Predicting future injury in runners using participant-specific models of internal structural loading
Background Incidence of running injury is high o 18.2 – 92.4% No decline despite years of research
Background Limitations 1.External variables vGRF Pronation Footwear Strike
Background
ΔITBσ/t PFCF or ΔPFCF/t AJCF or ΔAJCF/t PLσ or ΔPLσ/t ? AJCF or ΔAJCF/t ?
Background Limitations 2.Cross-sectional and retrospective designs
Background Overcoming previous limitations o Estimates internal loading o Prospective design
Presentation aims Discuss methods and analyses
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
Recruitment n = 102 o >18 yrs. old o run ≥3 per wk. o no running-related/lower-limb injury within 6 mos. o no other sports at competitive level, or >2 per wk.
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
MoCap 45-marker set 50m indoor track 8 Kistler force plates o Embedded in series 12 Vicon cameras (T-40, T-160) 4 Hyun-Joon laser speed gates
MoCap 2 conditions o Constrained 3m/s±5% 5 min. ~18 to 20 laps (~3 to 3.3m/s) o Typical “Use the pace that you run for the majority of your mileage” 5 min. ~17 to 26 laps (~2.8 to 4.3m/s)
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
Vicon Nexus Next steps… o Label data o ~40 trials / participant x 102 participants ~4000 trials
Vicon Nexus Next steps… o Label data o ~40 trials / participant x 102 participants ~4000 trials S’up undergrads?
Vicon Nexus Next steps… o Label data o ~40 trials / participant x 102 participants ~4000 trials Auto-labelling?
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis
Visual3D Next steps… o Export labelled data o Correct coordinate systems o Build an Inverse Kinematics model o Calculate external variables o joint forces and moments o vGRF, ΔvGRF/t o pronation o etc…
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables
Strength testing Biodex o Isotonic Ankle, knee, hip 2 trials: 10°/s “away,” 60°/s “toward” 2 trials: 60°/s “away,” 10°/s “toward”
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables
MatLab: Strength Next steps… o Participant-specific strength parameters o Write into OpenSim
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables
OpenSim Next steps… o Build model… Arnold et al., 2010 Lenhart et al., 2014 44 muscle lower-limb with patella o Import… V3D IK models Strength parameters
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables Internal variables
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables Internal variables
Surveys Baseline o Sex o Experience years competitive level o Past habits other PA mileage location warm up o Footwear shoes orthotics o Lower-limb and running injury history
Surveys 26 weekly o Other PA o Mileage, time per day o Changes in footwear o Pain/Injury Location Pain severity Differential diagnosis Changes in running/PA
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables Internal variables
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables Internal variables
~500 columns per participant per survey 102 participants x 26 surveys ~ 2600 surveys
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables Internal variables Baseline and Prospective variables
Recruitment Strength Testing MoCap Surveys Nexus Visual3D OpenSim Arnold 2010 Lenhart 2014 MatLab or Excel Analysis External variables Internal variables Baseline and Prospective variables
Analysis External variables o Δ vGRF/t o Pronation o Footstrike Internal variables o PLσ o ΔPLσ/t o PFCF o ΔPFCF/t o AJCF o ΔAJCF/t o ΔITBσ/t o Achilles…? o Plantar fascia…? Baseline and prospective variables o Sex o Experience o History of injury o Footwear o Frequency Mileage Estimated strides o Injury # reported Time off/altered Pain
Analysis External variables o Δ vGRF/t o Pronation o Footstrike Internal variables o PLσ o ΔPLσ/t o PFCF o ΔPFCF/t o AJCF o ΔAJCF/t o ΔITBσ/t o Achilles…? o Plantar fascia…? Baseline and prospective variables o Sex o Experience o History of injury o Footwear o Frequency Mileage Estimated strides o Injury # reported Time off/altered Pain
Analysis Injury # reported Days missed Pain Proposed internal variable
Analysis Covariates...? More complex or hierarchical models…? Fitting data to theoretical curve…?
Analysis Proposed internal variable Estimated strides/week
Analysis Aggregate loading metric…? o Average z-score of each injury-related variable
Analysis Group-wise comparisons…? o Footstrike (fore vs. rear) o Footwear (minimal vs. support)