Figure 1. A depiction of the basic configuration of a quantitative gait analysis laboratory with passive reflective markers placed on patient walking along a straight pathway. Patient is monitored by force platforms mounted in the walkway and by an array of specialized video cameras that strobe infrared light (refer also to Video 1).

Figure 2. Knee kinematics for an adolescent with cerebral palsy spastic diplegia (shown in Video 3). The knee is excessively flexed at initial contact (Point A, when the foot first contacts the ground at beginning of the gait cycle) and remains excessively flexed while in contact with the ground (Point B, throughout stance phase of the gait cycle). Blue band on plot signifies first standard deviation of the mean normal reference in degrees.

Figure 3. Knee kinematics and associated hamstrings EMG tracing for an adolescent with cerebral palsy spastic diplegia (shown in Video 3) indicating that the hamstrings are active throughout stance phase (Point A). The blue band on the knee angle plot signifies first standard deviation of the mean normal reference in degrees. Normal firing patterns are indicated by blue bars above each signal.

Figure 4. Knee and hip kinematics for an adolescent with cerebral palsy spastic diplegia (shown in Video 3). The excessive hip flexion in late stance (Point A, ie, the hip does not achieve extension) could either be associated with excessive knee flexion in stance or inappropriate pelvic position (anterior tilt). Blue band on each plot indicates first standard deviation of the mean normal reference in degrees.

Figure 5. Knee, hip and pelvic kinematics for an adolescent with cerebral palsy spastic diplegia (shown in Video 3). Posterior tilt of pelvis in stance (Point A) is consistent with hamstring tightness which tends to tether the pelvis. Consequently, the crouch gait pattern (excessive knee flexion in stance) appears to be caused by this hamstring muscle tension. Blue band on each plot indicates first standard deviation of the mean normal reference in degrees.

Figure 6. Knee and ankle kinematics for an adolescent with cerebral palsy spastic diplegia (shown in Video 3). The absence of excessive ankle dorsiflexion in stance (Point A) indicates that plantar flexor weakness is not contributing to his crouch gait pattern (excessive knee flexion in stance). Blue band on each plot indicates first standard deviation of the mean normal reference in degrees.

Figure 7. Knee kinematics and associated EMG tracings for the rectus femoris, vastus lateralis, and vastus medialis muscles in an adolescent with cerebral palsy spastic diplegia (shown in Video 3). Delay in timing of peak knee flexion in swing (Point A), reduced range of motion of the knee in swing (Point B), and prolonged activity of rectus femoris (Point C) all serve to implicate rectus femoris spasticity as the cause of the knee kinematic anomalies in swing phase. Note absence of inappropriate activity of the two vastii muscles that were monitored. Blue band on knee angle plot indicates first standard deviation of the mean normal reference in degrees. The normal firing patterns are indicated by the blue bars above each signal.

Figure 8. Transverse plane rotation of right (red) and left (green) pelvis and hip and foot progression for a patient with cerebral palsy (Video 4). The left side pelvis is rotated externally and the right internally. There is internal rotation of left hip and normal rotation of right hip. Foot progression is internal of normal bilaterally. Note asymmetry in pelvic and hip motion in gait analysis data that is not appreciated on visual observation or clinical examination. Blue band on each plot indicates first standard deviation of the mean normal reference in degrees.

Figure 9. Sagittal plane kinematics for the right knee and ankle in a patient with cerebral palsy (Video 5). There is less than normal knee extension in terminal swing and the knee angle at initial contact is about 35 degrees (Point A). The ankle angle at initial contact is slightly dorsiflexed (Point B). Application of an ankle-foot orthosis set in neutral would not change the kinematics and the patient would continue to have a toe initial contact. Blue band on each plot indicates first standard deviation of the mean normal reference in degrees.

Figure 10. Illustration of the changes in absolute foot segment position at initial contact for: a) knee in full extension and neutral ankle, and b) knee in 30 degrees flexion and neutral ankle. These illustrations demonstrate that foot attitude is influenced not only by ankle position, but also knee position.

Figure 11. Fine-wire EMG data in raw format for the tibialis posterior and tibialis anterior for four strides for: a) Patient 1, b) Patient 2 and c) Patient 3 (all shown in Video 6). Three distinct firing patterns for the posterior tibialis are illustrated; premature onset in swing (Patient 1), negligible activity (Patient 2) and continuous activity (Patient 3). Normal firing patterns are indicated by blue bars above each signal.

Figure 12. Surface and fine-wire EMG data in raw format for the tibialis posterior, tibialis anterior and gastrocnemius for the left side of a patient three years post left open femoral fracture and femoral artery and peroneal nerve laceration (Video 7). The posterior tibialis shows a biphasic pattern in stance and variable to no firing in swing. The anterior tibialis is on continuously throughout the gait cycle. The gastrocnemius shows normal function.

Figure 13. Illustration of the net internal knee joint moment in the coronal plane for a person with a knee valgus thrust. The lateral trunk lean positions the body center of gravity lateral to the knee joint center so that there is a valgus thrust on the knee. The body's response to this thrust is a net knee adductor moment.

Figure 14. The coronal plane knee moment for the left side (red) of a patient with myelomeningocele (Video 8). The magnitude of the stance phase knee moment is less than the normal abductor moment (Point A). Blue band on plot indicates first standard deviation of the mean normal reference in Newton-meters/kg.

Figure 15. Coronal (first column), sagittal (second column) and transverse (third column) plane motion (degrees) for upper body, pelvis, hip, knee and ankle motion for right (red) and left (green) sides of a patient with myelomeningocele (Video 8). The plots document greater than normal internal rotation of the pelvis (Point A), rapid internal rotation of the hips (Point B), knee flexion (Point C), asymmetrical normal foot progression (Point D), which is more external on the right side during weight-acceptance phase of the gait cycle. This combination of movement during weight-acceptance contributes to the "visual" valgus thrust observed at the knees. Blue band on each plot indicates first standard deviation of the mean normal reference in degrees.