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 Knock-ons Off-sides

The Scrum Purpose Positioning Correct Posture Injuries

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

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

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

Biomechanics Assumptions 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  Back Force Averages: Men = 300lb Women = 240lb

Force Diagram (Machine) Z y F bmax F wall F by F bz θ

Force Diagram (Actual) Z F bmax1 F bmax2 F by F bz θ base of neck

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

Solution Device Attachment to an existing rugby scrum machine Design Structure  Fully adjustable  Compatible with most commercially available scrum machines  Quick and easy adjustment Target techniques  Staying low  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 Testing Collect user input Apply for patent Explore future improvements Feedback mechanism (light sensor and plumb line) Method to improve practice technique to better resemble actual contact