Can photobiomodulation improve quadriceps strength and endurance outcomes in asymptomatic adults? A double-blind randomized controlled trial.

AIM: To explore the effect of photobiomodulation on quadriceps strength and endurance torques in asymptomatic adults. METHODS: Twenty-eight asymptomatic adults were randomized to one of two interventions: photobiomodulation (n = 14) or sham (n = 14). Quadriceps strength was evaluated by maximum voluntary isometric contraction test (60°) and endurance by an elastic resistance in multiple-set knee extension/flexion repetitions using a traction dynamometer. The outcomes were measured at three time points: pre-baseline; baseline and; final assessment. The photobiomodulation was applied to the quadriceps and triceps surae muscles of each participant's dominant lower limb, using a cluster with 1 infrared laser diode and 3 led amber of 170 mW for 240 s over four consecutive days. The sham group went through the same procedures, but the equipment was off, and patients and assessors were blinded to the intervention. Reliability and minimal detectable change of the measures were obtained from the pre-baseline and baseline time points. Differences between interventions were tested by an analysis of covariance. RESULTS AND DISCUSSION: There was no difference between photobiomodulation compared to sham in maximum isometric torque (mean difference (95% CI) = 0.008 (-0.29 to 0.31) and endurance torques (mean difference (95% CI) = 0.04 (-0.03 to 0.12). The mean difference was lower than the minimal detectable change for the maximum isometric torque (1.02 Nm.kg-1) and endurance torque (0.49 Nm.kg-1). CONCLUSION: Photobiomodulation does not improve quadriceps strength and endurance outcomes in asymptomatic adults.

Influence of pain prognosis and electrical stimulation modality on the amplitude of current elicited at sensory threshold in chronic lumbar pain sufferers / Influência do prognóstico para dor e da modalidade de estimulação elétrica na amplitude de corrente elicitada no limiar sensorial em lombálgicos crônicos

ABSTRACT BACKGROUND AND OBJECTIVES: Sensory function may be altered in chronic low back pain (CLBP), which may alter the perception of therapeutic currents. The aim of this study was to verify whether the risk of poor prognosis for CLBP pain influences the amplitude elicited at the sensory threshold (ST) in different modalities of neuromuscular electrical stimulation (NMES). METHODS: This is a quasi-experimental counterbalanced study with 40 subjects divided into four groups (n=10 each), according to the risk of poor prognosis for pain: no risk (control group - CG), low (LrG), medium (MrG), and high (HrG) risks. Four modalities of NMES were tested: two medium frequency currents (Aussie current [AC] and Russian current [RC]) and two low frequency currents (commonly known as functional electrical stimulation [FES]), with two phase durations of200 μs (FES_200) and 500 μs (FES_500), in the region of the lumbar multifidus muscles. All subjects were exposed to all current modalities with interval periods, and when the ST was reached, the amplitude of the current measured in mA was recorded. RESULTS: The currents that elicited the highest and lowest amplitude in the ST were FES_200 and AC, respectively. As for the risk of poor prognosis, the highest amplitudes were for the HrG and the lowest for the LrG. CONCLUSION: The amplitude of the current elicited in the ST tended to be higher among those with a higher risk of poor prognosis for pain and, among the currents, those of medium frequency elicited lower amplitudes.

RESUMO JUSTIFICATIVA E OBJETIVOS: A função sensorial é potencialmente alterada na presença de dor lombar crônica (DLC), o que pode alterar a percepção de passagem de correntes terapêuticas. O objetivo deste estudo foi verificar se o risco de mau prognóstico para DLC influencia a amplitude elicitada no limiar sensorial (LS) em diferentes modalidades de estimulação elétrica neuromuscular (EENM). MÉTODOS: Trata-se de um estudo quase-experimental contrabalanceado composto por 40 voluntários alocados em quatro grupos (n=10 cada), de acordo com o risco de mau prognóstico para dor: sem risco (grupo controle - GC), baixo risco (GBR), médio risco (GMR) e alto risco (GAR). Foram testadas quatro modalidades de EENM: duas correntes de média frequência (corrente Aussie [CA] e corrente Russa [CR]) e duas correntes de baixa frequência (comumente denominada estimulação elétrica funcional [FES]), com duas durações de fases 200 μs (FES_200) e 500 μs (FES_500) na região dos músculos multífidos lombares. Todos os voluntários foram submetidos a todas as modalidades de corrente, com períodos de intervalos, e ao ser atingido o LS, foi realizado o registro da amplitude da corrente medida em mA. RESULTADOS: As correntes que elicitaram a maior e a menor amplitude no LS foram, respectivamente, FES_200 e CA. Quanto ao risco de mau prognóstico, as maiores amplitudes foram do GAR e as menores do GBR. CONCLUSÃO: A amplitude da corrente elicitada no LS tendeu a ser mais alta entre aqueles com maior risco de mau prognóstico para dor e, dentre as correntes, aquelas de média frequência elicitaram amplitudes mais baixas.A amplitude da corrente elicitada no LS tendeu a ser mais alta entre aqueles com maior risco de mau prognóstico para dor e, dentre as correntes, aquelas de média frequência elicitaram amplitudes mais baixas.

KiloHertz currents on aspects of muscle function: A scoping review.

