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The effects of ball carrying on sprint mechanics: An insight into the technical demands of rugby

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Abstract and Figures

Sprinting ability is fundamental to success in rugby, where athletes are repetitively required to accelerate and occasionally reach maximal velocities while carrying a ball. Despite this, the mechanical influences of ball carrying are not understood. The aim of this study was to examine the effects of ball carrying technique on sprint performance and underlying mechanics. Sprint kinetics were collected with a radar gun on 16 male rugby athletes during three maximal 40-m sprints under three conditions: no ball, ball in two hands and ball in one hand. Carrying a ball in two hands produced similar mechanics to no ball over acceleration while carrying a ball in one hand had advantageous alterations at maximal velocity. A new sprint training protocol is proposed based on these findings.
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The effects of ball carrying on sprint mechanics:
An insight into the technical demands of rugby
Scott R Brown1, Kim Simperingham1, Jean-Benoît Morin1,2
1 Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, NZL
2 Laboratory of Human Motricity, Education Sport and Health (LAMHESS), University of Nice Sophia Antipolis, Nice, FRA
This project…
Parallel to PhD research at Auckland University of Technology (NZL)
Collaboration with University of Nice Sophia Antipolis (FRA)
Collaboration with Nelson Marlborough Institute of Technology (NZL)
Collaboration with Tasman Rugby Academy (NZL)
Recap from ISBS 2015 in Poitiers
Applied Session: Sprint acceleration Biomechanics
by Prof Jean-Benoît Morin and Dr Steffen Willwacher
“Gold nuggets”
A radar device can measure sprint performance
Simple, valid & reliable
Sprint effort broken down
mechanical & technical characteristics
New technical variables provide the how & what
Maximal ratio of force (RFmax)
Slope/rate of decrease in RF (DRF)
Morin, J.-B., & Samozino, P. (2016). Interpreting power-force-velocity profiles for
individualized and specific training. International Journal of Sports Physiology and
Performance,11(2), 267-272.
Timing-splits
What (time)
Radar
What & How (v, FH, Pmax )
Radar vs timing-splits
Time (s)
0
1
2
3
4
5
6
010 20 30 40
Radar Timing lights
0
2
4
6
8
10
12
14
16
18
20
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 4 5
Force (N∙kg-1)& Power (W∙kg-1)
Distance (m)Time (s)
Velocity (m∙s-1)
Haugen, T., & Buchleit, M. (2016). Sprint running performance monitoring:
Methodological and practical considerations. Sports Medicine,46(5), 641-656.
Sprinting in rugby
Short-distance (≤ 20-m): Acceleration
Theoretical force (F0), maximal power (Pmax) & RFmax
Longer-distance (> 20-m): Maximal velocity
Theoretical maximal velocity (v0) & DRF
Sprinting is an essential skill
Universally trained
Specifically requires a ball
Morin, J.-B., Edouard, P., & Samozino, P. (2011). Technical ability of force application as a determinant
factor of sprint performance. Medicine and Science in Sports and Exercise, 43(9), 1680-1688.
Sprinting in rugby
Purpose
Add to our understanding of the how instead of just the what
Examine the mechanical and technical determinants of ball
carrying during sprinting.
Methods
Characteristics
16 male academy rugby
19 ± 1 years
1.8 ± 0.1 metres
94 ± 9 kilogrammes
Controls
Rubberised athletics track
Standard athletic footwear
Protocol
Dynamic warm-up
Three build-up sprints
60, 80 & 90%
Three maximal 40-m sprints
Randomised
No ball (NB)
Ball in two hands (TH)
Ball in one hand (OH)
Sprinting in rugby
Data processing
Samozino, P., Rabita, G., Dorel, S., Slawinski, J., Peyrot, N., Saez de Villarreal, E., &
Morin, J.-B. (2016). A simple method for measuring power, force, velocity
properties, and mechanical effectiveness in sprint running. Scandinavian Journal
of Medicine and Science in Sports,26(6), 648-58.
