How can i hit harder?!
Question: are there any exercise to improve strenght of my punch
Answers: are there any exercise to improve strenght of my punch
yes... work out your shoulders & arms (biceps / triceps)
military presses... shoulder presses...
concentration curls... bicep curls (barbels or dumbbells) and triceps extension...
aside from those... you could try to do some boxing moves while carrying a decent weight... to increase the speed of your punch... but the strength is improved by improving your arms...