Kinetics of full scrum and staggered scrum engagement in under 19 schoolboy rugby union players

Abstract

Two hundred and eight male Rugby Union players from 13 high schools, whose ages ranged from 16 to 19 years, were used to examine the kinetics of the full scrum versus staggered scrum engagement techniques. Telemetric pressure transducers were used to measure the engagement and sustained forces acting on the shoulders of the players. The front, second and back row forwards applied a significantly greater (p<0.01) engagement force during the implementation of the full scrum engagement technique as opposed to when the staggered scrum technique was utilised. No differences in the magnitude of sustained force applications by the front, second or back row forwards, with implementation of the respective techniques, were recorded. The large engagement force recorded during full scrum engagement is therefore unnecessary and may only increase the incidence of injury to the cervical spine should misalignment of the front row occur at engagement. The largest total engagement force applied (9.971 kN) by an individual front row during the implementation of the full scrum engagement technique was significantly greater (p<0.01) than the average engagement force application (7.526 kN) of the sample. Similar results were obtained during sustained scrumming with the largest force applied, with the implementation of both engagement techniques (9.758 kN), by an individual front row being significantly greater (p<0.01) than the average sustained force application (6.145 kN). The great difference in measured force application in the various schools tested emphasises the importance of different leagues to accommodate the varying strengths observed amongst rugby playing schools. Although the staggered scrum engagement technique ensures a soft and controlled engagement, thus protecting the weaker side, a mismatch of scrumming ability could still be detrimental during sustained scrumming.

South African Journal for Research in Sport, Physical Education and Recreation Vol. 27(2) 2005: 15-28