The idea that the body builds “tension” as it twists during the golf back swing and that this tension being released in the down swing adds power to the swing is nonsense. Elasticized material stores power as it is stretched, but the body is made of nothing that is particularly elastic. The truth is that as the body is manipulated to and past its mechanical limits of movement it tells us this by sending pain signals to the brain. It is these signals which are useful. The brain is anxious to return the body to its pre limit position as rapidly as possible which makes the transition to down swing feel more natural and guides that transition accordingly.
But be aware also that pain is your body telling you “watch out, you are about to damage me”.
Why am I telling you this? Don’t try and force positions through the pain barrier in your back swing. Go to where it feels your body wants to stop and stop there. Don’t pay undue attention to preventing hip rotation in your back swing. It will only hamper and restrict your ability to get into a good position at the top. Muscle, coordination, technique and mechanical advantage build power, not being a contortionist.
Outside of weight lifting maybe, no athletic move should be based on creating or building tension. Tension will have a negative effect on the efficiency of the move and lead to injury. The epidemic of back injury plaguing professional golf is ample evidence of this. Ask Tiger, he will tell you.
The golf swing should not be uncomfortable. No athletic move should be. It should be fluid and graceful. Fluidity allows the body to perform at its peak and makes the golf swing far more instinctive and natural.
Don’t build tension into your golf swing. Don’t make it happen, allow it to happen.