ISB 2015Motion AnalysisISB 2015-1289DEFINING GAIT FOR SEATED WEIGHT-BEARING FORWARD LOCOMOTION PRODUCED BY THEGLENOHUMERAL JOINT: A BIOMECHANICAL ANALYSIS OF THE LINEAR STROKING CYCLEAlicia M. Gal* 1, Adrian Chan1, Dean Hay2

1Systems and Computer Engineering, Ottawa Carleton Institute for Biomedical Engineering, Ottawa, 2School of Physicaland Health Education, Nipissing University, North Bay, Canada

Preferred Presentation: Poster PresentationClinical Biomechanics Award: NoDavid Winter Young Investigator Awards: YesDavid Winter Award - presentation Preference: PosterEmerging Scientific Award sponsored by Professor J De Luca: YesPromising Scientist Award sponsored by Motion Analysis: YesIntroduction and Objectives: Gait analysis for weight-bearing locomotion (WBL) produced by the acetabulofemoral jointhas been extensively investigated; data has provided the general public with normalized results and an explanation forthis means of movement; walking [1]. Results provide distinct information about loading and unloading this dynamic jointillustrating the gait cycle using universally known terminology, stance and swing phases respectively [1]. Illustratingcomplex information assists in understanding how reflexed movement actually occurs, highlighting key components suchas heel-strike and toe-off [1]. The simplicity of this analysis has been derived from collectively integrating numerousinvestigations from various disciplines [1]. Information such as this is crucial for advancement within bipedal locomotion;more importantly the improvement of QoL within the human species. A lack of scientific evidence supporting gait analysis for WBL produced by the glenohumeral joint (GHJ) renders gapswithin comprehension of GHJ reflexed movement leaving GHJ-dependent populations without the ability for prosperousdevelopment, decreasing their QoL. Locomotion produced by the GHJ is a mandatory motion for some populations, inparticular sledge hockey players. GHJ produced locomotion has been mainly investigated through athletic movementsuch as double poling (DP) in cross-country skiing, both upright and sit-skiing [2-3]. Current data indicates upright DPconsists of two phases compared to seated DP with three phases; propulsion (PRO), recovery (REC) and preparation(PREP) [2-3]. This study developed a theoretical model predicting kinematic and Newton-Euler derived kinetic results fora prototype's movement through the additional phase of PREP [4-7]. This provided baseline measures and boundariesused in conjunction with expert and naive populations for seated WBL produced by the GHJ. The purpose of this study isto define gait for seated WBL produced by the GHJ.Methods: A solid-static plywood prototype replicating an average male upper torso and single arm holding a sledgehockey stick, the GHJ the only dynamic component, was used to create baseline measures for PREP [4-7]. Anexperimental group (EX) of expert GHJ-dependent populations were defined as physically disabled elite male sledgehockey players. A control group mimicking the physical characteristics of the EX was selected from abled-male universitystudents with limited knowledge of the physical tasks required (naive to sledge hockey). A Vicon motion analysis systemis used in conjunction with sEMG and 4 force plates (FP) positioned in an offset 't' for individual stick and sledge contact.sEMG were placed bilaterally on the biceps, deltoid trio, latissimus dorsi, pectoralis major, trapezius and triceps; standardmaximal voluntary isometric contractions were modified for the seated position. Participants propelled themselvesthrough the capture zone making precise FP contact situated central zone. Participants then propelled themselves from astationary position on the FP through the remainder of the capture zone. 3 usable trials of sub-maximal and maximalefforts were collected for both tasks with a minimum rest of 2min between trials. PREP was defined as full-arm extensionto pick-on; PRO as pick-on to pick-off; and REC pick-off to full arm extension [6].  

Results: A pilot study using a single naive abled-male suggested seated weight-bearing GHJ produced gait is dominantlya posteriorly driven motion with the triceps ranking superior [6]. This study anticipates similar results with a slightly alteredmuscular ranking due to the addition of the trapezius data. Data also suggested that pick-plant GRF were 15xBW [6]prompting this study's investigation of GRF in relation to impulse. On average PREP lasted 0.16s travelling 0.37m of0.96m x-direction; this study foresees clear separation of PREP duration and distance between the groups, however,insignificant to gait as a whole. With the boundaries from the prototype and the addition of stationary-start this study willprovide detailed information supporting/eliminating the PREP phase from seated propulsion.  Figure:

Caption: Gait model seated WBL produced by the GHJ [6].Conclusion: In conclusion this study will provide normalized data to complement the newly defined gait cycle for seatedWBL produced from the GHJ. It is this study's intent to provide muscular contribution within the respected phases of thissimplified model similar to currently existing acetabulofemoral produced gait models. Providing generalized results willimprove the QoL and comprehension for GHJ-dependent populations.References: [1] Kirtley. Clinical Gait Analysis, Elsevier, 2006.[2] Holmberg et al., Med & Sci Sport & Exerc, 37(5): 807-818, 2005.[3] Gastaldi et al., Clin J Sport Med, 22:58-64, 2012.[4] Robertson et al. Research Methods in Biomechanics, Human Kinetics, 2004.[5] Gordon et al., US Army Natick Cnt 2013.[6] Gal et al., Con 3D-AHM, 2014.[7] Gastaldi et al., Clin J Sport Med, 22:58-64, 2012.

Disclosure of Interest: None Declared