This study consists of three phases that aim to develop an exercise intervention to promote maximal activation of ankle plantar flexors in the paretic lower extrimty (LE) in order to restore a more normalized gait pattern in chronic stroke survivors. The aim of the first phase is to determine if there are differences between standing on different levels of inclination on plantar flexion activation during forward movement of the contralateral LE in adults with chronic with stroke. The aim of second phase is to determine if there are differences between different percentages of weight bearing on the paretic LE on plantar flexion activation during forward movement of the contralateral LE in adults with chronic stroke. The aim of the third phase is to determine if there are differences between a 4-week plantar flexion training intervention and conventional physical therapy.
Description of Arms: This study has three phases. The first phase is performed in a cross-over fashion. Participants will stand on two different incline angles on the paretic LE and simultaneously move a small skateboard forward with the non-paretic LE. The testing order for the two different incline angles will be randomized, and all participants will be required to complete both incline angle conditions within a single test session. The second phase will also be performed in a cross-over fashion. Participants will stand with three different percentages of body weight on their paretic LE while moving the skateboard forward with the non-paretic LE. The testing order for the three body weight percentages will be randomized. All participants will be required to complete all three body weight conditions within a single test session. In the third phase, participants will be randomized to either a control 4-week exercise intervention (conventional physical therapy) or a 4-week experimental exercise intervention (plantar flexion training). Both the control and exerimental arms will complete over-ground multi-directional gait training and home exercise.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
15
Participants will stand on a specified incline angle (0 degrees) and with a specified body weight (50%) on the paretic LE and will simultaneously move a small skateboard forward with the non-paretic LE.
Participants will stand on a specified incline angle (5 degrees) and with a specified body weight (50%) on the paretic LE and will simultaneously move a small skateboard forward with the non-paretic LE.
Participants will stand on a specified incline angle (either 0 or 5 degrees, whichever is determined during phase 1 to be optimal) and with a specified body weight (75%) on the paretic LE and will simultaneously move a small skateboard forward with the non-paretic LE.
Participants will stand on a specified incline angle (either 0 or 5 degrees, whichever is determined during phase 1 to be optimal) and with a specified body weight (90%) on the paretic LE and will simultaneously move a small skateboard forward with the non-paretic LE.
This intervention occurs in phase 3. Subjects will participate in 1-hour sessions three times per week for four weeks. The control group will perform three sets of ten repetitions of the following 4 exercises, for a total of 120 repetitions: 1) standing hip abduction against green theraband resistance with upper extremity support, 2) sit to stands from chair with no upper extremity support, 3) bilateral calf raises with upper extremity support, and 4) right and left weight shifting exercises using a wobble board with upper extremity support available if needed.
This intervention occurs in phase 3. Subjects will participate in 1-hour sessions three times per week for four weeks. The experimental group will perform the skateboard exercise with the optimal parameters established during studies 1 and 2 (that is, an incline angle of either 0 or 5 degrees and a body weight percentage of 50%, 75%, or 90%)--the forward and backward speed of the skateboard will be cued with a metronome that will set at a beats per minute that matches the foot strike cadence of someone walking at 0.7 m/s, and the magnitude of forward excursion of the skateboard will be individualized to the participant based on GAITRite® data (that is, step length of the non-paretic LE).
In the over-ground multi-directional gait protocol, the participant will walk 750 steps forward, 50 steps backward, and 200 side steps over level surfaces. The over ground gait training will focus on equalizing step length while performing multi-directional gait training.
Home exercise consists of three sets of ten repetitions of the following three exercises to be performed on non-therapy days over the four weeks of phase 3: 1) sit to stands from chair with no upper extremity support, 2) bilateral calf raises with hand support, and 3) resisted side stepping to the non-paretic side using a green theraband with upper extremity support.
