Relação entre a unidade de biofeedback de pressão, deslocamento do centro de pressão e atividade eletromiográfica durante o active straight leg raising em indivíduos com e sem dor lombo-pélvica.

Introdução: A unidade de biofeedback de pressão, em indivíduos com dor lombo-pélvica, é utilizada durante exercícios de estabilização segmentar, no entanto ainda carece de evidência científica. Objetivo: Determinar a relação entre a unidade de biofeedback de pressão (UBFP), o deslocamento do centro de pressão no sentido médio-lateral (COPml) e a atividade eletromiográfica abdominal durante o active straight leg raising (ASLR) em indivíduos com e sem dor lombo-pélvica, bem como identificar diferenças entre os grupos. Metodologia: Estudo transversal analítico em 18 estudantes universitários voluntários com dor lombo-pélvica crónica inespecífica (GCD) e em 20 sem dor (GSD). Durante o ASLR (desafio postural dinâmico) foram avaliadas as variações máxima e média da pressão (recorrendo à UBFP) e do deslocamento do COPml (através da plataforma de forças), bem como a atividade muscular abdominal, bilateralmente, com recurso à eletromiografia de superfície. Estatisticamente recorreu-se à correlação de Spearman e ao teste Mann-Whitney U, ambos com um nível de significância de 0,05. Resultados: No GCD, ao contrário do GSD, não foi verificada uma relação entre a UBFP e a atividade do transverso abdominal/obliquo interno (TrA/OI) contra-lateral. Correlações moderadas, mas com sentidos opostos, foram evidenciadas em ambos os grupos, entre o deslocamento do COPml e a atividade do TrA/OI contra-lateral. Em ambos os grupos, a UBFP demonstrou estar fortemente correlacionada com o COPml. Não foram observadas diferenças significativas entre os grupos nas variáveis avaliadas. Conclusão: A UBFP, no GCD, não se apresentou relacionada com a atividade do TrA/OI. Contudo, demonstrou uma relação com o deslocamento do COPml, em ambos os grupos, sendo portanto um indicador de estabilidade do tronco e assim, uma ferramenta útil em ambiente clínico. No GCD observou-se que uma maior atividade muscular TrA/OI pressupõe maior deslocamento do COPml, sendo uma relação contrária à verificada no GSD, podendo ser um indicador da perda da sua ação tónica.Background: Pressure biofeedback unit, in subjects with low back pain, is used during segmental stabilization exercises, however scientific evidence is still lacking. Objective: Determine the relationship between pressure biofeedback unit (UBFP), center of pressure medial-lateral displacement (COPml) and electromyographic activity of the abdominal muscles during the active straight leg raising (ASLR) in individuals with and without low back pain, as well as identify differences between groups. Methods: Analytical cross-sectional study in 18 college students volunteers with chronic nonspecific low back pain (GCD) and 20 without pain (GSD). During the ASLR (dynamic postural challenge) were evaluated pressure (using the UBFP) and COPml displacement's mean and maximal variation, as well as bilateral abdominal muscles activity using surface electromyography. Statistically it were used Spearman correlations and Mann-Whitney U tests, both with a significance level of 0,05. Results: Unlike GSD, in the GCD it was not found a relationship between UBFP and contra-lateral transversus abdominis/internal oblique (TrA/OI) muscle activity. Moderate correlations, but with opposite directions, were found in both groups between COPml displacement and contra-lateral TrA/OI activity. In both groups, UBFP showed to be strongly correlated with COPml. There were no significant differences between groups in the evaluated variables. Conclusion: The UBFP, in GCD, did not appear to be related with TrA/OI activity. However, it was found a relationship with COPml displacement in both groups, thus being an indicator of trunk stability and so can be useful in the clinical environment. In GCD it was observed that a greater TrA/OI muscle activity implies a greater COPml displacement, being contrary to the relationship found in GSD, and could be an indicator of their loss of tonic action

Pressure biofeedback unit to assess and train lumbopelvic stability in supine individuals with chronic low back pain

To determine if pressure biofeedback unit readings are related to abdominal muscle activation and centre of pressure displacement as well as to test the effects of using it as a biofeedback tool to control lumbopelvic motion. Eighteen volunteers with chronic nonspecific low back pain (21.28 ± 1.41 years old) who performed an active straight leg raising (dynamic postural challenge) with and without pressure biofeedback. Changes in the pressure biofeedback unit and on centre of pressure displacement were assessed, as well as bilateral electromyographic abdominal muscle activity. Participants were not allowed to use a Valsalva manoeuvre. Pressure variation was not significantly correlated with abdominal muscle activity or with mediolateral centre of pressure displacement. When used as a biofeedback instrument, there was a significant increase in almost all abdominal muscles activity as well as a significant decrease in pressure variation and in mediolateral centre of pressure displacement while performing an active straight leg raising with a normal breathing pattern. Despite not being an indicator of abdominal muscle activity or mediolateral load transfer in the supine position, the pressure biofeedback unit could have great relevance when used in the clinic for biofeedback purposes in individuals with low back pain.info:eu-repo/semantics/publishedVersio

