Hemiparesis and/or hemiplegia is one of the most common clinical signs of stroke, characterized by partial or complete loss of motor function, resulting in varying degrees of impairment and disability. The aim of this study is evaluate the acute effects of application of phototherapy to detect if this therapeutic approach may be beneficial in gait and balance post-stroke individuals. For such, 10 volunteers, with a history of injury (stroke) between 6 months to 5 years, with deficit in functional capacity in the gait due spasticity of extensor muscles of the affected limb, specifically the Triceps Sural. The evaluation will consist of three-dimensional gait analysis, muscle activity during gait, mobility, static and functional balance, and mobility of volunteers.

This is a clinical, randomized, placebo-controlled, crossover and triple-blind study. Ten participants with injury history (stroke) will perform the protocol. The intervention will be held once a week for 4 weeks. Each week a different dose of phototherapy (Placebo, 10J, 30J and 50J) will be applied. The phototherapy, active or placebo, will be applied in 9 different points of anterior muscle of the thigh, 6 different points of posterior muscle of the thigh and 2 different points of the gastrocnemius muscle, bilaterally, before the tests. Only one investigator, that will not participat in any phase of the assessments sessions, will know about what program is active or placebo in phototherapy device. Randomisation will occur by a simple drawing of lots (A, B, C, or D) in the first visit. The phototherapy unit emitted the same sound regardless of the program used, active or placebo. For three-dimensional gait assessment and muscle activity will be used a SMART-D system 140® - BTS Engineering with six cameras, two Kistler force platforms Platform model 9286BA and FREEEMG® electromyography - BTS Engineering wireless system with four channels. In addition, the evaluation will quantify the static balance (force platform), the functional balance (Berg Balance Scale) and mobility (6 minute walk test and go upand team test).

Inclusion Criteria:

• Hemiparetic adults with a single stroke event, with crural predominance;
• Injury (stroke) from 6 months to 5 years;
• Aged between 40 and 60 years old;
• In treatment at the Uninove physical therapy clinic;
• Able to walk barefoot, with or without support;
• With verbal comprehension, controlled systemic disease and clinically stable;
• Able to perform the 6-minute walk test.

Exclusion Criteria:

• Subjects with fixed deformities, previous surgery, previous osteoarticular dysfunction, any disease that influences the performance of the march;
• Cognitive impairment detrimental to the tests;
• Subjects who do not fit the inclusion criteria.