Validating a Solid-Static Single-Armed Male Prototype Tasked to Produce Dynamic Movement from the Shoulder Through the

Preparation Phase A.M. Gal1, A.D.C. Chan1 and D.C. Hay2

1 Ottawa Carleton Institute Biomedical Engineering – Carleton University Canada 2 School of Physical and Health Education – Nipissing University Canada

PURPOSE

to design, implement, and validate a methodology to determine baseline measures during the preparation phase (PREP) of seated

weight-bearing locomotion

Upright VS Seated Double Poling

1)  contact phase known as propulsion

2)  return phase of the cycle known as recovery

3rd phase introduced known as preparation

a)  shorter pole length Full arm extension to plant

b)  longer pole length Pick-off to start of swing return

Propulsion

Shoulder

short pole

long pole forward

cycle

PP: poling phase TP: transition phase RP: recovery phase

Why was this Phase Introduced?

Observable changes in sledge movement in con-junction with biomechanical trends

However, currently the direct benefit of this additional phase is unclear to the overall

biomechanics of the complete cycle

Propulsion in Sledge Hockey: A Biomechanical Analysis to Define Gait

Gal A.M., Chan A.D.C. & Hay D.C.

In the sport of sledge hockey movement is created by a forward cyclical weight-bearing shoulder-dependent motion. This motion is known as propulsion, and in its simplest form (a linear stroking pattern) gait for the shoulder joint can be defined. Gait has become the foundation for weight-bearing hip-dependent motion having a standardize definition for analysis. Hip-dependent gait is defined by contralateral movements consisting of steps and strides, where propulsion in sledge hockey is a double-poling cycle or bilateral movement and will consist of only strides; however, analysis of left vs right cadence will be observed. Propulsion in sledge hockey reflects similar movements seen in walking and running, and by using 3-dimensional motion analysis with reference to hip-dependent gait, evidence supporting the definition of gait for a forward cyclical shoulder-dependent motion can be acquired. Previous evidence for seated shoulder-dependent sports outlines three distinct phases within the stroking cycle known as preparation, propulsion and recovery (Fig 1) compared to two distinct phases in standing poling sports; propulsion and recovery. Evidence for shoulder-dependent gait using sport-specific terminology will also assist with a deeper understanding of the exact importance of the preparation stage seen in seated shoulder-dependent propulsion. Segmented data will illustrate the co-ordination of the primary musculature involved in creating this tri-planar movement. The shoulder joint was designed to promote the largest range of motion in turn leaving its stability vulnerable. This vulnerability foreshadows that mobility could supersede stability causing structural failure. For shoulder-dependent populations this could be detrimental leading to a stationary lifestyle until healed. Kinematic and kinetic analysis of upper body musculoskeletal movement during linear propulsion may reveal etiology-specific locomotor patterns that may provide insight for enhancing protection and structural soundness of this joint. Sports with high-impact, high-velocity shoulder-dependant movements, such as sledge hockey, invite a risk for increased trauma onto this joint. Unlike able-bodied sports, sledge hockey has a diverse range of physical abilities due to congenital and/or injury-induced impairments. By combing 3-dimensional motion analysis with muscular activity, sport-specific advancements can be made aiding in athletic performance, skill development, injury prevention and rehabilitation.

INTRODUCTION PHASES OF PROPULSION

This study examines the linear stroking pattern found within the sport of sledge hockey, known as propulsion, to assist in defining gait for the shoulder joint in a forward cyclical weight-bearing motion.

PURPOSE

Figure 1. An illustration depicting previously outlined stages of propulsion for seated shoulder-dependent sports such as sledge hockey; preparation (PREP), propulsion (PRO) and recovery (REC). PREP is defined as full arm extension to pick-plant; PRO from pick-plant to pick-off; and REC from pick-off to full arm extension. A single cycle occurs between two identical consecutive phase exchanges (REC-PREP1 to REC-PREP2).

Participants in the study are healthy elite adult male sledge hockey players medically diagnosed with a physical impairment, and healthy able-bodied physically active adult males with no or limited knowledge of the physical tasks. An indoor 3-dimensional motion capture system (Vicon) with artificial ice surface (bladed-sledge) or rubber matted flooring (wheeled-sledge) will be used in conjunction with surface electromyography (sEMG) electrodes and force plates. Primary superficial movers and stabilizers for shoulder-dependent weight-bearing locomotion included the biceps brachii, deltoid threesome (anterior, medial, posterior), latissimus dorsi, pectoralis major, trapezius and triceps brachii. A note should be made that the rotator cuff is ultimately the primary stabilizer for the shoulder joint; however the deep location of this four muscle cuff presents issues for sEMG acquisition during dynamic movements. Ground reaction forces (GRF) from pick-plant to pick-off will be acquired from force plates in an offset ‘t’ formation isolating the left and right sticks, and sledge/participant data. Anthropometric measurements for 3-dimensional reconstruction, and impairment history will be collected. Participants propel themselves through the 3x3x2 m capture zone making precise force plate contact with submaximal and maximal efforts, followed by stationary start-propulsion on the force plates through the remaining capture space, again with submaximal and maximal efforts. A minimum of 3 useable trials are required for each of the four tests, and a minimum of 2 minutes rest is allotted between trials. Baseline parameters are defined by a using a solid-static wood model mimicking the average male upper torso with a single arm; the shoulder joint being the only dynamic element. The linear stroking pattern is defined as placing the sledge stationary outside the capture zone (at the marking indicated for precise force plate contact), on a random whistle the participant will propel themselves through the capture zone to the finish marker outside of the capture zone. The start-linear stroking pattern is defined as placing the sledge stationary on the force plates inside the capture zone (at the marking indicated for precise force plate contact), on a random whistle have the participant propel themselves through the remainder of the capture zone to the finish marker outside of the capture zone.

