Stroke often affects sensory-motor networks and descending tracts, as reflected by several signs of upper motor neuron syndrome. One symptom is post-stroke spasticity. It is due to an abnormal processing of a normal input from muscle spindles in the spinal cord. It is often defined by a velocity-dependent increase in muscle tone and a resistance to passive muscle stretch. It has neural (increased reflex activity) and non-neural (altered visco-elastic properties due to immobilization) components. The prevalence of spasticity ranges from 25%-43% at 6 months post-stroke. Chronic spasticity can decrease the number of sarcomeres. As a result, the proportion of connective tissue in the muscle and fasciae can increase. These subjects present fibrosis that have augmented passive muscle stiffness due to structural and functional adaptations inside the muscle cells. Soft tissue changes may cause the pulling forces to be transmitted more readily to the muscle spindles, which can intensify sensory input thus increasing spasticity. It has a potential impact on lower limb function, which affects passive muscle stretch, range of motion, and motor unit recruitment during voluntary contraction. In the stance phase of gait, the deformity also produces an inadequate base of support, which is associated with balance impairments. This increases the risk of falls, reduces patient participation in daily activities, and decreases health-related quality of life. Physiotherapy treatments of spasticity aim to decrease excessive muscular tone, ease mobility, give the patient the sense of right position and avoid joint limitations.~Functional massage is a non-invasive manual therapy technique that combines rhythmical passive joint mobilization with compression and decompression of the muscular belly with the tendinomuscular insertions to treat. It is indicated in cases of muscle stiffness associated with pain.~Tecar therapy or Capacitive Resistive Electric Transfer Therapy (CRet) is a non-invasive diathermy technique which provides high frequency energy (300 KHz-1.2 MHz) generating a thermal effect on soft tissues. CRet is used to facilitate tissue regeneration, and it does not need a surface-cooling system, as its wave frequency is lower than in conservative diathermy. CRet effectiveness has been evaluated in several studies. It is effective in the treatment of chronic musculoskeletal disorders, where a temperature increase on deep tissues is needed in order to generate changes on its viscoelasticity. This effect may be beneficial in the spasticity treatment since spasticity onset and development may be affected by structural changes in muscular and tendinous fibers.~No studies on the effects of CRet in post-stroke spasticity treatment were found.
Spasticity is due to an abnormal processing of a normal input from muscle spindles in the spinal cord.