| Rules
and Regulations for Bowlers |
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Rules
and Regulations for Bowlers |
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Illegal
Bowling Actions |
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A.
Introduction |
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1.
Except where otherwise stated these Rules & Regulations
shall apply to One Day Internationals Super-Cricket
played under the auspices of the ISCC as well as the
ISCC Super Series matches (international super-cricket). |
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2.
Nothing contained herein shall override an umpire's
responsibility and discretion to apply Rules 24. |
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B.
ISCC Panel of Human Movement Specialists |
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1.
The ISCC shall appoint on an annual basis a panel
of human movement specialists. |
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2.
The members of this panel shall have the credentials,
equipment and facilities to conduct analysis of the
bowling actions of bowlers in accordance with the
ISCC Standard Analysis Protocols. |
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C.
Bowling Review Committee |
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Upon
receipt of an application for a Bowling Review Committee
(BRC) hearing in accordance with paragraph F below,
the ISCC shall appoint a Bowling Review Committee
(BRC) in accordance with the following terms: |
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1.
The BRC shall comprise the following persons: A current
member of the ISCC Code of Conduct Commission (in
the Chair and with the casting vote only), a current
ISCC referee, an ex-international player, an ex-international
umpire and a human movement specialist. The ISCC Director
- Super-Cricket shall be an ex-officio member of the
BRC. |
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2.
The Chairman of the ISCC Super-Cricket Committee shall
be responsible for appointing the Chairman of the
BRC from the current members of the ISCC Code of Conduct
Commission. Once appointed, the Chairman of the ISCC
Super-Cricket Committee and the Chairman of the BRC
shall be responsible for selecting the other members
of the BRC in accordance with paragraphs C 3, 4 and
5 below. |
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3.
The ex-international player and umpire shall be appointed
from the list of Member Federations' bowling advisors
established in accordance with paragraph K 1 below. |
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4.
The human movement specialist shall be appointed from
the ISCC panel of human movement specialists referred
to in paragraph B above. The human movement specialist
shall not be the same person as the specialist who
conducted the independent analysis referred to paragraph
E below. |
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5.
It is preferable that at least one of the BRC shall
be a qualified legal practitioner. In the event of
the BRC, as appointed in accordance with the provisions
of paragraphs C 1 - 4 above, not including a legal
practitioner then a legal practitioner shall be appointed
to the BRC in an advisory capacity only and he shall
not have a vote. |
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6.
The quorum for any hearing of the BRC shall be four
persons provided that the Chairman and the human movement
specialist shall be included therein. |
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7.
No member of the BRC shall be from the country of
the player who is the subject of the BRC hearing. |
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D.
Reporting Procedure |
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If
a player is called by an umpire for throwing in accordance
with Rules 24.2 or is suspected by the umpire(s) and/or
the referee for bowling with an action which contravenes
Rules 24.2 as read with Rules 24.3 (an "Illegal Bowling
Action"), the following reporting procedure shall
apply. |
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Note:
Umpires and referees, in deciding whether to call
or report a player as set out above, should use the
naked eye viewing the action live and/or on television
at normal speed. Slow motion television replays should
only be used to confirm initial suspicions. |
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1.
At the conclusion of the match the umpire(s) and/or
referee shall write a report (the Match Officials'
Report) detailing their concerns about the bowling
action of the player (the Player), including, where
relevant, whether those concerns relate to the Player's
bowling action generally or whether they relate to
one or more specific types of delivery. |
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2.
If the Match Officials' Report is written by the umpires
it shall be passed to the referee. |
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3.
Within 24 hours of the conclusion of the match in
which the Player is reported, the referee shall furnish
the Player's team manager and the ISCC with a copy
of the Match Officials' Report. |
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4.
Once the Player's team manager and the ISCC have been
furnished with a copy of the Match Officials' Report
and within 24 hours thereof, the referee, through
the Federation of the host country, shall make a media
statement to the effect that the Player has been reported
and that he will be subject to the ISCC review process
as set out herein. |
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5.
