and isnt a jab sometimes bordering very closely on being a back-hand punch? For example if you throw a left hook that misses, and then try to quickly throw a left jab, that jab will be starting out quite in a back-hand position, as you will not bring the missed left hook all the way back to the starting position to throw the subsequent jab. Therefore the left hand after missing the left hook will be somewhere around your right pectoral muscle, and from that position throwing a left jab is rather close to being a back-handed punch.