This short guide is about tonus and stat capping.
Tonus Explanatory Guide
Some punches or kicks reduce your attributes while using it, it says that in the description.
Like -1 per round of fighting. So if you use a strength kick that has -1 str per round and put it 4x in your slots you have -4 str after one round.
The complete reduction is shown above your attribute with the current value.
To regain your str you need to train, this first puts your tonus back to 0, then it continues with your stat increase.
Training your tonus back up is faster than normal training.