Effects of golf shaft stiffness on strain, clubhead presentation and wrist kinematics

Nils F. Betzler; Stuart A. Monk; Eric S. Wallace; Steve R. Otto

doi:10.1080/14763141.2012.681796

Effects of golf shaft stiffness on strain, clubhead presentation and wrist kinematics

Nils F. Betzler, Stuart A. Monk, Eric S. Wallace, Steve R. Otto

Research output: Contribution to journal › Article › peer-review

19 Citations (Scopus)

Abstract

The aim of this study was to quantify and explain the effect of shaft stiffness on the dynamics of golf drives.Twenty golfers performed swings with two clubs designed to differ only in shaft bending stiffness.Wrist kinematics and clubhead presentation to the ball were determined using optical motion capture systems in conjunction with a radar device for capturing ball speed, launch angle, and spin. Shaft stiffness had a marginally small effect on clubhead and ball speeds, which increased by 0.45%( p , 0.001) and 0.7% ( p =0.008), respectively, for the less stiff club. Two factors directly contributed to these increases: (i) a faster recovery of the lower flex shaft from lag to lead bending just before impact( p , 0.001); and (ii) an increase of 0.4% in angular velocity of the grip of the lower flex club at impact( p =0.003). Unsurprisingly, decreases in shaft stiffness led to more shaft bending at the transition from backswing to downswing ( p , 0.001). Contrary to previous research, lead bending at impact marginally increased for the stiffer shaft ( p ¼=0.003). Overall, and taking effect sizes into account, thechanges in shaft stiffness in isolation did not have a meaningful effect on the measured parameters, for the type of shaft investigated.

Original language	English
Pages (from-to)	223-238
Journal	Sports Biomechanics
Volume	11
Issue number	2
DOIs	https://doi.org/10.1080/14763141.2012.681796
Publication status	Published (in print/issue) - Jun 2012

