1. Investigación

Introduction: In recent years, pain neuroscience education (PNE) has been the focus of extensive research in the scientific literature in the field of physical therapy, but the results obtained are controversial and its clinical application remains unclear. The main aim of this umbrella review was to assess the effectiveness of PNE in patients with chronic musculoskeletal pain (CMP). Methods: We searched systematically in PubMed (Medline), PEDro, EMBASE, CINAHL and PsycINFO. Methodological quality was analyzed using AMSTAR-2 scale and overlapping analysis using GROOVE tool. Results: 16 systematic reviews were included. A qualitative synthesis was performed for the following sets of patients with CMP: overall CMP, chronic spinal pain, patients with fibromyalgia and patients with osteoarthritis. In general terms, it seems that the addition of the PNE-based intervention to other treatments, mostly exercise-based interventions although we might refer to it in terms of a multimodal approach, leads to greater clinical improvements than the multimodal approach alone. We have found this especially in the reduction of the influence of psychosocial variables. However, it seems that studies testing the effectiveness of PNE in isolation, systematic reviews with or without meta-analysis did not show statistically significant improvements overall in terms of pain intensity, disability levels or psychosocial variables. Discussion: There is a great heterogeneity in the results obtained and the PNE protocols used, a critically low quality in the reviews included and a very high overlap, so there is a need to improve the studies in this field before clinical application.

OBJECTIVE: To evaluate the pain-relieving effect of transcutaneous electrical nerve stimulation (TENS) during office-based hysteroscopy without sedation. METHODS: We conducted a randomized, double-blind, placebo-controlled trial. Participants were randomly assigned to the active TENS, placebo TENS, or control group. The active TENS intervention consisted of a varying high-frequency (80–100 Hz), 400-microseconds, individually adjusted, high-intensity TENS application with two self-adhesive electrodes placed parallel to the spinal cord at the T10–L1 and S2–S4 levels. In the placebo group, participants were connected to the TENS unit but delivering no electrical stimulation. The primary outcome was self-reported pain intensity (0–100 mm) measured on a visual analog scale at several stages (entry, contact, biopsy, and residual). The minimum clinically relevant difference for the visual analog scale has been previously reported as 10 mm. Sample size was calculated to provide 80% power to show a 10-mm difference (α=0.0125) in the primary outcome. Secondary outcomes included duration of the procedure, vital parameters, vasovagal symptoms, and participant satisfaction index (0–10 rating scale). RESULTS: A total of 138 women (46 per group) participated in the study between January 2016 and April 2016. No differences were found between groups regarding age, weight, body mass index, parity status, menopausal status, or previous hysteroscopy status. Visual analog scale scores highlighted a decrease in pain in the active TENS group compared with the placebo group (entry: −11 mm, 95% confidence interval [CI] −17 to −5; contact: −21.9 mm, 95% CI −30 to −13.9; biopsy: −30.5 mm, 95% CI −47.1 to −13.8, P<.001). Moreover, the reduction in pain reached the minimum clinically relevant difference. Regarding satisfaction, results also revealed differences between active TENS and placebo groups (1.3, 95% CI 0.5–2.2, P=.001). CONCLUSION: Transcutaneous electrical nerve stimulation reduces pain and increases patient satisfaction during office hysteroscopy without sedation.

Various stimuli such as the flexibility of lumbopelvic structures influence the neuromuscular responses of the trunk musculature, leading to different load sharing strategies and reflex muscle responses from the afferents of lumbopelvic mechanoreceptors. This link between flexibility and neuromuscular response has been poorly studied. The aim of this study was to investigate the relationship between lumbopelvic flexibility and neuromuscular responses of the erector spinae, hamstring and abdominal muscles during trunk flexion-extension. Lumbopelvic movement patterns were measured in 29 healthy women, who were separated into two groups according to their flexibility during trunk flexion-extension. The electromyographic responses of erector spinae, rectus abdominis and biceps femoris were also recorded. Subjects with greater lumbar flexibility had significantly less pelvic flexibility and vice versa. Subjects with greater pelvic flexibility had a higher rate of relaxation and lower levels of hamstring activation during maximal trunk flexion. The neuromuscular response patterns of the hamstrings seem partially modulated by pelvic flexibility. Not so with the lumbar erector spinae and lumbar flexibility, despite the assertions of some previous studies. The results of this study improve our knowledge of the relationships between trunk joint flexibility and neuromuscular responses, a relationship which may play a role in low back pain.

Objetivo: Determinar los efectos del estiramiento de la musculatura isquiotibial sobre el patrón de activación del erector spinae durante los movimientos de flexoextensión de tronco. Hipótesis: El estiramiento repetido de la musculatura isquiotibial podría acortar la duración del período del silencio mioeléctrico del erector spinae durante la flexoextensión de tronco. Metodología: Se registraron en 14 sujetos sanos la activación electromiográfica (EMG) del erector spinae y los grados de flexión de cadera durante movimientos de flexoextensión de tronco antes y después de realizar el estiramiento isquiotibial. Las variables de estudio fueron el rango máximo de movimiento de cadera, los porcentajes de flexión de cadera en el offset/onset del erector spinae y la actividad EMG media de este músculo en las fases excéntrica y concéntrica. Resultados: La prueba T mostró que no existen diferencias significativas en el momento de aparición del offset y del onset antes y después del estiramiento. Se observó un aumento significativo de la actividad EMG del erector durante la contracción concéntrica tras el estiramiento. Conclusión: El estiramiento prolongado de las estructuras isquiotibiales no produce variaciones en la duración del período del silencio mioeléctrico del erector spinae, pero sí sobre su actividad EMG media durante la extensión de tronco, con lo que podría estar alterándose la coactivación muscular necesaria para proporcionar estabilidad al raquis lumbar.

