Scrum Machine Meredith Grow Alencia Woodard Advised by

Scrum Machine Meredith Grow Alencia Woodard Advised by: Elizabeth Schlaeger, P. E. Dr. Kris Sadler

Rugby English sport Ancestor of American football General rules of the game Penalties n n Knock-ons Off-sides

The Scrum Purpose Positioning Correct Posture Injuries

Injury Rates (US) 1970 – 1995 n 35 injuries w 63% during engagement w 37% when scrum collapsed w 80% hookers w 17% prop w 3% second row

Problem Poor scrummage technique n n Causes spinal injuries Loss of scrum power Needed n n Additional instructional tools Increased player experience

System 3 phases n Kinetic w Both sides push together (engaging) n Static w Engagement until ball is rolled in w Possible to calculate force components n Kinetic w Opposing sides attempt to displace each other

Biomechanics Assumptions n n Flat back Constant leg force Back force = Leg force (i. e. neglecting lost force between back and legs) Maximum back force = 1. 5 * body weight w Back Force Averages: n n Men = 300 lb Women = 240 lb

Force Diagram (Machine) y Fwall Z Fby θ Fbz Fbmax

Force Diagram (Actual) base of neck Fbmax 2 Z Fby θ Fbz Fbmax 1

Objective Maximize Fbz and eliminate Fby n Done by ensuring Fbz = Fbmax (i. e. θ = 90°) Reduce possiblity of cervical spine injuries n Resulting from the buckling effect of spine caused by Fby

Solution Device n Attachment to an existing rugby scrum machine Design n Structure w Fully adjustable w Compatible with most commercially available scrum machines w Quick and easy adjustment n Target techniques w Staying low w Keeping the back flat

Progress Patent block received Solution finalized Model constructed Biomechanical analysis complete

Current Work Select prototype materials Collect survey wishes and demands Create poster presentation Write final paper

Future Work Construct prototype n n Testing Collect user input Apply for patent Explore future improvements n n Feedback mechanism (light sensor and plumb line) Method to improve practice technique to better resemble actual contact