1. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Diagram of the musculoskeletal model showing the rigid body segments, right leg muscle models, and ground contact elements

2. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Joint angles (hip, knee, ankle) and GRF (horizontal, vertical) for the tracking simulation (thick lines) and for the human subjects (thin lines). No experimental data were available for the toe joint angle. The stride (x-axis) begins and ends at heel-strike.

3. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Portions of the stride when the muscle models were on (nonzero excitation; black bars) for the data tracking simulation (“Track”). “EMG” are nominal timing data derived from electromyograms by Knutson and Soderberg [27]. The stride (x-axis) begins and ends at heel-strike.

4. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Stick figures of walking motions for the four predictive simulations, plus descriptive metrics. (a) Minimized metabolic cost, (b) minimized peak axial knee joint contact force, (c) minimized peak knee flexion angle in stance, (d) minimized peak axial knee joint contact force and tracked the mean experimental knee angle. Speed = average horizontal speed, SL = stride length, SF = stride frequency, CoT = metabolic cost of transport, and SD = average deviation from the experimental joint angles and GRF.

5. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Joint angles (in deg) and GRF (in multiples of bodyweight) for each of the four predictive simulations. (a) Minimized metabolic cost, (b) minimized peak axial knee joint contact force, (c) minimized peak knee flexion angle in stance, (d) minimized peak axial knee joint contact force and tracked the mean experimental knee angle. No experimental data were available for the toe joint angle. The stride (x-axis) begins and ends at heel-strike.

6. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Muscle model activations for each of the four predictive simulations. (a) Minimized metabolic cost, (b) minimized peak axial knee joint contact force, (c) minimized peak knee flexion angle in stance, (d) minimized peak axial knee joint contact force and tracked the mean experimental knee angle. ILP = iliopsoas, GLU = glutei, VAS = vasti, BFS = biceps femoris (short head), TA = tibialis anterior, SOL = soleus, RF = rectus femoris, HAM = hamstrings, and GAS = gastrocnemius. The stride (x-axis) begins and ends at heel-strike.

7. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Axial knee joint contact forces (thick line) the four predictive simulations. (a) Minimized metabolic cost, (b) minimized peak axial knee joint contact force, (c) minimized peak knee flexion angle in stance, (d) minimized peak axial knee joint contact force and tracked the mean experimental knee angle. Thin solid line (“Knee mus/lig”) is the contribution from muscles and ligaments spanning the knee. Thin broken line (“Reaction”) is the contribution from the knee joint reaction force (i.e., the resultant joint force from inverse dynamics). The stride (x-axis) begins and ends at heel-strike. The directions of the joint reaction and contact forces are flipped for presentation.

8. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Knee muscle force components along the long axis of the tibia from the four predictive simulations. Column (a) is minimized metabolic cost; Column (b) is minimized peak axial knee joint contact force; Column (c) is minimized peak knee flexion angle in stance; Column (d) is minimized peak axial knee joint contact force and tracked the mean experimental knee angle. VAS = vasti, BFS = biceps femoris (short head), RF = rectus femoris, HAM = hamstrings, and GAS = gastrocnemius. The stride (x-axis) begins and ends at heel-strike.

9. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Changes in axial knee muscle impulses (force-time integral) between the minimum contact force simulations and the minimum metabolic cost simulation. White bars are changes due to muscle activation level. Black bars are changes due to muscle kinematics. (a) Simulation that minimized peak axial knee joint contact force, (b) simulation that minimized peak knee flexion angle in stance, (c) simulation that minimized peak axial knee joint contact force and tracked the mean experimental knee angle.

10. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Peak axial knee joint contact forces from three of the predictive simulations (black bars) and estimated using static optimization for a single human subject (white bars) who walked while attempting to emulate the kinematics shown in Figs. 4(c) and 4(d) (“Straight Knee” and “Quicker Steps”). Error bars are ± one standard deviation between ten trials.

11. Date of download: 1/15/2018
Copyright © ASME. All rights reserved.
From: Predicting Sagittal Plane Biomechanics That Minimize the Axial Knee Joint Contact Force During Walking
J Biomech Eng. 2012;135(1): doi: /
Figure Legend:
Axial knee joint contact forces from two additional simulations that used a nodal control scheme (e.g., Miller et al. [21]) with 41 parameters per muscle. The solid line minimized the sum of the joint angle and GRF tracking errors and the metabolic cost. The dashed line minimized the peak of the contact force. The stride (x-axis) begins and ends at heel-strike.