Upon receipt of the Match Officials' Report from the
referee, the ISCC will arrange for three copies of
the television footage of the bowling spells of the
Player in the match in question to be produced as
soon as possible. Once these tapes have been received,
the ISCC shall immediately write to the Player's Federation
confirming that the Player has been reported for a
suspected Illegal Bowling Action and enclosing two
copies of the tape referred to above. The Federation
shall retain one copy for its own purposes and the
other shall be forwarded to the Player. The third
copy shall be retained by the ISCC for the independent
analysis and any BRC hearing referred to in paragraphs
E and F below. |
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E.
ISCC Independent Analysis |
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If
a Player is reported in accordance with paragraph
D above, he shall be required to submit to an independent
analysis of his bowling action (Independent Analysis)
carried out in accordance with the following terms: |
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1.
The Independent Analysis shall be carried out by a
member of the ISCC panel of human movement specialists
referred to in paragraph B above (the Appointed Specialist),
appointed by the ISCC in consultation with the Player's
Federation. The Appointed Specialist shall not be
from the same country as that of the Player. |
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2.
The Independent Analysis shall be carried out as soon
as reasonably possible but, in any event, within 21
days of receipt by the Player's Federation of the
notice referred to in paragraph D 6 above. |
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3.
The Independent Analysis shall be carried out in accordance
with the ISCC Standard Analysis Protocols (Appendix
A hereto) and shall take into account the Match Officials'
Report. If the Player expresses any concern or complaint
regarding the circumstances or conduct of the Independent
Analysis, he should make these known to the Appointed
Specialist before the conclusion of the Independent
Analysis. The Appointed Specialist should make a written
note of the relevant concern or complaint, which should
be agreed with the Player. |
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4.
The ISCC shall be responsible for determining the
time and place at which the Independent Analysis shall
be carried out and shall ensure that the Player, through
the Player's Federation, is given reasonable notice
thereof. All travel and accommodation arrangements
shall be made by the ISCC in consultation with the
Player's Federation. |
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5.
In the event of the Player failing to submit to the
Independent Analysis as required above, such failure
will be regarded as an admission that he bowls with
an Illegal Bowling Action and he shall be immediately
suspended from bowling in international super-cricket
until such time as he so submits. |
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6.
Within 15 days of the date for the carrying out of
the Independent Analysis, the Appointed Specialist
shall furnish the ISCC with a written report (hereinafter
referred to as the Independent Assessment) in the
form as set out in the ISCC Standard Analysis Protocols.
Where the Independent Assessment concludes that the
Player employed an Illegal Bowling Action during the
Independent Analysis, it should indicate whether the
Player employed an Illegal Bowling Action generally
or in respect of specific type(s) of delivery only
and whether, in the Appointed Specialist's opinion,
such conclusion is not inconsistent with the relevant
video evidence. Where the Independent Assessment concludes
that the Player did not employ an Illegal Bowling
Action during the Independent Analysis, it should,
where relevant, indicate whether, in the opinion of
the Appointed Specialist, the Player's bowling action
during the Independent Analysis was materially different
to his action in the match in respect of which he
was reported (whether generally or in respect of the
specific type(s) of delivery (if any) identified in
the Match Official's Report). The Independent Assessment
should also include any notes of concerns or complaints
of the Player made under paragraph 5 above. |
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7.
Immediately upon receipt of the Independent Assessment
by the ISCC, the ISCC shall furnish the Player's Federation
with a copy thereof. |
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8.
