout. This will help prevent muscular soreness in the days after exercise. In addition to stretching prior to exercise, specific training to improve ROM should be performed at least three times per week.

Maintaining flexibility becomes even more important as people age. It can improve the quality of life by allowing people to perform what once were simple daily tasks, such as tying their shoes or reaching to the top shelf of a cabinet. Other benefits of flexibility include a reduced risk of injury to muscles and joints, increased body awareness and balance, better posture, improved coordination and enhanced performance of skilled movements

As with many types of exercise, there are some contraindications to stretching, including a bone blocking the motion, a recently fractured bone, an inflamed or swollen joint, osteoporosis, sharp pain when stretching, a recent sprain or strain, or a vascular disease, such as a blood clot. Please make sure you’re staying within your limitations, don’t do further harm by trying to stretch.

Flexibility training has more recently been recognized among the other components of fitness as a means to better mental health. Health practitioners are using flexibility training as a vehicle to facilitate mental and physical relaxation and stress reduction.

Flexibility Guidelines
It is certain to increase ROM, you need to slowly stretch just past the point of limitation. Depending on your fitness level, goals, limiting factors of flexibility, and other exercise program participation, your individualized flexibility program can be designed using the following guidelines:

1. Assess your flexibility in order to pinpoint strengths and weaknesses.

2. Design a program that stretches the specific muscles you will use during physical activity or sport participation.

3. Warm-up before stretching to increase the body temperature and range of motion.

4. Perform stretching exercises daily.

5. Stretch all major muscle groups, as well as opposing muscle groups.

6. Focus on the muscles involved in the stretch, minimizing the movement of other body parts.

7. Hold stretches between 15 and 30 seconds. Recent research suggests that four sets of 15 to 20 seconds per stretch will result in optimal gains.

8. Stretch to the limit of movement, not to the point of pain. This is referred to as the "endpoint" of the stretch.

9. Keep the breathing slow and rhythmical while holding the stretches.

10. Stretch the muscles in various positions, as stretching in different planes may enhance muscle relaxation and improve overall range of motion at the joint.

11. Attempt to relax the target muscle before going into the stretch.

12. Stretch after each vigorous workout to reduce the potential of delayed-onset muscle soreness and to encourage mind and body relaxation.

13. If the stretch yields pain in the joint area, back off the movement and make sure the stretching technique is correct. It may be necessary to try another position or another stretch for the target muscles.