We've all seen those swimmers that make front crawl look effortless, rotating well and thinking how do they do that?
A large part of this is how they rotate from their hips on a long axis to 45 degrees on each side, using the core and glutes to drive the rotation.
Try this swimming drill to help improve your rotation: It's called 6/3/6
Do 6 kicks on your side followed by 3 strokes, 6 times (6/3/6) - this will help with with rotation, balance and streamlining.
Rotate your body on a long axis from your head to your feet, driving this movement from your trunk and hips.
Point your shoulder and hip to the bottom of the pool whilst on your side, with your head underwater, and belly button pointed to the side of the pool
Breathe only once after each 3rd stroke, then drop back into your side-kick position for another 6-10 kicks.
Keep finding your correct side balance point immediately after each stroke & breath, and stay kicking in balance for at least 6 kicks before stroking again. Keep your ear close to your shoulder when on your side
Do this drill for 50-100m x4 with 30 seconds of rest
You may find fins help, although it's best to do the drill without them if you can.
This is called core-driven rotation on a long axis, effectively swimming through a narrow tube of horizontal water reducing drag and resistance.
If you're not rotating from your hips or to 45 degrees on each side in your normal swim stroke then one of the following could be happening:
Turning your head to breathe and lifting your body
Rolling your shoulders first
Lead arm dropping affecting balance
Over rotating to breathe
Uneven body roll to one side
Dropping your elbow in the catch phase
Legs and hips too low
All of these will negatively affect your body position and balance in the water, therefore increasing drag and resistance, and resulting in creating turbulence, making it harder to swim.