Bibliographical note

Reference text: Ball, K. A., & Best, R. J. (2007). Different centre of pressure patterns within the golf stroke I: Cluster analysis.
Journal of Sports Sciences, 25, 757–770.
Betzler, N. F.,Monk, S. A.,Wallace, E. S., & Otto, S. R. (2012). Variability in clubhead presentation characteristics
and ball impact location for golfers’ drives. Journal of Sports Sciences, 30, 439–448.
Betzler,N. F., Slater, C., Strangwood, M., Monk, S. A., Otto, S. R., &Wallace, E. S. (2011). The static and dynamic
stiffness behaviour of composite golf shafts and their constituent materials. Sports Engineering, 14, 27–37.
Butler, J. H., & Winfield, D. C. (1994). The dynamic performance of the golf shaft during the downswing. In A. J.
Cochran, and M. R. Farrally (Eds.), Science and Golf II: Proceedings of the World Scientific Congress of Golf
(pp. 259–264). London: E & FN Spon.
Cappozzo, A., Catani, F., Della Croce, U., & Leardini, A. (1995). Position and orientation in space of bones during
movement: Anatomical frame definition and determination. Clinical Biomechanics, 10, 171–178.
Coleman, S. G. S., & Rankin, A. J. (2005). A three-dimensional examination of the planar nature of the golf swing.
Journal of Sports Sciences, 23, 227–234.
Crisco, J. J., Rainbow, M., &Wang, E. (2009). Modeling the Lacrosse stick as a rigid body underestimates shot ball
speeds. Journal of Applied Biomechanics, 25, 184–191.
Field, A. (2005). Discovering statistics using SPSS, 2nd ed. London: Sage.
Harper,T. E., Jones, R.,&Roberts, J. (2005a). Robotic simulation of golfer shaft loading. In A. Subic, and S. Ujihashi
(Eds.), The impact of technology on sport (pp. 386–391). Melbourne: Australasian Technology Alliance.
Harper, T. E., Roberts, J. R., & Jones, R. (2005b). Driver swingweighting: A worthwhile process? Proceedings of the
Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 219, 385–393.
Hocknell, A., Jones, R., & Rothberg, S. (1996). Experimental analysis of impacts with large elastic deformation:
I. Linear motion. Measurement Science and Technology, 7, 1247–1254.
Horwood, G. P. (1994). Golf shafts—a technical perspective. In A. J. Cochran, and M. R. Farrally (Eds.), Science
and Golf II: Proceedings of the World Scientific Congress of Golf (pp. 247–258). London: E & FN Spon.
Kojima, A., & Horii, H. (1995). Effect of torsional properties of CFRP golf club shafts on the speed and the
directional stability of the ball. In Z. Maekawa, E. Nakata, and Y. Sakatani (Eds.), Proceedings of the 4th Japan
International SAMPE Symposium (pp. 1328–1334). Yokohama: SAMPE.
Lee, N., Erickson, M., & Cherveny, P. (2002). Measurement of the behaviour of a golf club during the golf swing.
In E. Thain (Ed.), Science and Golf IV: Proceedings of theWorld Scientific Congress of Golf (pp. 374–385). London:
Routledge.
Effects of golf shaft stiffness 15
Downloaded by [University of Ulster at Coleraine] at 13:28 02 June 2012
MacKenzie, S., & Sprigings, E. (2009a). A three-dimensional forward dynamics model of the golf swing. Sports
Engineering, 11, 165–175.
MacKenzie, S., & Sprigings, E. (2009b). Understanding the role of shaft stiffness in the golf swing. Sports
Engineering, 12, 13–19.
MacKenzie, S., & Sprigings, E. (2010). Understanding the mechanisms of shaft deflection in the golf swing. Sports
Engineering, 12, 69–75.
Maltby, R. D. (1995). Golf club design, fitting, alteration, and repair: The principles and procedures. Newark, OH:
R. Maltby Enterprises.
Mather, J. S. B., & Jowett, S. (1998). The effect of centrifugal stiffening on the bending stiffness of a golf shaft.
In S. Haake (Ed.), The engineering of sport (pp. 515–522). London: Blackwell Science.
Mather, J. S. B., & Jowett, S. (2000). Three dimensional shape of the golf club during the swing. In A. Subic,
and S. Haake (Eds.), The engineering of sport (pp. 77–85). London: Blackwell Science.
Mather, J. S. B., Smith, M. J., Jowett, S., Gibson, K. A. H., & Moynihan, D. (2000). Application of a
photogrammetric technique to golf club evaluation. Sports Engineering, 3, 37–47.
McCane, B., Abbott, J. H., & King, T. (2005). On calculating the finite centre of rotation for rigid planar motion.
Medical Engineering & Physics, 27, 75–79.
Milne, R. D., & Davis, J. P. (1992). The role of the shaft in the golf swing. Journal of Biomechanics, 25, 975–983.
Newman, S., Clay, S., & Strickland, P. (1997). The dynamic flexing of a golf club shaft during a typical swing,
In Proceedings of the Fourth Annual Conference on Mechatronics and Machine Vision in Practice (pp. 265–270).
Toowoomba, Australila: IEEE Computer Society.
Ozawa, T., Namiki, H., & Horikawa, N. (2002). A study on clubface direction during a golf swing. In S. Ujihashi,
and S. Haake (Eds.), The engineering of sport 4, Vol. 5 (pp. 688–694). Oxford: Blackwell.
Penner, A. R. (2003). The physics of golf. Reports on Progress in Physics, 66, 131–171.
Pierce, C. A., Block, R. A., & Aguinis, H. (2004). Cautionary note on reporting eta-squared values from multifactor
ANOVA designs. Educational and Psychological Measurement, 64, 916–924.
R&A Rules Limited. (2005). Procedure for measuring the moment of inertia of golf clubheads, Retrieved from
http://www.randa.org/en/Equipment/,/media/RandA/Equipment%20protocol%20documents/Moment%
20of%20Inertia.ashx
Schwartz, M. H., & Rozumalski, A. (2005). A new method for estimating joint parameters from motion data.
Journal of Biomechanics, 38, 107–116.
Stanbridge, K., Jones, R., &Mitchell, S. (2004). The effect of shaft flexibility on junior golfers’ performance. Journal
of Sports Sciences, 22, 457–464.
Tsujiuchi, N., Koizumi, T., & Tomii, Y. (2002). Analysis of the influence of golf club design on the golf swing. In S.
Ujihashi, and S. Haake (Eds.), The engineering of sport 4 (pp. 537–544). Oxford: Blackwell.
Tsunoda, M., Bours, R., & Hasegawa, H. (2004). Three dimensional motion analysis and inverse dynamic modeling
of the human golf swing. In M. Hubbard, R. D. Mehta, and J. M. Pallis (Eds.), The engineering of sport 5, Vol. 2
(pp. 326–332). Sheffield: International Sports Engineering Association.
Wallace, E. S., & Hubbell, J. E. (2001). The effect of golf club shaft stiffness on golf performance variables—
implications for club-fitting. Paper presented at the Materials & Science in Sports Symposium, Coronado Island
Marriott Resort, Coronado, CA.
Worobets, J. T., Fairbairn, J., & Stefanyshyn,D. (2006). The influence of shaft stiffness on potential energy and puck
speed during wrist and slap shots in ice hockey. Sports Engineering, 9, 191–200.
Worobets, J. T., & Stefanyshyn, D. J. (2008). Shaft stiffness: Implications for club fitting. In D. J. Crews, and R. Lutz
(Eds.), Science and Golf V: Proceedings of theWorld Scientific Congress of Golf (pp. 431–437). Mesa, AZ: Energy in
Motion.
Zheng, N., Barrentine, S. W., Fleisig, G. S., & Andrews, J. R. (2008). Kinematic analysis of swing in pro and
amateur golfers. International Journal of Sports Medicine, 487–493.