BACKGROUND: Neuromuscular electrical stimulation (NMES) with kiloHertz currents (kHz) is a resource used in rehabilitation for producing muscle contractions with functional objectives, resulting from the optimization of the performance of aspects of muscle function (AOMF). However, parameters such as inadequate frequency, phase duration, amplitude, and therapy time may limit the effectiveness of NMES by the absence of adequate stimuli to generate positive adaptations in the AOMF. This study aimed to present an overview of the effectiveness and dosimetry of NMES by kHz on AOMF, such as torque and hypertrophy, in healthy people. METHODS: The study was outlined as a scoping review. From the search, 3892 studies were found of which were incorporated into Rayyan software for exclusion of duplicates and further selection by titles and abstracts, which resulted in 33 articles for this review. RESULTS: According to the included studies, kHz can increase torque and generate hypertrophy. Only the studies with Russian current showed hypertrophy gains. Dosimetry was not always detailed in the studies, which hinders stipulating optimal parameters for kHz. CONCLUSION: From this review, it is concluded that NMSC by kHz is a valid resource to optimize AOMF, although the dosimetric parameters are still inconsistent.

Effects of Platelet Rich Plasma on Pain in Adult and Elderly Patients with Knee Osteoarthritis: a Systematic Review / Efeitos do Plasma Rico em Plaquetas na Dor em Pacientes Adultos e Idosos com Osteoartrite de Joelho: uma Revisão Sistemática

Platelet-rich plasma (PRP) has been shown to be a promising treatment for osteoarthritis (OA) of the knee in adult and elderly patients, acting in the repair of joint tissues damaged by OA - a degenerative disease that mainly affects articular cartilage. This process of degradation of joint components leads to an increase in the level of pain in these patients. Therefore, this study aimed to evaluate the effectiveness of intra-articular injection of PRP in knee OA in relation to pain. For this systematic review, five databases were used: PubMed, Lilacs, PEDro, Cochrane Library and Google Scholar. Search strategies included the keywords Osteoarthritis, Knee, Platelet-rich plasma, and Pain. In order to be included in this review, the studies had to be of the randomized clinical trial type; use as a sample people between 18 and 80 years old diagnosed with knee OA; use intra-articular PRP treatment compared to placebo; and assess pain intensity. After completion of the selection phase, 5 studies were included in this review. These showed positive results in reducing pain in patients with lower-degeneration OA, and less effective in advanced OA. Furthermore, few side effects were reported after the application of PRP. Therefore, the intra-articular application of PRP can be an important tool for the treatment of knee OA, as it is an effective therapy in decreasing pain levels in patients affected by this pathology. (AU)

O plasma rico em plaquetas (PRP) tem se mostrado um tratamento promissor na osteoartrite (OA) de joelho de pacientes adultos e idosos, atuando no reparo dos tecidos articulares lesados pela OA - doença degenerativa que afeta principalmente a cartilagem articular. Esse processo de degradação dos componentes articulares leva ao aumento do nível de dor nesses pacientes. Sendo assim, este estudo objetivou avaliar a eficácia da injeção intra-articular de PRP na AO de joelho em relação a dor. Para esta revisão sistemática, cinco bases de dados foram utilizadas: PubMed, LILACS, PEDro, Cochrane Library e Google Scholar. As estratégias de busca incluíram as palavras-chave Osteoarthritis, Knee, Platelet-rich plasma e Pain. Para serem incluídos nesta revisão, os estudos deveriam ser do tipo ensaio clínico randomizado; utilizar como amostra pessoas entre 18 e 80 anos diagnosticadas com AO de joelho; utilizar o tratamento com PRP intra articular comparado ao placebo; e avaliar a intensidade da dor. Após o término da fase de seleção, 5 estudos foram incluídos nesta revisão. Estes apresentaram resultados positivos na redução da dor em pacientes com OA de menor grau de degeneração, e menor efetividade na OA avançada. Ademais, poucos efeitos colaterais foram relatados após a aplicação do PRP. Portanto, a aplicação intra-articular do PRP pode ser um importante instrumento para o tratamento da OA de joelhos, visto que é uma terapia eficaz na diminuição dos níveis dor dos pacientes acometidos por tal patologia. (AU)

Effect of neuromuscular electrical stimulation on muscle function in chronic low back pain patients: systematic review / Efeito da estimulação elétrica neuromuscular na função muscular em pacientes com dor lombar crônica: revisão sistemática

ABSTRACT BACKGROUND AND OBJECTIVES: Neuromuscular electrical stimulation (NMES) is one of the resources that can be used in the treatment of patients with chronic low back pain. It is possible that issues related to the stimulation parameters may affect the results obtained with the use of these currents. Therefore, the aim of this review was to investigate the effects of NMES on aspects of lumbopelvic muscle function in individuals with chronic low back pain. CONTENTS: The study is a systematic review that used 10 databases for the search through a comprehensive combination of descriptors that met the research question. The selection criteria based on the PICOT strategy were population - individuals with chronic low back pain (specific and/or non-specific); intervention - NMES; outcomes - paravertebral and/or abdominal muscle changes (muscle power and endurance). The articles were selected by two independent reviewers, who developed the tools for data extraction. Four articles were included in this review. In three of them, there was a significant increase in muscle strength and endurance, as well as muscle cross-sectional area in the group that received NMES compared to the control group. CONCLUSION: NMES showed positive effects in optimizing aspects of muscle function in individuals with chronic low back pain. However, the methods employed are very heterogeneous, which made it impossible to perform a quantitative analysis.

