Golfers call it Factor X -- the ability to propel a golf ball harder and further than was ever thought possible.

For modern coaches, the secret of Factor X has always lain in creating torque by twisting the body around the spine and turning the shoulders relative to the hips. This energy is then released by first rotating the hips towards the ball and allowing the shoulders to follow so that the hips, torso, shoulders, arms, wrists and club "whip" though the ball and create maximum angular velocity at the club head.

Along with twisting the body around the shaft of the spine, coaches have also emphasised what they call "loading the hips," which for right-handers means keeping the right hip still so creating even more stretch as the pelvis rotates on the back swing. It is the power created by this movement that the Northumbria team has demonstrated.

"Up until now, the evidence for 'loading the hips' has all been anecdotal," says Dr Su Stewart , who led the research. "Coaches emphasise it, and certainly any golfer can feel the tension the movement creates. What we have shown is how closely this relatively small movement correlates with increased angular velocity at the club head. A great golf drive is not simply about creating torque by rotating the body around the spine, it is also about creating torque within the hips by rotating the pelvis around the right hip joint itself."

In the study, eight right-handed male golfers with handicaps below five were tested in the laboratory with a variety of techniques including an array of 12 motion-capture cameras and 39 reflective markers (35 on the participants, four on the club).

When the results were analysed, significant correlations were found between club-head angular velocity at the moment of impact with the ball and left and right maximum hip moment. What's more right-hip torque was significantly correlated to swing intensity both at the top of the backswing and at mid-downswing showing that the right hip is instrumental in initiating and driving the downswings that achieve the greatest distance and so suggesting new avenues for both research and coaching.

Previous biomechanical research on the golf swing has focused mainly on the upper body, while research conducted on the lower body has focused mainly on the feet and knees.

The new research was directed by Dr Stewart and undertaken by her undergraduate student James Haigh. James was awarded a first for the study and, in a rare accolade for an undergraduate, is presenting the findings at the British Association of Sport and Exercise Science conference in Glasgow.

Note: If no author is given, the source is cited instead.

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