The effect of low level laser therapy for pain in major muscles controlling two joints.

BACKGROUND AND AIMS: Chronic pain is a significant health care problem which is often encountered in medical institute out-patient clinics . In previous studies we have reported on the benefits of low level laser therapy (LLLT) for chronic musculoskeletal pain patients. The present study is a report on the effects of LLLT in patients with pain in major muscles which govern the motion of two joints (2-joint muscles). MATERIALS AND METHODS: Over the past 5 years, 19 subjects visited our out-patient clinic with complaints of pain in 2-joint muscles (biceps brachii muscle or gastrocnemius muscle). They were treated with LLLT using a 1000 mW semi-conductor laser device delivering 20.1 J/cm2 per point at 830 nm in continuous wave. Four shots were given per session (1 treatment) twice a week for 2 months (total of 16 treatments). RESULTS: A treatment approach modified from the methods of Shiroto and Ohshiro, was used, and the efficacy of LLLT for pain attenuation in the affected muscle was determined. After the end of the treatment regimen, excellent and good improvement was observed in 16 patients out of 19. Discussions with the patients revealed that it was important for them to learn how to modify their everyday life to avoid posture and activities of daily life that could cause them pain in the 2-joint muscles, in order to enjoy continuous benefits from the treatment. CONCLUSION: The present study demonstrated that LLLT was an effective form of treatment for pain in the biceps brachii and gastrocnemius muscles. To maximize and prolong treatment efficacy, advice should be given to patients to avoid adopting any posture and activities of daily living which would cause pain in these specific muscles.

Increase in rate of force development with skin cooling during isometric knee extension.

Rate of force development (RFD) plays an important role when performing rapid and forceful movements. Cold-induced afferent input with transient skin cooling (SC) can modulate neural drive. However, the relationship between RFD and SC is unknown. The purpose of this study was to investigate whether SC increases RFD during isometric knee extension. Fifteen young healthy men (25 ± 8 yrs old) contracted their quadriceps muscle as fast and forcefully as possible with or without SC. Skin cooling was administered to the front of the thigh. Torque and electromyographic activity were measured simultaneously. Peak torque was not affected by SC. Skin cooling induced a significant increase in RFD at the phase 0-30 and 0-50 ms. The root mean square of the electromyography of vastus medialis, rectus femoris and vastus lateralis at the phases 0-30-50-100 ms increased significantly or tended to increase with SC. These results suggest that SC may increase neural drive and improve RFD in the very early phases of contraction.

Low Level Laser Therapy for chronic knee joint pain patients.

BACKGROUND AND AIMS: Chronic knee joint pain is one of the most frequent complaints which is seen in the outpatient clinic in our medical institute. In previous studies we have reported the benefits of low level laser therapy (LLLT) for chronic pain in the shoulder joints, elbow, hand, finger and the lower back. The present study is a report on the effects of LLLT for chronic knee joint pain. MATERIALS AND METHODS: Over the past 5 years, 35 subjects visited the outpatient clinic with complaints of chronic knee joint pain caused by the knee osteoarthritis-induced degenerative meniscal tear. They received low level laser therapy. A 1000 mW semi-conductor laser device was used to deliver 20.1 J/cm(2) per point in continuous wave at 830nm, and four points were irradiated per session (1 treatment) twice a week for 4 weeks. RESULTS: A visual analogue scale (VAS) was used to determine the effects of LLLT for the chronic pain and after the end of the treatment regimen a significant improvement was observed (p<0.001). After treatment, no significant differences were observed in the knee joint range of motion. Discussions with the patients revealed that it was important for them to learn how to avoid postures that would cause them knee pain in everyday life in order to have continuous benefits from the treatment. CONCLUSION: The present study demonstrated that 830 nm LLLT was an effective form of treatment for chronic knee pain caused by knee osteoarthritis. Patients were advised to undertake training involving gentle flexion and extension of the knee.

Change in EMG with skin friction at different frequencies during elbow flexion.

Modulation of muscle activation in superficial and deeper regions may be induced by tactile stimulation. The purpose of this study was to examine changes in muscle activation with skin friction. Subjects performed an isometric elbow flexion at 30% maximal voluntary cotraction (MVC) with skin friction at different frequencies (0.5-2.7 Hz). Surface electromyography (S-EMG) and intramuscular EMG were obtained from the elbow flexor muscles (BBS: short head of biceps brachii, BBL: long head of biceps brachii, BRA: brachialis). S-EMG activity decreased at a higher frequency of 2.7 Hz and increased linearly with an increase in skin friction frequency (0.5-2.7 Hz) in BBS. A decrease in high-threshold motor unit (HT-MU) firing rate in superficial regions and an increase in low-threshold motor unit (LT-MU) firing rate in deeper regions were observed with skin friction (2.7 Hz) in BBS. The actions of inhibitory interneurons may be influenced by cutaneous afferent input with skin friction. Muscle activation of BBS depended on the intensity of the stimulus. Skin friction over BBS results in an inhibitory response in superficial regions of BBS, most likely due to the increase in firing rate of low-threshold cutaneous mechanoreceptors.

