The poor eating habits and sedentary lifestyle of young people can reflect on structural changes in adult life, leading to vascular brain diseases. The cerebrovascular accident (AVC) represents the second cause of death throughout the country. Presents rapid development of clinical signs, providing focal disorders or brain function. It is necessary to the knowledge and development of new treatment techniques that may minimize the sequelae caused by the AVC, which is a common disease and of great impact on public health, represents the main cause of adult neurological disability, affecting the basic functions of the limbs, motor control and balance, strength and mobility, which involves changes in daily life and low self-esteemIn addition to the high cost of treatment and in the long run.

Thus, this study aims to analyze the response of low intensity laser on the prevention of pain and fatigue induced in rectus femoris, vastus of patients with sequelae of spasticity associated with effects on the laser promotes on muscle performance and muscle activity.

It is believed that this study get positive results as regards the increase of time antecedent to muscular fatigue associated with the skeletal muscle performance, so that the normotonics muscles gain strength and overcome the resistance of hypertonic muscles. In this way, it is expected that after the application of low intensity Laser Therapy (LILT) occurs to the adequacy of spasticity, muscle function the gain that had provided the highest quality of physiotherapy care.

It is known that treatment with the laser on the skeletal musculature, presents positive results and on the peak torque, by means of the skeletal muscle performance and consequently gain increase muscle performance (LEAL JUNIOR et al, 2010; ALMEIDA et al, 2011).

Armed with this information you can infer that the low intensity laser therapy on the spastic muscle, would result in improving muscle performance, with an increase of pre-stressing, improving the functional capacity of individuals under the exercises imposed by physical therapy. In this way, the sessions will take more satisfactory results which jointly provided better quality of life for these patients.

With the course of the years, became notorious the transformation in the epidemiological profile of the Brazilian population, with the progressive decline of infectious diseases and illness narratives and the gradual growth of the chronic degenerative diseases, particularly cardiovascular diseases of (ARAÚJO, 2012)

According to statistics of the Ministry of health, in the year 2010 were recorded about 100 thousand deaths due to cerebrovascular accident (AVE), a result of the sudden interruption of blood flow of the brain, which is currently responsible for leading cause death in Brazil (MINISTRY of health, 2012).

The heterogeneity of the Brazilian population, would explain the current epidemiological transition, and as a result the high rates of mortality. The diseases of the circulatory system are as main cause death of Brazil, emphasizing the cerebrovascular disease, responsible for one third of deaths in the country.

The cerebral arteries are responsible for giving the necessary nutrients as a source of energy to neurons, the brain requires intense blood flow to meet your high intake of nutrients. Being that the interruption of the flow of oxygen and glucose for a period in excess of five minutes can cause irreversible damage to the brain.

Several pathological processes can cause the interruption of blood flow in certain brain areas. Between these processes include hemorrhages, embolisms, stroke and diseases that lead to suspension of blood flow, and therefore the deficit in the supply of nutrients.

The blood deficit promotes changes in cellular metabolism, which can lead to injury and/or death of brain tissue. According to estimates, 80% of the incidence of BIRD arteriolar occlusion resulting from atheroma plates or secondary brain artery emboli that deprive the brain of blood supply.

The likelihood of the AVE doubles every decade of life, from 55 years of age. Although leverage the ranking of deaths in the country, statistics from the Ministry of health in 2010, showed decreased mortality rate in the age group up to 70 years, representing an annual average reduction of 3.2% (MINISTRY of health, 2012).

As established earlier, the differences in the prevalence of risk factors among the population due to high heterogeneity, that is, different customs, habits and lifestyles. So in that, poor eating habits and physical youth population may reflect structural changes in adulthood, and may lead to vascular brain diseases. Among the risk factors associated with the AVE is hypertension, dyslipidemias, diabetes, smoking, alcoholism.

In general the clinical picture presents itself with motor and sensory changes, that may be associated with deficits in cognitive and perceptual functions by damaging both physical and physiological functions of the patient (DIETZ; SINKJAER, 2007). Due to the AVE be associated with motor disability tables, resulting in physical limitations, mainly resulting from spasticity, is necessary to search for ways to minimise this damage. In this way, it is believed that with the help of biomedical instrumentation, which in addition to providing quantitative and reliable data on the functional capacity of the individual, allows the development and recruitment of equipment to help in the evaluation of the General State of the patient and so consequently best results before the practice of neurological rehabilitation. Therefore it is of utmost importance to biomedical resource utilization as surface electromyography that refers to a method of non-invasive monitoring, providing values for the square root of the mean squared Value (RMS - R Englishoot Mean Square), demonstrating this parameter the results of signal amplitude through the average power in the time interval analyzed, containing information about the amount of traction units fired at any given movement

Isokinetic dynamometry bound that provides resistance to joint movement over a given range, enabling the analysis of muscle force-related parameters such as torque, power, and endurance. These two features combined will contribute to the determination of the time when the o muscle spastics had to fatigue muscles. On this information, the sessions can be reworded to the concrete limitations of patients and consequently the improvement of rehabilitation, which will automatically improves the quality of life of these individuals.

Inclusion Criteria:

• People with spastic hemiparesis;

  • Medical referral for physiotherapy;
  • Age between 40 and 80 years;
  • Women who are in menopause;
  • Cognitive preserved, being able to respond to verbal stimuli;
  • Modified Ashworth scale, with a maximum of 2 degree of spasticity in the flexor muscles of the knee, specifically in the muscles that make up the Quadriceps femoris.

Exclusion Criteria:

• · Patients with Hypoesthesia and/or Hyperesthesia of the side to be studied

  • The presence of active infection and rashes at the site of application of the electrodes;
  • Joint stiffness, contractures and deformities;
  • Broca's aphasia
  • Uncontrolled arterial hypertension;
  • Presence of neoplastic lesion at the site of application;
  • Intake of analgesics and/or anti-inflammatory medication during the two weeks of evaluation.