關於愛，我是個小學生。

~ August 23rd, 2013, edited from Minimalist Golf

ALL HUMAN MOVEMENT takes place when muscles act across joints to move skeletal segments (ie bones). A simple example - the bicep (brachii) muscle lies on either end of your elbow. When (via signals from the brain) the bicep muscles contract or shorten, they pull the forearm bones towards the upper arm bone, creating a bend in your elbow joint. Is the golf swing a HUMAN MOVEMENT? YES. Then the main thing we need to understand is which muscles act to move joints in which directions. EVERYTHING ELSE (swing plane, across the line shaft, open clubface - even the gripping of the club's handle) can be boiled down to what HUMAN MOVEMENT caused the club to get into which position - it's not some magical fairy wand that can move about all by itself!

In 1992, George Peper, longtime editor of Golf Magazine revealed The X-Factor to a golf world hungry for ball-striking improvement, and said, “Millions of words have been written about how to hit a golf ball. It's rare, therefore, to come across a completely original contribution to the wisdom of instruction, but that is exactly what Jim McLean has produced in the X-factor. With the assistance of Sportsense swing computers, McLean has done beyond mere theory and shown actual proof of a more powerful way to swing.”(see  http://www.youtube.com/watch?v=DE8ODf3IeAU ) What is the X-Factor? In the words of discoverer Jim McLean (according to the video link pasted above) it is the ‘gap’ or ‘differential’ between hip and shoulder turn at the top of the backswing. It ‘creates explosion going forward’. The discovery was based on the fact that the 5 longest hitters on the PGA Tour have a much greater X-factor than the 5 shortest hitters. The golf world fell all over itself trying to facilitate this concept by one of golf's most famous teachers. The famous fitness people began to talk of thoracic-lumbar dis-association, and how they could help golfers to achieve it. Tons of research dollars were spent studying the X-Factor. To read about the numbers of scientists who have conducted research on the subject, and finally Professor Kwon's (head-biomechanist at Texas Woman's University) study (and debunking) of the subject, see http://50.87.35.246/~chriscq7/wp-content/uploads/2013/05/X-Factor-paper.pdf  Why did no one assess it based on simple BODY MOVEMENT capabilities and basic physics principles first? IS the movement a true differential between hips and shoulders? Is it desirable for golfers to make this move from both an efficiency and injury stand-point? Could anything else be used instead? Did anyone wonder whether the X-factor was correlation or causation? In other words, was it a mere co-incidence that those long hitters hit the ball much farther (for instance that they had better over-all flexibility) or was the X-factor really the CAUSE of the longer hitting? Does anyone care that the movements the PGA Tour players make are not necessarily the most efficient HUMAN MOVEMENTS to make, just a serendipitous way their brains and bodies have found to arrive at the ball correctly despite non-ideal backswing joint placements? YOU can get into X-FACTOR position as easily as John Daly who has the biggest X-factor, as follows (although you may not wish to by the end of this article): Set-up in your normal address position, bend at the lead (left, for a right-handed golfer) knee, hip and shoulder - voila you're in an ‘X-Factor‘ position. When the lead shoulder drops forwards, the trail shoulder has to go backwards, and that is being mistaken for any rotation. (In other words it is nothing but a lateral flexion of lead-side trunk, along with hip and knee flexion and ankle extension.)

The TPI, among other golf fitness expert groups, recommends alternate joints to be stable and mobile for good golf performance. It calls the thoracic spine an area of the body that must be made (via fitness or other physical interventions) into a ‘mobile’ segment of the body, with the segments directly above and below being considered ‘stable’. These ‘stable‘ joints would be the lumbar and cervical spines. Ironically, the neck (cervical spine) has the most muscles which can facilitate the maximum range of motion in many directions, while the thoracic spine is meant to be a rigid area of the body with a giant rib-cage attached. Which fundamental HUMAN MOVEMENT requires the cumbersome ribcage joints to rotate, while keeping the neck and lower-back stable? Also, imagine trying to rotate one segment of the spine against another. The spine has very small rotational muscles, and most global rotation of the body comes from the abdominal muscles, which cannot not be called upon to rotate only vertebrae number 8 to 19 from the top, and no other! Expect INEFFICIENCY of ball striking and a greater scope for INJURY! Bottom line, to make an efficient ‘coil’ during the backswing, the entire body - from ankles to top of the head - must rotate as one unit. As the neck-and-shoulder area of the spine has much more mobility than the hips or legs, especially when the feet are planted on the ground, the proportions of shoulder vs. hip rotation will be maintained, especially if the golfer were to make a minimal golf swing, which cuts out the HUMAN BODY's ability to over-or-under-twist any part of the body during the backswing. (It does that by completing required rotation pre-swing, so that there is NO confounding rotation - correct or incorrect - during the backswing). Now-the X-Factor-Stretch, is a whole nother animal, powerful and easy to acquire, with no need for the X-Factor. It is created simply, for any skill level of golfer, using the above-said simple swing.

不是我馬後炮，早就懷疑這理論了，但因為提出者太屌所以才一直不敢廢話，現在終於看到反對說。我始終相信應該是 x factor = st - pt 還要再加上 (st + pt) + eh，於是等於 2*st + eh，這樣才合理、且符合人體工學與力學原理。所以 x factor 應該改名字為 'potential power factors' 較宜。