A simulated rugby match protocol induces physiological fatigue without decreased individual scrummaging performance

Abstract

Background: A rugby union game consists of 80 minutes of strenuous exertion. Forwards are required to participate in the arduous activity of scrummaging throughout a game.Objectives: The purpose of this study was to identify whether rugby-match simulated fatigue modified individual scrummaging technique and reduced performance.Methods: Twelve forwards (body mass 106.2±13.3 kg; stature 179.5±8.4 cm) had individual scrum kinetics and kinematics assessed prior to and following a protocol that simulated a rugby match. The simulated rugby match protocol required participants to run at various velocities and perform rugby specific tasks. Rating of Perceived Exertion (RPE) was assessed using a 6-20 Borg scale and Visual Analogue Scale (VAS). Blood lactate, heart rate and RPE were measured prior to, at mid-point and after the simulated game, while markers of muscle damage (blood creatine kinase activity (CK) and urea) were measured prior to and following the protocol.Results: RPE (p<0.0001) and VAS (p<0.0001) showed significant increases between the pre- and post-simulation values. Of the physiological markers, heart rate (p<0.0001) and blood urea concentration (p=0.004) increased following the match simulation. No significant differences were observed for blood CK (p=0.281), individual scrummaging forces (p=0.433) or in the kinematic variables following the protocol. While physiological fatigue and subjective ratings of physiological fatigue may develop during a rugby simulation, no differences were observed in peak forces or in body kinematics at peak force.Conclusion: Physiological fatigue does not influence individual scrummaging performance and technique.

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

“…Most studies did not specify the time of season when testing occurred. Cohrane et al [11] stated they conducted testing after the competitive season, Green, Kerr, Olivier, et al [18] performed testing 4 weeks prior to the start of the inter-varsity tournament, Babault et al [19] started their intervention 2 weeks after the mid-winter break, and Wu et al [20] assessed players during the competition preparation phase. Sample sizes in each study ranged from only three players up to a study with 432 players drawn from 54 forward packs (and across five playing levels), though the majority of studies recruited fewer than 30 participants.…”

“…Two studies recruited a mix of forwards and backs (Dobbs 2017;Wu et al 2006) [27]. Six studies did not specify the participants' playing position [18,19,[28][29][30][31]. 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.…”

“…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].…”

“…Nine studies had players perform scrums on natural grass turf [3,7,9,10,13,18,[21][22][23], three used synthetic turf [11,24,29], two used rubber matting [12,14], and three were done indoors on lab or track floors [20,28,30]. One study had participants stand on a force plate, which the researchers had put skateboard tape on to reduce slippage [27].…”

A review of the biomechanical determinants of rugby scrummaging performance

“…The steady state phase (pre-ball feed) The steady state phase, which occurs on immovable scrummaging machines, reflects the sustained force period with the players remaining in a largely isometric position. During the sustained phase, the lower limbs exhibit a large degree of extension [13,15,30,31,34] , and the trunk will gradually rise above the horizontal position. [18,19] This movement and body position may result in players 'overextending' which could cause the scrum to collapse.…”