Keywords

Shaft bending
shaft flexion
motion analysis
equipment
ball speed

Access to Document

10.1080/14763141.2012.681796

http://uir.ulster.ac.uk/22836/3/Betzler_et_al_2012_Golf_shaft_stiffness_final.pdf

Cite this

@article{c4a64fddc373470e8fc3c0fca2603e71,

title = "Effects of golf shaft stiffness on strain, clubhead presentation and wrist kinematics",

abstract = "The aim of this study was to quantify and explain the effect of shaft stiffness on the dynamics of golf drives.Twenty golfers performed swings with two clubs designed to differ only in shaft bending stiffness.Wrist kinematics and clubhead presentation to the ball were determined using optical motion capture systems in conjunction with a radar device for capturing ball speed, launch angle, and spin. Shaft stiffness had a marginally small effect on clubhead and ball speeds, which increased by 0.45%( p , 0.001) and 0.7% ( p =0.008), respectively, for the less stiff club. Two factors directly contributed to these increases: (i) a faster recovery of the lower flex shaft from lag to lead bending just before impact( p , 0.001); and (ii) an increase of 0.4% in angular velocity of the grip of the lower flex club at impact( p =0.003). Unsurprisingly, decreases in shaft stiffness led to more shaft bending at the transition from backswing to downswing ( p , 0.001). Contrary to previous research, lead bending at impact marginally increased for the stiffer shaft ( p ¼=0.003). Overall, and taking effect sizes into account, thechanges in shaft stiffness in isolation did not have a meaningful effect on the measured parameters, for the type of shaft investigated.",

keywords = "Shaft bending, shaft flexion, motion analysis, equipment, ball speed",

author = "Betzler, {Nils F.} and Monk, {Stuart A.} and Wallace, {Eric S.} and Otto, {Steve R.}",