METHODOLOGY

Figure 2. Illustrations of sport-specific exchange points segmenting the stages of propulsion through on-ice (top), off-ice (middle) and motion capture (bottom) analysis; REC-PREP (left), PREP-PRO (middle) and PRO-REC (right).

A wheeled-sledge pilot study from a single unfamiliar participant has suggested that propulsion in sledge hockey is a posteriorly driven motion with dominant contribution from the triceps brachii, followed by the latissimus dorsi then posterior deltoid. Findings have also suggested that the biceps brachii produced almost no force at all. Marker trajectory from this pilot study suggested that the wrist, blade and joint of the stick move in an almost identical fashion prompting further research analyzing forearm musculature. Evidence from the pilot study are this study’s guidelines used to provide 2 and 3-dimensional kinematic and kinetic evidence of the linear stroking cycle for the sport of sledge hockey, using sport-specific analogy to provide a complete illustration of this cyclical weight-bearing movement.

Pilot Study

REFERENCES & ACKNOWLEDGMENT Acknowledgment: M. Lamontagne & B. Hallgrimsson [1] A.M. Gal, D.C. Hay, A.D.C. and Chan, “2 and 3-Dimensional Analysis of the Linear Stroking Cycle in the Sport of Sledge Hockey: Glenohumeral Joint Kinematic, Kinetic and surface EMG muscle Modelling On and Off Ice,” International Symposium: 3D Analysis of Human Movement, poster, 2014. [2] K.  Lomond,  and  R.  Wiseman,  “Sledge  Hockey  Mechanics  Take  Toll  on  Shoulders:  Analysis  of  Propulsion  Technique  can  Help  Experts Design  Training  Programs  to  Prevent  Injury,”  J Biomechanics, vol. 10, no. 3, pp. 71-76, 2003. [3] L. Gastaldi, S. Pastorelli, and S. Frassinelli,  “A  Biomechanical  Approach  to  Paralympic  Cross-Country Sit-Ski  Racing,”  Clin J Sports Med, vol. 22, pp. 58-64, 2012. [4] H.  Holmberg,  et  al.,  “Biomechanical  Analysis  of  Double  Poling  in  Eltie Cross-Country  Skiers,”  Med & Sci in Sports & Exerc, vol. 37(5), pp. 807-818, 2005. [5] C.G.  Gordon  et  al.,  “2010  Anthropometric  Survey  of  U.S.  Marine  Corps  Personnel:  Methods  and  Summary  Statistics,”  U.S. Army Natick Solider Research, Development and Engineering Center, NATICK/TR-13/018, 2013. [6] H.E.J. Veeger, and F.C.T. van der Helm, "Shoulder Function: The Perfect Compromise Between Mobility and Stability," J Biomechanics, vol. 40, pp. 2119-2129, 2007. [7] J.A. Nyland, D.N.M. Cabora, and D.L. Johnson, "The Human Glenohumeral Joint: A Proprioceptive and Stability Alliance," Knee Surg, Sports Traumatol, Arthrosc, vol. 6, pp. 50-61, 1998. [8] J. Jerosch, and M. Prymka, "Proprioception and joint stability," Knee Surg, Sports Traumatol, Arthrosc, vol. 4, pp. 191-179, 1996. [9] C.R. Ethier, and C.A. Simmons, Introductory Biomechanics: From Cells to Organisms, Cambridge UK: Cambridge University Press, 2007. [10] C. Kirtley, Clinical Gait Analysis: Theory and Practice, UK: Elsevier Churchill Livingstone, 2006.

Figure 3 is a foam blueprint of the solid-static baseline model. A nylon string will be used to create the shoulder angle from mid-neck to centre of gravity of the upper arm. From there the string will be released; the downward poling motion will be captured and GRF recorded upon impact. Since the model mimics the average male body segments, kinematic and kinetic evidence can be used as neutral muscular activity (no additional force production). In comparison to participant data baseline parameters will assist in supporting or dismissing assumptions made for the internal mechanics of the human arm, and assist in the analysis of the preparation phase. Baseline parameters will investigate the GRF from a combination of wrist/stick, elbow and shoulder angles in the downward poling motion. Ranges outlining stick angle for pick contact, shoulder extension and elbow flexion will be determined and used for comparison from participant data.

BASELINE MEASURES This study aims to provide descriptive support for kinematic and kinetic 2 and 3-dimensional analysis of the shoulder joint during a double poling motion, specifically propulsion in the sport of sledge hockey. Biomechanical analysis will provide detailed information regarding the primary movers and stabilizers of the shoulder joint during this stroking cycle to gain a more in depth understanding of the biomechanics required to perform such weight-bearing tasks and their affects onto the joint. A control group of unfamiliar abled-bodied participants along with baseline parameters should validate the performance of expert physically-impaired individuals. Sport-specific evidence supporting the theory that propulsion is a posteriorly driven movement is an anticipated finding. Contributions of this research will provide a sporting community in desperate need of scientific evidence guidelines to base program development and education. Data collected from this study will provide stroking pattern information, body position and muscle activation during each phase of the cycle for both the linear-stroking cycle, and the start-cycle. In addition to assisting this vastly growing Paralympic sport, data acquired can present information transferable to shoulder-dependent populations to improve with their quality of life. Information defining gait in a forward cyclical motion can assist the general population in the same manor as it does for the beginner or expert athlete. Overusing a joint in a fashion it was not mechanically designed for can almost guarantee minor trauma as a result; an on-set for future major issues. By understanding the biomechanics of this motion rehabilitative and developmental protocols can be improved and/or developed. The presentation of data is designed to increase the quality of life for this special population, in turn providing a developing sport some guidance. In conclusion, sport-specific analysis will provide the opportunity to gain a deeper understanding of the exact importance of the preparation stage during seated-propulsion, as well as provide segmented data observing the co-ordination of the musculature involved in the linear stoking cycle for the sport of sledge hockey.

