Although men were the exclusive subjects of this study, Rose said the findings likely extend to women, as well, but need to be examined.
Researchers analyzed several biomechanical elements of subjects' golf swings, including S-factor (tilt of the shoulders), O-factor (tilt of the hips) and X-factor the relative rotation of the hips to the shoulders, measured in degrees which is considered key to power generation. Previous research has shown that pro golfers who hit the ball far generally have a larger peak X-factor than their peers, but this study is more extensive in that it considers X-factor in relation to other rotational biomechanics of the golf swing over the full duration of the motion.
Among the 10 pros in this study, peak X-factor during a hard swing was highly consistent, varying just 7.4 percent from a mean of 56 degrees. Their club speeds at impact with the ball also were highly consistent, varying just 5.9 percent from a mean of 79 mph. In contrast, peak X-factor of the three least skilled amateurs the handicap-30 golfer and two novices fell below the professional range: 48, 46 and 46 degrees, respectively. These smaller X-factor angles correlated with slower club speeds at impact: 68, 66 and 56 mph, respectively.
In addition, the study describes S-factor, a term coined by the researchers, for the first time. S-factor is the angle or tilt of the leading shoulder relative to the level position. The researchers found that peak S-factor occurred right after impact and was highly consistent among the pros, varying just 8.4 percent from a mean of 48 degrees. The handicap-15 player and two novices had lower S-factors of 42, 42 and 33 degrees, respectively, while
|Contact: John Sanford|
Stanford University Medical Center