Forward trunk lean with arm support affects the activity of accessory respiratory muscles and thoracoabdominal movement in healthy individuals

Despite the reported benefits of postures involving leaning the trunk forward with arm support for relieving dyspnea, how those postures influence the mechanics of breathing remains unclear. In response, the aim of the study reported here was to evaluate how posture (i.e., standing and sitting) and leaning the trunk forward with arm support affect the activity of accessory respiratory muscles and thoracoabdominal movement in healthy individuals. Thirty-five volunteers (15 males and 20 females) aged 18-29 years breathed with the same rhythm in standing and sitting positions while upright and while leaning the trunk forward with arm support. Surface electromyography was performed to assess the activity of accessory inspiratory (i.e., during inspiration) and abdominal (i.e., during inspiration and expiration) muscles, and a motion capture system was used to assess thoracoabdominal movement. Results revealed that upper trapezius activity was significantly lower in forward-leaning postures than in upright ones (P = 005; ηp2 = 0.311), although the activity of the sternocleidomastoideus and scalenus (P < 0.001; ηp2 = 0.427-0.529), along with the anterior-to-posterior movement of the upper ribcage (P < 0.001; ηp2 = 0.546), were significantly greater in forward-leaning postures than in upright ones. The activity of the external oblique and transversus abdominis/internal oblique was significantly lower in sitting than in standing postures (P < 0.050; ηp2 = 0.206-0.641), and though the activity of the transversus abdominis/internal oblique was significantly lower in forward-leaning than in upright postures (P ≤ 0.001; ηp2 = 0.330-0.541), a significantly greater anterior-to-posterior movement of the abdomen was observed (P < 0.001; ηp2 = 0.662). However, the magnitude of the lower ribcage's medial-to-lateral movement was significantly lower in forward-leaning than in upright postures (P = 0.039; ηp2 = 0.149). Leaning the trunk forward with arm support not only increased the use of accessory inspiratory muscles but also decreased the use of the transversus abdominis/internal oblique, which improved thoracoabdominal movement.info:eu-repo/semantics/publishedVersio

Efeitos imediatos de uma postura de Stretching Global Ativo na força e na flexibilidade

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Immediate effect of grade II cervical rotation technique on joint position sense in subjects with and without non-specific pain

A mobilização articular passiva em indivíduos com dor cervical possui eficácia reconhecida no alívio da dor e no aumento da amplitude articular, mas há poucos estudos sobre a sua influência na capacidade propriocetiva. Estudar o efeito imediato da técnica de rotação cervical grau II na sensação de posição articular, em jovens adultos com e sem dor cervical unilateral de origem não específica. Estudo quase experimental, duplamente cego, numa amostra de conveniência de 37 indivíduos (18 a 24 anos de ambos os sexos) divididos em 2 grupos: 22 sem dor e 15 com dor cervical. O instrumento Cervical Range of Motion foi utilizado para avaliar a sensação de posição articular ativa da cervical a 30⁰ de rotação, para a direita e para a esquerda, antes e imediatamente após a execução da técnica de mobilização articular de rotação cervical grau II de Maitland (quatro mobilizações de 30 segundos cada). O teste foi repetido seis vezes para cada lado. Calculou-se o erro absoluto e o erro variável utilizando-se o teste t para comparação entre os grupos e momentos com nível de significância de 5%. Apenas se observaram diferenças significativas entre grupos no erro variável na rotação esquerda após a realização da técnica e entre momentos na rotação esquerda e direita no grupo sem dor sendo, no entanto, de magnitudes iguais ou inferiores a 1⁰ em média. A técnica de rotação cervical grau II não parece produzir efeitos imediatos clinicamente relevantes na precisão e consistência do reposicionamento avaliada a 30⁰ de rotação.info:eu-repo/semantics/publishedVersio

The effect of inspiratory and expiratory loads on abdominal muscle activity during breathing in subjects “at risk” for the development of chronic obstructive pulmonary disease and healthy

The abdominal muscle activity has been shown to be variable in subjects with chronic obstructive pulmonary disease (COPD) when respiratory demand increases and their recruitment pattern may change the mechanics, as well as the work and cost of breathing. The scientific evidence in subjects "at risk" for the development of COPD may be important to understand the natural history of this disease. This study aims to evaluate the effect of inspiratory and expiratory loads on the abdominal muscle activity during breathing in subjects "at risk" for the development of COPD and healthy. Thirty-one volunteers, divided in "At Risk" for COPD (n=17; 47.71±5.11years) and Healthy (n=14; 48.21±6.87years) groups, breathed at the same rhythm without load and with 10% of the maximal inspiratory or expiratory pressures, in standing. Surface electromyography was performed to assess the activation intensity of rectus abdominis (RA), external oblique and transversus abdominis/internal oblique (TrA/IO) muscles, during inspiration and expiration. During inspiration, in "At Risk" for COPD group, RA muscle activation was higher with loaded expiration (p=0.016); however, in Healthy group it was observed a higher activation of external oblique and TrA/IO muscles (p<0.050). During expiration, while in "At Risk" for COPD group, RA muscle activation was higher with loaded inspiration (p=0.009), in Healthy group TrA/IO muscle showed a higher activation (p=0.025). Subjects "at risk" for the development of COPD seemed to have a specific recruitment of the superficial layer of ventrolateral abdominal wall for the mechanics of breathing.info:eu-repo/semantics/publishedVersio