Low level laser therapy for patients with cervical disk hernia.

BACKGROUND AND AIMS: In previous studies we have reported the benefits of low level laser therapy (LLLT) for chronic shoulder joint pain, elbow, hand and finger pain, and low back pain. The present study is a report on the effects of LLLT for chronic neck pain. MATERIALS AND METHODS: Over a 3 year period, 26 rehabilitation department outpatients with chronic neck pain, diagnosed as being caused by cervical disk hernia, underwent treatment applied to the painful area with a 1000 mW semi-conductor laser device delivering at 830 nm in continuous wave, 20.1 J/cm(2)/point, and three shots were given per session (1 treatment) with twice a week for 4 weeks. RESULTS: 1. A visual analogue scale (VAS) was used to determine the effects of LLLT for chronic pain and after the end of the treatment regimen a significant improvement was observed (p<0.001). 2. After treatment, no significant differences in cervical spine range of motion were observed. 3. Discussions with the patients revealed that in order to receive continued benefits from treatment, it was important for them to be taught how to avoid postures that would cause them neck pain in everyday life. CONCLUSION: The present study demonstrates that LLLT was an effective form of treatment for neck and back pain caused by cervical disk hernia, reinforced by postural training.

Low level laser therapy (lllt) for chronic joint pain of the elbow, wrist and fingers.

BACKGROUND AND AIMS: In previous studies, we successfully applied Low Level Laser Therapy (LLLT) in patients with non-specific chronic pain of the shoulder joint and lower back. The purpose of the present study was to assess the effectiveness of LLLT for chronic joint pain of the elbow, wrist, and fingers. SUBJECTS AND METHODS: Nine male and 15 female patients with chronic joint pain of the elbow, wrist, or fingers, who were treated at the rehabilitation outpatient clinic at our hospital from April, 2007 to March, 2009 were enrolled in the study. We used a 1000 mW semiconductor laser device. Each tender point and three points around it were irradiated with laser energy. Each point was irradiated twice for 20 s per treatment, giving a total of three minutes for all 4 points. Patients visited the clinic twice a week, and were evaluated after four weeks of treatment. Pain was evaluated with a Visual Analogue Scale (VAS). Statistical analysis of the VAS scores after laser irradiation was performed with Wilcoxon's signed rank sum test, using SPSS Ver.17. RESULTS: All VAS scores were totaled and statistically analyzed. The average VAS score before irradiation was 59.2±12.9, and 33.1±12.2 after the irradiation, showing a significant improvement in VAS score (p<0.001) after treatment. The treatment effect lasted for about one and a half days in the case of wrist pain, epicondylitis lateralis (tennis elbow), and carpal tunnel syndrome. In other pain entities, it lasted for about three to fifteen hours. No change in the range of motion (ROM) was seen in any of the 24 subjects. CONCLUSION: We concluded that LLLT at the wavelength and parameters used in the present study was effective for chronic pain of the elbow, wrist, and fingers.

Low level laser therapy (LLLT) for patients with sacroiliac joint pain.

BACKGROUND AND AIMS: Sacroiliac joint pain not associated with a major etiological factor is a common problem seen in the orthopedic clinical setting, but diagnosis is difficult because of the anatomical area and thus it is sometimes difficult to effect a complete cure. Low level laser therapy (LLLT) has been well-reported as having efficacy in difficult pain types, so the following preliminary study was designed to assess the efficacy of LLLT for sacroiliac pain. MATERIALS AND METHODS: Nine patients participated, 4 males and 5 females, average age of 50.4 yrs, who attended the outpatient department with sacroiliac pain. The usual major disorders were ruled out. Pain was assessed subjectively pre-and post-LLLT on a visual analog scale, and trunk range of motion was examined with the flexion test to obtain the pre- and post-treatment finger to floor distance (FFD). The LLLT system used was an 830 nm CW diode laser, 1000 mW, 30 sec/point (20 J/cm(2)) applied on the bilateral tender points twice/week for 5 weeks. Baseline and final assessment values (after the final treatment session) were compared with the Wilcoxon signed rank test (nonparametric score). RESULTS: All patients completed the study. Eight of the 9 patients showed significant pain improvement and 6 demonstrated significantly increased trunk mobility (P <0.05 for both). CONCLUSIONS: LLLT was effective for sacroiliac pain, and this may be due to improvement of the blood circulation of the strong ligaments which support the sacroiliac joint, activation of the descending inhibitory pathway, and the additional removal of irregularities of the sacroiliac joint articular surfaces. Further larger-scale studies are warranted.