RESUMO JUSTIFICATIVA E OBJETIVOS: A estimulação elétrica neuromuscular (EENM) é um dos recursos que podem ser utilizados no tratamento de pacientes com dor lombar crônica. É possível que questões relacionadas aos parâmetros de estimulação possam afetar os resultados obtidos com o uso dessas correntes. Portanto, o objetivo deste estudo foi investigar os efeitos da EENM em aspectos da função muscular da região lombopélvica em indivíduos com dor lombar crônica. CONTEÚDO: Trata-se de uma revisão sistemática que utilizou 10 bases de dados para a busca por meio da combinação abrangente de descritores que atendessem a pergunta da investigação. Os critérios de seleção com base na estratégia PICOT foram: população - indivíduos com dor lombar crônica (específica e/ ou não específica); intervenção - EENM; desfechos - alterações musculares de paravertebrais e/ou abdominais (potência e resistência muscular). A seleção dos artigos foi feita por dois revisores independentes que elaboraram as ferramentas para extração dos dados. Ao todo, quatro artigos foram incluídos nesta revisão. Em três deles, houve aumento significativo de força e resistência muscular, assim como da área de secção transversa muscular no grupo que recebeu EENM, em relação ao controle. CONCLUSÃO: A EENM apresentou efeitos positivos na otimização dos aspectos da função muscular em indivíduos com dor lombar crônica. Porém, os métodos empregados são muito heterogêneos, o que impossibilitou a realização da análise quantitativa.

Cryotherapy in Anterior Cruciate Ligamentoplasty Pain: A Scoping Review.

Cryotherapy is used in individuals in the postoperative period (PO) of anterior cruciate ligament (ACL) repair, owing to its effects such as increased pain threshold, decreased cellular activity, and vasoconstriction. The aim of this study was to analyze the effect of cryotherapy on pain intensity in the immediate PO of ACL reconstruction. A scoping review was performed in the databases: Cochrane, Embase, Lilacs, LIVIVO, PEDro, PubMed, Scopus, and Web of Science; and gray literature: Google Scholar, CAPES Thesis Database, and Open Grey. PRISMA recommendation was followed. Two blinded reviewers performed the selection of studies: Phase 1-reading of titles and abstracts and Phase 2-Reading of the full texts and disagreements resolved in consensus. The references of 701 studies were identified, 603 from the main databases and 98 from the gray literature. After removal of duplicates, 387 studies were left for Phase 1-reading of titles and abstracts according to eligibility criteria and for Phase 2-28 studies for reading of full texts. Two studies were excluded: one randomized clinical trial and another sandwich study. Finally, 15 studies were included in this review. Cryotherapy is effective in reducing pain intensity because there were reductions in the scores of subjective pain scales in the immediate PO of ACL reconstruction. Cryocompression was shown to be superior to conventional cryotherapy.

Using a single dose of photobiomodulation (laser + LED) to improve performance of lower limbs in functional test: Randomized clinical trial.

BACKGROUND: Photobiomodulation (PBM) improves motor performance despite doubts whether it occurs immediately or late after a single dose. We evaluated the effect of a cluster PMB (laser + LED) single dose on muscle fatigue recovery in young sedentary adults, both immediately and in the short term (period between 24 and 48 h) after the fatiguing event. METHODS: Randomized clinical trial with 60 volunteers randomized in 5 groups (n = 12 in each): control/(CG); placebo/(SG); PBM in knee extensor/(KE_G); plantar-flexor/(PF_G); knee extensor + plantar-flexor/(KE + FP_G). Before the intervention (pre) a fatiguing event (FE) was applied, which consisted in going up and down one step until exhaustion. Repetition number (RN) and time to exhaustion (TTE) were recorded. Then each group received its respective intervention and immediately after that, the FE was performed again (immediate post). In the period between 24 and 48 h after irradiation, a new FE was performed (late post). In addition to the comparative statistics, complementary metrics (if the mean difference [Diff] between the comparison pairs was higher or lower than minimum detectable change [MDC] and effect size [ES]) were calculated. RESULTS: Through the integrated analysis of inferential statistics and complementary metrics, it was observed that although there was no time of evaluation effect, there was a group effect. PBM improved performance in KE + FP_G (p-value<0.05; Diff>MDC; ES = moderate) and PF_G (p-value>0.05; but Diff > MDC; ES = moderate) regarding CG for both RN and TTE. CONCLUSION: A PBM single dose irradiation may improve motor performance and there is specificity of the irradiated muscle group, although it does not depend on the moment.

Causal relationship between spatiotemporal parameters of walking and the locomotor rehabilitation index in healthy people.

BACKGROUND: Walking speed is a functional vital sign affecting mechanical parameters individually. Further, there is a tendency for pathological gait to occur at slower speeds, which does not always allow for an adequate comparison with normal gait. Therefore, recognizing the influence of spatiotemporal adjustments on healthy gait can broaden our understanding of the applicability of gait quality markers. RESEARCH QUESTION: This study aimed to identify the causal relationship between the stride length-frequency walking ratio index (R_SL/SF) at the self-selected walking speed (SSWS) and optimal walking speed (OWS) and the locomotor rehabilitation index (LRI) in healthy adults. MATERIALS AND METHODS: Healthy adults (n = 68) of both sexes aged 20-59 years were included in this study. The SSWS was determined using a 30-m walkway. The OWS and LRI were predicted by equations proposed in the literature. The volunteers walked on the treadmill at speeds corresponding to the OWS and SSWS in two bouts of 60 s each, with a break in between. The spatiotemporal parameters were recorded using a high-speed digital video camera, digitalized, and mathematically processed. Multiple linear regression was applied using the forced regression method. RESULTS: Significant correlations were found between the LRI and R_SL/SF at the SSWS (R = 0.397; p < 0.001) and OWS (R = 0.266; p = 0.014). The regression model showed that 16 % of the variability in the LRI was attributable to the R_SL/SF variability at the SSWS. The average and 95 % confidence interval LRI were 94.7 % (91.6 %-97.8 %). CONCLUSION: The LRI average is around 95 % for healthy and young adults and the R_SL/SF explained just 16 % of the variance in LRI.

