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Dr Wayne Viljoen Dawie Theron James Brown Clint Readhead Dr Evert Verhagen PowerPoint PPT Presentation


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2008-2011 – Catastrophic Scrum Injuries – can this influence the game going forward?. Dr Wayne Viljoen Dawie Theron James Brown Clint Readhead Dr Evert Verhagen Prof Willem van Mechelen Prof Mike Lambert. SOME DESCRIPTIVE STATS. ASCI specific data - basics.

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Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • 2008-2011

  • – Catastrophic Scrum Injuries – can this influence the game going forward?

  • Dr Wayne ViljoenDawie Theron

  • James BrownClint Readhead

  • Dr Evert Verhagen

  • Prof Willem van MechelenProf Mike Lambert


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • SOME DESCRIPTIVE STATS


Asci specific data basics

ASCI specific data - basics

  • There have been 45 ASCI’s since 2008, all of which have occurred in males.

  • This equated to an average annual incidence of 1.73 ASCI’s per 100 000 players (95% CI’s: 0.72 – 2.74) and an average annual incidence of 1.04 permanent ASCI outcomes per 100 000 players (95% CI’s: 0.25 – 1.82).

  • Seven % of the ASCI’s (n = 3 of 42) were fatal, 26% (n = 11 of 42) resulted in Quadriplegia, 31% (n = 13) resulted in neurological deficit and the remaining 36% (n = 15 of 42) were classified as “Near Misses” (outcome not provided in n = 3 cases).

  • Henceforth for further comparison, outcomes of ASCI were also grouped as either “Permanent” (Neurological Deficit, Quadriplegia, Fatal) or Non-Permanent (near miss).


Asci specific data basics1

ASCI specific data – basics

  • Fifty-eight % (n = 26 of 45) of all ASCI’s occurred at Senior level with an estimated player base of 121 663 players, resulting in a significantly higher incidence (7.12 per 100 000 players; 2.38 – 11.87) than Junior level (1.20 per 100 000 players; 0.26 – 2.13), with an estimated player base of 529 483 players.

  • In Senior players, 85% (n = 22 of 26) of their injuries had permanent outcomes in comparison to 26% (n = 5 of 19) in Junior players.

  • Permanent injuries to Senior players (6.03 per 100 000 players; 1.66 – 10.39) were significantly higher than to Junior players (0.31 per 100 000 players; -0.16 – 0.79).

  • Furthermore, when examining in isolation the total of 27 permanent injuries the player was significantly more likely to be a Senior (82%, n = 22 of 27) rather than Junior level player (Absolute Value - Odds Ratio: 16.1, 95% CI’s: 3.2 – 80.2).


Asci specific data positional risk

ASCI specific data – Positional Risk

  • 40 ASCI were related to 15-a-side, hence were compared further for positional risk

  • The hooker and loose-forward positional groupings were associated with 38% (n = 15 of 40) and 25% (n = 10 of 40) of all ASCI’s.

  • Together, the hooker, prop, and lock positional grouping (tight five) accounted for all the scrum injuries.

  • When examining permanentinjuries, only the forwards were represented (prop, hooker, lock and loose-forward).

  • Of these permanent outcomes in isolation, the hooker alone accounted for 46% (n = 12 of 26) of all injuries, 83% of which (n = 10 of 12) were as a result of the scrum.


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Proportion of all ASCI per position per phase of play


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Position of Injured Player

Hooker (n = 15)

Prop (n = 5)

Front Row ASCI = 20, 50%

PERMANENT ASCI

FRONT ROW

n = 15/18, 83%,

Not Provided = 2

PERMANENT ASCI

HOOKER

n = 12/15, 80%


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Proportion of Permanent ASCI per position per phase of play


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • EVENT CAUSING INJURY


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Tackler

n = 8/16, 50%

Event causing injury

  • Tackle ASCI (n = 17, 38%)

  • Scrum ASCI (n = 19, 42%)

Ball carrier

n = 8/16, 50%

Not provided = 1


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Impact on engagement

n = 10/18, 56%

Event causing injury

  • Tackle ASCI (n = 17, 38%)

