It is unlikely that the fitness skin will crack. You may be talking about dry lines on your skin.

The contraction line is also called the expansion line. It is the primary striped atrophy of the skin, which is reddish at first and turns pale white after a long time. No conscious symptoms.

The skin is fragile because of elastic fiber degeneration, and then it is broken by overstretching, which leads to this disease. During this period, skin stretching or trauma is only the inducement that affects the distribution of skin lesions.