Inertial measurement unit (IMU)-based gait analysis can be used to quantitatively analyze the bilateral coordination and gait asymmetry (GA). The purpose of this study was to investigate changes in bilateral coordination and GA due to gait speed using an IMU based gait analysis and identify spatiotemporal factors affecting bilateral coordination and GA. Eighty healthy adults (40 men and 40 women) participated in the study. The mean age was 26.2 years, and the mean body mass index was 22.8 kg/m2. Three different walking speeds (80%, 100%, and 120% of preferred walking speed) on a treadmill were applied for 1 min of continuous level walking using a shoe-type IMU-based gait analysis system. The phase coordination index (PCI) and GA were calculated on three different walking speeds. Several variables (gait speed, height, body mass index, cadence, and step length) were analyzed as possible factors affecting the PCI and GA. Bilateral coordination and GA improved during fast walking (p = 0.005 and p = 0.019, respectively) and deteriorated during slow walking (p<0.001 and p = 0.008, respectively), compared with the participants’ preferred walking speeds. The correlation analysis revealed that PCI was negatively correlated with step length at each walking condition and lower gait speed was negatively correlated with PCI and GA during slow walking. Both bilateral coordination and GA had a negative linear relationship with gait speed, showing an improvement in the fast walking condition and deterioration in the slow walking condition. Step length was the factor associated with the change in the bilateral coordination.

Background: The literature has seldom investigated the anterior cruciate ligament (ACL) tunnel position while considering the effect of rotation of 3-dimensional computed tomography (3D-CT) images during measurements. Hypothesis: We hypothesized that (1) measurement of the ACL tunnel position in the femur and tibia through use of 3D-CT is considerably influenced by rotation of the 3D model and (2) there exists a reliable measurement method for ACL tunnel position least affected by rotation. Study Design: Controlled laboratory study. Methods: The 3D-CT images of 30 randomly selected patients who underwent single-bundle ACL reconstruction were retrospectively reviewed. For femoral tunnel assessments, rectangular reference frames were used that involved the highest point of the intercondylar notch and outer margins of the lateral femoral condyle (method 1), the highest point of the intercondylar notch and outer margins of the lateral wall of the intercondylar notch (method 2), and the lowest point of the intercondylar notch and outer margins of the lateral femoral condyle (method 3). For tibial tunnel assessments, rectangular reference frames with the cortical outline at the articular surface of the tibia (method A) and the cortical outline of the proximal tibia (method B) were used. For both femoral and tibial assessments, the tunnel positions at 5°, 10°, and 15° of rotation of the 3D model were compared with that at a neutral position. Results: The values measured by methods 1 and 3 showed significant differences at greater than 5° of rotation compared with the value at the neutral position, whereas method 2 showed relatively consistent results. However, the values measured with both methods A and B showed significant differences at greater than 5° of rotation compared with the value at the neutral position. Conclusion: The tunnel position on 3D-CT images was significantly influenced by rotation during measurements. For femoral tunnel position, measurement with a reference frame using the lateral wall of the intercondylar notch (method 2) was the least affected by rotation, with relatively consistent results. Clinical Relevance: This study demonstrates that measurement using the lateral wall of the intercondylar notch might be a consistent and reliable method for evaluating the ACL femoral tunnel position considering the effect of 3D-CT image rotation during measurements. However, both methods to measure tibial tunnel position described in this study were similarly affected by rotation.

Study design: Comparison group design.Objective: To compare the temporal distance factors during gait initiation between patients with incomplete cervical spinal cord injury, incomplete lumbosacral spinal lesion, and unimpaired control adults. Setting: Human performance and movement analysis laboratory, Taiwan. Participants: Five patients with an incomplete cervical spinal cord injury (Group 1), five patients with an incomplete lumbosacral spinal lesion (Group 2) and nine unimpaired control adults (Group 3). Methods: Subjects underwent a three-dimensional gait analysis. The total gait initiation period, reaction time, each relative phasing of gait initiation and the length of the first step were identified by using the kinematic measurement system. Main outcome measures: The total gait initiation period (start of the auditory cue for gait initiation to heel-strike of the first swing leg); each relative phasing of gait initiation indicated that the duration of the preparatory phase (start of auditory cue for gait initiation to heel-off of the first swing leg), the duration of the push-up phase (heel-off to toe-off of the first swing leg), and the duration of the single-stance phase (toe-off to heel-strike of the first swing leg) established by the total gait initiation period; and the length of the first step. Results: The gait initiation period was greater in Groups 1 and 2 than that of Group 3 (Po0.05). Each relative phasing including the duration of the preparatory phase, the push-up phase, and the swing phase relative to the total gait initiation period, did not differ among Groups 1-3 (P40.05). The length of the first step, measured while the nonpreferred leg stepped first in Groups 1 and 2, was shorter than that of Group 3 (Po0.05). Conclusions: Patients with incomplete cervical spinal cord injuries or lumbosacral spinal lesions took more time in gait initiation than unimpaired control adults. The first step length also reduced in these patients while the nonpreferred leg stepped first, as compared to unimpaired control adults. The data indicated that centrally programmed gait initiation might be preserved in ASIA-D spinal patients who, in this study, executed gait initiation with varying temporal distance strategies to compensate for peripheral impairments, as compared to unimpaired control adults.