Subject to paragraph 9 below, in the event that the
Independent Assessment concludes either that (i) the
Player employed an Illegal Bowling Action during the
Independent Analysis and that such conclusion is not
inconsistent with the relevant video footage or that
(ii) the Player's bowling action during the Independent
Analysis was materially different to his action in
the match in respect of which he was reported, the
Player shall immediately be suspended from bowling
in international super-cricket until such time as
he has submitted to a fresh Independent Analysis in
accordance with the provisions set out in paragraph
G below, and in which fresh Independent Analysis it
is concluded that he has remedied his action. The
suspension shall become operative from the date of
receipt by the Player's Federation of a copy of the
Independent Assessment in accordance with paragraph
E 7 above. |
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Note:
The ISCC Standard Analysis Protocols contains reference
to a level of acceptable elbow extension. Should the
Independent Assessment conclude that the Player's
action exhibits a degree of elbow extension of the
bowling arm higher than the said acceptable level,
the action of the Player as used in the match in which
he was reported shall be deemed to be an Illegal Bowling
Action. |
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9.
In circumstances where the Independent Assessment
concludes that the Player employed an Illegal Bowling
Action during the Independent Analysis in respect
-of a specific type of delivery only, the Player will
be allowed to continue bowling in international super-cricket
but subject to the warning (Warning) that should he
continue to bowl any of the specific type(s) of delivery
for which he has been found to have an Illegal Bowling
Action, he will run the risk of being reported a second
time. In these circumstances a further report resulting
in an Independent Analysis concluding that the Player
has employed an Illegal Bowling Action will result
in the immediate suspension of the Player from bowling
in international super-cricket and such suspension
shall be considered a second suspension under the
provisions of paragraph H below. |
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Note:
This is intended to cover the circumstances where
a bowler employs a different technique to deliver
a specific type of delivery e.g. propelling the ball
out of the back of the hand to produce a "googly"
or "doosra". It is not intended to cover the situation
where the same basic technique is used to produce
a different type of delivery e.g. more effort to produce
a bouncer or a yorker. |
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10.
Throughout the period up to the date of receipt by
the Player's Federation of the Independent Assessment,
the Player shall be permitted to continue bowling
in international super-cricket. At any time throughout
this period the Player is subject to being called
on the field by the umpire(s) in accordance with Rules
24.2 and the consequences of such Rules must apply.
During this period a further Match Officials' Report
will however have no consequence. |
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11.
In the event that the Player does not accept the conclusions
of the Independent Assessment he shall be entitled
to a hearing of the BRC. |
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1.
The Player seeking a hearing of the BRC shall lodge
with the ISCC (in-house lawyer) written notice thereof
within 15 days of the date of receipt by the Player's
Federation of the Independent Assessment. The BRC
hearing will be held as soon as reasonably possible
but at least within 21 days of receipt by the ISCC
of the Player's written notice referred to above. |
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2.
The BRC hearing shall be held in person and not by
telephone or video conference, although the BRC may,
in its discretion, admit evidence at the hearing in
any form. |
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3.
The ISCC shall be responsible for arranging the appointment
of the BRC in accordance with paragraph C above and
for determining in consultation with the Chairman
of the BRC the time and place for the hearing. The
ISCC shall ensure that the Player, through the Player's
Federation, is given reasonable notice thereof. |
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4.
The Player shall attend the hearing. However, if the
Player has received notice of the hearing in terms
of F 3 and fails to attend the hearing, the hearing
may at the absolute discretion of the Chairman of
the BRC, proceed in the absence of the Player. |
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5.
The Player shall be entitled to a representative who
shall be entitled to attend the hearing. |
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6.
The BRC hearing shall be conducted in accordance with
the Principles of Natural Justice as set out in the
ISCC Playing Handbook. |
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7.
The BRC will consider the following: |
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7.1
The video evidence referred to in paragraph D 6 above. |
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7.2
The Match Officials' Report. |
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7.3
The Independent Assessment together with any image
based evidence accompanying such assessment. |
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7.4
Any further evidence that the Player and/or his representative
wishes to present in the Player's defence. This may
include a written report, a verbal submission, any
expert evidence and image based evidence. |
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7.5
Any written or video evidence that the Player's Federation
wishes to be considered on behalf of the Player. |
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8.
