Efficacy of Split Gait in the Treatment of Dynamic Asymmetries in Subjects With Pathologic Claudication

Condition(s) studied

Investigational drug(s) / intervention(s)

Split-belt treadmill walking.: The intervention will consist of split-belt treadmill walking. During the test session, participants will walk on a split-belt treadmill mounted on force sensors with the belts running at the same or at different velocities. They will walk freely without any support. The test sequence will be the following: 1. Baseline phase. 3 minutes walking at increasing speed, speed will be increased of 0.1 m s-1 every 30 s. A brief pause of around 1 minute will follow. 2. Habituation phase. 30 seconds walking at 0.2 m s-1. 3. Adaptation phase. The velocity of the belt under the non-affected lower limb will be increased to 0.6 m s-1, while the other belt will maintain its velocity of 0.2 m s-1 for 6 minutes. 4. Post-adaptation phase. Belts' velocities will be restored at 0.2 m s-1 for 6 minutes. Participants will be informed before the changes in belts' velocities with a verbal warning. Participants will repeat the same protocol with the affected lower limb on the fast belt after one week.

Study summary

Walking on a split-belt treadmill (each of the two belts running at a different speed) imposes an asymmetrical gait, mimicking limping that has been observed in various pathologic conditions. This walking modality has been proposed as an experimental paradigm to investigate the flexibility of the neural control of gait and as a form of therapeutic exercise for hemi-paretic patients. However, the scarcity of dynamic investigations both for segmental aspects and for the entire body system, represented by the centre of mass, challenges the validity of the available findings on split gait.

Compared with overground gait in hemiplegia, split gait entails an opposite spatial and dynamic asymmetry. The faster leg mimics the paretic limb temporally, but the unimpaired limb from the spatial and dynamic point of view. These differences suggest that a partial shift in perspective may help to clarify the potential of the split gait as a rehabilitation tool.

The aim of the present study is to investigate the dynamic asymmetries of lower limbs in adults with unilateral motor impairments (e.g. hemiplegia post-stroke, Parkinson's disease, multiple sclerosis, unilateral amputation, surgical orthopedic interventions) during adaptation to gait on a split-belt treadmill. The sagittal power provided by the ankle and the total mechanical energy of the centre of mass will be thoroughly studied. The time course of phenomena both during gait when the belts are running at different speed and when the belts are set back to the same speed (i.e. the after-effect) will be investigated.

A greater dynamic symmetry between the lower limbs is expected after split gait. The question whether this symmetry will occur when the pathological limb is on the faster or the lower belt will be disclosed. Some alterations of the motion of the centre of mass during split gait are also expected.

Eligibility

Primary outcome measure(s)

• Ankle Joint Power — Two assessments, at one week-interval
  Joint kinematics will be recorded through an optoelectronic method as per the Davis anthropometric model. The 3D displacement of the markers will be captured using 10 near-infrared stroboscopic cameras. Joint power will be computed through the spatiotemporal synchronization of ground reaction force vectors and the joint centers of rotation. Only the sagittal plane will be considered for the analysis. Joint power will be computed as the product of joint torque and joint rotation speed. Power will be defined as positive or generated when the joint moment and rotation speed shared the same directions (i. e., when agonist muscles are contracting while shortening), as negative or absorbed otherwise. Positive work will be computed as the integral of the generated (positive) power over time.

Trial sites (1)

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