Abstract
Cutting-edge technologies and space-age synthetics are dramatically recreating ice hockey sticks today. But how does current scholarship view these high-priced innovations, particularly during performance of the slap shot, hockey’s most explosive maneuver? This literature review on both slap shot biomechanics and technological developments in ice hockey sticks suggests that player technique and strength exert much greater influence on slap shot puck velocity than does stick composition. Moreover, this study illuminates how stick flexibility, rather than composition, should be the key mechanical consideration in stick selection, since highly flexible sticks can enhance both stick deflection and strain energy storage, two important variables in the velocity of slap shots.
Biomechanics of Ice Hockey Slap Shots: Which Stick Is Best?
At its historical core, hockey is a game rooted in the natural environment. First played on the frozen lakes and rivers of upper North America, ice hockey—begun as the Native American game of shinny—featured carved wooden poles as sticks and hand-sewn fabrics as balls (Oxendine, 1988). As Europeans took up the game, they applied their technologies to this traditional equipment, gradually yet substantially changing the hockey stick by constructing it out of multiple pieces of wood, curving the stick blade, and wrapping the stick in fiberglass and laminate plastics to increase its durability and performance (Pearsall, Montgomery, Rothsching, & Turcotte, 1999).
Now, however, burgeoning technologies are virtually recreating hockey sticks with each passing day. Wood sticks, once the paragon of the sport, have largely been replaced by high-tech—and high-priced—graphite and composite models. Because of the seeming popularity of these “one-piece” composite sticks amongst professional players, hordes of youth and high-school-age hockey participants are now outfitting themselves with these technological marvels, much to the delight of proliferating hockey equipment companies. Certainly, the need for scholarly research on hockey technology has never been greater: Thousands of participants in the sport stand to benefit from a deeper understanding of the new developments in hockey stick technology.
This paper, then, provides a scholarly education on hockey sticks, both by analyzing the biomechanics of ice hockey shooting and by investigating the extant literature on hockey stick research. In particular, this essay explores the implications of stick technologies and biomechanics for the hockey slap shot, presenting the stick selections and key bodily mechanics that stand to enhance performance of this complex and critical hockey skill.
Slap Shot Mechanics
The Slap Shot’s Six Phases
A variety of scholars have explored the biomechanical aspects of ice hockey, with studies centering primarily around skating (Bracko, 2004; De Koning & Van Ingen Schenau, 2000) and shooting (Doré & Roy, 1978; Hache, 2002; Pearsall, Turcotte, & Murphy, 2000; Roy & Doré, 1976). Of these, several studies have analyzed the mechanics involved in various types of hockey shots, including the wrist, snap, slap, and backhand shots, performed both while stationary and when skating (Carr, 2004, p. 42; Doré & Roy, 1976, 1978; Hache, 2002, p. 84; Alexander, 1964, cited in Pearsall et al., 2000, p. 689; Cotton, 1966, cited in Pearsall et al., 2000, p. 689; Furlong, 1968, cited in Pearsall et al., 2000, p. 689). The slap shot in particular has garnered much scholarly attention, with researchers dividing the shot into six distinct phases: backswing, downswing, preloading, loading, release, and follow-through (Pearsall et al., 1999; Villasenor, Turcotte, & Pearsall, 2006). Three of the six—the preloading, loading, and release phases—concern the mechanical behaviors exhibited by the stick after its contact with the ice surface. This blade-ice contact time has been the intense focus of the majority of researchers investigating the hockey slap shot.
Blade Orientation
Past studies have uncovered several key differences between elite and novice performers of this critical blade-ice contact portion of the slap shot. For example, researchers have cited the orientation of the stick blade during its contact with the ice as an element differentiating elite from recreational performers. For instance, in their study of 15 college-age hockey players, Lomond, Turcotte, and Pearsall (2007) reported that experts tended to demonstrate a unique blade orientation whereby on contact with the ice, the stick blade was tilted forward (or cupped) more than recreational players’ sticks. In addition, Lomond et al. described a distinctive “rocker” component between the loading and release phases of the shot, during which the cupped stick blade almost instantaneously tilted perpendicular to the ice, infusing the puck with additional kinetic energy generated from the slight recoil of the stick blade itself. The authors noted this “rocker” component in the slap shot execution of all subjects in their study, both elite and recreational; blade “rocker” would seem, then, to be a component of slap shots in general. The Lomond et al. report does, however, emphasize the importance of the more tilted blade orientation demonstrated by expert players, a finding corroborated by greater puck velocities during their slap shots (Lomond et al., 2007).
