The most common occurence is when you are doing vertical climbing and your calves start trembling. This is due to your feet being too pointed (hence ur calves are contracted). You can avoid this by pointing your feet straight into the wall and not downwards all the time.
So the same applies to your entire body. If you're trembling from head to toe, means your muscles are too contracted. Consciosuly loosen your muscles starting from your neck to your shoulders to your arms.
Hope it helps?