note = "Reference text: Ball, K. A., & Best, R. J. (2007). Different centre of pressure patterns within the golf stroke I: Cluster analysis. Journal of Sports Sciences, 25, 757–770. Betzler, N. F.,Monk, S. A.,Wallace, E. S., & Otto, S. R. (2012). Variability in clubhead presentation characteristics and ball impact location for golfers{\textquoteright} drives. Journal of Sports Sciences, 30, 439–448. Betzler,N. F., Slater, C., Strangwood, M., Monk, S. A., Otto, S. R., &Wallace, E. S. (2011). The static and dynamic stiffness behaviour of composite golf shafts and their constituent materials. Sports Engineering, 14, 27–37. Butler, J. H., & Winfield, D. C. (1994). The dynamic performance of the golf shaft during the downswing. In A. J. Cochran, and M. R. Farrally (Eds.), Science and Golf II: Proceedings of the World Scientific Congress of Golf (pp. 259–264). London: E & FN Spon. Cappozzo, A., Catani, F., Della Croce, U., & Leardini, A. (1995). Position and orientation in space of bones during movement: Anatomical frame definition and determination. Clinical Biomechanics, 10, 171–178. Coleman, S. G. S., & Rankin, A. J. (2005). A three-dimensional examination of the planar nature of the golf swing. Journal of Sports Sciences, 23, 227–234. Crisco, J. J., Rainbow, M., &Wang, E. (2009). Modeling the Lacrosse stick as a rigid body underestimates shot ball speeds. Journal of Applied Biomechanics, 25, 184–191. Field, A. (2005). Discovering statistics using SPSS, 2nd ed. London: Sage. Harper,T. E., Jones, R.,&Roberts, J. (2005a). Robotic simulation of golfer shaft loading. In A. Subic, and S. Ujihashi (Eds.), The impact of technology on sport (pp. 386–391). Melbourne: Australasian Technology Alliance. Harper, T. E., Roberts, J. R., & Jones, R. (2005b). Driver swingweighting: A worthwhile process? Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 219, 385–393. Hocknell, A., Jones, R., & Rothberg, S. (1996). Experimental analysis of impacts with large elastic deformation: I. Linear motion. Measurement Science and Technology, 7, 1247–1254. Horwood, G. P. (1994). Golf shafts—a technical perspective. In A. J. Cochran, and M. R. Farrally (Eds.), Science and Golf II: Proceedings of the World Scientific Congress of Golf (pp. 247–258). London: E & FN Spon. Kojima, A., & Horii, H. (1995). Effect of torsional properties of CFRP golf club shafts on the speed and the directional stability of the ball. In Z. Maekawa, E. Nakata, and Y. Sakatani (Eds.), Proceedings of the 4th Japan International SAMPE Symposium (pp. 1328–1334). Yokohama: SAMPE. Lee, N., Erickson, M., & Cherveny, P. (2002). Measurement of the behaviour of a golf club during the golf swing. In E. Thain (Ed.), Science and Golf IV: Proceedings of theWorld Scientific Congress of Golf (pp. 374–385). London: Routledge. Effects of golf shaft stiffness 15 Downloaded by [University of Ulster at Coleraine] at 13:28 02 June 2012 MacKenzie, S., & Sprigings, E. (2009a). A three-dimensional forward dynamics model of the golf swing. Sports Engineering, 11, 165–175. MacKenzie, S., & Sprigings, E. (2009b). Understanding the role of shaft stiffness in the golf swing. Sports Engineering, 12, 13–19. MacKenzie, S., & Sprigings, E. (2010). Understanding the mechanisms of shaft deflection in the golf swing. Sports Engineering, 12, 69–75. Maltby, R. D. (1995). Golf club design, fitting, alteration, and repair: The principles and procedures. Newark, OH: R. Maltby Enterprises. Mather, J. S. B., & Jowett, S. (1998). The effect of centrifugal stiffening on the bending stiffness of a golf shaft. In S. Haake (Ed.), The engineering of sport (pp. 515–522). London: Blackwell Science. Mather, J. S. B., & Jowett, S. (2000). Three dimensional shape of the golf club during the swing. In A. Subic, and S. Haake (Eds.), The engineering of sport (pp. 77–85). London: Blackwell Science. Mather, J. S. B., Smith, M. J., Jowett, S., Gibson, K. A. H., & Moynihan, D. (2000). Application of a photogrammetric technique to golf club evaluation. Sports Engineering, 3, 37–47. McCane, B., Abbott, J. H., & King, T. (2005). On calculating the finite centre of rotation for rigid planar motion. Medical Engineering & Physics, 27, 75–79. Milne, R. D., & Davis, J. P. (1992). The role of the shaft in the golf swing. Journal of Biomechanics, 25, 975–983. Newman, S., Clay, S., & Strickland, P. (1997). The dynamic flexing of a golf club shaft during a typical swing, In Proceedings of the Fourth Annual Conference on Mechatronics and Machine Vision in Practice (pp. 265–270). Toowoomba, Australila: IEEE Computer Society. Ozawa, T., Namiki, H., & Horikawa, N. (2002). A study on clubface direction during a golf swing. In S. Ujihashi, and S. Haake (Eds.), The engineering of sport 4, Vol. 5 (pp. 688–694). Oxford: Blackwell. Penner, A. R. (2003). The physics of golf. Reports on Progress in Physics, 66, 131–171. Pierce, C. A., Block, R. A., & Aguinis, H. (2004). Cautionary note on reporting eta-squared values from multifactor ANOVA designs. Educational and Psychological Measurement, 64, 916–924. R&A Rules Limited. (2005). Procedure for measuring the moment of inertia of golf clubheads, Retrieved from http://www.randa.org/en/Equipment/,/media/RandA/Equipment%20protocol%20documents/Moment% 20of%20Inertia.ashx Schwartz, M. H., & Rozumalski, A. (2005). A new method for estimating joint parameters from motion data. Journal of Biomechanics, 38, 107–116. Stanbridge, K., Jones, R., &Mitchell, S. (2004). The effect of shaft flexibility on junior golfers{\textquoteright} performance. Journal of Sports Sciences, 22, 457–464. Tsujiuchi, N., Koizumi, T., & Tomii, Y. (2002). Analysis of the influence of golf club design on the golf swing. In S. Ujihashi, and S. Haake (Eds.), The engineering of sport 4 (pp. 537–544). Oxford: Blackwell. Tsunoda, M., Bours, R., & Hasegawa, H. (2004). Three dimensional motion analysis and inverse dynamic modeling of the human golf swing. In M. Hubbard, R. D. Mehta, and J. M. Pallis (Eds.), The engineering of sport 5, Vol. 2 (pp. 326–332). Sheffield: International Sports Engineering Association. Wallace, E. S., & Hubbell, J. E. (2001). The effect of golf club shaft stiffness on golf performance variables— implications for club-fitting. Paper presented at the Materials & Science in Sports Symposium, Coronado Island Marriott Resort, Coronado, CA. Worobets, J. T., Fairbairn, J., & Stefanyshyn,D. (2006). The influence of shaft stiffness on potential energy and puck speed during wrist and slap shots in ice hockey. Sports Engineering, 9, 191–200. Worobets, J. T., & Stefanyshyn, D. J. (2008). Shaft stiffness: Implications for club fitting. In D. J. Crews, and R. Lutz (Eds.), Science and Golf V: Proceedings of theWorld Scientific Congress of Golf (pp. 431–437). Mesa, AZ: Energy in Motion. Zheng, N., Barrentine, S. W., Fleisig, G. S., & Andrews, J. R. (2008). Kinematic analysis of swing in pro and amateur golfers. International Journal of Sports Medicine, 487–493.",