Hand Position
In addition, researchers have cited player hand position as a distinguishing factor in expert slap shot performance. Wu and colleagues, studying male and female collegiate hockey players, noted that a lowered bottom hand, even past the midpoint of the shaft, generated additional stick bend and thus more strain energy, resulting in greater puck velocities (Wu et al., 2003); work of Canadian physicist and hockey enthusiast Alain Hache has seconded these mechanical benefits (Hache, 2002, p. 88). Thus, while it remains unquantified for now, some contribution to force generation in the hockey slap shot seems to result from a low bottom-hand grip on the stick, even past the shaft midpoint.
Impulse Duration
Beyond blade orientation and hand position, two additional factors likely play considerable roles in determining slap shot velocity. The first of these significant contributors is impulse duration, or the force applied to an object over time, the elongation of which increases the transfer of force to an object (Carr, 2004, p. 38). Carr cites the “whiplike” effect of a kinetic chain—a progressive increase in velocity from the most massive to the least massive body parts—as one key technique that allows for a lengthened application of impulse which imparts greater force to the struck object (2004, p. 39). Hockey players employ this “whiplike” technique in a slap shot by rotating the torso, the shoulders, the biceps, and the forearms in sequence, elongating the duration of stick blade contact with the puck. This extended impulse duration has been noted as a primary factor in heightened velocities of hockey slap, wrist, and backhand shots (Roy & Doré, 1976).
Further, Villasenor, Turcotte, and Pearsall (2006) found that among 20- to 30-year-old male slap shot performers, both expert and recreational, the longer the blade contacted the puck, the greater the final puck velocity. Moreover, all elite players in the study demonstrated longer blade-puck contact time than their nonelite counterparts (an average 38 ms for elite players vs. an average 27 ms for nonelite players), corresponding to substantially greater slap shot velocities for experts than for novices (averaging 120 km/h for elite players vs. 80.3 km/h for nonelite players) (Villasenor et al., 2006). Clearly, extending the blade’s contact time with the puck provides an advantage for players seeking greater slap shot velocity.
Stick Bending
A final (and perhaps most important) area contributing to the speed of slap shots is the bending of the stick’s shaft, which begins when the stick blade contacts the ice and lasts through the recoil of the stick just before a player’s follow-through. Hockey scientists David Pearsall, Rene Turcotte, and Stephen Murphy have gone so far as to attribute 40% to 50% of final slap shot velocity to the amount of deflection, or bending, in the stick shaft (Pearsall et al., 2000, p. 690), and photographs in Alain Hache’s Physics of Hockey attest to the considerable stick bend generated by contemporary National Hockey League players (Hache, 2002).
In exploring the stick-bending phenomenon, Villasenor et al. (2006) determined that several crucial relationships exist between stick bending and increased slap shot velocities. First, they noted that elite hockey performers initiated stick bending at the instant of, or shortly before, first contact with the puck, whereas recreational players commenced stick bending after contacting the puck and fully halfway through their stick blade’s contact time with the ice. Expert players also spent a greater percentage (28.8%) of the ice-stick blade contact window bending the stick, in comparison to their nonexpert counterparts (18.2%). Finally, elite performers employed a lower “kick point”—or area of maximum deflection—along the stick shaft than less skilled players did, which has spurred current hockey stick companies to engineer composite sticks designed to lower this spot of maximum bend (Hache, 2002, p. 95). Overall, Villasenor et al. describe a “strong relationship” between final puck velocity and maximum angle of stick deflection, underlining the importance to hockey athletes of initiating considerable stick bend during their slap shots (Villasenor et al., 2006). Alongside blade orientation, hand position, and impulse duration, stick bending contributes to the multiplicity of mechanical factors generated by the player during the performance of this most forceful of hockey skills.