This study aimed to analyze the position of the lumbopelvic region and lumbar muscle activity in the most common breastfeeding positions. We recorded the curvatures of the lumbar spine and pelvis by means of an electrogoniometer, and the muscle activation levels of the erector spinae with electromyography, in 34 women in erect standing and breastfeeding their children in several positions. Both side lying and clutch-hold positions showed a greater degree of lumbar spine flexion compared to standing. In all sitting postures it was observed that the pelvis was placed in retroversion when compared to standing and side lying. In muscle activity, it was observed that the activation intensity of the right erector in the right side-supported side lying position was significantly lower compared to the rest of breastfeeding postures and standing. Side lying may be a better position to avoid muscle fatigue.

Transcutaneous electrical nerve stimulation (TENS) is a nonpharmacological modality widely used to manage pain; however, its effectiveness for individuals with fibromyalgia (FM) has been questioned. In previous studies and systematic reviews, variables related to dose of TENS application have not been considered. The objectives of this meta-analysis were (1) to determine the effect of TENS on pain in individuals with FM and (2) determine the dose-dependent effect of TENS dose parameters on pain relief in individuals with FM. We searched the PubMed, PEDro, Cochrane, and EMBASE databases for relevant manuscripts. Data were extracted from 11 of the 1575 studies. The quality of the studies was assessed using the PEDro scale and RoB-2 assessment. This meta-analysis was performed using a random-effects model that, when not considering the TENS dosage applied, showed that the treatment had no overall effect on pain (d+ = 0.51, P > 0.050, k = 14). However, the moderator analyses, which were performed assuming a mixed-effect model, revealed that 3 of the categorical variables were significantly associated with effect sizes: the number of sessions (P = 0.005), the frequency (P = 0.014), and the intensity (P = 0.047). The electrode placement was not significantly associated with any effect sizes. Thus, there is evidence that TENS can effectively reduce pain in individuals with FM when applied at high or at mixed frequencies, a high intensity, or in long-term interventions involving 10 or more sessions.

BACKGROUND CONTEXT: The kinematics of the lumbar region and the activation patterns of the erector spinae muscle have been associated with the genesis of low back pain, which is one of the most common complications associated with pregnancy. Despite the high prevalence of pregnancy-related low back pain, the biomechanical adaptations of the lumbar region during pregnancy remain unknown. PURPOSE: This study analyzes lumbar spine motion and the activation pattern of the lumbar erector spinae muscle in healthy pregnant women. STUDY DESIGN: A case-control study. PATIENT SAMPLE: The study involved 34 nulliparous women (control group) and 34 pregnant women in the third trimester (week 36 § 1). OUTCOME MEASURES: We recorded the parameters of angular displacement of the lumbar spine in the sagittal plane during trunk flexion-extension, and the EMG activity of the erector spinae muscles during flexion, extension, eccentric and concentric contractions, and the myolectrical silence. METHODS: The participants performed several series of trunk flexion-extension movements, which were repeated 2 months postpartum. The position of the lumbar spine was recorded using an electromagnetic motion capture system. EMG activity was recorded by a surface EMG system and expressed as a percentage of a submaximal reference contraction. RESULTS: Antepartum measurements showed a decrease (relative to control and postpartum measurements) in lumbar maximum flexion (52.5 § 10.5° vs 57.3 § 7.7° and 58.7 § 8.6°; p < .01), the percentage of lumbar flexion during forward bending (56.4 § 5.6% vs 59.4 § 6.8% and 59.7 § 5.6%; p < .01), and the time keeping maximum levels of lumbar flexion (35.7 § 6.7% vs 43.8 § 5.3% and 50.1 § 3.7%; p < .01). Higher levels of erector spinae activation were observed in pregnant women during forward bending (10.1 § 4.8% vs 6.3 § 2.4% and 6.6 § 2.7%; p < .01) and eccentric contraction (12.1 § 5.2% vs 9.4 § 3.1% and 9.1 § 2.9%; p < .01), as well as a shortened erector spinae myoelectric silence during flexion. CONCLUSIONS: Pregnant women show adaptations in their patterns of lumbar motion and erector spinae activity during trunk flexion-extension. These changes could be associated with the genesis of pregnancy-related low back pain, by means of biomechanical protection mechanisms against the increase on abdominal mass and ligamentous laxity.

Vibratory platforms (VPs) and unstable footwear (UF) have both shown benefits on balance in some populations. However, there is no evidence about the combined effects of using UF while training on an VP in healthy and physically active young people. We aimed to evaluate the effects of wearing unstable footwear (UF) while training on a whole-body VP on balance in healthy, physically active young people. 23 participants were randomized into groups assigned UF (n = 11) or stable footwear (SF; n = 12). Both groups followed the same training program on an VP with the assigned footwear type twice a week for 12 weeks. The training consisted of performing 8 isometric exercises for progressively longer periods and higher oscillation amplitudes (15–60 s, 1–3 mm), at a fixed vibration frequency (20 Hz). The main outcomes were the antero-posterior and medio-lateral velocities of the center of pressure (COP) recorded using a plantar pressure corridor at baseline, post-treatment and 1-month follow-up. We found a statistically significant difference in the antero-posterior velocity during the monopodal test in the UF group between the different time-points (χ2(2) = 13.282, p = 0.001). Mediolateral COP velocity ranking during the bipodal test was lower for UF than for SF group (U = 19.50, z = − 2.86, p = 0.003) at follow-up. The traditional vibratory platform training does not seem to be effective to improve static balance in physically active young people, however, adding UF provided slightly greater effect.