Instruction :
Group following sports based on their similarities. Consider the instruments used, place and duration:

Tennis, kick-boxing, football, squash, boxing, rugby, table tennis, taekwondo

Response:
These sports can be categorized into as following groups;
- Footballs sports: Football, rugby 
- Racket sports: tennis, table tennis, squash
- Combat sports: kick-boxing, boxing, taekwondo