Stick Composition
Beyond each hockey player’s individual slap shot technique, an additional facet of the shot remains variable: the stick. With the onslaught of new hockey technologies over the past decade, no shortage of stick options exists. Whereas hockey sticks were once constructed almost exclusively out of Rock elm, then in the 1990s from aluminum for the shaft and wood for the blade, 21st-century trends now incorporate space-age composite materials like graphite, Kevlar, and carbon in hockey stick design (Sports Materials, 2005; Hache, 2002; Marino, 1998; Pearsall et al., 1999; Wu et al., 2003). Technological advancement, however, has not come without cost, both in monetary terms (most composite sticks retail for at least $100, compared to $40 for a wood stick) and in reduced sensitivity for puckhandling (“feel”) attributed to composite sticks (Barpanda, 1998; Hache, 2002, p. 94; Hove, 2004; Marino, 1998). Nevertheless, today’s hockey players largely face three distinct stick options: an all-wood stick, a stick with a composite shaft and wood blade, or a fully composite stick. The remainder of this paper explores mechanical differences that can be discerned among these construction types during the performance of hockey slap shots.
Stick Construction Materials’ Role in Shot Velocity
Key to enhancing slap shot velocity is maximizing strain energy stored in and released from the hockey stick. Indeed, the current revolutions in hockey stick materials are efforts to capitalize on this mechanical principle. Several scholars have recently studied the effect of hockey stick composition on slap shot velocities, yielding intriguing and somewhat unexpected results. In a study of wood, graphite, and aluminum stick constructions and their role in slap shot velocity, for instance, Wu et al. found that puck velocity was influenced not by stick type but by player skill level and overall body strength. Although the authors reported stick bend to be a key factor in force generation during a slap shot, they attributed any significant differences in stick bend (and therefore puck speed) to the athlete’s bottom hand placement rather than to differences in stick composition (Wu et al., 2003).
Analyzing synthetic-shaft sticks in slap shots performed by varsity high school players, Rothsching found that, although relatively flexible sticks achieved the greatest puck velocities overall, “substantial variation between subjects occurred, emphasizing the greater importance of player technique and strength” (1997, cited in Pearsall et al., 2000, p. 691). Similarly, in an experiment with identical models of wood sticks with laminate shafts, Villasenor et al. (2006) found that stick deflection angles and subsequent puck velocities were significantly higher for elite versus recreational players, indicating that slap shot speeds generated by identically constructed sticks vary greatly from athlete to athlete. To date, then, and contrary to much conventional belief, scholars have not linked any particular stick material to increased slap shot velocity. Rather, what has surfaced from research reports is the clear primacy of the athlete’s variables—technique and strength—over any differences in stick composition.
Stick Stiffness and Flexibility
Beyond the individual athlete’s overriding influence on slap shot speeds, what has also emerged from recent scholarly investigations is the notion that stick flexibility, not stick composition, is of primary concern. In fact, several slap shot studies involving both wood and composite sticks demonstrate the influence of stick flexibility on shooting velocity. For instance, in a study of composite sticks exhibiting eight different stiffness levels (from “low” to “pro-stiff”), Worobets, Fairbairn, and Stefanyshyn (2006) found that in wrist shots, highly flexible sticks stored the most strain energy during the loading phase. Complicating matters, however, are the authors’ conclusions that the benefits of utilizing a flexible stick did not extend to slap shots, where “it is the athlete and not the equipment influencing shot speed” (p. 191). With this conclusion, Worobets et al. issue hockey players a strong reminder of the primacy of their own performance over any technological innovations in hockey sticks.
In a related investigation, Pearsall et al. (1999) explored slap shot velocities generated by four different “flexes” of carbon-fiber composite shafts with wood blades. The authors reported that, for each of the 6 college- and professional-level hockey player subjects, puck velocities were highest with the least stiff stick (“medium flex”); conversely, puck velocities were lowest when the subjects used the “extra stiff flex” stick. A “significant advantage” for puck velocity during slap shots was attributed to those hockey sticks with less shaft stiffness (p. 9). Qualifying such positive language, however, the authors also noted that variability in shooting velocity across subjects was greater than variability across shaft stiffness, concluding that “the subjects themselves are perhaps more important in determining slap shot velocity than the stick characteristics” (p. 10).
