Physical caps can only be seen (visually) by supporters. Otherwise - with normal progression - a physical skill should increase once every 4-5 training cycles. If it does not increase, the player has (most likely) capped. Use a spreadsheet to follow your players progression.

All non physical skills (soft) cap according to talent, which I have listen below.

Talent Max cap

0,50 11
1,00 12
1,50 13
2,00 14
2,50 15
3,00 16
3,50 17
4,00 18
4,50 19
5,00 20

Otherwise, check the training FAQ.