The objectives of the study are to evaluate a 4-week mixed training paradigm consisting of explosive strength training and balance perturbation training efficacy on balance control during standing and locomotion, and to understand the mechanisms of neuroplasticity that would improve sensorimotor integration at supraspinal and spinal levels.
After obtaining their consent, participants will undertake evaluations at different times: 1. Assessment 1 week prior to training 2. Training over 4 weeks (nature of the training depends on the group) 3. Assessment 1 week after training 4. Assessment 1 month after training (follow-up) Each assessment will be divided in 2 sessions and data will be collected over 2 days, at one session per day. Days can be consecutive or non-consecutive but will be within a given week. The assessment consists of: * Session 1 (S1; duration: 3h) will include presentation of the Study and obtainment of consent, clinical tests, galvanic vestibular stimulation testing, postural reactions and gait assessment. * Session 2 (S2; duration: 3h) will include muscle strength, short-afference inhibition, paired pulse and trans cranial magnetic stimulation conditioning of H reflex. After the initial assessment, iSCI participants will be separated in 2 groups and will receive combination of explosive strength and balance training or no intervention. The training will span over 12 sessions (3 times per week for 4 weeks) and each training session will last approximately 1h (including effective training and installation periods).
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
36
Training will consist to perform one hour of combined ankle explosive strength training and specific balance training using randomized perturbations. Explosive strength training: Participants will perform only 2 sets of 3 min (12 contractions for each set) for both lower limbs and both ankle plantar- and dorsiflexion movements. Balance specific training: Participants will be standing, secured by an adjusted harness, which do not support the weight but is strictly there to prevent a fall. They will have online visual feedback of their CoP via an avatar on the screen in front of them. Each training session will consist of 10 sequences of 3 min, including the 5 different conditions: * Forward tilt of base of support; * Backward tilt of base of support; * Translation forward; * Translation backward; * Without moving their feet, participants will have to move their avatar to reach different targets placed around them on the screen, at different distance from the center.
Neuromobility lab
Montreal, Quebec, Canada
RECRUITINGChange in muscles EMG responses following balance perturbation
Evaluation of the latency on Soleus and Tibialis anterior muscles EMG following backward and forward perturbations will be done.
Time frame: Pre-intervention, immediately after and one-month after intervention
Change in center of pressure displacement following balance perturbation using a force platform
Excursion of centre of pressure will be analyzed following forward and backward perturbation.
Time frame: Pre-intervention, immediately after and one-month after intervention
Change in ankle muscle strength using force transducer
Evaluation of isometric dorsi- and planti-flexors muscle strength in Newton will be done using a force transducer attached to the participant's feet.
Time frame: Pre-intervention, immediately after and one-month after intervention
Change in intracortical mechanisms using transcranial magnetic stimulation (TMS)
A paired-pulses paradigm (two trans cranial magnetic stimulations at motor cortex level) will be used to evaluate the intracortical mechanisms
Time frame: Pre-intervention, immediately after and one-month after intervention
Change in the influence of peripheral afferents on cortical output using short-afference inhibition
A stimulation (using TMS) at motor cortex level will be triggered just after a peripheral electrical stimulation of tibial nerve to evaluate the peripheral afferents on cortical output.
Time frame: Pre-intervention, immediately after and one-month after intervention
Change in the modulation of the H reflex by the corticospinal tract
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A stimulation (using TMS) at motor cortex level will be triggered just before a tibial nerve stimulation to evaluate the modulation of the H reflex by the corticospinal tract.
Time frame: Pre-intervention, immediately after and one-month after intervention
Change in EMG responses following vestibular stimulations during quiet standing
Galvanic vestibular stimulation will be triggered during quiet standing. EMG responses of Soleus and Tibialis Anterior muscles will be analyzed.
Time frame: Pre-intervention, immediately after and one-month after intervention
Change in the excursion of the center of pressure following vestibular stimulations
Galvanic vestibular stimulation will be triggered during quiet standing. The displacement of the center of pressure will be analyzed using a force platform.
Time frame: Pre-intervention, immediately after and one-month after intervention