The answer is <u>"External factors are easy to control".</u>
Flexibility alludes to the range of movement in a joint or arrangement of joints, and length in muscles that cross the joints to incite a twisting development or movement.
Internal factors are harder to control in that you would need to alter your body to transform them, however this should be possible now and again. You can stretch to protract your muscles and ligaments, yet it will require some serious energy and exertion. There are a considerable measure of outer variables that you can control, for example, the temperature of the room or your body, your duty to the extending, or what garments you wear. In any case, there are some outer variables that you can't control, for example, your age, your sexual orientation, or your body's rate and capacity to recuperate joints or muscles.