Relationship Between Body Size & Flexibility

Flexibility is the ability of a joint to move through its full range of motion. How flexible you are depends on your age, genetics, gender and physical activity habits. A person's weight and musculature can sometimes enhance or impede flexibility as well, but not necessarily for reasons directly related to body size.

The bones, surrounding tissue, your nervous system and your muscles all influence a joint’s ability to move. Oftentimes, very stiff muscles or connective tissue can inhibit flexibility. Your body’s structure – particularly how bones insert into particular joints – can also inhibit or enhance natural flexibility. Repetitive movement that fails to move you through a full range of motion also inhibits flexibility. For example, runners tend to have tight hamstrings and hips because they regularly train in a limited range of motion.

People who are big due to a lot of muscle mass may have limited flexibility due to their training habits, not their size. Weight training that moves you through a limited range of motion leads to shortened muscle fibers and tight connective tissue. If you weight train using a full range of motion and stretch regularly, you can maintain flexibility regardless of how muscular you are.

Overweight and obese people are not less flexible than people who are of normal weight, unless they fail to use their body’s full range of motion. Very overweight and obese people may move infrequently because it is uncomfortable or they are out of shape. An excess of fat may also prevent full range of motion at certain joints. Being sedentary will lead to tight muscles and connective tissue, impeding flexibility, even if you are skinny.

You can improve your flexibility with regular, gentle stretching. Never stretch a cold muscle – do at least five to 10 minutes of light activity prior to stretching or include stretching as part of your cool down. Avoid holding your breath while stretching and never stretch to the point of pain. Recognize that some people are naturally more flexible than others. This doesn’t have to do with size, but with the shape of your bones and joint cavities. If you spend 30 minutes stretching at least three times per week, you can rest assured that you are doing what you can to maintain and enhance your own flexibility.