Answer: 5-10 per cent per week
Explanation:
The volume of the exercise should not be increased more than 5-10 % per week because increasing the exercise more than this percentage will be difficult for the body to adjust.
This is because the body needs time to recover and repair itself. The muscles of the body also needs time to repair itself.
The increase in the volume of the exercise must be done gradually so as to make the muscles more toned fit.