Practice generates heat as the chi begins to flow. Therefore it is important to practice more than one form. In the first form the body starts to warm up. In the second form the practitioner can check the body for alignment, for peng, ding, for any stuck spots. In the third form the chi begins to flow once the body is aligned, peng, loose, heavy, relaxed. This is like cooking chicken. The chicken needs time to warm up before it is tender.
Practice is for health, for kung fu and for chi development and movement.