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Karl%E.%Zelik % Biomechanics%&%Assistive%Technology%Lab % - - PowerPoint PPT Presentation
Karl%E.%Zelik % Biomechanics%&%Assistive%Technology%Lab % - - PowerPoint PPT Presentation
Karl%E.%Zelik % Biomechanics%&%Assistive%Technology%Lab % Vanderbilt%University,%Nashville,%TN,%USA % Mathematics (Base 10 Blocks) 10x 1x 100x = = Currency 100x 10x 1x = = Experimental Biomechanics - Grand Challenge WHOLE-BODY
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Mathematics (Base 10 Blocks)
100x 10x 1x
= =
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Currency
100x 10x 1x
= =
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Experimental Biomechanics - Grand Challenge
WHOLE-BODY
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JOINT-SEGMENT WHOLE-BODY
Experimental Biomechanics - Grand Challenge
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MUSCLE-TENDON JOINT-SEGMENT WHOLE-BODY
Experimental Biomechanics - Grand Challenge
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Neuromechanics - Even Grander Challenge
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5 Gaps & Challenges
MUSCLE-TENDON JOINT-SEGMENT WHOLE-BODY
1 2 3 4 5
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Hodgepodge of Thoughts on Multi-Scale Biomechanics
MUSCLE-TENDON JOINT-SEGMENT WHOLE-BODY
1 2 3 4 5
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Whole-Body
5
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5 Whole-Body
Center-of-Mass (COM) energy change (estimated from force plates)
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5
Peripheral energy change (motion relative to COM)
Whole-Body
Center-of-Mass (COM) energy change (estimated from force plates)
+
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Whole-Body ! Mostly Resolved
5 Trust whole-body mechanics b/c they add up properly
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Whole-Body ! Mostly Resolved
5 Trust whole-body mechanics b/c they add up properly
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Whole-Body ! Mostly Resolved
5
Zelik & Kuo 2010; Zelik, Takahashi & Sawicki 2015
Trust whole-body mechanics b/c they add up properly
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Whole-Body ! Mostly Resolved
5
Zelik & Kuo 2010; Zelik, Takahashi & Sawicki 2015
Trust whole-body mechanics b/c they add up properly
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4 Joint-Segment vs. Whole-Body
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4 Joint-Segment vs. Whole-Body
Whole-Body Energy Change
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4 Joint-Segment vs. Whole-Body
Whole-Body Energy Change
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4 Joint-Segment vs. Whole-Body
walking at 1.4 m/s
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4 Joint-Segment vs. Whole-Body
Joint-Segment Work
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4 Joint-Segment vs. Whole-Body
Joint-Segment Work Inverse Dynamics
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4 Joint-Segment vs. Whole-Body
Joint-Segment Work
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4 Joint-Segment vs. Whole-Body
Joint-Segment Work
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4 Joint-Segment vs. Whole-Body
walking at 1.4 m/s
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3DOF joint-segment work fails to explain whole-body energy
Joint-Segment vs. Whole-Body ! Partly Resolved Zelik, Takahashi & Sawicki 2015
4
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6DOF joint-segment work explains whole-body energy
Joint-Segment vs. Whole-Body ! Partly Resolved
but commonly-used 3DOF analysis does not
Zelik, Takahashi & Sawicki 2015
4
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6DOF inverse dynamics
How much work to move body segments?
Buczek 1994, Duncan 1997
rotational work + translational work
6DOF joint-segment work explains whole-body energy
Joint-Segment vs. Whole-Body ! Partly Resolved
but commonly-used 3DOF analysis does not
4
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3 Joint-Segment
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3 Joint-Segment
estimates still miss negative soft tissue work
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Reasonable estimates, but soft tissues & feet usually neglected
Joint-Segment ! Partly Resolved, But Concerning
though they perform substantial work
Fu, Zelik, Board, Browning & Kuo 2015
3
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Reasonable estimates, but soft tissues & feet usually neglected
Joint-Segment ! Partly Resolved, But Concerning
3
though they perform substantial work
Fu, Zelik, Board, Browning & Kuo 2015
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2 Muscle-Tendon vs. Joint-Segment
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Consistency hard to assess
Muscle-Tendon vs. Joint-Segment ! Unknown
5
2
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Consistency hard to assess, but anecdotal evidence of problem
Muscle-Tendon vs. Joint-Segment ! Unknown
5
2
What is mechanical function of foot during push-off in walking or running?
Acts like a spring!
Ker et al. 1987 Stearne et al. 2016
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Consistency hard to assess, but anecdotal evidence of problem
Muscle-Tendon vs. Joint-Segment ! Unknown
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2
What is mechanical function of foot during push-off in walking or running?
Acts like a spring! Acts like a damper!
Ker et al. 1987 Stearne et al. 2016 Stefanyshyn & Nigg 1997 Takahashi & Stanhope 2013
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Consistency hard to assess, but anecdotal evidence of problem
Muscle-Tendon vs. Joint-Segment ! Unknown
5
2
Potential approach: data-driven musculoskeletal modeling
Honert & Zelik, In Review
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Consistency hard to assess, but anecdotal evidence of problem
Muscle-Tendon vs. Joint-Segment ! Unknown
5
2
Potential approach: data-driven musculoskeletal modeling
Honert & Zelik, In Review
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5
1 Muscle-Tendon
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5
1 Muscle-Tendon
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Net positive work by passive tendons indicates a problem
Muscle-Tendon ! Troubling
some current estimates indicate tendons act like motors
Sakuma et al. 2012
1
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Net positive work by passive tendons indicates a problem
Muscle-Tendon ! Troubling
some current estimates indicate tendons act like motors
Sakuma et al. 2012
1
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Net positive work by passive tendons indicates a problem
Muscle-Tendon ! Troubling
some current estimates indicate tendons act like motors
1
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Net positive work by passive tendons indicates a problem
Muscle-Tendon ! Troubling
some current estimates indicate tendons act like motors
tendon elastically storing energy
1
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Net positive work by passive tendons indicates a problem
Muscle-Tendon ! Troubling
some current estimates indicate tendons act like motors
returning 2x more energy
1
tendon elastically storing energy
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