Effect of transcutaneous electrical nerve stimulation and hypnosis on chronic low back pain / Efeito da estimulação elétrica nervosa transcutânea e hipnose na dor lombar crônica

ABSTRACT BACKGROUND AND OBJECTIVES Among the main non-pharmacological analgesic techniques are physical therapies such as electrotherapy and cognitive-behavioral techniques, such as hypnosis. The objective of this study was to compare the analgesic effect of transcutaneous electrical nerve stimulation (TENS) and hypnosis in the control of chronic low back pain. METHODS A crossover study that included 19 young adults of both genders with chronic low back pain who underwent TENS and hypnosis, and pain education as a control group. The quality of pain was assessed by the McGill's questionnaire; pain intensity and threshold were assessed by the visual analog scale. The intensity of spontaneous pain, the threshold and intensity of pain induced by cold and the pressure pain threshold before the interventions, immediately after the interventions and 30 minutes after the end of the interventions were evaluated. Statistical analysis was performed with Generalized Mixed Linear Models, with 5% significance, and Cohen's G effect sizes. RESULTS There was a statistically significant decrease in the intensity of spontaneous and cold induced pain in the hypnosis and TENS groups compared to the pain education group. There was a statistically significant reduction of pain in the sensory and evaluation categories in the intervention groups compared to the control group. There was no significant difference for the pressure pain threshold and latency time for cold induced pain. CONCLUSION Hypnosis and TENS decreased the intensity of chronic low back pain with no statistically significant difference between them, but statistically different from the pain education control group.

RESUMO JUSTIFICATIVA E OBJETIVOS Entre as principais técnicas analgésicas não farmacológicas estão as terapias físicas como a eletroterapia e técnicas cognitivo-comportamentais, como a hipnose. O objetivo deste estudo foi comparar o efeito analgésico da estimulação elétrica nervosa transcutânea (TENS) e hipnose no controle da dor lombar crônica. MÉTODOS Estudo do tipo cruzado que incluiu 19 adultos jovens de ambos os sexos portadores de dor lombar crônica, submetidos a TENS, hipnose e educação em dor como grupo controle. A qualidade da dor foi avaliada pelo questionário de McGill, a intensidade e o limiar da dor pela escala analógica visual. Foi avaliada a intensidade da dor espontânea, o limiar e a intensidade de dor ao frio e o limiar da dor à pressão, imediatamente após as intervenções e 30 minutos depois do final das intervenções. A análise estatística foi realizada com modelos lineares generalizados mistos, com 5% de significância, e tamanhos de efeito G de Cohen. RESULTADOS Houve diminuição estatisticamente significativa da intensidade da dor espontânea e ao frio nos grupos hipnose e TENS comparados ao grupo de educação em dor. Ocorreu redução do quadro álgico estatisticamente significativo nas categorias sensorial e avaliativa nos grupos intervenção comparados ao grupo controle. Não houve diferença significativa para o limiar de dor à pressão e o tempo de latência para a dor ao frio. CONCLUSÃO A hipnose e a TENS diminuíram a intensidade da dor lombar crônica sem diferença estatisticamente significativa entre si, porém estatisticamente diferentes em relação ao grupo controle.

When mechanical work meets energetics: Obese versus non-obese children walking.

NEW FINDINGS: What is the central question of this study? The aim was to compare the cost of transport and mechanical work between obese and non-obese children at different walking speeds. What is the main finding and its importance? Our data show that the cost of transport, mechanical efficiency and work are similar and directly mass dependent in obese and non-obese children. The optimal walking speed (most economical walking speed) is reduced in obese children. ABSTRACT: Although studies have shown the influence of gait biomechanics on the metabolic economy in obese adults and adolescents, little is known regarding obese children. We compared the metabolic cost of transport, apparent mechanical efficiency and gait biomechanics (assessed by mechanical energy fluctuations) in obese children (n = 12; mean ± SD: 8.6 ± 0.51 years of age, 1.38 ± 0.04 m, 44.6 ± 6.65 kg, 24.1 ± 3.50 kg m-2 ) and age- and sex-matched non-obese children (n = 12, 7.8 ± 0.90 years of age, 1.31 ± 0.08 m, 26.8 ± 2.24 kg, 16.4 ± 1.40 kg m-2 ) while walking at different speeds (from 1 to 5 km h-1 ) on a treadmill. We found that the mechanical efficiency was higher at 3 km h-1 compared with the remaining speeds for both groups (P < 0.05). Although the internal mechanical work has been greater in obese compared with non-obese children at 4 and 5 km h-1 , the external, total mechanical work and the mechanical efficiency remained similar between obese and non-obese children at all speeds. Likewise, the cost of transport was similar in the two groups, although the optimal walking speed was an average of 0.4 km h-1 slower in obese children. Clearly, these results show that the walking economy is associated with the total mechanical work in obese and non-obese children. Finally, the reduced functional mobility in obese children observed in previous studies seems to be associated with a reduction in optimal walking speed in comparison to non-obese children.

Evaluation of nociception induced by whole-body vibration remobilization in Wistar rats / Avaliação da nocicepção induzida pela remobilização com vibração de corpo inteiro em ratos Wistar

ABSTRACT BACKGROUND AND OBJECTIVES: The vibrating platform can attenuate the deleterious effects of immobilization related to muscle atrophy. However, there is still a gap regarding the effect of this modality on hyperalgesia related to immobilization. The objective of this study was to analyze the effect of remobilization with whole-body vibration on the nociception of Wistar rats. METHODS: Sixteen rats were randomly distributed into two groups: the FRG group - immobilization and free remobilization and the VPRG - immobilization and remobilization with the vibrating platform. For remobilization with the vibrating platform, the frequency of 60Hz for 10 minutes, five days a week for two weeks was used. The nociception was evaluated on the right paw by a digital analgesiometer, before and at the end of the immobilization, and after two weeks of remobilization. RESULTS: There were differences between evaluations but not between groups, indicating that immobilization reduced the nociceptive threshold and free remobilization, and the remobilization associated with vibration improved the nociceptive threshold compared to the post-immobilization moment. However, they were not able to return to the initial parameters. CONCLUSION: Joint immobilization reduced the nociceptive threshold; however, two weeks of whole-body vibration remobilization were not able to revert the threshold in the immobilized groups.