Discussion

Figure 3. The average male upper torso solid-static baseline model foam blueprint.

The Connection to Society able. If triceps function is limited, the generationof friction in a downward or outward direction ishampered. Therefore, the inwards-directed latero-medial force component can serve as an effectivealternative for friction generation.The finding that elite athletes show FEF values

well under 100% (table II) suggests that the non-tangential force direction recorded is not the resultof insufficient experience or poor proficiency.Never-theless, the strategy of force application, that is, thedistribution of forces over the push angle, is de-pendent on the proficiency of the wheelchair user.[8]Changing the external conditions will change the

direction of force application: FEF parameters de-creasewith speed[37,51] and are in general lower under

maximal speed conditions compared with steady-state wheeling (table II). However, the maximalspeed conditions in table II involved aWingate an-aerobic test (WAnT) with supplementary resistanceon the rear wheels. Therefore, a straightforwardconclusion about the underlying parameter of FEFchanges cannot be made.Boninger et al.[11] calculated the maximal rate of

rise of Ft, Fr and Fy from the corresponding force-versus-time curves. These parameters were chosento identify possible impact spikes and were assumedto represent values that could be related to injurymechanisms. For most strokes analysed by Bonin-ger et al.,[11] there was an impact spike in the radialdirection following first hand contact. The rate of

Wrist

Elbow

Shoulder

Effectiveforce

direction

Wrist

Elbow

Shoulder

Actualforce

direction

Joint torqueDirection of joint rotation

Fig. 3. The relationship between force direction and calculated net joint torques around shoulder and elbow (from Veeger et al.,[52]with permission).

Wheelchair Propulsion Biomechanics 351

Adis International Limited. All rights reserved. Sports Med 2001; 31 (5)

Population that is shoulder dependent for daily mobility

Overloading and/or overuse of a joint not designed for weight-bearing

tasks

Solid-Static System - Limb

Limb morphology replicated average male 80kg

US Marine Corp & AR Tilley’s – The Measures of Man and Women

Isolated shoulder as pivot point (dynamic)

Fixed Elbow 135o Wrist-Stick 45o

Dynamic movement

requires accurate internal force assumptions

METHODOLOGY

Mathematical Model – Inverse Dynamics

Physical Model – Average Male Torso Single Armed

+ , 0o and - to the horizon upper arm start height

3 drops / start height

Vicon Motion Capture

System Bertec Force Plate

NOT Test Position

RESULTS

Trajectory – Limb Movement

Pick Wrist Elbow Shoulder (origin) ___ Vertical … Mediolateral --- Antroposterior

Vertical Trajectory – Start Heights

+ (yellow) 0o (blue) – (red)

Limitations & Corrections

Balanced bucket for the sledge à plate weights instead of dumbbells

Factor +/- 10o start height à +/- 30o

Tripod to mark consistent start heights

Sampling rate force plates 1000Hz à 2000Hz

Remove filter for force plate data

CONCLUSION

Theoretical Model & Experimental results proved mechanical testability of the prototype

Validated for future research to define baseline measures for the preparation phase

Propulsion in Sledge Hockey: A Biomechanical Analysis to Define Gait

Gal A.M., Chan A.D.C. & Hay D.C.

In the sport of sledge hockey movement is created by a forward cyclical weight-bearing shoulder-dependent motion. This motion is known as propulsion, and in its simplest form (a linear stroking pattern) gait for the shoulder joint can be defined. Gait has become the foundation for weight-bearing hip-dependent motion having a standardize definition for analysis. Hip-dependent gait is defined by contralateral movements consisting of steps and strides, where propulsion in sledge hockey is a double-poling cycle or bilateral movement and will consist of only strides; however, analysis of left vs right cadence will be observed. Propulsion in sledge hockey reflects similar movements seen in walking and running, and by using 3-dimensional motion analysis with reference to hip-dependent gait, evidence supporting the definition of gait for a forward cyclical shoulder-dependent motion can be acquired. Previous evidence for seated shoulder-dependent sports outlines three distinct phases within the stroking cycle known as preparation, propulsion and recovery (Fig 1) compared to two distinct phases in standing poling sports; propulsion and recovery. Evidence for shoulder-dependent gait using sport-specific terminology will also assist with a deeper understanding of the exact importance of the preparation stage seen in seated shoulder-dependent propulsion. Segmented data will illustrate the co-ordination of the primary musculature involved in creating this tri-planar movement. The shoulder joint was designed to promote the largest range of motion in turn leaving its stability vulnerable. This vulnerability foreshadows that mobility could supersede stability causing structural failure. For shoulder-dependent populations this could be detrimental leading to a stationary lifestyle until healed. Kinematic and kinetic analysis of upper body musculoskeletal movement during linear propulsion may reveal etiology-specific locomotor patterns that may provide insight for enhancing protection and structural soundness of this joint. Sports with high-impact, high-velocity shoulder-dependant movements, such as sledge hockey, invite a risk for increased trauma onto this joint. Unlike able-bodied sports, sledge hockey has a diverse range of physical abilities due to congenital and/or injury-induced impairments. By combing 3-dimensional motion analysis with muscular activity, sport-specific advancements can be made aiding in athletic performance, skill development, injury prevention and rehabilitation.

INTRODUCTION PHASES OF PROPULSION

This study examines the linear stroking pattern found within the sport of sledge hockey, known as propulsion, to assist in defining gait for the shoulder joint in a forward cyclical weight-bearing motion.

PURPOSE

Figure 1. An illustration depicting previously outlined stages of propulsion for seated shoulder-dependent sports such as sledge hockey; preparation (PREP), propulsion (PRO) and recovery (REC). PREP is defined as full arm extension to pick-plant; PRO from pick-plant to pick-off; and REC from pick-off to full arm extension. A single cycle occurs between two identical consecutive phase exchanges (REC-PREP1 to REC-PREP2).