year = "2012",

month = jun,

doi = "10.1080/14763141.2012.681796",

language = "English",

volume = "11",

pages = "223--238",

journal = "Sports Biomechanics",

issn = "1752-6116",

publisher = "Taylor & Francis",

number = "2",

}

TY - JOUR

T1 - Effects of golf shaft stiffness on strain, clubhead presentation and wrist kinematics

AU - Betzler, Nils F.

AU - Monk, Stuart A.

AU - Wallace, Eric S.

AU - Otto, Steve R.

N1 - Reference text: Ball, K. A., & Best, R. J. (2007). Different centre of pressure patterns within the golf stroke I: Cluster analysis. Journal of Sports Sciences, 25, 757–770. Betzler, N. F.,Monk, S. A.,Wallace, E. S., & Otto, S. R. (2012). Variability in clubhead presentation characteristics and ball impact location for golfers’ drives. Journal of Sports Sciences, 30, 439–448. Betzler,N. F., Slater, C., Strangwood, M., Monk, S. A., Otto, S. R., &Wallace, E. S. (2011). The static and dynamic stiffness behaviour of composite golf shafts and their constituent materials. Sports Engineering, 14, 27–37. Butler, J. H., & Winfield, D. C. (1994). The dynamic performance of the golf shaft during the downswing. In A. J. Cochran, and M. R. Farrally (Eds.), Science and Golf II: Proceedings of the World Scientific Congress of Golf (pp. 259–264). London: E & FN Spon. Cappozzo, A., Catani, F., Della Croce, U., & Leardini, A. (1995). Position and orientation in space of bones during movement: Anatomical frame definition and determination. Clinical Biomechanics, 10, 171–178. Coleman, S. G. S., & Rankin, A. J. (2005). A three-dimensional examination of the planar nature of the golf swing. Journal of Sports Sciences, 23, 227–234. Crisco, J. J., Rainbow, M., &Wang, E. (2009). Modeling the Lacrosse stick as a rigid body underestimates shot ball speeds. Journal of Applied Biomechanics, 25, 184–191. Field, A. (2005). Discovering statistics using SPSS, 2nd ed. London: Sage. Harper,T. E., Jones, R.,&Roberts, J. (2005a). Robotic simulation of golfer shaft loading. In A. Subic, and S. Ujihashi (Eds.), The impact of technology on sport (pp. 386–391). Melbourne: Australasian Technology Alliance. Harper, T. E., Roberts, J. R., & Jones, R. (2005b). Driver swingweighting: A worthwhile process? Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 219, 385–393. Hocknell, A., Jones, R., & Rothberg, S. (1996). Experimental analysis of impacts with large elastic deformation: I. Linear motion. Measurement Science and Technology, 7, 1247–1254. Horwood, G. P. (1994). Golf shafts—a technical perspective. In A. J. Cochran, and M. R. Farrally (Eds.), Science and Golf II: Proceedings of the World Scientific Congress of Golf (pp. 247–258). London: E & FN Spon. Kojima, A., & Horii, H. (1995). Effect of torsional properties of CFRP golf club shafts on the speed and the directional stability of the ball. In Z. Maekawa, E. Nakata, and Y. Sakatani (Eds.), Proceedings of the 4th Japan International SAMPE Symposium (pp. 1328–1334). Yokohama: SAMPE. Lee, N., Erickson, M., & Cherveny, P. (2002). Measurement of the behaviour of a golf club during the golf swing. In E. Thain (Ed.), Science and Golf IV: Proceedings of theWorld Scientific Congress of Golf (pp. 374–385). London: Routledge. Effects of golf shaft stiffness 15 Downloaded by [University of Ulster at Coleraine] at 13:28 02 June 2012 MacKenzie, S., & Sprigings, E. (2009a). A three-dimensional forward dynamics model of the golf swing. Sports Engineering, 11, 165–175. MacKenzie, S., & Sprigings, E. (2009b). Understanding the role of shaft stiffness in the golf swing. Sports Engineering, 12, 13–19. MacKenzie, S., & Sprigings, E. (2010). Understanding the mechanisms of shaft deflection in the