RESUMO JUSTIFICATIVA E OBJETIVOS: A plataforma vibratória pode atenuar os efeitos deletérios da imobilização relacionados à atrofia muscular, contudo, ainda há uma lacuna com relação ao efeito desta modalidade na hiperalgesia relacionada ao imobilismo. Assim, o objetivo deste estudo foi analisar o efeito da remobilização com plataforma vibratória sobre a nocicepção de ratos Wistar. MÉTODOS: Dezesseis ratos foram distribuídos aleatoriamente no grupo GRL - imobilização e remobilização livre, e no grupo GRPV - imobilização e remobilização com plataforma vibratória. Para a remobilização com plataforma vibratória foi utilizada a frequência de 60Hz, durante 10 minutos, cinco dias por semana, durante duas semanas. A nocicepção foi avaliada na pata direita, por meio de um analgesímetro digital, antes e ao final da imobilização, e após duas semanas de remobilização. RESULTADOS: Houve diferenças entre as avaliações, mas não entre os grupos, indicando que a imobilização reduziu o limiar nociceptivo, e a remobilização livre e associada à vibração melhoraram o limiar nociceptivo comparados com o momento pós-imobilização, no entanto, não foram capazes de retornar aos parâmetros iniciais. CONCLUSÃO: A imobilização articular reduziu o limiar nociceptivo. No entanto, duas semanas de remobilização com a vibração de corpo inteiro não foram capazes de reverter o limiar nos grupos imobilizados.

Nordic walking training in elderly, a randomized clinical trial. Part II: Biomechanical and metabolic adaptations.

BACKGROUND: Nordic walking is an attractive method of endurance training. Nevertheless, the biomechanic response due to the additional contribution of using poles in relation to free walking training has been less explored in the elderly. PURPOSE: This randomized parallel controlled trial aimed to assess the effects of 8 weeks of Nordic walking and free walking training on the walking economy, mechanical work, metabolically optimal speed, and electromyographic activation in elderly. METHODS: Thirty-three sedentary elderly were randomized into Nordic walking (n = 16) and free walking group (n = 17) with equalized loads. Submaximal walking tests were performed from 1 to 5 km h-1 on the treadmill. RESULTS: Walking economy was improved in both free and Nordic walking groups (x2 4.91, p = 0.014) and the metabolically optimal speed was increased by approximately 0.5 km h-1 changing the speed-cost profile. The electromyographic activation in lower and upper limbs, pendular recovery, and total, external, and internal mechanical work remained unchanged (p > 0.05). Interestingly, the internal mechanical work associated with arm movement was higher in the Nordic walking group than in the free walking group after training, while the co-contraction from upper limb muscles was reduced similarly to both groups. CONCLUSIONS: Eight weeks of Nordic walking training effectively improved the walking economy and functionality as well as maintained the gait mechanics, similar to free walking training in elderly people. This enhancement in the metabolic economy may have been mediated by a reduction in the co-contraction from upper limb muscles. TRIAL REGISTRATION: ClinicalTrails.gov NCT03096964.

Chronic low back pain and walking speed: effects on the spatiotemporal parameters and in gait variability / Dor lombar crônica e velocidade de caminhada: efeitos nos parâmetros espaço-temporais e na variabilidade da marcha

ABSTRACT BACKGROUND AND OBJECTIVES: Walking is described as one of the abilities most affected by chronic low back pain. This study aimed to determine if chronic nonspecific low back pain and walking speed affect the spatiotemporal parameters (stride length, swing time, contact time, stride time, stride frequency and walking ratio) and the coefficients of variation of stride length and contact time. METHODS: Ten participants with chronic nonspecific low back pain (low back pain - LG) and ten healthy participants in the control group (CG) walked on the treadmill at preferred self-selected speed, slower and faster than the preferred speed. Spatiotemporal parameters and coefficients of variation were determined by kinematic analysis. Main effects (group and speed) and their interactions were tested using generalized estimating equations method. RESULTS: Our results showed that there were no significant differences between groups or significant interaction between group and speed factors. There was a speed effect. Stride frequency and length increased while contact and stride time decreased as the speed increased. The walking ratio (stride length/stride frequency) was relatively consistent across speeds (~1.6 m·stride-1.s) without statistical differences. The coefficients of variation were below 5%. CONCLUSION: The chronic nonspecific low back pain did not affect the gait spatiotemporal profile, at least for those patients classified as chronic nonspecific low back pain according to the signs and symptoms criteria. Although the preferred speed has affected the spatiotemporal parameters, both groups patients were able to adjust their kinematic parameters to each task demand.

