Golfers, baseball pitchers, baseball batters and MMA fighters use the terms trunk coiling for power and trunk turning for power as being synonymous. For example, golfers believe that the backswing, in which there is much turning of the shoulders and hips, is an indication of good coiling.
To some extent, coiling and turning mean the same thing. However, the results of turning and coiling are quite different. In effective coiling, there is rotation of the shoulders with minimal or no rotation of the hips. In turning, the hips and/or shoulders can be in motion at the same time. In other words, hips and shoulders may turn as a unit which is typical of a body thrower or hitter.
Simultaneous rotation of the hips and shoulders is seen quite often in in golfers, quarterbacks, baseball pitchers and hitters. The hips and shoulders rotate together to the rear as well as forward in the power phase of the swing or hit. When these body parts rotate together there is less force produced than when there is a separation between the hips and shoulders.
For example, in effective coiling the midsection rotary (oblique) muscles undergo a strong eccentric stretch. You feel tension not only in the abdominal oblique muscles but also in the erector spinae muscles on one side of the lower back. In essence, the lower back muscles contract to turn the shoulders to place the abdominal oblique muscles on stretch.
When you have true coiling, there will be tension in the midsection muscles to prepare them for a release of energy in the downswing. Merely having a full turn of the body (hips and shoulders together) does not ensure the tension that is needed in the midsection muscles to produce a powerful shoulder turn.iin this variant tension is built up in the hip joint rotary muscles.
When the muscles are properly prepared in the truck coiling for power, the shoulder turn can create up to 50% of the total force produced in the forward swing. But this will only happen if the muscles are pre-stretched via the eccentric contraction.This is why a separation between the hips and shoulders is so critical for production of great force in the swing or hit. If there is no separation and your hips and shoulders turn together, you rely mainly on the hip joint muscles to rotate the body. As a result much less force is produced.
For a good coiling action, it is important that you limit, or even eliminate, the rearward rotation of the hips. The more the hips rotate to the rear, the less the build-up of tension in the abdominal oblique muscles.
To get the greatest amount of effective coiling requires flexibility in the midsection, more specifically in the rotational muscles of the waist. One of the best exercises to develop this flexibility is the reverse trunk twist. For greater strength of the oblique muscles you should do the Russian twist.
See Explosive Golf for more information on coiling and the exercises you can do to ensure an effective coiling action to generate maximum force in the trunk coiling for power..