The effect of playing level and engagement method on forces generated in rugby scrummaging

E. Preatoni, K. Stokes, M. H. England, G. Trewartha

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Introduction
The scrum is an important phase of the rugby union game. During the scrum, players experience very peculiar biomechanical demands (high forces coupled with unstable balance) and repetitive mechanical stresses (Milburn, 1990; Preatoni et al., 2013), which may be a factor for both acute injuries and chronic degeneration of the spine. Since physical condition and technique likely play a fundamental role for both performance and injury prevention, the aim of this study was to analyse the effects of playing level and engagement conditions on forces generated in scrummaging.
Methods
Force measures were analysed as a function of: 6 playing levels (International, Elite, Community, Academy, Women and School), and 5 different engagement conditions (Hit&Hold, 3-Stage, FoldIn, 7+1 and 5+3). The different engagement conditions were designed in part to modify the loading conditions on players.
Thirty-four teams participated in the study and performed 4-8 machine scrummaging trials for each of the 5 engagement conditions. A commercial scrum machine (Dictator, Rhino Rugby, UK), equipped with a bespoke force measurement system (Preatoni et al., 2012) measured the compression, lateral and vertical forces generated by the scrum pack. A set of parameters was selected to analyse applied forces in the subsequent phases of the engagement, from initial shock absorption to the sustained push.
A mixed design ANOVA was used to assess main effects between and within groups and the playing level-engagement condition interaction.
Results
During the shock-absorption phase: (i) peaks of force (in all three directions) were lower in the FoldIn engagement than in the other conditions, and (ii) International and Elite teams produced higher peak compression forces than the other categories. For example, peak compression force ranged between 8.6 (2.0) kN for International and 4.2 (0.8) kN for School in the FoldIn engagement, and between 16.5 (1.4) kN for International and 8.7 (0.1) kN for Women in the Hit&Hold. Sustained compression force ranged between 8.53 (0.69) kN (International, 5+3) and 4.37 (0.15) (Women, 3-Stage), with greater sustained push for International and Elite, and the FoldIn engagement producing higher sustained compression force than the other conditions (significant for 3-Stage and 5+3).
Discussion
This study provides a more comprehensive picture of the influence of playing levels and engagement conditions on contemporary scrummaging biomechanics. It also informs practitioners and governing bodies about biomechanical factors that may influence performance and injury prevention.
References
Milburn PD. (1990). J Sports Sci, 8, 47-60.
Preatoni E et al. (2012). P I Mech Eng P - J Sports Eng Tech, 226(3/4), 266-273.
Preatoni E et al. (2013). Scand J Med Sci Spor, DOI: 10.1111/sms.12048.
Acknowledgement
Research funded by the International Rugby Board
Original languageEnglish
Title of host publicationBook of Abstracts of the 18th Annual Congress of the European College of Sport Science in Barcelona, Spain from 26-29 June 2013
EditorsN Balagué, C Torrents, A Vilanova, J Cadefau, R Tarragó, E Tsolakidis
Pages324
Number of pages1
ISBN (Electronic)9788469577868
Publication statusPublished - 2013
Event 18th Annual Congress of the European College of Sport Science - Barcelona, Spain
Duration: 25 Jun 201329 Jun 2013

Conference

Conference 18th Annual Congress of the European College of Sport Science
CountrySpain
CityBarcelona
Period25/06/1329/06/13

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