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The objective of this study was to evaluate the effects of cardiorespiratory rehabilitation (CR) and transcranial photobiomodulation (tPBM) on exercise tolerance (ET), heart rate variability (HRV), and peripheral muscle activity in individuals with spasticity. Fifteen participants with spasticity were randomly assigned to two groups: the tPBM group (tPBMG) consisted of eight volunteers who underwent tPBM (on mode) and CR, while the control group (CG) consisted of seven volunteers who underwent simulated tPBM (off mode) and CR. The CR program included 12 weeks of treatment, twice a week for one hour, involving aerobic exercises and lower limb strengthening. For tPBM, a cluster with three lasers (λ = 680 nm, 808 nm), with a power of 100 mW/laser and energy of 36 J, applied to the F7, F8, and Fpz points. The following parameters were evaluated after 8 and 12 weeks: ET, HRV, and surface electromyography (EMG) of the rectus femoris muscle during orthostasis (ORT), isometric squatting (ISOM), and isotonic squatting (ISOT). Both groups showed a 40% increase in ET for the CG and a 30% increase for the tPBMG. The CG had more pronounced parasympathetic modulation alterations during post-exercise effort and recovery compared to the tPBMG. The EMG results showed that the tPBMG exhibited progressive improvement in muscle activity during ISOM and ISOT, as well as a decrease in the interlimb difference. In conclusion, both CR and tPBMG demonstrated improvements in ET. However, tPBMG specifically showed promising effects on HRV modulation and peripheral muscle electrical activity, providing additional benefits compared to CR alone., (© 2023. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Stroke results in impairment of basic motor functions, such as muscle weakness in limbs affected by spasticity, leading to peripheral fatigue and impaired functionality. The clinical use of photobiomodulation therapy (PBMT) has provided major advances in the treatment of muscular disorders and prevention of muscle fatigue. The aim of this study was to analyze the effects of two distinct therapies in biceps spasticity of chronic hemiparetic patients. We analyzed range of elbow motion, torque, electromyography, and mean spectral frequency after 10 sessions of PBMT (Laser 100 mW, 808 nm, 159.24 J/cm 2 /point, 5 J/point); PBMT active or placebo was associated with exoskeleton-assisted functional treatment. A double-blind placebo-controlled sequential clinical trial was conducted with 12 healthy volunteers and 15 poststroke patients who presented upper-limb spasticity. The healthy volunteers performed only the evaluation protocol, and the poststroke volunteers participated in three consecutive phases (PBMT, PBMT + exoskeleton, placebo + PBMT) with a washout period of 4 weeks between each phase. We could observe significant increases in range of elbow motion after PBMT from 57.7 ± 14 to 84.3 ± 27.6 degrees (p < 0.001). The root mean square (RMS) values also increased after PBMT + exoskeleton from 23.2 ± 15 to 34.9 ± 21 μV (p = 0.0178). Our results suggest that the application of PBMT may contribute to an increased range of elbow motion and muscle fiber recruitment, increases in muscle strength, and, hence, to increase signal conduction on spastic muscle fibers in spastic patients.

Background: Muscular fatigue is caused by biochemical alterations that modify the mechanics of muscle contraction, resulting in negative changes in the performance of the contraction. Several resources are studied to mitigate this situation among which we can cite low-level laser therapy (LLLT). The effects of LLLT are being studied in healthy subjects with fibromyalgia and who are athletes, and currently the studies are being performed in spastic muscles with poststroke individuals. The aim will be to evaluate the effects of LLLT on the fatigue of the biceps brachii muscle of healthy individuals and individuals with spastic hemiparesis., Methods: A cross-sectional, comparative, randomized, placebo, double-blind clinical trial will be divided into 2 phases: phase I shall consist of 30 healthy subjects and phase II of 30 poststroke individuals. The study will consist of 3 groups (control group, placebo group, and LLLT group), and all individuals will pass through all groups, following the randomization criteria. The protocol consists of the application of LLLT in the biceps brachii muscle on the dominant side in healthy individuals and in the hemiparetic side of poststroke individuals, and, subsequently, 3 maximal isometric voluntary contractions (MIVCs) will be performed for 50 seconds in the dynamometer, with an interval of 50 seconds between them. Pain intensity will be evaluated by means of the visual analog scale, and the myoelectric activity by means of surface electromyography associated with the evaluation of muscular strength by means of the dynamometer. The local temperature will be evaluated by infrared thermography and blood lactate concentration through the lactimeter, which will be measured at 4 different times, before the application of the laser (basal), and 3, 15, and 25 minutes after the MIVC.

A cerebrovascular accident (CVA) may affect basic motor functions, including spasticity that may be present in the upper extremity and/or the lower extremity, post-stroke. Spasticity causes pain, muscle force reduction, and decreases the time to onset of muscle fatigue. Several therapeutic resources have been employed to treat CVA to promote functional recovery. The clinical use of low-level laser therapy (LLLT) for rehabilitation of muscular disorders has provided better muscle responses. Thus, the aim of this study was to evaluate the effect of the application of LLLT in spastic muscles in patients with spasticity post-CVA. A double-blind clinical trial was conducted with 15 volunteer stroke patients who presented with post-stroke spasticity. Both males and females were treated; the average age was 51.5 ± 11.8 years old; the participants entered the study ranging from 11 to 48 months post-stroke onset. The patients participated in three consecutive phases (control, placebo, and real LLLT), in which all tests of isometric endurance of their hemiparetic lower limb were performed. LLLT (diode laser, 100 mW 808 nm, beam spot area 0.0314 cm(2), 127.39 J/cm(2)/point, 40 s) was applied before isometric endurance. After the real LLLT intervention, we observed significant reduction in the visual analogue scale for pain intensity (p = 0.0038), increased time to onset of muscle fatigue (p = 0.0063), and increased torque peak (p = 0.0076), but no significant change in the root mean square (RMS) value (electric signal in the motor unit during contraction, as obtained with surface electromyography). Our results suggest that the application of LLLT may contribute to increased recruitment of muscle fibers and, hence, to increase the onset time of the spastic muscle fatigue, reducing pain intensity in stroke patients with spasticity, as has been observed in healthy subjects and athletes.

The cerebrovascular accident (CVA), high-impact disease II, affects the basic functions of the limbs, leading to changes of sensory, language, and motor functions. The search for resources that minimize the damage caused by this disease grows every day. The clinical use of low-intensity laser therapy (LILT) has provided major breakthroughs in the treatment of muscular disorders and prevention of muscle fatigue. Thus, the objective of the present study is to analyze the answers and immediate adaptations of the rectus femoris and vastus medialis of spastic hemiparetic patients, facing the increase in peak torque and triggering muscle fatigue, after application of LILT. Double-blind clinical trials were conducted with 15 volunteers post-CVA with spasticity, of both genders, between 40 and 80 years old. To this end, the volunteers went through three consecutive stages of rating (control, placebo, and laser). All performed tests of isometric contraction on the patient's hemiparetic side. Significant differences were observed with regard to the increase in muscle performance (p = 0.0043) and the reduction in blood lactate concentration (p < 0.0001) of the post-LILT muscles. The LILT (diode laser, l100 mW 808 nm, 4.77 J/cm(2)/point, 40 s/AP) can be employed during and after spastic muscle-strengthening exercises, contributing to the improvement of motor function of the patient. After application of LILT, we found increased torque as well as decreased in lactate level in patients with spasticity.