1. Late Breath with Crossover & Scissor Kick.
More than 80% of the swimmers I see have this combination of stroke faults take a look at the pictures below and you’ll probably have seen a picture like this on your analysis.
A late breath is a breath that occurs after the body has reached its desired level of rotation(NO MORE THAN 60 DEGREES, FOR MOST 45 DEGREES IS BETTER). This means breathing a fraction of a second after your lead arm is at full extension. Late breathing shortens the time available to breathe, causes over rotation and often means the swimmer lifts the head much more than is necessary to achieve a breath.
The head should rotate to breathe with the body not after it. A simple way to visualise this is to turn the head away from the entering hand as it passes the head. Just before the hand enters the water the head should turn smoothly and in a chin tucked position away from the extending hand.
The UNCO drill is useful for getting the hang of breath timing try it using fins to suffer less.
Very few swimmers are conscious of their scissor kick until they see it on video. Clearly parting the legs like this causes lots of drag, most swimmers come to a virtual stop in the water when they do this. Coming to a stop means inertia needs to be overcome so the swimmer performs an energy sapping scissor kick to get moving again. The legs unconsciously part to balance the body due to an over rotation. This is often caused by both a crossover and a late breath remove the over rotation and the scissor kick will stop.
A crossover is when the hand crosses an imaginary centre line down the body this most often happens in front of the head but often swimmers crossover underneath the body also.