  • Scrum ASCI (n = 19, 42%)

Collapsed scrum

n = 7/18, 39%

Popping out

n = 1/18, 6%

Not provided = 1


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

n = 36/45, 80%

PERMANENT ASCI

TACKLE

n = 8/16, 50%,

Not provided = 1

Event causing injury

  • Tackle ASCI (n = 17, 38%)

  • Scrum ASCI (n = 19, 42%)

PERMANENT ASCI

SCRUM

n = 14/17, 82%, Not provided = 2


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Proportion of All ASCI per phase of play


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Proportion of Permanent ASCI per phase of play


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • MATCH RELATED TRENDS

  • 2008 2011

  • THUS FAR


Of the 27 permanent asci the scrum had the strongest tendency to cause permanent outcome n 14 27 52

Of the 27 Permanent ASCI, the Scrum had the strongest tendency to cause Permanent outcome (n = 14/27, 52%)


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

Of the 27 Permanent ASCI, the Hookeraccounted for 46% of all Permanent outcomes (n = 12/26, Not provided = 1)


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • INITIAL IRB SCRUM RESEARCH KEY FINDINGS…


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • Different engagement techniques

  • Comparison across playing levels

BIOMECHANICS OF THE RUGBY SCRUM

METHODS: PROJECT STRUCTURE

21.NOVEMBER .2011

PHASE 1

Machine Scrummaging

Phase 2

Live Scrummaging

CONTACTS

Dr Grant Trewartha, [email protected]

  • Wearable sensors

  • Techniques and playing levels

Slides used with Permission

25


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

METHODS: STUDY DESIGN

21.NOVEMBER .2011

  • Cross-sectional (single shot) design

  • Field-based study – outdoor, natural turf, simulated training

  • Teams recruited into six different playing levels (total of 34 teams):

    • School (under 18)

    • Academy / University

    • Men Community

    • Women

    • Elite Club

    • International Standard

  • Modify the engagement technique (six techniques)

  • Compare:

    • Playing level

    • Technique

    • Technique across playing levels

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

26


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

METHODS: ENGAGEMENT TECHNIQUES

21.NOVEMBER .2011

  • Final choice of engagement techniques decided by the ‘steering group’, international group of scrum experts convened by IRB

  • Engagement techniques:

    • Hit & Hold

    • Double Shove

    • Three-Stage Call

    • Passive Engagement

    • Engage as 7, add number 8 (7+1)

    • Engage as front 5, add back row (5+3)

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

27


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

METHODS: FORCE MEASUREMENT

21.NOVEMBER .2011

  • Scrum machine fixed to ground (spikes and straps)

  • Data sampled @ 500 Hz

  • All engagement commands produced by pre-recorded audio files (consistency of timing)

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

28


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

METHODS: VIDEO ANALYSIS

21.NOVEMBER .2011

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

29


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

METHODS: DATA FLOW

21.NOVEMBER .2011

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

30


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

METHODS: TESTING COMPLETED

21.NOVEMBER .2011

  • 41 forward packs tested across playing levels:

    • U18 - 6

    • Academy/Uni - 8

    • Women - 4,

    • Community - 6

    • Elite - 11

    • International Standard - 6

  • All teams performed 4-8 scrums per engagement condition

  • A total of 1220 scrums to be analysed

  • 34 packs analysed

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

31


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

ANALYSIS: KINEMATICS

21.NOVEMBER .2011

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

32


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

ANALYSIS: KINEMATICS

21.NOVEMBER .2011

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

33


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

RESULTS: Peak Compression @ engagement

21.NOVEMBER .2011

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

34


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

RESULTS: Compression - sustained

21.NOVEMBER .2011

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

35


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

RESULTS: Time of Onset

21.NOVEMBER .2011

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

36


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

RESULTS: Comparing different levels

21.NOVEMBER .2011

Grouped data– peak compression force @ engagement (Hit & Hold)

