Slides used with Permission - IRB Passport

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Description of Injury
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Near Misses
(
Acute Spinal Cord Injury or neck fractures without ASCI
whom are now ambulant and a full recovery is expected
)
8
9
9
3
11
10
8
3
4
4
4
Neurological deficit
0
0
0
0
0
0
6
2
2
4
5
Quadriplegics
3
3
3
1
4
5
5
2
3
2
5
Fatality
2
2
1
0
0
1
1
0
1
1
0

Not provided
0
0
0
0
0
0
0
1
1
1
0
Fully recovered
0
0
0
0
0
1
0
0
2
0
0
With disability
0
0
0
0
0
0
1
1
0
0
0
Fatality
0
3
0
0
1
1
0
1
2
1
0
Fatality
0
1
0
2
1
0
0
0
2
0
0
Fatality
0
1
1
1
1
0
0
0
0
0
0
TOTAL
13
19
14
7
18
18
21
10
17
13
14
0
Catastrophic injuries (Quadriplegics, Neuro deficit Deaths
ASCI)
5
5
4
1
4
6
12
4
6
7
10
0
Spinal cord injuries combined
13
14
13
4
15
16
20
8
11
12
14
0
Catastrophic injuries (Disability, Deaths TBI)
0
3
0
0
1
1
1
2
2
1
0
0
Non-Catastrophic injuries (full recovery, fractures/ASCI)
8
9
9
3
11
10
8
3
4
4
4
0
Non-Catastrophic injuries (full recovery, TBI)
0
0
0
0
0
1
0
0
2
0
0
0
Other, cardiac, etc.
0
2
1
3
2
0
0
0
2
0
0
0
Control total
13
19
14
7
18
18
21
10
17
13
14
0
Head, neck & Spine injuries (Total minus Other/Cardiac)
13
17
13
4
16
18
21
10
15
13
14
0
Acute Spinal Cord and Head Injuries including deaths in
both SCHOOL
AND
CLUB RUGBY COMBINED
in South Africa as
reported
to the Chris Burger
Petro Jackson Players' Fund & more recently BokSmart from 2001 -> 31 December 2011
UNKNOWN
ACUTE SPINAL CORD INJURY (ASCI)
TRAUMATIC BRAIN INJURIES (TBI)
CARDIAC RELATED EVENTS
Catastrophic rugby injuries

(2001
-
2011)

Acute Spinal Cord Injury (ASCI) [n = 140]

Traumatic Brain Injury (TBI) [n = 14]

Cardiac events [n = 6]

Unknown [n = 4]

TOTAL [n = 164]

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


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


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
permanent

injuries,
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
.

Proportion of
all
ASCI per position
per phase of play

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%

Proportion of
Permanent

ASCI per position
per
phase of play

Event causing injury


Tackle ASCI (n = 17,
38%)


Scrum ASCI (n = 19,
42%)

Tackler

n = 8/16, 50%

Ball carrier

n

= 8/16, 50%

Not provided = 1

Event causing injury


Tackle ASCI (n = 17,
38%)


Scrum ASCI (n = 19,
42%)

Impact on
engagement

n

= 10/18, 56%

Collapsed scrum

n = 7/18, 39%

Not provided = 1

Popping out

n

= 1/18, 6%

Event causing injury


Tackle ASCI (n
=
17, 38%)


Scrum
ASCI (n
=
19, 42%)


n

= 36/45, 80%

PERMANENT ASCI

TACKLE

n = 8/16, 50%,

Not provided = 1

PERMANENT ASCI

SCRUM

n = 14/17, 82%,

Not provided = 2

Proportion of
All
ASCI per
phase
of play

Proportion of
Permanent
ASCI per
phase of play



NP

"Miss"

Neuro.

Quad.

Fatal

Total

Scrum

(n

=

16
)

2008

0

1

0

1

0

2

2009

0

0

1

2

0

3

2010

1

1

1

1

0

4

2011

0

0

3

3

1

7

Tackle

(n

=

14
)

2008

0

2

0

0

0

2

2009

1

2

1

1

1

6

2010

0

1

2

0

0

3

2011

0

1

1

1

0

3

Ruck

(n

=

6
)

2008

0

0

0

0

0

0

2009

0

1

0

0

0

1

2010

0

2

0

1

0

3

2011

0

1

1

0

0

2

Total

2

12

10

11

1

36

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
Hooker

accounted for
46%

of all Permanent
outcomes (
n = 12/26
, Not provided = 1)

25

METHODS: PROJECT STRUCTURE

PHASE 1

Machine Scrummaging



Wearable sensors


Techniques and playing levels


Different engagement techniques


Comparison across playing levels

PHASE 2

Live
Scrummaging

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

26

METHODS: STUDY DESIGN


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
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

27

METHODS: ENGAGEMENT TECHNIQUES


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


Engagement techniques:

1)
Hit & Hold

2)
Double Shove

3)
Three
-
Stage Call

4)
Passive Engagement

5)
Engage as 7, add number 8 (7+1)

6)
Engage as front 5, add back row (5+3)

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

METHODS: FORCE MEASUREMENT

28

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM


Scrum machine fixed to
ground (spikes and straps)


Data sampled @ 500 Hz



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

Slides used with Permission

29

METHODS: VIDEO ANALYSIS

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

30

METHODS: DATA FLOW

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

31

METHODS: TESTING COMPLETED


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
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

32

ANALYSIS: KINEMATICS

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

33

ANALYSIS: KINEMATICS

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

34

RESULTS: Peak Compression @ engagement

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

35

RESULTS: Compression
-

sustained

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

36

RESULTS: Time of Onset

CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

RESULTS: Comparing different levels

Grouped data


peak compression force @ engagement (Hit & Hold)


CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
All
School
Academy
Community
Women
Elite
International
Category
Force [N]
37

Slides used with Permission

0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
Hit&Hold
3-stage
Passive
7+1
5+3
Force [N]

Condition

Elite

RESULTS: Comparing different techniques

Elite data


peak compression force @ engagement


CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

*

38

Slides used with Permission

RESULTS: Comparing different techniques

Elite data


peak downward force @ engagement


CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

-6000
-5000
-4000
-3000
-2000
-1000
0
Hit&Hold
3-stage
Passive
7+1
5+3
Force [N]

Condition

Elite

39

Slides used with Permission

RESULTS: Comparing different techniques

Elite data


average compression force during sustained


CONTACTS


Dr

Grant

Trewartha
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

0
1000
2000
3000
4000
5000
6000
7000
8000
9000
Hit&Hold
3-stage
Passive
7+1
5+3
Force [N]

Condition

Elite

40

Slides used with Permission

41

DISCUSSION


PHASE 1


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
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

42

DISCUSSION


INJURY MECHANISMS


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
,

g
.
trewartha@bath
.
ac
.
uk


21.NOVEMBER .2011

BIOMECHANICS

OF

THE

RUGBY

SCRUM

Slides used with Permission

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 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 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 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 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 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 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 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 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 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



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 Universit
y

of Cape Town and
Vrije

Universiteit

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