It helps with both developing your posture and alignment in the water as well as rotation
It also improves your catch set up position and full stroke arm timing
Key Points
Kick on your side for approximately six kicks
Perform three strokes whilst gently exhaling
Breathe in after the third arm pull
Kick on the other side for six kicks
If it helps use the mantra:
6-3-breathe-6
Middle Finger Visualisation
Think about where your middle finger on the lead hand is pointing
Try to point straight forwards in front of your shoulder, towards the end of the lane
You can also use this visualization during full stroke to maintain your stroke alignment and prevent arm cross overs
Progression to full stroke
Perform some freestyle immediately after the drill, keeping your fins on
As you start the full stroke following the drill think about maintaining your alignment and extending the middle finger on your lead hand in front of the shoulder