What the results mean
The test score gives you an idea of how flexible you are for this particular task. Having a low score indicates that more work is needed to improve the ability of the hamstring muscle group to stretch when you do the sit-and-reach movement. Keep in mind that if the muscles in your low back are tight, that can also limit the score on this test.
How to improve flexibility
Each joint is different and we need to do exercises specific for each joint to maintain or improve its unique range of motion. There is no test of “overall flexibility,” so you should plan a program of stretching exercises that involves most of your joints.
There are a variety of exercise programs (for example, Pilates and yoga) that naturally include stretching activities. However, many do not. For example, if you are a walker, runner, or cyclist you need to perform a group of specific stretches to work all of your joints.
There are a wide variety of stretches you can do to improve your flexibility. These examples are from Exercise: A Guide from the National Institute on Aging.
Frequency: Do flexibility exercises at least 3 days a week
Intensity: Take static stretches to the point of tension, not pain
Time: Hold each stretch for 10 to 30 seconds; repeat one or two more times.
Type: Begin with static stretches. Add dynamic stretches to increase variety.