Hip Flexion Angle
5 Subject Mean ±1 SD
60
1.0 m/s
1.25 m/s
1.5 m/s
1.75 m/s
2.0 m/s
3.0 m/s
4.0 m/s
5.0 m/s
40
20
0
Degrees
−20
−40
60
40
20
0
−20
−40
0
50
100
0
50
100
0
% Gait Cycle
50
100
0
50
Fig. S1. Experimentally measured hip flexion angle, for subjects walking (1.0–1.75 m s–1) and running (2.0–5.0 m s–1) (N=5).
Hip angle (flexion positive/extension negative) was calculated from marker data using an inverse kinematics algorithm and a
musculoskeletal model scaled to each subject. Data represent the group mean (black line) ±1 s.d. (shaded region).
100
Knee Flexion Angle
5 Subject Mean ±1 SD
1.0 m/s
1.25 m/s
1.5 m/s
1.75 m/s
2.0 m/s
3.0 m/s
4.0 m/s
5.0 m/s
120
80
Degrees
40
0
120
80
40
0
0
50
100
0
50
100
0
% Gait Cycle
50
100
0
50
100
Fig. S2. Experimentally measured knee flexion angle, for subjects walking (1.0–1.75 m s–1) and running (2.0–5.0 m s–1) (N=5). Knee
angle (flexion positive) was calculated from marker data using an inverse kinematics algorithm and a musculoskeletal model scaled to
each subject. Data represent the group mean (black line) ±1 s.d. (shaded region).
Ankle Dorsiflexion Angle
5 Subject Mean ±1 SD
1.0 m/s
1.25 m/s
1.5 m/s
1.75 m/s
2.0 m/s
3.0 m/s
4.0 m/s
5.0 m/s
20
0
Degrees
−20
−40
20
0
−20
−40
0
50
100
0
50
100
0
% Gait Cycle
50
100
0
50
100
Fig. S3. Experimentally measured ankle dorsiflexion angle, for subjects walking (1.0–1.75 m s–1) and running (2.0–5.0 m s–1) (N=5).
Ankle angle (dorsiflexion positive/plantarflexion negative) was calculated from marker data using an inverse kinematics algorithm and
a musculoskeletal model scaled to each subject. Data represent the group mean (black line) ±1 s.d. (shaded region).
Ankle Moment Comparison
5 Subject Mean ±1 SD
1.0 m/s
5
1.25 m/s
1.5 m/s
1.75 m/s
3.0 m/s
4.0 m/s
5.0 m/s
Simulation
Inverse Dynamics
4
3
Plantarflexion Moment/Body Mass
[N·m/Kg]
2
1
0
−1
2.0 m/s
5
4
3
2
1
0
−1
0
50
100
0
50
100
0
% Gait Cycle
50
100
0
50
100
Fig. S4. Comparison of simulated and inverse dynamics ankle joint moment divided by body mass in walking and running. Ankle
joint moment generated by tibialis anterior, soleus, and gastrocnemius medialis and lateralis during each simulation was summed
(red) and compared with the moments calculated with inverse dynamics (blue). Data represent the group mean (lines) ±1 s.d. (shaded
regions).
Ankle Power Comparison
5 Subject Mean ±1 SD
1.0 m/s
8
1.25 m/s
1.5 m/s
1.75 m/s
3.0 m/s
4.0 m/s
5.0 m/s
Simulation
Inverse Dynamics
6
4
Ankle Power/Body Mass
[W/Kg]
2
0
−2
2.0 m/s
30
20
10
0
−10
−20
−30
0
50
100
0
50
100
0
% Gait Cycle
50
100
0
50
100
Fig. S5. Comparison of simulated and inverse dynamics ankle joint power divided by body mass in walking and running. Ankle
joint power generated by tibialis anterior, soleus, and gastrocnemius medialis and lateralis during each simulation was summed (red)
and compared with the ankle power calculated with inverse dynamics (blue). Data represent the group mean (lines) ±1 s.d. (shaded
regions).
FTAct/FM
Max
1
Gastrocnemius Lateralis
Gastrocnemius Medialis
Soleus
Tibialis Anterior
Biceps Femoris LH
Semitendinosus
Rectus Femoris
Gluteus Maximus
Gluteus Medius
Vastus Lateralis
Vastus Medius
0.5
0
FTAct/FM
Max
1
0.5
0
FTAct/FM
Max
1
0.5
0
FTAct/FM
Max
1
0
25
50
75
% Gait Cycle
Walking
1.00 m/s
0.5
1.25 m/s
1.50 m/s
1.75 m/s
0
0
25
50
75
% Gait Cycle
100
0
25
50
75
% Gait Cycle
100
Running
2.0 m/s
3.0 m/s
4.0 m/s
5.0 m/s
100
Fig. S6. Average simulated normalized active force for 11 muscles for subjects walking at four speeds and running at four speeds
(N=5). Active force generated along the tendon (FTAct) is normalized to the maximum isometric force of each muscle (FMMax).