golf swing. Sports Engineering, 12, 69–75. Maltby, R. D. (1995). Golf club design, fitting, alteration, and repair: The principles and procedures. Newark, OH: R. Maltby Enterprises. Mather, J. S. B., & Jowett, S. (1998). The effect of centrifugal stiffening on the bending stiffness of a golf shaft. In S. Haake (Ed.), The engineering of sport (pp. 515–522). London: Blackwell Science. Mather, J. S. B., & Jowett, S. (2000). Three dimensional shape of the golf club during the swing. In A. Subic, and S. Haake (Eds.), The engineering of sport (pp. 77–85). London: Blackwell Science. Mather, J. S. B., Smith, M. J., Jowett, S., Gibson, K. A. H., & Moynihan, D. (2000). Application of a photogrammetric technique to golf club evaluation. Sports Engineering, 3, 37–47. McCane, B., Abbott, J. H., & King, T. (2005). On calculating the finite centre of rotation for rigid planar motion. Medical Engineering & Physics, 27, 75–79. Milne, R. D., & Davis, J. P. (1992). The role of the shaft in the golf swing. Journal of Biomechanics, 25, 975–983. Newman, S., Clay, S., & Strickland, P. (1997). The dynamic flexing of a golf club shaft during a typical swing, In Proceedings of the Fourth Annual Conference on Mechatronics and Machine Vision in Practice (pp. 265–270). Toowoomba, Australila: IEEE Computer Society. Ozawa, T., Namiki, H., & Horikawa, N. (2002). A study on clubface direction during a golf swing. In S. Ujihashi, and S. Haake (Eds.), The engineering of sport 4, Vol. 5 (pp. 688–694). Oxford: Blackwell. Penner, A. R. (2003). The physics of golf. Reports on Progress in Physics, 66, 131–171. Pierce, C. A., Block, R. A., & Aguinis, H. (2004). Cautionary note on reporting eta-squared values from multifactor ANOVA designs. Educational and Psychological Measurement, 64, 916–924. R&A Rules Limited. (2005). Procedure for measuring the moment of inertia of golf clubheads, Retrieved from http://www.randa.org/en/Equipment/,/media/RandA/Equipment%20protocol%20documents/Moment% 20of%20Inertia.ashx Schwartz, M. H., & Rozumalski, A. (2005). A new method for estimating joint parameters from motion data. Journal of Biomechanics, 38, 107–116. Stanbridge, K., Jones, R., &Mitchell, S. (2004). The effect of shaft flexibility on junior golfers’ performance. Journal of Sports Sciences, 22, 457–464. Tsujiuchi, N., Koizumi, T., & Tomii, Y. (2002). Analysis of the influence of golf club design on the golf swing. In S. Ujihashi, and S. Haake (Eds.), The engineering of sport 4 (pp. 537–544). Oxford: Blackwell. Tsunoda, M., Bours, R., & Hasegawa, H. (2004). Three dimensional motion analysis and inverse dynamic modeling of the human golf swing. In M. Hubbard, R. D. Mehta, and J. M. Pallis (Eds.), The engineering of sport 5, Vol. 2 (pp. 326–332). Sheffield: International Sports Engineering Association. Wallace, E. S., & Hubbell, J. E. (2001). The effect of golf club shaft stiffness on golf performance variables— implications for club-fitting. Paper presented at the Materials & Science in Sports Symposium, Coronado Island Marriott Resort, Coronado, CA. Worobets, J. T., Fairbairn, J., & Stefanyshyn,D. (2006). The influence of shaft stiffness on potential energy and puck speed during wrist and slap shots in ice hockey. Sports Engineering, 9, 191–200. Worobets, J. T., & Stefanyshyn, D. J. (2008). Shaft stiffness: Implications for club fitting. In D. J. Crews, and R. Lutz (Eds.), Science and Golf V: Proceedings of theWorld Scientific Congress of Golf (pp. 431–437). Mesa, AZ: Energy in Motion. Zheng, N., Barrentine, S. W., Fleisig, G. S., & Andrews, J. R. (2008). Kinematic analysis of swing in pro and amateur golfers. International Journal of Sports Medicine, 487–493.