Finally, exploring slap shot velocities produced by 11-year-olds utilizing wood sticks of two different stiffness levels, Roy and Doré (1976) found that using the more flexible stick produced slightly higher slap shot speeds (56.8 km/h) than did using the stiffer model (54.4 km/h). The results prompted the authors to advise flexible sticks for use by younger players, since with flexible sticks, “lower forces are required to achieve the same puck velocity” recorded with stiffer shafts (Roy and Doré, 1976, cited in Pearsall et al., 2000, p. 690). Overall, then, the findings of Worobets et al., Pearsall et al. (1999), and Roy and Doré strongly suggest that the use of flexible hockey sticks contributes substantially to final puck velocity during the slap shot, especially when used by younger players. If any characteristic of a stick deserves to be considered for its effect on the slap shot, then, it appears to be stick flexibility, not stick composition.
Improved Slap Shot Performance
This review suggests that both player techniques and stick characteristics are important to slap shot success. Technical aspects of hockey shooting that may, if performed correctly, heighten ensuing puck velocities include intentionally tilting the stick blade forward to cup the puck and gripping the stick shaft low, even beyond the stick’s mid-point, to generate increased strain energy throughout the stick. In addition, expert shooters contacted the ice roughly 1 foot behind the puck to initiate stick bending at or before first contact with the puck—a crucial factor in maximizing shot velocity. Finally, accelerating the downswing phase first with the torso, then with the shoulders and arms, allows a hockey player to create a “whiplike” kinetic chain, lengthening the duration of impulse application to the stick, thereby increasing final puck velocity. Clearly, hockey coaches and players stand to adjust a variety of technical details to hone their technique and positively influence their level of success in the slap shot.
Recommendations for Hockey Stick Selection
Equally clear as the need for these technical adjustments is the extant literature’s recurring theme that player technique and strength are the most important variables influencing slap shot velocity. Across studies of players from youths to professionals and of sticks from wood to composite, stiff to flexible, the preeminence of player influence on achieved slap shot speeds rings consistently true and thus deserves to be the primary focus of performance-driven hockey coaches and players alike.
That said, this review has uncovered several findings relating to hockey sticks themselves. First, current research does not clearly demonstrate any advantage for one particular stick composition (wood, aluminum, or composite) over others. Instead, scholarly findings point to stick flexibility as the key mechanical consideration in stick selection. Several investigations attest to the mechanical benefits—most notably in stick deflection and strain energy storage—achieved with highly flexible sticks. It would seem sensible for coaches to advise hockey players to use the most flexible sticks possible (without incurring constant breakage) to maximize shooting velocity. This recommendation seems particularly apt for younger, less powerful players who may generate more stick bending with less applied force. Research suggests, then, that attention to hockey stick flexibility over any particular stick material may best aid players in heightening slap shot speeds.
While shooting remains only one of a multitude of hockey stick tasks—including the precision skills of stickhandling, passing, and receiving—players nevertheless stand to positively affect slap shot performance by supplementing the principal concerns of player technique and bodily strength with the use of flexible hockey sticks. In this regard, improvement in various aspects of ice hockey slap shots contributes toward every player and coach’s ultimate goal: enhancing athletic performance.
References
Barpanda, D. (1998). Dynamic performance characterization of hockey sticks and golf clubs using a combined vibrational energy level and modal analysis approach. Unpublished doctoral dissertation, University of Mississippi.
Bracko, M. R. (2004, September). Biomechanics powers ice hockey performance. BioMechanics 11(9), 1–7. Retrieved March 29, 2008, from http://www.biomech.com/full_article/?ArticleID=827&month=09&year=2004
Carr, G. (2004). Sport mechanics for coaches (2nd ed.). Champaign, IL: Human Kinetics.
De Koning, J. J., & Van Ingen Schenau, G. J. (2000). Performance-determining factors in speed skating. In V. M.
