Heather Driscoll

Tracking of foot movement during sprinting in studded footwear

Mechanical tests and finite element simulations are often used to assess the traction between a studded outsole and the surface. Appropriate boundary conditions are required in these experiments in order to replicate realistic loading scenarios. The result of using different boundary conditions has been well researched (Nigg 1990, Kuhlman et al. 2009. Kirk et al. (2007) used a high-speed video camera to investigate kinematic boundary conditions in 2D during the acceleration phase in sprinting. The study was limited as the angle of the shoe could only be calculated in one plane. Analysis of high-speed footage in 3D is possible using a two camera system, as per Choppin et al. (2007) who determined the orientation of a tennis racquet during play in three planes.

Kinetic and kinematic analysis of stamping impacts during simulated rucking in rugby union

ABSTRACT Laceration injuries account for up to 23% of injuries in rugby union. They are frequently caused by studded footwear as a result of a player stamping onto another player during the ruck. Little is known about the kinetics and kinematics of rugby stamping impacts; current test methods assessing laceration injury risk of stud designs therefore lack informed test parameters. In this study, twelve participants stamped on an anthropomorphic test device in a one-on-one simulated ruck setting. Velocity and inclination angle of the foot prior to impact was determined from high-speed video footage. Total stamping force and individual stud force were measured using pressure sensors. Mean foot inbound velocity was 4.3 m ∙ s−1 (range 2.1–6.3 m ∙ s−1). Mean peak total force was 1246 N and mean peak stud force was 214 N. The total mean effective mass during stamping was 6.6 kg (range: 1.6–13.5 kg) and stud effective mass was 1.2 kg (range: 0.5–2.9 kg). These results provide representative test parameters for mechanical test devices designed to assess laceration injury risk of studded footwear for rugby union.

Prevalence of laceration injuries in professional and amateur rugby union: a systematic review and meta-analysis

Background Studded footwear can cause severe lacerations in rugby union; the prevalence of these injuries is currently unknown. Objective To summarise the skin and laceration injury prevalence in published epidemiological studies and to investigate any differences in skin injury risk between amateur and professional players. Design Systematic literature review and meta-analysis of epidemiological studies. Data sources PubMed, Web of Science, Scopus and Ovid. Eligibility criteria for selecting studies Prospective, epidemiological studies published in English after 1995, measuring a minimum of 400 match or 900 training exposure hours. Participants should be adult rugby union players (amateur or professional). The study should report a separate skin or laceration injury category and provide sufficient detail to calculate injury prevalence within this category. Results Twelve studies were included. Mean skin injury prevalence during matches was 2.4 injuries per 1000 exposure hours; during training sessions, the prevalence was 0.06 injuries per 1000 exposure hours. Skin injuries accounted for 5.3% of match injuries and 1.7% of training injuries. Skin injury risk was similar for amateur compared with professional players during matches (OR: 0.63, p=0.46.), but higher during training sessions (OR: 9.24, p=0.02). Conclusions The skin injury prevalence of 2.4 injuries per 1000 exposure hours is equivalent to one time-loss injury sustained during matches per team, per season. Amateur players are more likely to sustain skin injuries during training sessions than professional players. There is a need for more studies observing injuries among amateur players. Trial registration number PROSPERO CRD42015024027.

Application of Newtonian Physics to Predict the Speed of a Gravity Racer.

Gravity racing can be studied using numerical solutions to the equations of motion derived from Newton’s second law. This allows students to explore the physics of gravity racing and to understand how design and course selection influences vehicle speed. Using Euler’s method, we have developed a spreadsheet application that can be used to predict the speed of a gravity powered vehicle. The application includes the effects of air and rolling resistance. Examples of the use of the application for designing a gravity racer are presented and discussed. Predicted speeds are compared to the results of an official world record attempt.

Finite Element Model of an Impact on a Palmar Pad from a Snowboard Wrist Protector

Wrist injuries are the most common types of injury in snowboarding. Protectors can reduce injury risk by limiting wrist hyperextension and attenuating impact forces. There are a range of wrist protector concepts available, but it is unclear if any particular design is more effective. The aim of this study was to develop and validate a finite element model of an impact on the palmar pad from a protector. Pad material from a protector was characterised to obtain stress vs strain data, and determine whether it was rate dependent. Material data was implemented into a finite element model to predict impact behavior at 2.5 J. Four material models were investigated, with an Ogden model paired with a Prony series providing the best agreement to experimental data. Future work will build a model of a complete protector for predicting the protective levels of these products.

Image Based Stroke-Rate Detection System for Swim Race Analysis

Swim race analysis systems often rely on manual digitization of recorded videos to obtain performance related metrics such as stroke-rate, stroke-length or swim velocity. Using image-processing algorithms, a stroke tagging system has been developed that can be used in competitive swimming environments. Test images from video footage of a women’s 200 m medley race recorded at the 2012 Olympic Games, was segmented into regions of interest (ROI) consisting of individual lanes. Analysis of ROI indicated that the red component of the RGB color map corresponded well with the splash generated by the swimmer. Detected red values from the splash were filtered and a sine-fitting function applied; the frequency of which was used to estimate stroke-rate. Results were compared to manually identified parameters and demonstrated excellent agreement for all four disciplines. Future developments will look to improve the accuracy of the identification of swimmer position allowing swim velocity to be calculated.

Identifying representative test parameters to assess skin laceration injury risk for individual studs

Skin injuries account for ∼6% of all injuries in rugby union. Skin lacerations resulting from stud–skin interactions in rugby union are frequently caused by stamping in the ruck (Oudshoorn, Driscoll, Dunn, & James, 2016 Oudshoorn, B. Y., Driscoll, H. F., Dunn, M., & James, D. (2016). Procedia Engineering, 147, 496–500. [CrossRef], [Google Scholar] ). Stud design is regulated by World Rugbys Regulation 12, but no supporting evidence currently exists for the selected test parameters used in these standards. Ideally, mechanical tests that assess injury risk should replicate conditions observed during play (Ura & Carre, 2016 Ura, D., & Carre, M. (2016). Procedia Engineering, 147, 550–555. [CrossRef], [Google Scholar] ). Relevant mechanical test parameters, such as foot inbound velocity, stud impact energy, inclination angle and effective mass, can be derived through biomechanical analysis of rugby stamping. However, due to human movement variability, the measured kinetics and kinematics of stamping impacts can have a large range and replicating all possible parameters within a mechanical test device is unfeasible. Identifying different stamp techniques by clustering provides an economical solution.