Inclusion Criteria:
* Stroke, with cortical and/or subcortical lesions, of at least 6-months duration at study inclusion
* Spasticity in the lower extremity plantarflexors (gastrocnemius, soleus muscles) due to stroke with a baseline score of 1-4 as assessed by the Tardieu scale
* Minimum 1-month duration of spasticity as confirmed by medical history
* Modified Rankin score \< 4
* Cognitive functions sufficient to understand the experiments and follow instructions and ability to provide informed consent in accordance with ICH and GCP
* Affiliated with the French social security scheme, universal medical coverages (CMU), or an equivalent scheme.
Exclusion Criteria:
* Enrollment in another biomedical research study at the time of the MyoRegulator study.
* Fixed contractures or profound muscle atrophy in the spastic limb
* Ongoing use of digitalis, morphine, intrathecal pump
* Plantar orthosis or history of orthopedic surgery that can interfere with gait analysis
* Botulinum toxin treatment within 12 weeks of study enrollment
* Prior phenol or alcohol injections within 6 months of study enrollment
* Change in the antispastic treatment (baclofen, clonidine, benzodiazepine, dantrolene, gabapentine, tizanidin) in the 2 months prior to visit 1.
* Allergy to latex
* Presence of potential tsDCS risk factors:
* Damaged skin at the stimulation sites (i.e., skin with ingrown hairs, acne, razor nicks, wounds that have not healed, recent scar tissue, broken skin, cancerous lesions, etc.)
* Lack of sensory perception at the stimulation sites
* Presence of an electrically, magnetically or mechanically activated implant (including cardiac pacemaker, epidural stimulation electrodes, etc.), an intravascular clip or any other electrically sensitive support system
* Metal in or on the body in the direct path of the stimulation current (jewelry must be removed during stimulation)
* Past history of seizures or unexplained spells of loss of consciousness during the previous 36 months
* Prior trans-spinal direct current stimulation for any reason or prior trans-cranial direct current stimulation in the past 12 months
* Any medical condition that would prevent the subject from being able to participate in the clinical outcome measures
* Pregnancy in women (as determined by a urine pregnancy test in pre-menopausal women), or lactating women or women planning pregnancy during the course of the study
* Patient under guardianship or curatorship, or under judicial supervision
