you need to have a little bit of elbow bend when you ride, otherwise all the vibrations will rattle through your wrists.Do you normally ride with your arms dead straight like that? Are you elbows locked?
That left leg is pretty straight as it is, and the heel is up so it looks like he is already stretching down slightly to the pedal.I’d say your seat post needs to go up so your leg is straight or thereabouts on the pedal at 6 o’clock