Participants in the study are healthy elite adult male sledge hockey players medically diagnosed with a physical impairment, and healthy able-bodied physically active adult males with no or limited knowledge of the physical tasks. An indoor 3-dimensional motion capture system (Vicon) with artificial ice surface (bladed-sledge) or rubber matted flooring (wheeled-sledge) will be used in conjunction with surface electromyography (sEMG) electrodes and force plates. Primary superficial movers and stabilizers for shoulder-dependent weight-bearing locomotion included the biceps brachii, deltoid threesome (anterior, medial, posterior), latissimus dorsi, pectoralis major, trapezius and triceps brachii. A note should be made that the rotator cuff is ultimately the primary stabilizer for the shoulder joint; however the deep location of this four muscle cuff presents issues for sEMG acquisition during dynamic movements. Ground reaction forces (GRF) from pick-plant to pick-off will be acquired from force plates in an offset ‘t’ formation isolating the left and right sticks, and sledge/participant data. Anthropometric measurements for 3-dimensional reconstruction, and impairment history will be collected. Participants propel themselves through the 3x3x2 m capture zone making precise force plate contact with submaximal and maximal efforts, followed by stationary start-propulsion on the force plates through the remaining capture space, again with submaximal and maximal efforts. A minimum of 3 useable trials are required for each of the four tests, and a minimum of 2 minutes rest is allotted between trials. Baseline parameters are defined by a using a solid-static wood model mimicking the average male upper torso with a single arm; the shoulder joint being the only dynamic element. The linear stroking pattern is defined as placing the sledge stationary outside the capture zone (at the marking indicated for precise force plate contact), on a random whistle the participant will propel themselves through the capture zone to the finish marker outside of the capture zone. The start-linear stroking pattern is defined as placing the sledge stationary on the force plates inside the capture zone (at the marking indicated for precise force plate contact), on a random whistle have the participant propel themselves through the remainder of the capture zone to the finish marker outside of the capture zone.

METHODOLOGY

Figure 2. Illustrations of sport-specific exchange points segmenting the stages of propulsion through on-ice (top), off-ice (middle) and motion capture (bottom) analysis; REC-PREP (left), PREP-PRO (middle) and PRO-REC (right).

A wheeled-sledge pilot study from a single unfamiliar participant has suggested that propulsion in sledge hockey is a posteriorly driven motion with dominant contribution from the triceps brachii, followed by the latissimus dorsi then posterior deltoid. Findings have also suggested that the biceps brachii produced almost no force at all. Marker trajectory from this pilot study suggested that the wrist, blade and joint of the stick move in an almost identical fashion prompting further research analyzing forearm musculature. Evidence from the pilot study are this study’s guidelines used to provide 2 and 3-dimensional kinematic and kinetic evidence of the linear stroking cycle for the sport of sledge hockey, using sport-specific analogy to provide a complete illustration of this cyclical weight-bearing movement.

Pilot Study

REFERENCES & ACKNOWLEDGMENT Acknowledgment: M. Lamontagne & B. Hallgrimsson [1] A.M. Gal, D.C. Hay, A.D.C. and Chan, “2 and 3-Dimensional Analysis of the Linear Stroking Cycle in the Sport of Sledge Hockey: Glenohumeral Joint Kinematic, Kinetic and surface EMG muscle Modelling On and Off Ice,” International Symposium: 3D Analysis of Human Movement, poster, 2014. [2] K.  Lomond,  and  R.  Wiseman,  “Sledge  Hockey  Mechanics  Take  Toll  on  Shoulders:  Analysis  of  Propulsion  Technique  can  Help  Experts Design  Training  Programs  to  Prevent  Injury,”  J Biomechanics, vol. 10, no. 3, pp. 71-76, 2003. [3] L. Gastaldi, S. Pastorelli, and S. Frassinelli,  “A  Biomechanical  Approach  to  Paralympic  Cross-Country Sit-Ski  Racing,”  Clin J Sports Med, vol. 22, pp. 58-64, 2012. [4] H.  Holmberg,  et  al.,  “Biomechanical  Analysis  of  Double  Poling  in  Eltie Cross-Country  Skiers,”  Med & Sci in Sports & Exerc, vol. 37(5), pp. 807-818, 2005. [5] C.G.  Gordon  et  al.,  “2010  Anthropometric  Survey  of  U.S.  Marine  Corps  Personnel:  Methods  and  Summary  Statistics,”  U.S. Army Natick Solider Research, Development and Engineering Center, NATICK/TR-13/018, 2013. [6] H.E.J. Veeger, and F.C.T. van der Helm, "Shoulder Function: The Perfect Compromise Between Mobility and Stability," J Biomechanics, vol. 40, pp. 2119-2129, 2007. [7] J.A. Nyland, D.N.M. Cabora, and D.L. Johnson, "The Human Glenohumeral Joint: A Proprioceptive and Stability Alliance," Knee Surg, Sports Traumatol, Arthrosc, vol. 6, pp. 50-61, 1998. [8] J. Jerosch, and M. Prymka, "Proprioception and joint stability," Knee Surg, Sports Traumatol, Arthrosc, vol. 4, pp. 191-179, 1996. [9] C.R. Ethier, and C.A. Simmons, Introductory Biomechanics: From Cells to Organisms, Cambridge UK: Cambridge University Press, 2007. [10] C. Kirtley, Clinical Gait Analysis: Theory and Practice, UK: Elsevier Churchill Livingstone, 2006.

Figure 3 is a foam blueprint of the solid-static baseline model. A nylon string will be used to create the shoulder angle from mid-neck to centre of gravity of the upper arm. From there the string will be released; the downward poling motion will be captured and GRF recorded upon impact. Since the model mimics the average male body segments, kinematic and kinetic evidence can be used as neutral muscular activity (no additional force production). In comparison to participant data baseline parameters will assist in supporting or dismissing assumptions made for the internal mechanics of the human arm, and assist in the analysis of the preparation phase. Baseline parameters will investigate the GRF from a combination of wrist/stick, elbow and shoulder angles in the downward poling motion. Ranges outlining stick angle for pick contact, shoulder extension and elbow flexion will be determined and used for comparison from participant data.

