Range of motion describes the distance a lever or movable object travels while attached to a fixed point. When applying this to the field of biomechanics, it is used to describe a joint’s range. Because the body was designed to move in a specific way, the importance of maintaining the full range of each joint is desirable for optimal physical health.
When a bone moves passively at the joint, such as when an exercise teacher moves it, it is referred to as static flexibility. When a bone moves due to muscular contraction it is referred to as dynamic flexibility. According to Susan J. Hall in "Basic Biomechanics," static flexibility is performed to stretch a muscle group or look for potential injury. Dynamic flexibility should be sufficient to perform daily tasks and exercises.
Range of motion is determined by joint flexibility. How much range a particular joint may have is based on bone surfaces, intervening muscles and fatty tissue. The bony structure of a joint will greatly determine how and where it can move. For instance, your hip, as a ball-and-socket joint, has a much greater range of motion than your elbow, which is a hinge joint. Your hip can move in three planes while your elbow can only move in two.
An Appropriate Range
Risk of injury is greater when joint flexibility is extremely low. A research study by Karen J. Wright and Carl De Cree published in the "Journal of Physical Therapy Science," found that low flexibility in gymnasts was a predisposition to injury. Limited joint flexibility places a greater load on tight collagenous tissues and muscles, increasing their propensity to tear. Extremely high flexibility or muscular imbalance between two sides of the body can also increase potential injury. It is important to maintain an appropriate range of motion at each joint.
Benefits of Stretching
Adding 15 minutes of stretching post-exercise will help increase range of motion, decrease injury potential and give you a better sense of mobility while performing daily tasks. Stretching tight areas can also decrease potential strain on already mobile areas because the load will be more equally distributed. The feeling of tightness may diminish and it will be easier to perform exercises which involve a greater range, such as a basic squat.
Focus on areas in which you are most tight. In general, most people are tight in their hamstrings, glutes and hip flexors. All of these muscles surround the hip socket, so start with simple hip stretches to increase range of motion. You can perform these stretches actively by using your own muscles to move the hip, or passively by using your hands. If in doubt, ask your personal trainer or fitness coach what stretches are appropriate.
- "Basic Biomechanics"; Susan J. Hall; 2007
- "Human Anatomy & Physiology"; Elaine N. Marieb, Katja Hoehn; 2005
- "Journal of Physical Therapy Science"; The Influence of Somatotype, Strength and Flexibility on Injury Occurrence among Female Competitive Olympic-Style Gymnasts--A Pilot Study; Karen J. Wright, Carl De Cree; vol 10, 1998
- Stretching USA; "Active Isolated Stretching:The Mattes Method"
- "Stretching"; Bob Anderson; 2000
- "Stretching: The Stress-Free Way to Stay Supple"; Suzanne Martin; 2005
- Jupiterimages/Brand X Pictures/Getty Images
This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.