RESUMO JUSTIFICATIVA E OBJETIVOS: A caminhada é descrita como uma das habilidades mais afetadas pela dor lombar crônica. Este estudo objetivou determinar se a dor lombar crônica não específica e a velocidade de caminhada afetam os parâmetros espaço-temporais (comprimento da passada, tempo de balanço, tempo de contato, tempo da passada, frequência da passada e razão de caminhada) e os coeficientes de variação do comprimento da passada e do tempo de contato. MÉTODOS: Dez participantes com dor lombar crônica não específica (grupo dor lombar GL) e 10 participantes saudáveis (grupo controle - GC) caminharam na esteira na velocidade preferida autosselecionada, e em velocidades mais lenta e mais rápida que a velocidade preferida. Parâmetros espaço-temporais e coeficientes de variação foram determinados por cinemetria. Os efeitos principais (grupo e velocidade) e as suas interações foram testadas pelo método de equações de Estimativas Generalizadas. RESULTADOS: Não houve diferenças entre os grupos ou interação entre os fatores (grupo e velocidade). Houve efeito da velocidade. A frequência e o comprimento de passada aumentaram, enquanto o tempo de contato e de passada diminuíram à medida que a velocidade aumentou. A razão de caminhada (comprimento da passada/frequência da passada) foi relativamente consistente entre as velocidades (~1,6 m·passada-1·s) sem diferenças estatísticas. Os coeficientes de variação ficaram abaixo dos 5%. CONCLUSÃO: A dor lombar crônica não específica não afetou os parâmetros espaço-temporais da caminhada, pelo menos para os pacientes classificados com dor lombar crônica não específica pelos critérios de sinais e sintomas. Embora a velocidade preferida tenha afetado os parâmetros espaço-temporais, os pacientes de ambos os grupos foram hábeis para ajustar seus parâmetros cinemáticos às demandas da tarefa.

Comparação da incapacidade entre estratos de risco para mau prognóstico na lombalgia crônica: estudo observacional / Comparison of disability between risk classifications for poor prognosis in chronic lombalgy: observational study

INTRODUÇÃO: A dor lombar crônica (DLC) é uma síndrome que compromete negativamente a capacidade funcional dos indivíduos. OBJETIVO: Verificar se há diferença no nível de incapacidade autorrelatado entre pacientes alocados nos diferentes estratos de risco para desenvolver mau prognóstico na DLC. MATERIAIS E MÉTODOS: Trata-se de um estudo piloto, observacional e transversal. A amostra foi composta por 17 voluntários com DLC, provenientes de um Centro de Reabilitação Física universitário local. Os voluntários foram solicitados a responder dois questionários, tanto para avaliação do nível de incapacidade quanto para determinar o risco de mau prognóstico. O nível de incapacidade autorrelatado foi determinado pela Versão Brasileira do Índice Funcional de Oswestry (IFO). O risco para desenvolver mau prognóstico foi determinado pelo questionário STarT Back Screening Tool (SBST), baseado na influência dos fatores psicossociais, e os voluntários foram classificados em baixo (n=6), médio (n=6) ou alto (n=5) risco de mau prognóstico. O teste estatístico utilizado foi o Generalized Linear Model (GLzM), com α=0,05. RESULTADOS: O grupo de baixo risco apresentou incapacidade mínima e os grupos com médio e alto risco apresentaram incapacidade severa, porém observouse diferença estatística no IFO apenas entre os grupos de baixo e alto risco. CONCLUSÃO: Houve diferença na incapacidade autorrelatada entre os estratos de risco de mau prognóstico, sendo a incapacidade significativamente mais alta no grupo alto risco em comparação com o baixo risco, sugerindo que os aspectos psicossociais impactam não só para o prognóstico, mas também o nível de incapacidade de pacientes com dor lombar crônica.

INTRODUCTION: Chronic low back pain (CLBP) is a syndrome that compromises individual functional capacity negatively AIM: To verify whether there is a difference in the self-reported disability level among patients allocated into different risk strata to develop poor prognosis in CLBP. MATERIALS AND METHODS: This is a pilot, observational and cross-sectional study. The sample consisted of 17 volunteers with CLBP from a local University Physical Rehabilitation Center. Volunteers were asked to answer two questionnaires to assess both the level of disability and to determine the risk of poor prognosis. The level of disability was determined by the Brazilian Version of the Oswestry Functional Index (IFO). The risk for developing poor prognosis was determined by the STarT Back Screening Tool (SBST) questionnaire, based on the influence of psychosocial factors, and volunteers were classified as low (n=6), medium (n=6) or high (n=5) risk of poor prognosis. The statistical test used was the Generalized Linear Model (GLzM), with α=0.05. RESULTS: The low-risk group presented minimal disability and the medium and high-risk groups presented severe disability, but there was a statistical difference in IFO only between the low and high-risk groups. CONCLUSION: There was a difference in disability between risk strata of poor prognosis, with disability significantly higher in the high-risk group compared to low-risk, suggesting that psychosocial aspects impact not only on prognosis but also on the level of disability of patients with chronic low back pain.

Landing-Takeoff Asymmetries Applied to Running Mechanics: A New Perspective for Performance.

BACKGROUND: Elastic bouncing is a physio-mechanical model that can elucidate running behavior in different situations, including landing and takeoff patterns and the characteristics of the muscle-tendon units during stretch and recoil in running. An increase in running speed improves the body's elastic mechanisms. Although some measures of elastic bouncing are usually carried out, a general description of the elastic mechanism has not been explored in running performance. This study aimed to compare elastic bouncing parameters between the higher- and lower-performing athletes in a 3000 m test. METHODS: Thirty-eight endurance runners (men) were divided into two groups based on 3000 m performance: the high-performance group (Phigh; n = 19; age: 29 ± 5 years; mass: 72.9 ± 10 kg; stature: 177 ± 8 cm; 3000time: 656 ± 32 s) and the low-performance group (Plow; n = 19; age: 32 ± 6 years; mass: 73.9 ± 7 kg; stature: 175 ± 5 cm; 3000time: 751 ± 29 s). They performed three tests on different days: (i) 3000 m on a track; (ii) incremental running test; and (iii) a running biomechanical test on a treadmill at 13 different speeds from 8 to 20 km h-1. Performance was evaluated using the race time of the 3000 m test. The biomechanics variables included effective contact time (t ce), aerial time (t ae), positive work time (t push), negative work time (t break), step frequency (f step), and elastic system frequency (f sist), vertical displacement (S v) in t ce and t ae (S ce and S ae), vertical force, and vertical stiffness were evaluated in a biomechanical submaximal test on treadmill. RESULTS: The t ae, f sist, vertical force and stiffness were higher (p < 0.05) and t ce and f step were lower (p < 0.05) in Phigh, with no differences between groups in t push and t break. CONCLUSION: The elastic bouncing was optimized in runners of the best performance level, demonstrating a better use of elastic components.