Zatsiorsky (Ed.), Biomechanics in sport: Volume IX of the Encyclopaedia of Sports Medicine (pp. 232–246). London: International Olympic Committee.
Doré, R., & Roy, B. (1976). Dynamometric analysis of different hockey shots. In P. V. Kumo (Ed.), Proceedings of the Fourth International Congress on Biomechanics, V-B (pp. 277–285). Baltimore: University Park Press.
Doré, R., & Roy, B. (1978). The biomechanics of hockey shots. In Proceedings: 1978 national coaches certification program level 5 seminar (pp. 59–71). Ottawa, Ontario, Canada: Canadian Amateur Hockey Association.
Hache, A. (2002). The physics of hockey. Baltimore: Johns Hopkins University Press.
Hove, P. (2004). Haptic perception of affordances of a sport implement: Choosing hockey sticks for power versus precision actions on the basis of “feel.” Unpublished doctoral dissertation, University of Cincinnati.
Lomond, K. V., Turcotte, R. A., & Pearsall, D. J. (2007). Three-dimensional analysis of blade contact in an ice hockey slap shot, in relation to player skill. Sports Engineering, 10(2), 87–100.
Madill, H. W. (1980). An EMG analysis of the validity of using weighted hockey sticks for specific overload training. Unpublished master’s thesis, McGill University, Montreal, Quebec, Canada.
Marino, G. W. (1998). Biomechanical investigations of performance characteristics of various types of ice hockey sticks. In H. J. Riehle & M. M. Vieten (Eds.), ISBS conference proceedings, 16th international symposium (pp. 184-187). Konstanz, Germany: International Society of Biomechanics in Sports. Retrieved March 30, 2008, from http://w4.ub.uni-konstanz.de/cpa/article/viewFile/1633/1535
Oxendine, J. B. (1988). American Indian sports heritage. Champaign, IL: Human Kinetics.
Pearsall, D. J., Montgomery, D., Rothsching, N., & Turcotte, R. (1999). The influence of stick stiffness on the performance of ice hockey slap shots. Sports Engineering, 2(1), 3–11.
Pearsall, D. J., Turcotte, R. A., & Murphy, S. D. (2000). Biomechanics of ice hockey. In W. E. Garrett, Jr., & D. T. Kirkendall (Eds.), Exercise and sport science (pp. 675–692). Philadelphia: Lippincott, Williams, and Wilkins.
Roy, B., & Doré, R. (1976). Kinematics of the slap shot in ice hockey as executed by players of different age classifications. In P. V. Komi (Ed.), International society on biomechanics (pp. 286–290). Baltimore: University Park Press.
Sports materials: materials for sports equipment have advanced dramatically over the past several years. Here is a sampling of some of the materials that enable players to move faster, hit the ball farther, pedal longer, and be better protected. (2005, October). Advanced Materials and Processes 163(10), 22-25. Retrieved March 29, 2008, from http://findarticles.com/p/articles/mi_hb5260/is_/ai_n20378099?tag=artBody;col1
Villasenor, A., Turcotte, R. A., & Pearsall, D. J. (2006). Recoil effect of the ice hockey stick during a slap shot. Journal of Applied Biomechanics, 22(5), 202–211.
Worobets, J. T., Fairbairn, J. C., & Stefanyshyn, D. J. (2006). The influence of shaft stiffness on potential energy and puck speed during wrist and slap shots in ice hockey. Sports Engineering, 9(4), 191–200.
Wu, T.-C., Pearsall, D., Hodges, A., Turcotte, R., Lefebvre, R., Montgomery, D., et al. (2003). The performance of the ice hockey slap and wrist shots: The effects of stick construction and player skill. Sports Engineering, 6(1), 31–40.
Author Note
David J. Laliberte, MSS, MA, Minnesota Hockey Coaches Association.
The author thanks Dr. Douglas Goar of the United States Sports Academy for his encouragement and insight regarding this essay.
Correspondence concerning this article should be addressed to David J. Laliberte, Minnesota Hockey Coaches Association, 1108 N. Seventh Ave., St. Cloud, MN 56303. E-mail: [email protected].