0
1
2
3
4
5
6
7
8
9
10
0123456
Time (s)
Velocity (m∙s-1) & Acceleration (m∙s-2)
Data processing
0
2
4
6
8
10
12
14
16
18
20
0
2
4
6
8
10
012345678910
Relative horizontal power (w·kg-1)
Relative horizontal force (N·kg-1)
Velocity (m·s-1)
Samozino, P., Rabita, G., Dorel, S., Slawinski, J., Peyrot, N., Saez de Villarreal, E., &
Morin, J.-B. (2016). A simple method for measuring power, force, velocity
properties, and mechanical effectiveness in sprint running. Scandinavian Journal
of Medicine and Science in Sports,26(6), 648-58.
v0
Pmax
F0
Data processing
Samozino, P., Rabita, G., Dorel, S., Slawinski, J., Peyrot, N., Saez de Villarreal, E., &
Morin, J.-B. (2016). A simple method for measuring power, force, velocity
properties, and mechanical effectiveness in sprint running. Scandinavian Journal
of Medicine and Science in Sports,26(6), 648-58.
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
Ratio of force (%)
Velocity (m·s-1)
DRF
RFmax
Results
No ball
Ball in two hands
Ball in one hand
Timing splits
2m (s)
0.79 ±0.03 0.79 ±0.03 0.81 ±0.04 ‡
5m (s)
1.35 ±0.05 1.35 ±0.04 1.37 ±0.06 ‡
10m (s)
2.07 ±0.07 2.09 ±0.06 2.11 ±0.08 ‡
20m (s)
3.33 ±0.10 3.35 ±0.10 3.38 ±0.12 ‡
30m (s)
4.51 ±0.13 4.55 ±0.14 † 4.56 ±0.15 ‡
40m (s)
5.67 ±0.17 5.72 ±0.19 † 5.73 ±0.19 ‡
30
-40m (s) 1.16 ±0.05 1.17 ±0.05 † 1.17 ±0.04
Mechanical
F
0(N·kg-1)8.1 ±0.8 8.0 ±0.7 7.7 ±0.8 ‡
v
0(m·s-1)9.02 ±0.43 8.90 ±0.45 ‡ 9.02 ±0.39
P
max (W·kg-1)18 ±218 ±217 ±2 ‡
RF
max (%) 52 ±352 ±251 ±3 ‡
D
RF (%) -8.1 ±1.0 -8.2 ±0.8 -7.8 ±0.8
In short…
Sprinting with a ball in one hand
Negatively affects acceleration (~0-20m)
F0, Pmax, RFmax & DRF
ES = -0.43, -0.45, -0.47 & 0.33
%Δ= -4.5, -4.4, -2.3 & -4.1%
Sprinting with a ball in two hands
Negatively affects maximal velocity (~>20m)
V0
ES = -0.26
%Δ= -1.3%
Discussion
Balance during acceleration
Arms move in opposition:
forward and backward sagittal plane motion
Counterbalance hip rotation
Barr, M. J., Sheppard, J. M., Gabbett, T. J., & Newton, R. U. (2015). The effect of
ball carrying on the sprinting speed of international rugby union players.
International Journal of Sports Science and Coa ching, 10(1), 1-9.
One hand may present
an asymmetry:
One arm drives sagittally
One arm drives laterally
across the body
Uneven torso rotation
Discussion
DRF unavoidable
Maximal velocity
Describes ability to delay effectiveness
More ive = faster effectiveness
Ball in one hand
Maintain net FH
v0compared to two hands
Morin, J.-B., & Samozino, P. (2016). Interpreting power-force-velocity profiles for
individualized and specific training. International Journal of Sports Physiology and
Performance,11(2), 267-272.
0.0%
Maximal velocity
Conclusions
Sprinting with a ball (one / two)
negatively affects split-times
However a ball is essential in rugby
Advantageous characteristics from each
method can be gained
Practical applications
010m 20m 30m 40m5m
Start and accelerate Continue to maximal velocity
Transfer
Practical applications
Theoretically:
1. Maintains F0, v0, Pmax , RFmax & split times
2. Replicates true maximal sprinting
3. Potentially improves effectiveness (DRF)
4. Provides rugby specific technical training
(i.e. ball handling)
ありがとうございまし
Thank you
scott.brown@aut.ac.nz
@scottiehype
scott_brown12
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