| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4050022 | Clinical Biomechanics | 2016 | 7 Pages |
•We examined stride time, stride length and trunk velocity with nonlinear analyses.•Mean values were equivalent between overground and treadmill walking.•Complexity in stride time variability was reduced on the treadmill.•Self-similarities in stride time and stride length were reduced on the treadmill.•Treadmill ambulation may alter typical gait dynamics.
BackgroundReduced inter-stride complexity during ambulation may represent a pathologic state. Evidence is emerging that treadmill training for rehabilitative purposes may constrain the locomotor system and alter gait dynamics in a way that mimics pathological states. The purpose of this study was to examine the dynamical system components of gait complexity, fractal dynamics and determinism during treadmill ambulation.MethodsTwenty healthy participants aged 23.8 (1.2) years walked at preferred walking speeds for 6 min on a motorized treadmill and overground while wearing APDM 6 Opal inertial monitors. Stride times, stride lengths and peak sagittal plane trunk velocities were measured. Mean values and estimates of complexity, fractal dynamics and determinism were calculated for each parameter. Data were compared between overground and treadmill walking conditions.FindingsMean values for each gait parameter were statistically equivalent between overground and treadmill ambulation (P > 0.05). Through nonlinear analyses, however, we found that complexity in stride time signals (P < 0.001), and long-range correlations in stride time and stride length signals (P = 0.005 and P = 0.024, respectively), were reduced on the treadmill.InterpretationTreadmill ambulation induces more predictable inter-stride time dynamics and constrains fluctuations in stride times and stride lengths, which may alter feedback from destabilizing perturbations normally experienced by the locomotor control system during overground ambulation. Treadmill ambulation, therefore, may provide less opportunity for experiencing the adaptability necessary to successfully ambulate overground. Investigators and clinicians should be aware that treadmill ambulation will alter dynamic gait characteristics.
