To increase or restore muscle ROM, it is necessary to overload the muscle with flexibility training. To improve joint ROM, it is necessary to lengthen the muscle and surrounding connective tissue in safe and effective ways.
Two main methods of flexibility training (static and dynamic) can be used, but all types of flexibility training will be more effective after a thorough warm-up, when the body temperature is elevated.
This method of flexibility training involves taking a specific joint or set of joints through a ROM to a comfortable end point (at least 20 seconds), resting for approximately 20 seconds, and then repeating the stretch two to three times.
The goal of static stretching is to overcome the stretch reflex (the automatic tightening of a muscle when stretched, which relaxes after approximately 20 seconds) to coax a joint into a wider ROM. This is done by holding the stretch gently and not overstretching the muscle.
• Example: Sit on the floor with your legs in front of you and bend forward at the hips with your spine in a neutral position until you feel a slight tension in the hamstring group. This stretch requires relaxation of the hamstrings and will increase ROM at the hip joint. Keep in mind that if you also flex the spine, you will be including the ROM of the vertebral joints, which may decrease the effect on the hamstrings.
• Advantages: Static stretching can be used by virtually anyone; it is easily taught and usually very safe. Once learned, it can be performed in almost any environment without external assistance or equipment.
• Disadvantages: Static stretching will improve flexibility at a specific body position and only to a small degree outside of that position, limiting its effectiveness for athletes or those wanting to increase flexibility in multiple ROMs. It is best suited to noncompetitive clients or as a complement to other methods of flexibility training.
This method of flexibility training uses increasingly dynamic movements through the full ROM of a joint. Dynamic stretching develops active ROM through the process of reciprocal inhibition, where the agonist muscle is contracting while the antagonist or opposite muscle is carried through the lengthening process.
When performed correctly, dynamic stretching warms up the joints, maintains current flexibility, and reduces muscle tension. The exercise begins at a slow pace and gradually increases in speed and intensity. This method of stretching is best performed before exercise or activity that is movement based, like tennis or hiking.
• Example: While standing on one foot, flex the hip joint of the nonsupporting leg (knee extended, like a pendulum). This motion contracts the hip flexors (agonists) and requires inhibition or relaxation of the hamstring group (antagonists).
• Advantages: Dynamic ROM is extremely useful for athletes and those who are warming up for an activity that requires a wide ROM, especially when speed is involved. Dynamic and static stretches combined can prepare the joints for explosive movements more than either type alone.
Common stretches for each major muscle group are a good starting point. Performing dynamic stretches prior to an exercise session in a warm-up, and static stretches after an exercise session in a cool-down. While other types of stretching exist, they are typically for therapeutic purposes and often outside of a personal trainer’s scope of practice.