Hi,
I just started boxing in a proper gym with a proper trainer though I was already used to the heavy bag and excesrcise in general.

However, I've noticed a pain in my left elbow when I do shadow boxing, particularly with the jab, just when the arm goes straight.

Anyone know exactly what it could be? A strained tendon perhaps?

And what's more important; how long does it usually take to cure?

Is shadow boxing particularly hard on joints?

Thanks in advance.