BASELINE MEASURES This study aims to provide descriptive support for kinematic and kinetic 2 and 3-dimensional analysis of the shoulder joint during a double poling motion, specifically propulsion in the sport of sledge hockey. Biomechanical analysis will provide detailed information regarding the primary movers and stabilizers of the shoulder joint during this stroking cycle to gain a more in depth understanding of the biomechanics required to perform such weight-bearing tasks and their affects onto the joint. A control group of unfamiliar abled-bodied participants along with baseline parameters should validate the performance of expert physically-impaired individuals. Sport-specific evidence supporting the theory that propulsion is a posteriorly driven movement is an anticipated finding. Contributions of this research will provide a sporting community in desperate need of scientific evidence guidelines to base program development and education. Data collected from this study will provide stroking pattern information, body position and muscle activation during each phase of the cycle for both the linear-stroking cycle, and the start-cycle. In addition to assisting this vastly growing Paralympic sport, data acquired can present information transferable to shoulder-dependent populations to improve with their quality of life. Information defining gait in a forward cyclical motion can assist the general population in the same manor as it does for the beginner or expert athlete. Overusing a joint in a fashion it was not mechanically designed for can almost guarantee minor trauma as a result; an on-set for future major issues. By understanding the biomechanics of this motion rehabilitative and developmental protocols can be improved and/or developed. The presentation of data is designed to increase the quality of life for this special population, in turn providing a developing sport some guidance. In conclusion, sport-specific analysis will provide the opportunity to gain a deeper understanding of the exact importance of the preparation stage during seated-propulsion, as well as provide segmented data observing the co-ordination of the musculature involved in the linear stoking cycle for the sport of sledge hockey.

Discussion

Figure 3. The average male upper torso solid-static baseline model foam blueprint.

Propulsion in Sledge Hockey: A Biomechanical Analysis to Define Gait

Gal A.M., Chan A.D.C. & Hay D.C.

In the sport of sledge hockey movement is created by a forward cyclical weight-bearing shoulder-dependent motion. This motion is known as propulsion, and in its simplest form (a linear stroking pattern) gait for the shoulder joint can be defined. Gait has become the foundation for weight-bearing hip-dependent motion having a standardize definition for analysis. Hip-dependent gait is defined by contralateral movements consisting of steps and strides, where propulsion in sledge hockey is a double-poling cycle or bilateral movement and will consist of only strides; however, analysis of left vs right cadence will be observed. Propulsion in sledge hockey reflects similar movements seen in walking and running, and by using 3-dimensional motion analysis with reference to hip-dependent gait, evidence supporting the definition of gait for a forward cyclical shoulder-dependent motion can be acquired. Previous evidence for seated shoulder-dependent sports outlines three distinct phases within the stroking cycle known as preparation, propulsion and recovery (Fig 1) compared to two distinct phases in standing poling sports; propulsion and recovery. Evidence for shoulder-dependent gait using sport-specific terminology will also assist with a deeper understanding of the exact importance of the preparation stage seen in seated shoulder-dependent propulsion. Segmented data will illustrate the co-ordination of the primary musculature involved in creating this tri-planar movement. The shoulder joint was designed to promote the largest range of motion in turn leaving its stability vulnerable. This vulnerability foreshadows that mobility could supersede stability causing structural failure. For shoulder-dependent populations this could be detrimental leading to a stationary lifestyle until healed. Kinematic and kinetic analysis of upper body musculoskeletal movement during linear propulsion may reveal etiology-specific locomotor patterns that may provide insight for enhancing protection and structural soundness of this joint. Sports with high-impact, high-velocity shoulder-dependant movements, such as sledge hockey, invite a risk for increased trauma onto this joint. Unlike able-bodied sports, sledge hockey has a diverse range of physical abilities due to congenital and/or injury-induced impairments. By combing 3-dimensional motion analysis with muscular activity, sport-specific advancements can be made aiding in athletic performance, skill development, injury prevention and rehabilitation.

INTRODUCTION PHASES OF PROPULSION

This study examines the linear stroking pattern found within the sport of sledge hockey, known as propulsion, to assist in defining gait for the shoulder joint in a forward cyclical weight-bearing motion.

PURPOSE

Figure 1. An illustration depicting previously outlined stages of propulsion for seated shoulder-dependent sports such as sledge hockey; preparation (PREP), propulsion (PRO) and recovery (REC). PREP is defined as full arm extension to pick-plant; PRO from pick-plant to pick-off; and REC from pick-off to full arm extension. A single cycle occurs between two identical consecutive phase exchanges (REC-PREP1 to REC-PREP2).

Participants in the study are healthy elite adult male sledge hockey players medically diagnosed with a physical impairment, and healthy able-bodied physically active adult males with no or limited knowledge of the physical tasks. An indoor 3-dimensional motion capture system (Vicon) with artificial ice surface (bladed-sledge) or rubber matted flooring (wheeled-sledge) will be used in conjunction with surface electromyography (sEMG) electrodes and force plates. Primary superficial movers and stabilizers for shoulder-dependent weight-bearing locomotion included the biceps brachii, deltoid threesome (anterior, medial, posterior), latissimus dorsi, pectoralis major, trapezius and triceps brachii. A note should be made that the rotator cuff is ultimately the primary stabilizer for the shoulder joint; however the deep location of this four muscle cuff presents issues for sEMG acquisition during dynamic movements. Ground reaction forces (GRF) from pick-plant to pick-off will be acquired from force plates in an offset ‘t’ formation isolating the left and right sticks, and sledge/participant data. Anthropometric measurements for 3-dimensional reconstruction, and impairment history will be collected. Participants propel themselves through the 3x3x2 m capture zone making precise force plate contact with submaximal and maximal efforts, followed by stationary start-propulsion on the force plates through the remaining capture space, again with submaximal and maximal efforts. A minimum of 3 useable trials are required for each of the four tests, and a minimum of 2 minutes rest is allotted between trials. Baseline parameters are defined by a using a solid-static wood model mimicking the average male upper torso with a single arm; the shoulder joint being the only dynamic element. The linear stroking pattern is defined as placing the sledge stationary outside the capture zone (at the marking indicated for precise force plate contact), on a random whistle the participant will propel themselves through the capture zone to the finish marker outside of the capture zone. The start-linear stroking pattern is defined as placing the sledge stationary on the force plates inside the capture zone (at the marking indicated for precise force plate contact), on a random whistle have the participant propel themselves through the remainder of the capture zone to the finish marker outside of the capture zone.

