1. Acknowledgements Dr. M. Lamontagne & Dr. D. Benoit (Human Movement
Biomechanics Laboratory U Ottawa) & M. Haefele (Research Assistant)
[1] A. Tözeren, Human body dynamics: classical mechanics and human movement. New York: Springer, 2000.
[2] Chris Kirtley, Clinical gait analysis theory and practice. Edinburgh: Churchill Livingstone, 2006.
[3] A. M. Gal, D. C. Hay, and A. D. C. Chan, “2 and 3-dimensional biomechanical analysis of the linear stroking cycle in the
sport of sledge hockey (Glenohumeral joint kinematic, kinetic and surface EMG muscle modeling on and off ice),” in 13th
International Symposium on 3D Analysis of Human Movement, 2014, pp. 108–111.
[4] Hockey Canada, “Sledge hockey coaching resource.” 2009.
[5] Vicon Motion Systems Ltd., Nexus. U.K.: Vicon Motion Systems Ltd.
[6] BTS Bioengineering, “BTS Wireless sEMG,” BTS Bioengineering, 2016. [Online]. Available:
http://www.btsbioengineering.com/.
[7] Bertec Corp., “Bertec Force Plate,” Bertec, 2016. [Online]. Available: http://bertec.com/products/force-plates/.
[8] Kistler Instrument Corp., “Kistler Force Plate,” Kistler: measure. analyze. innovate., 2016. [Online]. Available:
https://www.kistler.com/ca/en/.
[9] J. R. Potvin and S. H. . Brown, “Less is more: high pass filtering, to remove up to 99% of the surface EMG signal power,
improves EMG-based biceps brachii muscle force estimates,” J. Electromyogr. Kinesiol., vol. 14, no. 3, pp. 389–399, Jun. 2004.
[10] MathWorks, MATLAB. The Mathworks Inc., 1994.
REFERENCES & ACKNOWLEDGMENT
Pick-Plant Stick Angles Push-Off Stick Angles
Respective Torso Angles
Improving skating, a repetitive cyclical seated
weight-bearing locomotion
↑ player skill level
↑ sport-specific development
↓ risk for potential injury
Provided by understanding key differences
between motion production (if they exist):
At rest
Continuous motion
Skating is the foundational skillset & only
mechanical method for motion production in
sledge hockey
Bilateral forward skating is typically produced
with a flexed torso by elite players
Flexed torsos create the possibility
for more horizontal pick-plants
Mechanically producing ↑
forward force transfer
Task naïve population displays > observable
differences when a task ↑ in difficulty
Ability to flex the torso during skating is
predicted to be ∝ to skill level
∴ Optimal skating is more likely to be achieved
in elite players
Figure 4 (←). Study-specific 4
force plate design centrally
located within a 10 camera
MOCAP system. Participants
were equipped with 5 bilateral
upper torso/limb surface
electromyography (sEMG)
electrodes. sEMG were not
analyzed in this study.
Differences between sagittal plane static start and mid-cycle stroke biomechanics during
skating for the sport of sledge hockey:
Task naïve population
Gal A.M. 1, Chan A.D.C. 1 & Hay D.C. 21 2
1. INTRODUCTION SKATING
4. Discussion / Conclusion
3. RESULTS
Muscular energy
transfers into
forward propulsion,
a result of picks
digging into ice
surface
Identify sagittal plane biomechanical difference(s)
between
strokes at peak resultant force for
during skating off-ice, if they exist.
OBJECTIVE
Muscular force
produced from the
torso & each arm
Transmits along the
respective stick to
pick-surface interface
start cycle (SC) mid-cycle (MC)
pick-plant push-off
Figure 1 (↑). Off-ice study-specific modified on-ice sledge. Modifications
include: A) two youth size rollerblade chassis, each with two 65 mm wheels
(ABEC 5) in the front and backmost positions, B) front support wheel, and C)
telescopic leg-rest design allowing for 2” increment adjustments to a max of
15”.
Figure 2 (←). SC sagittal plane start
position. Post “Go”, participant
initiated initial contact phase was
acquired as they propelled
themselves and sledge through the
remaining MOCAP system (max 2
strokes to a coasting stop).
(independently & bilaterally)
2. METHODOLOGY
Improve Energy Transfer ↔
Improve Skating
Figure 3 (→). MC sagittal plane start
position. Post “Go”, participant
initiated 2nd or 3rd contact phase was
acquired as they propelled
themselves and sledge through the
remaining MOCAP system (max 4
strokes to a coasting stop).
5 adult male able-bodied athletes
Sledge hockey & poling sport naïve
Asymmetrical bilateral skating predicted
(< optimal)
Study-specific design acquired left, right & sledge-
body ground reaction forces (2000 Hz)
3 useable trials / effort test (good force plate
contact) for both SC and MC strokes
Submaximal efforts (Sub Max)
Maximal efforts (Max)
2 participants performed one additional MC
maximal effort test (coin-flip variation)
Data were processed offline using MATLAB
Low pass zero-lag 2nd order Butterworth filter
(12 Hz) applied against motion capture
(MOCAP) raw signals (250 Hz)
A
B C
‘C’ like spine curvature indicated that torso analysis
should be further segmented into the respective
regions in future research
More linear posture is predicted for elite
Stick contact ∡ were more vertical
↓ performance output
↑ risk for potential injury (↑ compressive forces)
∴ Instructional strategies involving proper torso
positioning on and off-ice are recommended for
naïve & introductory skill levels
↑ comfort in producing a flexed torso
↑ a player’s ability to extend the arms
↑ horizontal stick ∡ during
contact
↑ skating skill level
↓ bilateral asymmetry also ↑ energy transfer
↑ SC push-off technique to optimize movement
initiation
Figure 5 (↑). MOCAP and video recording results indicated naïve
sledge hockey players presented a more upright lumbar region with
a ‘C’ like curvature presented throughout the thoracic region. Elite
players are predicted to present a more linear upper torso with less
deviation between spinal column regions.
SC Torso ∡ ≈ MC Torso ∡ at
pick-plant
Sub Max Torso ∡ ≈ Max Torso ∡
SC Torso ∡ more vertical MC Torso ∡
at push-off
Left Stick ∡ ≈ Right Stick ∡ ∀ tests
Lumbar
Thoracic
Figure 6 (↑). MOCAP results indicated naïve sledge hockey players presented a more
vertical stick angle during the entire contact phase. Optimal propulsive energy transfer
occurs from a more horizontal contact phase; one example is presented (grey & navy).