Treinamento neuromuscular aquático com ênfase proprioceptiva: influência na potência mecânica muscular e na altura de salto / Aquatic neuromuscular training with proprioceptive emphasis: influence on muscle mechanical power and jump height

INTRODUÇÃO: Tarefas motoras treinadas em ambiente aquático parecem potencializar o sistema proprioceptivo. Porém, é necessário investigar o efeito do meio aquático no desempenho neuromuscular de atletas. OBJETIVO: Avaliar o efeito de uma intervenção por exercícios neuromusculares funcionais aquáticos, com ênfase no sistema sensorial proprioceptivo, nas variáveis altura do salto e potência muscular, tendo a acuidade proprioceptiva como covariável. METODOLOGIA: Amostra composta por 14 homens universitários praticantes de futsal e dividida em grupo controle (GC/n=7) e grupo intervenção (GI/n=7). As variáveis potência mecânica muscular e altura do salto foram avaliadas por meio do teste de salto vertical de 60 segundos. A acuidade proprioceptiva foi avaliada pelo senso de posição articular e pela cinestesia quantificados pelo teste de percepção de movimentos passivos lentos (Tpassivo) e pelo teste de senso de posição articular (Tativo). As variáveis de desfecho foram mensuradas em dois momentos: antes e após a intervenção. A intervenção aquática foi aplicada durante seis semanas com três sessões em cada semana. RESULTADOS: Não houve efeito de grupo e nem do momento da avaliação na altura do salto, sendo que o GC alcançou altura de salto de 19,9±0,8 cm em comparação com o GI chegando a altura de 20,3±1,4 cm. Na potência mecânica muscular não houve efeito do momento, mas houve efeito do grupo, em que o GC apresentou potência de 366,2±17,6 W, enquanto GI apresentou 332,0±21,2 W, sendo menor que o GC. Nem o Tativo e nem o Tpassivo influenciaram a altura de salto e a potência mecânica muscular. CONCLUSÃO: A intervenção de exercícios neuromusculares aquáticos funcionais, com ênfase na propriocepção não afetou nem a potência muscular nem a altura do salto, este resultado não foi influenciado pela acuidade proprioceptiva. [AU]

INTRODUCTION: Motor skills trained in aquatic environment seem to potentiate the proprioceptive system. However, it is necessary to investigate the effect of the aquatic environment on the neuromuscular performance of athletes. AIM: To evaluate the effect of an intervention by functional aquatic neuromuscular exercises, with emphasis on the proprioceptive sensory system, on the variables jump height and muscular power, with proprioceptive acuity as a covariate. METHODOLOGY: Sample composed of 14 college men practicing futsal and divided into control group (CG/n=7) and experimental group (EG/n=7). The variables mechanical muscle power and jump height were evaluated using the 60 seconds vertical jump test. Proprioceptive acuity was assessed by the sense of joint position and kinesthesia quantified by the slow passive sensory perception test (Tpassive) and by the joint position sense test (Tactive). The outcome variables were measured in two moments: before and after the intervention. The aquatic intervention was applied for six weeks with three sessions each week. RESULTS: There was no group effect nor of the moment at the time of the jump. In the muscular mechanical power, there was no effect of the moment, but there was an effect of the group, with the CG presenting higher values than the EG. Neither Tactive nor Tpassive influenced jump height and muscular mechanical power. CONCLUSION: The intervention of functional aquatic neuromuscular exercises with emphasis on proprioception affected neither muscular power nor jump height, this result was not influenced by proprioceptive acuity. [AU]

Effect of weighted sled towing on sprinting effectiveness, power and force-velocity relationship.

This study aimed to compare the components of force-velocity (F-V) and power-velocity (P-V) profiles and the mechanical effectiveness of force application (or force ratio-RF) among various sled-towing loads during the entire acceleration phase of a weighted sled sprint. Eighteen sprinters performed four 50-m sprints in various conditions: unloaded; with a load corresponding to 20% of the athlete's body mass (BM); with a load of 30% BM; and with a load of 40% BM. Data were collected with five video cameras, and the images were digitised to obtain velocity from the derivation of the centre-of-mass position. F-V and P-V components and RF were estimated from sprinting velocity-time data for each load using a validated method that is based on an inverse dynamic approach applied to the sprinter's centre-of-mass (it models the horizontal antero-posterior and vertical ground reaction force components) and requires only measurement of anthropometric and spatiotemporal variables (body mass, stature and instantaneous position or velocity during the acceleration phase). The theoretical maximal velocity decreased with load compared with the unloaded condition (for 20% BM: -6%, effect size (ES) = 0,38; for 30% BM: -15%, ES = 1.02; for 40% BM: -18%, ES = 1.10). The theoretical maximal horizontal force (F0) and maximal power were not different among conditions. However, power at the end of the acceleration phase increased with load (40% BM vs 0%: 72%; ES = 2.73) as well as the maximal mechanical effectiveness (12%; ES = 0.85). The linear decrease in RF was different between 30 or 40% BM and the unloaded condition (-23%; ES = 0.74 and 0.66). Better effectiveness may be developed with 40% BM load at the beginning of the acceleration and with the various load-induced changes in the components of the F-V and P-V relationships, allowing a more accurate determination of optimal loading conditions for maximizing power.