METHODOLOGY

Figure 2. Illustrations of sport-specific exchange points segmenting the stages of propulsion through on-ice (top), off-ice (middle) and motion capture (bottom) analysis; REC-PREP (left), PREP-PRO (middle) and PRO-REC (right).

A wheeled-sledge pilot study from a single unfamiliar participant has suggested that propulsion in sledge hockey is a posteriorly driven motion with dominant contribution from the triceps brachii, followed by the latissimus dorsi then posterior deltoid. Findings have also suggested that the biceps brachii produced almost no force at all. Marker trajectory from this pilot study suggested that the wrist, blade and joint of the stick move in an almost identical fashion prompting further research analyzing forearm musculature. Evidence from the pilot study are this study’s guidelines used to provide 2 and 3-dimensional kinematic and kinetic evidence of the linear stroking cycle for the sport of sledge hockey, using sport-specific analogy to provide a complete illustration of this cyclical weight-bearing movement.

Pilot Study

REFERENCES & ACKNOWLEDGMENT Acknowledgment: M. Lamontagne & B. Hallgrimsson [1] A.M. Gal, D.C. Hay, A.D.C. and Chan, “2 and 3-Dimensional Analysis of the Linear Stroking Cycle in the Sport of Sledge Hockey: Glenohumeral Joint Kinematic, Kinetic and surface EMG muscle Modelling On and Off Ice,” International Symposium: 3D Analysis of Human Movement, poster, 2014. [2] K.  Lomond,  and  R.  Wiseman,  “Sledge  Hockey  Mechanics  Take  Toll  on  Shoulders:  Analysis  of  Propulsion  Technique  can  Help  Experts Design  Training  Programs  to  Prevent  Injury,”  J Biomechanics, vol. 10, no. 3, pp. 71-76, 2003. [3] L. Gastaldi, S. Pastorelli, and S. Frassinelli,  “A  Biomechanical  Approach  to  Paralympic  Cross-Country Sit-Ski  Racing,”  Clin J Sports Med, vol. 22, pp. 58-64, 2012. [4] H.  Holmberg,  et  al.,  “Biomechanical  Analysis  of  Double  Poling  in  Eltie Cross-Country  Skiers,”  Med & Sci in Sports & Exerc, vol. 37(5), pp. 807-818, 2005. [5] C.G.  Gordon  et  al.,  “2010  Anthropometric  Survey  of  U.S.  Marine  Corps  Personnel:  Methods  and  Summary  Statistics,”  U.S. Army Natick Solider Research, Development and Engineering Center, NATICK/TR-13/018, 2013. [6] H.E.J. Veeger, and F.C.T. van der Helm, "Shoulder Function: The Perfect Compromise Between Mobility and Stability," J Biomechanics, vol. 40, pp. 2119-2129, 2007. [7] J.A. Nyland, D.N.M. Cabora, and D.L. Johnson, "The Human Glenohumeral Joint: A Proprioceptive and Stability Alliance," Knee Surg, Sports Traumatol, Arthrosc, vol. 6, pp. 50-61, 1998. [8] J. Jerosch, and M. Prymka, "Proprioception and joint stability," Knee Surg, Sports Traumatol, Arthrosc, vol. 4, pp. 191-179, 1996. [9] C.R. Ethier, and C.A. Simmons, Introductory Biomechanics: From Cells to Organisms, Cambridge UK: Cambridge University Press, 2007. [10] C. Kirtley, Clinical Gait Analysis: Theory and Practice, UK: Elsevier Churchill Livingstone, 2006.

Figure 3 is a foam blueprint of the solid-static baseline model. A nylon string will be used to create the shoulder angle from mid-neck to centre of gravity of the upper arm. From there the string will be released; the downward poling motion will be captured and GRF recorded upon impact. Since the model mimics the average male body segments, kinematic and kinetic evidence can be used as neutral muscular activity (no additional force production). In comparison to participant data baseline parameters will assist in supporting or dismissing assumptions made for the internal mechanics of the human arm, and assist in the analysis of the preparation phase. Baseline parameters will investigate the GRF from a combination of wrist/stick, elbow and shoulder angles in the downward poling motion. Ranges outlining stick angle for pick contact, shoulder extension and elbow flexion will be determined and used for comparison from participant data.