The University of Texas Health Science Center at Houston
Houston, Texas, United States
Step length asymmetry ratio as assessed by the GAITRite®
The step length asymmetry ratio will be calculated by dividing the paretic step length by non-paretic step lengths. The magnitude of the ratio indicates the nature of the asymmetry, with symmetrical gait defined as step length ratio of 0.9-1.1, and asymmetrical gait where the non-paretic step lengths are longer than the paretic step lengths with any step length ratio greater than 1.1.
Time frame: baseline, 6 weeks (relative to the phase 3 intervention)
Muscle activity of the medial gastrocnemius as assessed by surface EMG
Muscle activity of the medial gastrocnemius will be assessed using surface EMG (Delsys Trigno EMG system, Boston, MA, USA). The EMG instrument will be placed on the muscle belly of medial gastrocnemius muscle in the paretic lower extremity (LE).
Time frame: on the 1 day of the phase 1 intervention
Muscle activity of the soleus as assessed by surface EMG
Muscle activity of the medial gastrocnemius will be assessed using surface EMG (Delsys Trigno EMG system, Boston, MA, USA). The EMG instrument will be placed on the muscle belly of soleus muscle in the paretic lower extremity (LE).
Time frame: on the 1 day of the phase 1 intervention
Plantar flexion torque as assessed by isokinetic dynamometry
Peak plantar flexion torque will be acquired using an isokinetic dynamometer(Biodex Medical Systems, Shirely, New York, USA). Calibration of the Biodex® will be performed prior to the assessment of each individual. For each participant, the plantar flexors will be warmed-up on a LE ergometer for 10 minutes prior to testing. The participant will be fully secured to prevent compensatory behaviors from trunk or hips that may influence results. A pre-speed warm up on the Biodex of three submaximal repetitions and one maximal repetition will be conducted prior to testing so the participant understands what these repetitions feel like. The angular velocity will be set a 60°/second, five repetitions will be performed, and the peak torque of the plantar flexors will be collected.
Time frame: baseline, 6 weeks (relative to the phase 3 intervention)
Muscle activity of the medial gastrocnemius as assessed by surface EMG
Muscle activity of the medial gastrocnemius will be assessed using surface EMG (Delsys Trigno EMG system, Boston, MA, USA). The EMG instrument will be placed on the muscle belly of medial gastrocnemius muscle in the paretic lower extremity (LE).
Time frame: on the 1 day of the phase 2 intervention
Muscle activity of the soleus as assessed by surface EMG
Muscle activity of the medial gastrocnemius will be assessed using surface EMG (Delsys Trigno EMG system, Boston, MA, USA). The EMG instrument will be placed on the muscle belly of soleus muscle in the paretic lower extremity (LE).
Time frame: on the 1 day of the phase 2 intervention
Gait speed as assessed by the GAITRite®
Self-selected gait speed will be acquired using the GAITRite®.
Time frame: baseline, 6 weeks (relative to the phase 3 intervention)
Muscle activity of the medial gastrocnemius as assessed by surface EMG
Muscle activity of the medial gastrocnemius will be assessed using surface EMG (Delsys Trigno EMG system, Boston, MA, USA). The EMG instrument will be placed on the muscle belly of medial gastrocnemius muscle in the paretic lower extremity (LE).
Time frame: baseline, 6 weeks (relative to the phase 3 intervention)
Muscle activity of the soleus as assessed by surface EMG
Muscle activity of the medial gastrocnemius will be assessed using surface EMG (Delsys Trigno EMG system, Boston, MA, USA). The EMG instrument will be placed on the muscle belly of soleus muscle in the paretic lower extremity (LE).
Time frame: baseline, 6 weeks (relative to the phase 3 intervention)
Quality of life as assessed by the Stroke Impact Scale
The physical domain of the Stroke Impact Scale will used to determine quality of life. The Stroke Impact Scale is a self-report measure designed to capture eight domains of health status. The physical domain has nine items that are rated using a 5 point Likert scale in terms of how difficult certain physical tasks are. The domains are scored separately using a transformed scale formula: \[(raw score - lowest possible raw score) / highest possible raw score\] x 100. A composite score will be assessed.
Time frame: baseline, 6 weeks (relative to the phase 3 intervention)
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