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

37


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

RESULTS: Comparing different techniques

21.NOVEMBER .2011

Elite data– peak compression force @ engagement

*

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

38


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

RESULTS: Comparing different techniques

21.NOVEMBER .2011

Elite data– peak downward force @ engagement

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

39


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

RESULTS: Comparing different techniques

21.NOVEMBER .2011

Elite data– average compression force during sustained

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

40


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

DISCUSSION – PHASE 1

21.NOVEMBER .2011

  • Forces:

    • Differences between conditions

      • Passive vs 5+3 vs Hit&Hold/3-stage/7+1

      • Passive reduced compression (50%) and downward (20%)

      • Packs maintained sustained forces in Passive

    • Differences between playing levels

      • U18/Women, Academy/Community, Elite/International

  • Kinematics:

    • No consistent between-level differences

    • Passive reduces ‘closing speeds’, therefore accelerations

    • Passive lowered maximum ‘hazard index’

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

41


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

BIOMECHANICS OF THE RUGBY SCRUM

DISCUSSION – INJURY MECHANISMS

21.NOVEMBER .2011

  • Given magnitude of forces and speed of engagement imperative to ensure direct impact on top of head is avoided

  • Scrummaging has…..

    • High forces including vertical and lateral shear forces

    • Geometric misalignment

    • Constrained head motions

    • Constrained body segment motion

    • Repeated loading

    • …. a situation which has the potential to produce the repetitive sub-critical injuries that in theory could lead to chronic pain and early degenerative changes to the cervical and lumbar spine.

CONTACTS

Dr Grant Trewartha, [email protected]

Slides used with Permission

42


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • WHAT IS THE WAY FORWARD FOR SCRUMS?


Where to from here

Where to from here?

  • The high forces during scrum engagement in the modern era is potentially the result of:

    • A change in scrumming technique

    • Bigger, heavier players

    • Faster engagement speeds i.e. the “Hit”

  • Given the very high forces, heavier packs and faster engagement, it is imperative to control the engagement sequence to avoid direct impact on the head

  • What is the purpose of the scrum according to Law? – “to restart play quickly, safely and fairly, after a minor infringement or a stoppage”

    • Are we doing this with the original intent?

  • Modern scrumming involves a high initial impact or “hit” on engagement, followed by sustained pushing forces throughout the scrum

    • Is this safe, and does this serve the original purpose of the scrum?

    • Is this indeed in line with the Laws intended?


Where to from here1

Where to from here?

  • On 1 January 2007, the CTPE Law was implemented – this was designed to “standardise the distance between opposing packs and to reduce the forces at engagement”

    • Is this what we are currently doing?

    • Have the forces at engagement been reduced?

    • Does the current execution of the scrum limit or increase the risk of catastrophic cervical spinal injury during the “hit”?


Where to from here2

Where to from here?

  • Some interesting scrum stats:

    • 1995 – WC Final game was played over 100 minutes – ball in play 32min

    • 2009 – average Super Rugby ball in play 38 min (14 years to add 6 min!)

    • Current Super Rugby Average time 3-4 min ball out of play because of resets and penalties due to the scrum

    • IRE vs. ENG 6N 9 penalties in SCRUMS, total cost to ball in play more than 5 min

    • What brings people back to watch?


Where to from here3

Where to from here?

  • According to the IRB Game Analysis Group:

    • between 15-28 scrums per game

    • between 14-29% tries scored from scrum possession

    • teams retain 83-91% of their own scrum possession

  • With such high retention of ball and so few scrums, is the “hit” still justifiable?

  • And given the risk of permanent catastrophic cervical spinal injury?

  • Especially in the amateur game, which is mass participation based?

  • The Law’s also state: “Each player in the front row and any potential replacement(s) must be suitably trained and experienced”

    • Is this so? Do we see that at Amateur level rugby?

    • Who exactly determines this?


Where to from here4

Where to from here?