Variação da potência muscular mecânica após sessão de treinamento: efeito agudo da criomassagem / Variation of mechanical muscle power after training session: acute effect of cryomassage

Introdução: O efeito da criomassagem na recuperação de habilidades motoras de atletas ainda não é consensual. Objetivo: Verificar o efeito agudo da criomassagem na variação do pico de potência muscular mecânica (PPMM) após sessão de treinamento. Métodos: Onze atletas da Seleção Paranaense de Voleibol, categoria infanto-juvenil (16,3 ± 1,7 anos; 69,2 ± 8,0 kg) foram submetidas à avaliação do PPMM em três momentos: pré-treino (MPRE), imediatamente após o treino (MPOSI), e tardiamente após o treino (MPOST). As atletas passaram, de forma cruzada, tanto pela condição controle (CC), quanto pela condição experimental (CE). Determinou-se o PPMM por meio de saltos verticais máximos em tapete de contato que forneceu a potência mecânica. Para criomassagem, entre o MPOSI e o MPOST, utilizaram-se cubos de gelo diretamente sobre a pele na forma de deslizamento superficial em oito grupos musculares dos membros inferiores durante dois minutos para cada grupo. Aplicou-se ANOVA medidas repetidas de dois fatores (condição e momento) com pós-teste de Bonferroni e α = 0,05. Resultados: Não houve efeito principal da condição F(1,21) = 0,148; p = 0,705, porém houve efeito do momento F(2,42) = 9,595; p < 0,001. O PPMM no MPOST foi significativamente menor que os demais momentos em ambas as condições (p < 0,05). Conclusão: A criomassagem não influenciou agudamente o PPMM após sessão de treinamento. (AU)

Introduction: The effect of cryomassage in the recovery of motor skills of athletes it is still not consensual. Objective: To investigate the acute effect of cryomassage in the variation of the peak mechanical muscle power (PMMP) after a session of training. Methods: Eleven athletes of Paranaense Volleyball Team, juvenile category (16.3 ± 1.7 years, 69.2 ± 8.0 kg) underwent assessment of PMMP in three stages: pre workout (MPRE), immediately after training (MPOSI), and later after training (MPOST). Athletes participed in both the control condition (CC) as the experimental condition (EC). PMMP was determined by means of maximum vertical jumps in contact carpet which provided mechanical power. For cryomassage, between MPOSI and MPOST, it was applied ice cubes directly on the skin in the form of superficial sliding in eight muscle groups of the lower limbs for two minutes for each group. We applied repeated measures ANOVA on two factors (condition and time) with Bonferroni post-test and α = 0.05. Results: There was no main effect of condition F(1,21) = 0.148; p = 0.705, but there was effect of time F(2,42) = 9.595; p < 0.001. The PMMP in MPOST was significantly smaller than the other moments in both conditions (p < 0.05). Conclusion: Cryomassage does not influence acutely peak mechanical muscle power after the training session. (AU)

Efeitos da estimulação elétrica nervosa transcutânea e da corrente de alta voltagem em indivíduos saudáveis / Effects of transcutaneous electrical nerve stimulation and high voltage in healthy subjects

O objetivo deste trabalho foi comparar a estimulação elétrica nervosa transcutânea (TENS) e a corrente de alta voltagem (AV) em indivíduos saudáveis. Para concretizar tal análise, 20 voluntários realizaram as duas modalidades de eletroestimulação de forma cruzada. A nocicepção foi avaliada por meio de estímulos pressóricos e térmicos no membro superior esquerdo, foi aplicada aeletroanalgesia por 20 minutos, sobre a articulação do cotovelo. Os parâmetros da TENS foram: duração de fase de 200 µs e frequência de 100 Hz. Para AV: 50 µse 100 Hz, polo positivo sobre a região do nervo mediano e negativo sobre o ulnar. Os resultados do estudo não mostraram diferenças significativas para limiar de dor e intensidade da dor ao frio. A AV apresentou-se mais agradável e com maior número de acomodações. Desse modo, é possível constatar que os parâmetros utilizados não foram eficazes para alterar a dor em indivíduos saudáveis e a Alta Voltagem teve maior agradabilidade, porém acomodou mais vezes.

Current analysis compares transcutaneous electrical nerve stimulation and high voltage (HV) on healthy subjects. Twenty volunteers experienced the two electro-stimulating modalities. Nociception was evaluated by pressure and thermal stimuli on the upper left limb and electro-analgesia was applied for 20 minutes on the elbow articulation. TENS parameters comprised: phase of 200 µs and frequency of 100 Hz. In the case of HV: 50 µs and 100 Hz, positive pole on the median nerve region and negative pole on the ulnar region. There were no significant paralimiar differences of pain and pain intensity to the cold. HV was more agreeable and with a great number of adaptations. Parameters employed were not efficacious to change pain in healthy subjects; HV had a greater agreeability albeit accommodated several times.

Effect of Nonspecific Chronic Low Back Pain on Walking Economy: An Observational Study.

The authors investigated the effects of chronic low back pain (LBP) and walking speed (WS) on metabolic power and cost of transport (CT). Subjects with chronic nonspecific LBP (LBP group [LG]; n = 9) and healthy (control group [CG]; n = 9) were included. The test battery was divided into 3 blocks according to WS as follows: preferred self-selected speed (PS), and lower and higher than the PS. In each block, the volunteers walked 5 min, during which oxygen consumption was measured. Although without differences between groups, the LG had CT lower in slower speeds than in faster speeds. Walking speed affected CT only in the LG, which the group had the greatest walking economy at slower speeds.