Combined individual scrummaging kinetics and muscular power predict competitive team scrum success

Abstract

Scrummaging is a major component of Rugby Union gameplay. Successful scrummaging is dependent on the coordination of the forward players and the strength of the eight individuals. The study aim was to determine whether individual scrummaging kinetics and other candidate factors associated with scrummaging performance discriminate team scrum performances. Sixteen club-level forwards (stature: 1.80 ± 0.1 m; mass: 99.0 ± 18.2 kg) were initially divided into two scrummaging packs. A total of 10 various scrum permutations were tested, where players were randomly swapped between the two packs. Winning scrums were determined by two observers on opposite sides of the scrum. Fatigue (100 mm visual analogue scale (VAS)) and scrummaging effort (6-20 rating of perceived exertion (RPE)) were assessed following each scrum contest. Individual scrummaging kinetics were acquired through an instrumented scrum ergometer and muscular power indicated through vertical jump heights. Student's t-tests were used to differentiate between winning and losing scrum packs. VAS and RPE were assessed using repeated measures ANOVAs. Winning scrum packs had significantly larger combined force magnitudes (p < .002), regardless of the player contribution calculations. Additionally, winning packs had less individual movement (p = .033) and higher combined vertical jump heights (p < .001) but were not significantly heavier (p = .759) than losing scrum packs. While perceived VAS and RPE values progressively increased (p < .001), no differences in the individual scrum magnitudes were observed between the 1st and 10th scrum (p = .418). The results indicated that the combination of individual forces, variation in movement and factors related to scrummaging performance, such as vertical jump height, were associated with team scrummaging success.

Force Production during the Sustained Phase of Rugby Scrums: A Systematic Literature Review

“…Participants ranged in mean age from 16.6 to 34 years old, with the majority in their early 20s. Twelve studies used the full pack [3,4,[7][8][9]12,14,15,[21][22][23][24], while fourstudies used the front row [11,25,26] and two used the tight five only [10,13]. Two studies recruited a mix of forwards and backs (Dobbs 2017;Wu et al 2006) [27].…”

“…Few studies quantified rugby playing experience of their subjects: Dobbs [27] had an inclusion criteria for university athletes to have played at least 6 months. Green, Dafkin, et al [21] studied amateur players with an average of 11 years of playing experience, and Clayton [24] sampled players with an average of 8.4 years. The national players Wu et al [20] studied had played for 9.1 years on average.…”

“…Most of the studies (n = 21) had players scrum against a scrum machine [4,8,[10][11][12][13][14][15][17][18][19][20][21][22][23][24][25][26]28,29,31].…”

A review of the biomechanical determinants of rugby scrummaging performance

“…[14,15] Individual force contributions Scrum contests are usually won by packs with larger combined compressive forces. [23] Assessments of team scrummaging have identified the contribution of various playing positions in terms of the total scrummaging forces. Interestingly, the front rows contribute the most force, namely between 42% -46%, and locks generate between 21% -37%, respectively.…”

“…[45] Therefore, it is not surprising that researchers have shown significant relationships between scrum force and combined pack mass. [10,[13][14][15][16]20,24,30] In the only study to have considered a combined power metric, Green et al [23] demonstrated that winning scrums also had significantly higher combined vertical jump heights.…”