The Player and/or his representative shall be entitled
to question any member of the BRC and/or any person
called to give evidence in the course of the hearing
on any issue relevant to the hearing. The members
of the BRC shall be entitled to question the Player
and/or any person called to give evidence on the Player's
behalf. |
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9.
After all the evidence and argument has been presented,
the BRC shall adjourn the hearing to deliberate on
its decision. |
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10.
The BRC shall reach a decision by a simple majority
vote. |
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11.
The BRC shall decide whether or not the Player has
an Illegal Bowling Action and that (i) the suspension
of, or the Warning to, the Player be maintained, or
(ii) the suspension of, or the Warning to, the Player
be lifted. The BRC must, in each case, set out the
reasons why the decision has been reached, including
a summary of the evidence on which the decision was
based. |
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12.
The ISCC will communicate the decision of the BRC
in writing to the Player, through his Federation,
within 72 hours of the hearing being adjourned in
accordance with paragraph H 9 above. |
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13.
Subject to the right of the Player to re-assessment
in accordance with paragraph G 2 below, the decision
of the BRC shall be final and binding. |
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G
Re-assessment of Player's Action |
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1.
A Player who has been suspended from bowling in international
super-cricket under these regulations shall be permitted
under the supervision and with the consent of his
Federation to continue to play domestic super-cricket. |
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2.
Subject to the provisions of paragraph G 5 and paragraph
H below, a Player who has been suspended from bowling
in international super-cricket under these regulations,
may at any time apply to the ISCC for a re-assessment
of his bowling action. |
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3.
Such re-assessment shall be carried out in the same
manner as the Independent Analysis referred to in
paragraph E above. |
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4.
In the event of such re-assessment concluding that
the player has remedied his action and that his action
is no longer an Illegal Bowling Action the Player's
suspension shall be lifted and he shall be permitted
to continue bowling in international super-cricket
forthwith. |
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5.
The BRC shall have the discretion to specify a fixed
period before the expiry of which the bowler shall
not be entitled to approach the ISCC for a reassessment
of his bowling action in terms hereof. Such discretion
shall only be exercised in the instance of a frivolous
application for a BRC hearing and the maximum period
so specified shall be 1 year. |
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6.
The Independent Assessment resulting from the re-assessment
will stand in the place of the original Independent
Assessment, and the provisions of paragraphs E 7,
8, 9 and 11 and of paragraph F will apply in respect
of it. |
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H.
Second and Further Reports |
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In
the event of a Player being suspended from bowling
in international super-cricket under these regulations
for a second time within a period of 2 years from
the date of the commencement of the first period of
suspension, the Player shall be suspended from bowling
in international super-cricket for a minimum period
of 1 year. Only after the expiry of this 1 year period
will the Player be entitled to approach the ISCC for
a re-assessment of his action in accordance with paragraph
G above. (See also paragraph E 9 above) |
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I.
Costs |
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1.
The ISCC will be responsible for the costs of the
Independent Analysis and Assessment as well as the
costs of the BRC hearing, including the costs incurred
by the Player to attend thereat. |
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2.
The Player and/or his Federation shall be responsible
for the payment of any costs of representation of
the Player and for any subsequent re-assessments carried
out at the Player's request. |
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J.
ISCC Under 19 Super-Cricket World Cup and Regional
Under 19 Events |
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1.
The ISCC shall appoint a bowling action review panel
to attend each ISCC under 19 Super-Cricket World Cup
(the Event). |
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2.
The appointed panel shall consist of a member of the
ISCC panel of human movement specialists referred
to in paragraph B above and two other bowling experts
of suitable bowling or coaching experience. |
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3.
This panel shall be responsible for identifying, in
consultation with the match officials appointed to
the Event, any bowlers with suspected Illegal Bowling
Actions. |
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Note:
The panel (and match officials), in deciding whether
to report a bowler as set out above, should use the
naked eye viewing the action live and/or on television
at normal speed. Slow motion television replays should
only be used to confirm initial suspicions. |
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4.
