A kinematic analysis in golf swing concerning driver shot and No. 9 iron shot
Nagao, N.; Sawada, Y.
Journal of Sports Medicine and Physical Fitness 13(1): 4-16
1973
ISSN/ISBN: 0022-4707 PMID: 4733133 Document Number: 4928
This report deals with the result of a motion picture analysis of the body movements of representative Japanese professional golfers. The swinging motion in the full shot with driver and No. 9 iron were photographed in their front views by means of a ultrahigh -speed camera, Model 16 -HD Hitachi HIMAC, the resultant film being subjected to the NAC 16-S film data analyzer to produce the results that follow. Conclusion: 1. In the case of 14 professionals, as for the loci of their club head from the top of swing to the finish range in pattern from a horizontal heart type to an ellipse, but in the case showing an elliptical orbit at the time of driver shot, an elliptical orbit was also formed at the tirq of No. 9 iron shot, whereas in the case showing a horizontal heart type of orbit at the time of driver shot, a horizontal heart type of orbit was also formed at the time of No. 9 iron shot, indicating the similarity of patterns traced by the same individual. 2. As for the degrees of angle formed by the club shaft at the time of address, top of swing, impact and finish, there are differences of 8.2°, 26.7°, 10.4° and 85.9° respectively between driver shot and No. 9 iron shot and a statistically significant difference can be noticed in each of these values. 3. As for the time required for down swing, there is no significant difference between driver shot and No. 9 iron shot, but the time required for follow-through being somewhat longer in the case of No. 9 iron shot than in the case of driver shot. 4. It can be said that those pro-golfers taking a shorter time for driver shot in both down swing and follow-through take a shorter time also in the case of No. 9 iron shot. 5. It is deemed to indicate that at the times of full swing in driver and No. 9 iron shots, the grip is swung nearly similarly, on the other hand, however, the speed of club head at the time of driver shot is 1.34 times on the average as compared with the speed at the time of No. 9 iron shot, and the speed of club head is approximately in proportion to the length of club shaft, but small differences that can be seen are deemed co be attributable to difference in wrist turn-over directly before impact. 6. It can be said that in the case of driver shot, cocking is reserved in about the middle of the down swing process and released rapidly directly before impact, whereas in the case of No. 9 iron shot, cocking is not reserved and in about the middle of the down swing process it begins to be released. 7. The initial ball speed is, on the average, 66.6 m/sec. in the case of driver shot or 1.58 times the speed at the time of No. 9 iron shot, while the shooting angle at the time of No. 9 iron shot is 23.5° or 2.17 times the mean angle of 10.82° at the time of driver shot. The number of revolutions of ball involving a precise back spin in both shots is, on the average, 52.8 r.p.s. in the case of driver shot and 149.1 r.p.s. in the case of No. 9 iron shot, applying a large number of revolutions equivalent to 2.82 times the r.p.s. at the time of driver shot.
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