PY - 2012/6

Y1 - 2012/6

N2 - The aim of this study was to quantify and explain the effect of shaft stiffness on the dynamics of golf drives.Twenty golfers performed swings with two clubs designed to differ only in shaft bending stiffness.Wrist kinematics and clubhead presentation to the ball were determined using optical motion capture systems in conjunction with a radar device for capturing ball speed, launch angle, and spin. Shaft stiffness had a marginally small effect on clubhead and ball speeds, which increased by 0.45%( p , 0.001) and 0.7% ( p =0.008), respectively, for the less stiff club. Two factors directly contributed to these increases: (i) a faster recovery of the lower flex shaft from lag to lead bending just before impact( p , 0.001); and (ii) an increase of 0.4% in angular velocity of the grip of the lower flex club at impact( p =0.003). Unsurprisingly, decreases in shaft stiffness led to more shaft bending at the transition from backswing to downswing ( p , 0.001). Contrary to previous research, lead bending at impact marginally increased for the stiffer shaft ( p ¼=0.003). Overall, and taking effect sizes into account, thechanges in shaft stiffness in isolation did not have a meaningful effect on the measured parameters, for the type of shaft investigated.

AB - The aim of this study was to quantify and explain the effect of shaft stiffness on the dynamics of golf drives.Twenty golfers performed swings with two clubs designed to differ only in shaft bending stiffness.Wrist kinematics and clubhead presentation to the ball were determined using optical motion capture systems in conjunction with a radar device for capturing ball speed, launch angle, and spin. Shaft stiffness had a marginally small effect on clubhead and ball speeds, which increased by 0.45%( p , 0.001) and 0.7% ( p =0.008), respectively, for the less stiff club. Two factors directly contributed to these increases: (i) a faster recovery of the lower flex shaft from lag to lead bending just before impact( p , 0.001); and (ii) an increase of 0.4% in angular velocity of the grip of the lower flex club at impact( p =0.003). Unsurprisingly, decreases in shaft stiffness led to more shaft bending at the transition from backswing to downswing ( p , 0.001). Contrary to previous research, lead bending at impact marginally increased for the stiffer shaft ( p ¼=0.003). Overall, and taking effect sizes into account, thechanges in shaft stiffness in isolation did not have a meaningful effect on the measured parameters, for the type of shaft investigated.

KW - Shaft bending

KW - shaft flexion

KW - motion analysis

KW - equipment

KW - ball speed

U2 - 10.1080/14763141.2012.681796

DO - 10.1080/14763141.2012.681796

M3 - Article

SN - 1752-6116

VL - 11

SP - 223

EP - 238

JO - Sports Biomechanics

JF - Sports Biomechanics

IS - 2

ER -

Effects of golf shaft stiffness on strain, clubhead presentation and wrist kinematics

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Keywords

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