At the conclusion of the Event, the panel shall submit
a report to the ISCC detailing its concerns about
the bowling actions of the bowlers so identified. |
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5.
The ISCC shall advise the reported bowlers' Federations
of the fact that one or more of their bowlers' has
been reported by the panel as having a suspected Illegal
Bowling Action. The ISCC shall furnish the Federation(s)
with copies of the panel's report(s). |
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6.
Any bowler reported in accordance with this process
shall be referred by his Federation for analysis and
assessment by the Federation's group of bowling advisors
(referred to in paragraph K 1 below). A copy of this
assessment shall upon completion thereof be sent to
the ISCC. |
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7.
Any bowler reported in accordance with this process
shall not be selected by the Federation as a bowler
for any national representative team until such time
as his action has been assessed in accordance with
paragraph J 6 above and in the event of such assessment
confirming that the bowler has an Illegal Bowling
Action, until such time as his action has been remedied. |
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8.
This process shall be adopted by each Regional Association
for all regional under 19 events. |
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K.
Member Federations Policy |
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Each
Federation shall formulate and implement a policy
and strategy to deal with bowlers with suspected Illegal
Bowling Actions in its domestic super-cricket. Such
policy and strategy shall as a minimum requirement: |
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1.
Establish a group of bowling advisors comprising the
following persons: An ex-international fast bowler,
an ex-international finger spinner, an exinternational
wrist spinner, an ex-international umpire and, if
available, a human movement specialist. The persons
appointed shall be the best available and shall preferably
have appropriate coaching experience. |
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2.
Establish a mechanism for identifying bowlers with
suspected Illegal Bowling Actions. Primary responsibility
for this shall be the umpires. In addition, for all
national age group tournaments, a bowling action review
panel (similar to the panel appointed in accordance
with J 2 above) shall be appointed by the Federation
to attend such tournaments with the task of identifying
any bowlers with suspected Illegal Bowling Actions. |
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Note:
Umpires and those responsible for identifying bowlers
with suspected Illegal Actions, in deciding whether
to call or report a bowler as set out above, should
use the naked eye viewing the action live and/or on
television at normal speed. Slow motion television
replays should only be used to confirm initial suspicions. |
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3.
Require that having identified a bowler with a suspected
Illegal Bowling Action, be it by way of an umpire's
report or otherwise, such bowler shall be referred
to the Federation's group of bowling advisors for
analysis and assessment. |
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4.
Require that any bowler reported in accordance with
this process shall not be selected by the Federation
as a bowler for any national representative team until
such time as his action has been assessed in accordance
with paragraph K 3 above and in the event of such
assessment confirming that the bowler has an Illegal
Bowling Action, until such time as his action has
been remedied. |
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Annexure
A |
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ISCC
Standard Analysis Protocols |
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Biomechanical
Analysis of a Bowling Action |
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1.
Introduction |
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1.1
The ISCC has introduced a revised process for the
review of bowlers with suspected illegal bowling actions
(Bowling Review Process). |
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1.2
In order for the Bowling Review Process to be conducted
in a fair and consistent manner the following standard
protocols for the collection of data and the assessment
and analysis of bowling actions have been introduced. |
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1.3
The overall purpose of the report is to confirm the
legality / or not, of the action of the player as
used in the match situation. Thus the protocols are
provided not only for how the action should be analysed
in the laboratory setting, but also highlight the
need for a detailed comparison between the action
performed during the match in which the player was
reported and the bowling action analysed in the laboratory. |
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1.4
The ISCC has determined that it is the degree of elbow
extension, as opposed to hyperextension or abduction
/ adduction that is prohibited. Elbow hyperextension
and elbow abduction / adduction are involuntary movements
that cannot be controlled by the individual during
the bowling action. (See Paragraph 5.3 & Appendix
A) |
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1.5
The conclusion of the report should be that having
analysed the action in the laboratory and having compared
it to the action as used in the supplied match footage,
in the opinion of the expert, the bowler has faithfully
reproduced his match technique in the laboratory.