BASELINE MEASURES This study aims to provide descriptive support for kinematic and kinetic 2 and 3-dimensional analysis of the shoulder joint during a double poling motion, specifically propulsion in the sport of sledge hockey. Biomechanical analysis will provide detailed information regarding the primary movers and stabilizers of the shoulder joint during this stroking cycle to gain a more in depth understanding of the biomechanics required to perform such weight-bearing tasks and their affects onto the joint. A control group of unfamiliar abled-bodied participants along with baseline parameters should validate the performance of expert physically-impaired individuals. Sport-specific evidence supporting the theory that propulsion is a posteriorly driven movement is an anticipated finding. Contributions of this research will provide a sporting community in desperate need of scientific evidence guidelines to base program development and education. Data collected from this study will provide stroking pattern information, body position and muscle activation during each phase of the cycle for both the linear-stroking cycle, and the start-cycle. In addition to assisting this vastly growing Paralympic sport, data acquired can present information transferable to shoulder-dependent populations to improve with their quality of life. Information defining gait in a forward cyclical motion can assist the general population in the same manor as it does for the beginner or expert athlete. Overusing a joint in a fashion it was not mechanically designed for can almost guarantee minor trauma as a result; an on-set for future major issues. By understanding the biomechanics of this motion rehabilitative and developmental protocols can be improved and/or developed. The presentation of data is designed to increase the quality of life for this special population, in turn providing a developing sport some guidance. In conclusion, sport-specific analysis will provide the opportunity to gain a deeper understanding of the exact importance of the preparation stage during seated-propulsion, as well as provide segmented data observing the co-ordination of the musculature involved in the linear stoking cycle for the sport of sledge hockey.

Discussion

Figure 3. The average male upper torso solid-static baseline model foam blueprint.

Propulsion in Sledge Hockey: A Biomechanical Analysis to Define Gait

Gal A.M., Chan A.D.C. & Hay D.C.

In the sport of sledge hockey movement is created by a forward cyclical weight-bearing shoulder-dependent motion. This motion is known as propulsion, and in its simplest form (a linear stroking pattern) gait for the shoulder joint can be defined. Gait has become the foundation for weight-bearing hip-dependent motion having a standardize definition for analysis. Hip-dependent gait is defined by contralateral movements consisting of steps and strides, where propulsion in sledge hockey is a double-poling cycle or bilateral movement and will consist of only strides; however, analysis of left vs right cadence will be observed. Propulsion in sledge hockey reflects similar movements seen in walking and running, and by using 3-dimensional motion analysis with reference to hip-dependent gait, evidence supporting the definition of gait for a forward cyclical shoulder-dependent motion can be acquired. Previous evidence for seated shoulder-dependent sports outlines three distinct phases within the stroking cycle known as preparation, propulsion and recovery (Fig 1) compared to two distinct phases in standing poling sports; propulsion and recovery. Evidence for shoulder-dependent gait using sport-specific terminology will also assist with a deeper understanding of the exact importance of the preparation stage seen in seated shoulder-dependent propulsion. Segmented data will illustrate the co-ordination of the primary musculature involved in creating this tri-planar movement. The shoulder joint was designed to promote the largest range of motion in turn leaving its stability vulnerable. This vulnerability foreshadows that mobility could supersede stability causing structural failure. For shoulder-dependent populations this could be detrimental leading to a stationary lifestyle until healed. Kinematic and kinetic analysis of upper body musculoskeletal movement during linear propulsion may reveal etiology-specific locomotor patterns that may provide insight for enhancing protection and structural soundness of this joint. Sports with high-impact, high-velocity shoulder-dependant movements, such as sledge hockey, invite a risk for increased trauma onto this joint. Unlike able-bodied sports, sledge hockey has a diverse range of physical abilities due to congenital and/or injury-induced impairments. By combing 3-dimensional motion analysis with muscular activity, sport-specific advancements can be made aiding in athletic performance, skill development, injury prevention and rehabilitation.

INTRODUCTION PHASES OF PROPULSION

This study examines the linear stroking pattern found within the sport of sledge hockey, known as propulsion, to assist in defining gait for the shoulder joint in a forward cyclical weight-bearing motion.

PURPOSE

Figure 1. An illustration depicting previously outlined stages of propulsion for seated shoulder-dependent sports such as sledge hockey; preparation (PREP), propulsion (PRO) and recovery (REC). PREP is defined as full arm extension to pick-plant; PRO from pick-plant to pick-off; and REC from pick-off to full arm extension. A single cycle occurs between two identical consecutive phase exchanges (REC-PREP1 to REC-PREP2).

Participants in the study are healthy elite adult male sledge hockey players medically diagnosed with a physical impairment, and healthy able-bodied physically active adult males with no or limited knowledge of the physical tasks. An indoor 3-dimensional motion capture system (Vicon) with artificial ice surface (bladed-sledge) or rubber matted flooring (wheeled-sledge) will be used in conjunction with surface electromyography (sEMG) electrodes and force plates. Primary superficial movers and stabilizers for shoulder-dependent weight-bearing locomotion included the biceps brachii, deltoid threesome (anterior, medial, posterior), latissimus dorsi, pectoralis major, trapezius and triceps brachii. A note should be made that the rotator cuff is ultimately the primary stabilizer for the shoulder joint; however the deep location of this four muscle cuff presents issues for sEMG acquisition during dynamic movements. Ground reaction forces (GRF) from pick-plant to pick-off will be acquired from force plates in an offset ‘t’ formation isolating the left and right sticks, and sledge/participant data. Anthropometric measurements for 3-dimensional reconstruction, and impairment history will be collected. Participants propel themselves through the 3x3x2 m capture zone making precise force plate contact with submaximal and maximal efforts, followed by stationary start-propulsion on the force plates through the remaining capture space, again with submaximal and maximal efforts. A minimum of 3 useable trials are required for each of the four tests, and a minimum of 2 minutes rest is allotted between trials. Baseline parameters are defined by a using a solid-static wood model mimicking the average male upper torso with a single arm; the shoulder joint being the only dynamic element. The linear stroking pattern is defined as placing the sledge stationary outside the capture zone (at the marking indicated for precise force plate contact), on a random whistle the participant will propel themselves through the capture zone to the finish marker outside of the capture zone. The start-linear stroking pattern is defined as placing the sledge stationary on the force plates inside the capture zone (at the marking indicated for precise force plate contact), on a random whistle have the participant propel themselves through the remainder of the capture zone to the finish marker outside of the capture zone.

