ORIGINAL ARTICLE Dynamic strain profile of the ice hockey stick: comparisons of player calibre and stick shaft stiffness A. Hannon • Y. Michaud-Paquette • D. J. Pearsall • R. A. Turcotte Ó International Sports Engineering Association 2011 Abstract The goal of this research was to develop a method to quantify the dynamic strain profile (DSP) of an ice hockey stick shaft and assess the potential influence of player skill and stick shaft stiffness on DSP during slap (SS) and wrist shots (WS). Seventeen adult males per- formed shots with two different stick stiffness’ on synthetic ice. Subjects were subdivided as high (HC) and low calibre (LC). Dependent measures included strain measures from five strain gauge pairs along the shaft length recorded at 10 kHz. In general, this approach was sufficiently sensitive to clearly distinguish between shot types (strains SS [ WS), player calibre (strains HC [ LC) and stick models (strain flex77 [ flex102) as well as to identify within stick deflection differences along the shaft. This strain based analysis has a time and spatial resolution undetected by common motion capture based systems. 1 Introduction One of the most distinctive pieces of equipment in the game of ice hockey is the stick. The use of the stick to manoeuvre the puck can be seen in shooting tasks, espe- cially with regards to the slap (SS) and wrist shots (WS), which are the two most common shots employed by hockey players [1]. Although precision is important, puck speed is also a key component to a successful shot that results in a goal. The SS consists of a broad motion which includes a large backswing and follow-through to hit the puck, creating the highest speed shot possible, although inaccurate [2, 3]. On the other hand, the WS is the most accurate shooting technique, which starts with a sweep forward, followed by a snapping or pushing the puck for- ward [2, 4]. Many factors affect the speed of the puck, including the speed of the lower end of the stick prior to contact, the pre-loading phase, the ability to transfer elastic energy from loading the stick to the kinetic energy of the puck via the elastic recoil of the shaft, the contact time with the puck, as well as body size and strength of the individual shooter and skill level [3, 5–10]. In addition to these factors, the mechanical properties of the stick are important in determining the utility afforded; however, few studies have actually measured the discrete flexion and recoil response of sticks during shots [4, 5, 8, 10]. Using standard motion capture systems, it is possible to discern intersegment beam flexion along the shaft of the stick. For instance, with high speed video Villasen ˜or and colleagues [8] examined the deflection response of the hockey stick shaft during slap shots for elite and recrea- tional players. Several intriguing technique differences were identified related to puck speed outcome. In particu- lar, elite players optimised the timing of the stick’s bend and recoil response to coincide with greater puck contact thereby imparting greater impulse to the puck than observed by recreational players [8]. Though these findings are instructive, to understand the role of the shaft’s material responses to shot speed other techniques are needed. For instance, strain gauges can provide direct information on the elastic deformation response as well as greater spatial and temporal resolution of bend characteristics. For instance, with golf club shafts Milne and Davis [11] attached strain gauges to determine the ‘‘kick point’’ or deformation of the shaft at impact during a golf swing. A. Hannon (&) Á Y. Michaud-Paquette Á D. J. Pearsall Á R. A. Turcotte Department of Physical Education and Kinesiology, McGill University, Montreal, Canada e-mail: ashley.hannon@mail.mcgill.ca URL: http://icehockeyscience.mcgill.ca Sports Eng DOI 10.1007/s12283-011-0072-5