A statement concerning the legality of the action
with respect of the amount of elbow extension measured
and the 15 degree elbow extension tolerance threshold
should then follow. |
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2.
Video Footage from Match in which Player Reported |
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2.1
The television video footage of the entire bowling
spell(s) of the player in the match where the report
was made shall be presented on a master tape. (ISCC
to supply match footage) |
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2.2
The master tape shall be converted to 50HZ / 60Hz
(standard television footage is recorded at 25HZ)
to enable more accurate evaluation of the player's
bowling action on the day the bowler was actually
reported. |
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2.3
Descriptive analysis during the match footage should
compare the actions of the bowler e.g. positioning
of feet, angle of run up, position of the torso, velocity
of arm, velocity of delivery (95% of match speed etc).
These comparisons should be clearly presented in the
report. |
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3.
Anthropometric Assessment (Both the bowling & non-bowling
arms) See Appendix A |
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3.1
Carry Angle: The angle between the longitudinal axis
of the upper arm and forearm, in the frontal plane.
Note: The average range of carry angle for the human
population is between 5º-15º. |
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3.2
Hyperextension Angle: The angle between the longitudinal
axis of the upper arm and forearm, in the sagittal
plane. (i.e. beyond full normal extension): Two measurements
are required: a passive measurement, were there is
no force applied and a second measurement where 'reasonable'
force is applied. When the second measurement for
the hyperextension angle is measured, the bowler is
required to extend his arm back as far as possible.
This is achieved by applying a 'reasonable' force,
essentially the body weight of the bowler, leaning
on each arm. |
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3.3
Additional Physical Measurements: Height, weight and
assessment of general mobility of the shoulder, elbow
and wrist joints. |
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3.4
History of Previous Injuries: A brief history of previous
injuries should be determined as an aid in the biomechanical
assessment - particular focus should be brought to
the elbow and shoulder joints. |
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4.
Bowling Analysis (Indoors - Laboratory conditions) |
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4.1
All biomechanical assessment shall be carried out
with the player bowling off his normal full run-up,
on a correct length super-cricket pitch. |
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4.2
A minimum of three synchronised cameras (using optio
reflective markers) operating at a minimum of 200
frames per second and a maximum of 250 frames per
second (preferable) should be used to collect the
data. The cameras and computer to be operated and
positioned in appropriate positions to facilitate
a subsequent three-dimensional analysis of the shoulder,
elbow, wrist and ball. |
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4.3
Video data (50fps) should also be collected in order
to allow synchronization with the 'optio reflective
computer animation data'. A minimum shutter speed
of 1000Hz is required to prevent blurred images. |
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4.4
Calibration and accuracy procedures must be undertaken
in the delivery space prior to data collection. Accuracy
analysis should indicate that the 3D methods employed
are accurate to within ±1° (Note: A rigid bar (1m
in length), with markers representing the shoulder,
elbow and wrist (180º) can be used in the calibration
procedures. The rod must be rotated in the same manner
as a bowling arm. This should be repeated using a
rigid bar representing a 160º angle. Accuracy analysis
should again indicate that the 3D methods employed
are accurate to within ±1°). |
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4.5
Optimal "levels of filter" must be used in the laboratory
process. Ideally a laboratory environment using opto-reflective
marker system will produce the environment with the
least amount of error (Noise) and therefore less filtering
can be used. This value or cut off frequency is calculated
via the residual analysis method (See Appendix B) |
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4.6
Warm up (player's own) - but must include the bowling
of a number of deliveries at match pace prior to data
collection. The player to have no clothing on the
torso, in order to enable the correct marker set to
be placed on the bowling arm. (See Appendix C) Automatic
digitisation of the marker set will enable joint centres
to be determined during each delivery. |
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4.7
In respect of a fast bowler, fivex 'normal' - good
length deliveries, five 'yorkers' and five 'bouncers'
must be recorded. Five deliveries of each spin variation
for the leg or off spin bowler must be recorded. Standard
video cameras should be used to assess the position
the ball lands, along with the amount of bounce and
turn created with each delivery. This video should
also be presented in the report. |
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4.8
Three-dimensional analysis of the bowling arm to begin
from back foot contact, to include 'arm horizontal'
, maximum flexion, ball release and a minimum of 10