  • Reaching a high impact velocity leading to the “hit” at engagement is a result of coaches and players to “beat the opposition to the middle” or generate high force to attempt to limit the opposition’s forward motion (Bath Univ. IRB Scrum Research group)

  • Keep in mind the rebound- or damping effect that a larger “hit” creates, which results in suboptimal force production for a short period of time, before a sustained pushing force has been achieved

  • To a certain extent, the “hit” on engagement is initially counterproductive to sustained pushing forces that follow, especially in an event where domination is determined over the initial few seconds of the ball being put into the scrum

  • An important part of scrumming should be to maximise scrumming force, after the engagement; this would increase the chances of pushing the opposition off the ball


Where to from here5

Where to from here?

  • Sustained force generation during the scrum is a function of player technique and forward pack cohesion, whereas the force during the engagement is more related to pack weight and speed to the “hit”

  • Sustained pushing force manifests after the ball has been put into the scrum, and largely determines more or less effective scrumming


Where to from here6

Where to from here?

  • There is great need to manage catastrophic injury risk, and simultaneously maximise performance of the scrum

  • Even though scrum injuries are few, they are the most severe

  • The risk of injury per event in the scrum is the highest of all contact events in the game

  • Because the scrum is a controllable event, it should be more amenable to intervention and to look towards reducing the risk of injury further

  • Preventative strategies of the game must be maximised towards preventing permanent disability or death, and therefore the “hit” should be removed from Amateur rugby


Where to from here7

Where to from here?

  • Injury prevention should be direct at the following:

    • The Laws of the scrum (both Amateur and Professional separately)

    • Techniques of scrumming (both Amateur and Professional separately)

    • Correct Law interpretation and enforcement by the referees

    • Coaching of the correct Laws, and interpretations by the coaches

    • Player skill development

    • Progressive Long Term Coaching, Refereeing and Player Development Pathways


Where to from here8

Where to from here?

  • What is the proposed way forward?

    • Remove the “hit”

    • Bring back the “scrum”

    • Relook at what the Laws originally intended

    • Move to Passive engagement across the board = first prize

      • And if not, then in the interim, at least to the majority of Amateur levels

    • Passive engagement does not diminish the scrum, it should make it safer, and place more emphasis on scrumming

    • Should the “hit” be maintained at certain levels, then there should be an abridged version or mini-hit to transition from “no hit” to “full hit”

      • I.e. bring the front rows closer together i.e. ear-to-ear, and have them pre-bound and in their respective channels before the engagement

    • Clothing modifications?


Where to from here9

Where to from here?

  • Advantages of Passive engagement:

    • It removes the hit out of the equation, which will remove a large portion of catastrophic and permanent cervical spinal injuries

    • Significantly lower compressive forces (about 50% reduction, and potentially more, with a closer setup position)

    • Significantly lower downward forces (about 20-40% reduction, and potentially more, with a closer setup position) – this will reduce the chances of collapse, and associated catastrophic cervical spinal injury

    • Less horizontal angle deviation at high and peak forces, which lowers the hazard index

    • Players are better in alignment to sustain and accommodate the forces generated

    • Passive engagement can remove high initial impact forces, and does not negatively impact the power generating capacity of the scrum during the actual pushing phase, in fact the sustained pushing forces generated are generally higher than most impact engagement techniques

    • Passive engagement leads to less angled lateral head, neck and torso movement, and also less downward angles of the head, neck and torso


Acknowledgements

Acknowledgements

  • The Bath University IRB Scrum Research Group

    • Dr’s Trewartha, Preatoni, Stokes and England

  • The IRB

  • The SA ‘Scrum Smart’ working group

    • Wayne Viljoen, Clint Readhead, Dawie Theron, Balie Swart, Tappe Henning, Andre Watson, Justin Durandt, Hilton Adonis, Nico Serfontein, Graham Bentz

  • The University of Cape Town and VrijeUniversiteit Research groups

    • Prof Mike Lambert, James Brown, Dr Evert Verhagen, Prof Willem van Mechelen

  • The SARU Medical team

  • The Chris Burger/Petro Jackson Players Fund


Dr wayne viljoen dawie theron james brown clint readhead dr evert verhagen

  • THANK YOU FOR YOUR ATTENTION!


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