Repeatability and temporal consistency of lower limb biomechanical variables expressing interlimb coordination during the double-support phase in people with and without stroke sequelae

Reliable biomechanical methods to assess interlimb coordination during the double-support phase in post-stroke subjects are needed for assessing movement dysfunction and related variability. The data obtained could provide a significant contribution for designing rehabilitation programs and for their monitorisation. The present study aimed to determine the minimum number of gait cycles needed to obtain adequate values of repeatability and temporal consistency of lower limb kinematic, kinetic, and electromyographic parameters during the double support of walking in people with and without stroke sequelae. Eleven post-stroke and thirteen healthy participants performed 20 gait trials at self-selected speed in two separate moments with an interval between 72 h and 7 days. The joint position, the external mechanical work on the centre of mass, and the surface electromyographic activity of the tibialis anterior, soleus, gastrocnemius medialis, rectus femoris, vastus medialis, biceps femoris, and gluteus maximus muscles were extracted for analysis. Both the contralesional and ipsilesional and dominant and non-dominant limbs of participants with and without stroke sequelae, respectively, were evaluated either in trailing or leading positions. The intraclass correlation coefficient was used for assessing intra-session and inter-session consistency analysis. For most of the kinematic and the kinetic variables studied in each session, two to three trials were required for both groups, limbs, and positions. The electromyographic variables presented higher variability, requiring, therefore, a number of trials ranging from 2 to >10. Globally, the number of trials required inter-session ranged from 1 to >10 for kinematic, from 1 to 9 for kinetic, and 1 to >10 for electromyographic variables. Thus, for the double support analysis, three gait trials were required in order to assess the kinematic and kinetic variables in cross-sectional studies, while for longitudinal studies, a higher number of trials (>10) were required for kinematic, kinetic, and electromyographic variables.info:eu-repo/semantics/publishedVersio

Abdominal muscle activity during breathing in different postural sets in healthy subjects

This study aims to evaluate the effect of different postural sets on abdominal muscle activity during breathing in healthy subjects. Twenty-nine higher education students (20.86 ± 1.48 years; 9 males) breathed at the same rhythm (inspiration: 2 s; expiration: 4 s) in supine, standing, tripod and 4-point-kneeling positions. Surface electromyography was performed to assess the activation intensity of rectus abdominis, external oblique and transversus abdominis/internal oblique muscles during inspiration and expiration. During both breathing phases, the activation intensity of external oblique and transversus abdominis/internal oblique was significantly higher in standing when compared to supine (p ≤ 0.001). No significant differences were found between tripod position and 4-point-kneeling positions. Transversus abdominis/internal oblique activation intensity in these positions was higher than in supine and lower than in standing. Postural load and gravitational stretch are factors that should be considered in relation to the specific recruitment of abdominal muscles for breathing mechanics.info:eu-repo/semantics/publishedVersio

Co-activation of upper limb muscles during reaching in post-stroke subjects: An analysis of the contralesional and ipsilesional limbs

The purpose of this study was to analyze the change in antagonist co-activation ratio of upper-limb muscle pairs, during the reaching movement, of both ipsilesional and contralesional limbs of post-stroke subjects. Nine healthy and nine post-stroke subjects were instructed to reach and grasp a target, placed in the sagittal and scapular planes of movement. Surface EMG was recorded from postural control and movement related muscles. Reaching movement was divided in two sub-phases, according to proximal postural control versus movement control demands, during which antagonist co-activation ratios were calculated for the muscle pairs LD/PM, PD/AD, TRIlat/BB and TRIlat/BR. Post-stroke's ipsilesional limb presented lower co-activation in muscles with an important role in postural control (LD/PM), comparing to the healthy subjects during the first sub-phase, when the movement was performed in the sagittal plane (p<0.05). Conversely, the post-stroke's contralesional limb showed in general an increased co-activation ratio in muscles related to movement control, comparing to the healthy subjects. Our findings demonstrate that, in post-stroke subjects, the reaching movement performed with the ipsilesional upper limb seems to show co-activation impairments in muscle pairs associated to postural control, whereas the contralesional upper limb seems to have signs of impairment of muscle pairs related to movement.info:eu-repo/semantics/publishedVersio

Immediate effects of suboccipital myofascial induction on postural stability: a pilot study

Standing is a constant postural challenge due to high position of the center of mass regarding the small size of base of support. Somatosensory, vestibular and visual inputs are crucial to preserve the upright orientation and stability]info:eu-repo/semantics/publishedVersio