frames after ball release for each successful delivery. |
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4.9
The UPPER Arm is in the horizontal position in Figure
1b. "The horizontal position" i.e. The upper arm being
level with shoulder and parallel to the ground. |
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4.10
The point of release is defined as the FIRST frame
the BALL and HAND are NOT in contact. This is important
as the exact time (frame - 250Hz) of release can potentially
change results by three or four degrees. A marker
(a piece of reflective tape) on the ball, a change
in velocity of the ball, along with 50Hz video may
all help with this process. |
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Figure
1a: Arm Horizontal - NO Figure 1b: Arm Horizontal
- YES |
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4.11
Every effort must be made to ensure that the player
is bowling as close to match pace as possible. This
can be measured after each delivery if the equipment
is available (Radar Gun), or measured via the 3D data
during analysis. If deliveries are not at a suitable
speed (so as to represent match conditions) then the
data shall be invalid. |
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5.
Presentation of Results |
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5.1
A summary of the results of each delivery to be presented
- graphical or table format. |
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5.2
The presentation of the three-dimensional analysis
of the bowling arm to begin from a minimum of 10 frames
before the arm reaches horizontal, , to include 'arm
horizontal', 'maximum flexion', 'ball release' and
a minimum of 10 frames after ball release. |
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5.3
The 'flexion-extension' and the 'abduction-adduction'
curves should be presented separately. This data should
be presented in graphical form. (The hyperextension
component will show up in the flex-ext curve if it
is present and there is no need to separate it. If
it is present it will be shown as the curve going
beyond 180 degrees or below 0 degrees, depending on
which represents "straight arm") |
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5.4
The five trials for each type of delivery (e.g. Bouncer
/ Normal Length / Yorker), along with the average
should be plotted on the same graph to show conformity. |
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5.5
The average of the different types of delivery (e.g.
Bouncer / Normal Length / Yorker) to be displayed
along with the standard error reading. |
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5.6
Ball release speeds to be presented for each delivery.
|
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5.7
Stick figure representation, to include pictures of
the various key positions to aid in the presentation
of the results. (Alternatively, an avi file may be
provided.) |
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6.
Acceptable level of Elbow Extension |
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This
should be set at a maximum of 15 degrees 'Elbow extension'
for all bowlers and types of deliveries. This specifically
refers to extension of the forearm relative to the
upper arm to the straight position. Elbow hyperextension
or adduction is not included in the 15-degree tolerance
threshold. |
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Appendix
A: Movements. |
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Flexion
- This movement takes place about a transverse axis
and is a description of the movement that occurs when
you move your arm forward. It is described as the
approximation (moving closer together) of two ventral
surfaces of the body e.g. flexing the elbow joint.
There are a number of situations where this rule doesn't
seem to apply e.g. at the ankle where the terms dorsi
and plantar flexion are used to avoid confusion. |
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Extension
- This movement is the opposite of flexion; it also
takes place about a transverse axis and occurs when
you approximate two dorsal surfaces e.g. straightening
the elbow. |
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Hyperextension
- An abnormal movement beyond the normal limit of
extension, such as more than the 180 degrees of extension
of the knee or elbow joints. |
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Abduction
and Adduction - These movements take place about an
antero-posterior axis and occur when the arm is taken
sideways away from the body (abduction) and returned
from such a position to the side of the body (adduction). |
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Appendix
B: Filter Level. |
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When
measurements are made using image-based analysis systems
(Video and/or Automatic Tracking) they are contaminated
with 'Noise' generated during the recording and digitising
procedures. The sample signal can be considered to
be the sum of the true signal, systematic noise and
the random noise. The 'TRUE' signal can never be deduced
from the measurements; only the best estimate of the
signal. |
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There
have been a number of techniques developed for the
reduction of noise, including Butterworth filters,
Quintic splines and cross-validated splines. Each
of these techniques uses a mathematical function to
approximate the data. The precise frequency components
of the true signal are rarely known in sports biomechanics
and some procedures must be adopted for the determination
of the cut-off filter, or other smoothing parameter.