METHODOLOGY

Figure 2. Illustrations of sport-specific exchange points segmenting the stages of propulsion through on-ice (top), off-ice (middle) and motion capture (bottom) analysis; REC-PREP (left), PREP-PRO (middle) and PRO-REC (right).

A wheeled-sledge pilot study from a single unfamiliar participant has suggested that propulsion in sledge hockey is a posteriorly driven motion with dominant contribution from the triceps brachii, followed by the latissimus dorsi then posterior deltoid. Findings have also suggested that the biceps brachii produced almost no force at all. Marker trajectory from this pilot study suggested that the wrist, blade and joint of the stick move in an almost identical fashion prompting further research analyzing forearm musculature. Evidence from the pilot study are this study’s guidelines used to provide 2 and 3-dimensional kinematic and kinetic evidence of the linear stroking cycle for the sport of sledge hockey, using sport-specific analogy to provide a complete illustration of this cyclical weight-bearing movement.

Pilot Study

REFERENCES & ACKNOWLEDGMENT Acknowledgment: M. Lamontagne & B. Hallgrimsson [1] A.M. Gal, D.C. Hay, A.D.C. and Chan, “2 and 3-Dimensional Analysis of the Linear Stroking Cycle in the Sport of Sledge Hockey: Glenohumeral Joint Kinematic, Kinetic and surface EMG muscle Modelling On and Off Ice,” International Symposium: 3D Analysis of Human Movement, poster, 2014. [2] K.  Lomond,  and  R.  Wiseman,  “Sledge  Hockey  Mechanics  Take  Toll  on  Shoulders:  Analysis  of  Propulsion  Technique  can  Help  Experts Design  Training  Programs  to  Prevent  Injury,”  J Biomechanics, vol. 10, no. 3, pp. 71-76, 2003. [3] L. Gastaldi, S. Pastorelli, and S. Frassinelli,  “A  Biomechanical  Approach  to  Paralympic  Cross-Country Sit-Ski  Racing,”  Clin J Sports Med, vol. 22, pp. 58-64, 2012. [4] H.  Holmberg,  et  al.,  “Biomechanical  Analysis  of  Double  Poling  in  Eltie Cross-Country  Skiers,”  Med & Sci in Sports & Exerc, vol. 37(5), pp. 807-818, 2005. [5] C.G.  Gordon  et  al.,  “2010  Anthropometric  Survey  of  U.S.  Marine  Corps  Personnel:  Methods  and  Summary  Statistics,”  U.S. Army Natick Solider Research, Development and Engineering Center, NATICK/TR-13/018, 2013. [6] H.E.J. Veeger, and F.C.T. van der Helm, "Shoulder Function: The Perfect Compromise Between Mobility and Stability," J Biomechanics, vol. 40, pp. 2119-2129, 2007. [7] J.A. Nyland, D.N.M. Cabora, and D.L. Johnson, "The Human Glenohumeral Joint: A Proprioceptive and Stability Alliance," Knee Surg, Sports Traumatol, Arthrosc, vol. 6, pp. 50-61, 1998. [8] J. Jerosch, and M. Prymka, "Proprioception and joint stability," Knee Surg, Sports Traumatol, Arthrosc, vol. 4, pp. 191-179, 1996. [9] C.R. Ethier, and C.A. Simmons, Introductory Biomechanics: From Cells to Organisms, Cambridge UK: Cambridge University Press, 2007. [10] C. Kirtley, Clinical Gait Analysis: Theory and Practice, UK: Elsevier Churchill Livingstone, 2006.

Figure 3 is a foam blueprint of the solid-static baseline model. A nylon string will be used to create the shoulder angle from mid-neck to centre of gravity of the upper arm. From there the string will be released; the downward poling motion will be captured and GRF recorded upon impact. Since the model mimics the average male body segments, kinematic and kinetic evidence can be used as neutral muscular activity (no additional force production). In comparison to participant data baseline parameters will assist in supporting or dismissing assumptions made for the internal mechanics of the human arm, and assist in the analysis of the preparation phase. Baseline parameters will investigate the GRF from a combination of wrist/stick, elbow and shoulder angles in the downward poling motion. Ranges outlining stick angle for pick contact, shoulder extension and elbow flexion will be determined and used for comparison from participant data.

BASELINE MEASURES This study aims to provide descriptive support for kinematic and kinetic 2 and 3-dimensional analysis of the shoulder joint during a double poling motion, specifically propulsion in the sport of sledge hockey. Biomechanical analysis will provide detailed information regarding the primary movers and stabilizers of the shoulder joint during this stroking cycle to gain a more in depth understanding of the biomechanics required to perform such weight-bearing tasks and their affects onto the joint. A control group of unfamiliar abled-bodied participants along with baseline parameters should validate the performance of expert physically-impaired individuals. Sport-specific evidence supporting the theory that propulsion is a posteriorly driven movement is an anticipated finding. Contributions of this research will provide a sporting community in desperate need of scientific evidence guidelines to base program development and education. Data collected from this study will provide stroking pattern information, body position and muscle activation during each phase of the cycle for both the linear-stroking cycle, and the start-cycle. In addition to assisting this vastly growing Paralympic sport, data acquired can present information transferable to shoulder-dependent populations to improve with their quality of life. Information defining gait in a forward cyclical motion can assist the general population in the same manor as it does for the beginner or expert athlete. Overusing a joint in a fashion it was not mechanically designed for can almost guarantee minor trauma as a result; an on-set for future major issues. By understanding the biomechanics of this motion rehabilitative and developmental protocols can be improved and/or developed. The presentation of data is designed to increase the quality of life for this special population, in turn providing a developing sport some guidance. In conclusion, sport-specific analysis will provide the opportunity to gain a deeper understanding of the exact importance of the preparation stage during seated-propulsion, as well as provide segmented data observing the co-ordination of the musculature involved in the linear stoking cycle for the sport of sledge hockey.

Discussion

Figure 3. The average male upper torso solid-static baseline model foam blueprint.