The less noise in the system, the closer the raw data
will represent the 'TRUE' signal, and the less smoothing
will be required. |
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Ideally
a laboratory environment using opto-reflective marker
system will produce the environment with the least
amount of error (Noise) and therefore a lower filtering
value can be used. Optimal "levels of filter" must
be used in the laboratory process. This value or cut
off frequency is to be calculated for all bowling
analysis using the residual analysis method. |
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Previous
work in this area has identified a Butterworth digital
filter level of 12 - 14 Hz and a Woltring MSE of 20
- 25 cine appropriate. However a residual analysis,
should be conducted for the bowler being analysed
to derive the optimum filter level for the current
data. Any significant different optimum filter level
derived from the above values needs to be well justified
and documented. Raw data should be graphed with filtered
data and inspected by the expert to ensure the filtered
curve closely reflects the raw data. These should
be presented in the appendix to the report as background
technical information for each analysis. |
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Appendix
C: Marker Set |
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Super-Cricket
Upper Limb Model |
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The
following guidelines are established to ensure conformity
of elbow joint data across laboratories. Establishment
of joint centres at the shoulder, elbow and wrist
joints are therefore integral to this process. |
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Shoulder
Joint |
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This
joint centre should be determined from the recording
of markers anterior, posterior and superior (acromion
process) to the "joint centre of rotation". The anterior
and posterior markers should be placed such that a
line between the two represents the shoulder axis
of rotation (approximate midline of the upper arm).
The shoulder joint centre (SJC) is then calculated
as the centre of these three markers or from where
a vertical line dropped from the acromion intersects
the line between the anterior and posterior markers. |
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The
position of the calculated SJC is then recorded in
a static trial relative to the coordinate system of
the triad located on the upper arm. During a bowling
trial the SJC can then be reconstructed relative to
the position of the upper arm triad during every frame.
Optimisation or helical axis techniques may be used
to calculate the shoulder centre, which may modify
the markers used about this joint. |
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Elbow
Joint |
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The
elbow joint centre may be calculated using markers
placed on the lateral and medial elbow epicondyles
or using "epicondyle pointer trials" with the elbow
flexed to 90°. If a marker based approach is used
the markers should be as small as the resolution of
the opto-electronic camera system will allow. Generally
markers no bigger than 15mm in diameter are preferable.
The position of the epicondyles should be reported
with reference to a triad of markers placed on the
upper arm. The elbow joint centre is then calculated
as the mid point between these two re constructed
epicondyle virtual markers. This means that no joint
markers are required during bowling trials to reduce
errors associated with skin movement. The cameras
only need to track the upper arm triad during the
bowling action to know where the elbow and shoulder
joint centres are. |
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Wrist
Joint |
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The
wrist joint centre may be calculated using "pointer
trials" or by placing markers on the styloid processes
at the wrist during a static trial. If a marker based
approach is used the markers hould be as small as
the resolution of the opto-electronic camera system
will allow. Generally markers no bigger than 15mm
in diameter are preferable. The position of the styloid
processes should be calculated as reference points
(i.e. three-dimensional co-ordinates) to a triad of
markers placed on the forearm. This triad needs to
be placed relatively close to the wrist joint centre
to avoid excessive skin movement during pronation
/ supination. The markers on the styloid processes
can then be removed prior to bowling data collection.
The wrist joint centre is then calculated as the mid
point between the styloid process markers or landmarks
from the pointer trials. |
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