Effects of Whole Body Vibration on the Neuromuscular Amplitude of Vastus Lateralis Muscle.

The aim of this study was to investigate the effects of whole-body vibration (WBV) on vastus lateralis (VL) surface electromyographic (sEMG) amplitude during an isometric semi-squat exercise, using two different frequencies, and to verify the influence of additional filters on the analyzed sEMG signal's characteristics. Forty physically active women were randomly divided into two groups with 20 members each: one group performed an isometric semi-squat exercise at 30 Hz - while the other group performed the same exercise protocol at 50 Hz. The sEMG amplitude of the VL muscle was recorded during the exercise protocols in two conditions: with and without vibration. After removing vibration-induced artifacts using digital filters, sEMG amplitude of VL increased significantly (p < 0.05) without differences between the frequencies. The results of this study suggest that WBV at 30 Hz and 50 Hz increased the sEMG amplitude of the VL muscle during an isometric semi-squat exercise. Furthermore, applying sEMG filters during signal processing of WBV is necessary, because motion artifacts from the vibration frequencies may contribute to the contamination of the sEMG amplitude.

Delayed effect of Kinesio Taping on neuromuscular performance, balance, and lower limb function in healthy individuals: a randomized controlled trial.

BACKGROUND: Kinesio Taping (KT) is an elastic bandage that aims to improve neuromuscular performance, although there is no consensus as to its benefits. OBJECTIVE: To analyze the immediate and delayed effects of KT on the neuromuscular performance of the femoral quadriceps, on balance, and lower limb function in healthy subjects. METHOD: This is a randomized controlled trial. Thirty-six women with a mean age of 22.2±3.6 years and BMI of 22.5±2.3 Kg/m2 were divided into three groups: control, with ten minutes of rest (control, n=12), application of Kinesio Taping without tension (placebo, n=12) and with tension (KT, n=12) on the quadriceps. The primary outcome was isokinetic performance, while secondary outcomes were the single-hop test, one-footed static balance, and electromyographic activity. The evaluations were carried out in five stages: 1) before application of KT, 2) immediately after the application of KT, 3) after 24h, 4) after 48h, and 5) after 72h. Mixed ANOVA was used to determine differences between groups. RESULTS: There was no change in one-footed static balance, electromyographic activity of the VL in the lower limb function, nor in isokinetic performance between groups. CONCLUSION: KT promotes neither immediate nor delayed changes in neuromuscular performance of the femoral quadriceps in healthy women.

Immediate effects of whole-body vibration on neuromuscular performance of quadriceps and oscillation of the center of pressure: A randomized controlled trial.

BACKGROUND: Whole body vibration has become a popular practice in training and rehabilitation centers. Although proposed as a useful adjunct to improve various aspects of musculoskeletal function, its real benefits and immediate physiological responses are still uncertain. OBJECTIVES: This study analyzed the immediate effects of whole-body vibration with two distinct frequencies on neuromuscular performance of the quadriceps femoris and in the postural control of healthy subjects. DESIGN: Randomized controlled trial. METHODS: Sixty physically active women were submitted to an evaluation of the oscillation of the center of pressure through baropodometry and isokinetic performance of quadriceps femoris muscle of the non-dominant limb, associated with the electromyographic amplitude assessment of vastus lateralis muscle. Subjects were randomly divided into three groups: control group - performed an exercise protocol with the vibrating platform off; 30 and 50 Hz groups - conducted the exercise protocol with the platform on, with a frequency of 30 and 50 Hz, respectively. RESULTS: There was a significant reduction in the time of peak torque in three evaluated groups (p < 0.001), with no differences between the groups (p = 0.586). There were no significant differences in pressure center oscillation, peak torque normalized for body weight, total work, and average power nor in the value of the root mean square in any of the groups. CONCLUSION: This study suggests that the exercise protocol on the vibrating platform does not change neuromuscular performance or the pressure center oscillation of healthy women. CLINICALTRIALS. GOV IDENTIFIER: NCT02416362.

Delayed effect of Kinesio Taping on neuromuscular performance, balance, and lower limb function in healthy individuals: a randomized controlled trial

ABSTRACT Background Kinesio Taping (KT) is an elastic bandage that aims to improve neuromuscular performance, although there is no consensus as to its benefits. Objective To analyze the immediate and delayed effects of KT on the neuromuscular performance of the femoral quadriceps, on balance, and lower limb function in healthy subjects. Method This is a randomized controlled trial. Thirty-six women with a mean age of 22.2±3.6 years and BMI of 22.5±2.3 Kg/m2 were divided into three groups: control, with ten minutes of rest (control, n=12), application of Kinesio Taping without tension (placebo, n=12) and with tension (KT, n=12) on the quadriceps. The primary outcome was isokinetic performance, while secondary outcomes were the single-hop test, one-footed static balance, and electromyographic activity. The evaluations were carried out in five stages: 1) before application of KT, 2) immediately after the application of KT, 3) after 24h, 4) after 48h, and 5) after 72h. Mixed ANOVA was used to determine differences between groups. Results There was no change in one-footed static balance, electromyographic activity of the VL in the lower limb function, nor in isokinetic performance between groups. Conclusion KT promotes neither immediate nor delayed changes in neuromuscular performance of the femoral quadriceps in healthy women.

Immediate effects of Kinesio Taping(®) on neuromuscular performance of quadriceps and balance in individuals submitted to anterior cruciate ligament reconstruction: A randomized clinical trial.

OBJECTIVES: Investigate the immediate effects of Kinesio Taping(®) on neuromuscular performance of femoral quadriceps and balance in individuals submitted to anterior cruciate ligament reconstruction. DESIGN: This is a randomized clinical trial. METHODS: Forty-seven male participants, between 12 and 17 weeks after anterior cruciate ligament reconstruction, underwent initial assessment consisting of postural balance analysis using baropodometry, followed by eccentric and concentric isokinetic assessment at 60°/s of knee extensors, concomitant to electromyographic signals captured from the vastus lateralis muscle. They were then randomly allocated to one of the following groups: control, placebo and Kinesio Taping(®). Kinesio Taping(®) group participants were submitted to Kinesio Taping(®) on the femoral quadriceps of the affected limb, while placebo group subjects used the same procedure without the tension proposed by the method. The control group remained at rest for 10min. All participants were reassessed following the same procedure as the initial evaluation. The following variables were analyzed: peak torque/body weight and muscle potential using dynamometry; amplitude of antero-posterior and latero-lateral displacement from the center of pressure using baropodometry; and amplitude of muscle activation (root mean square) applying surface electromyography. RESULTS: None of the variables analyzed showed significant intergroup or intragroup differences. CONCLUSIONS: Kinesio Taping(®) does not alter the neuromuscular performance of femoral quadriceps or balance of subjects submitted to anterior cruciate ligament reconstruction, for any of the variables analyzed.

Immediate effects of TENS and cryotherapy in the reflex excitability and voluntary activity in hemiparetic subjects: a randomized crossover trial / Efeitos imediatos da TENS e crioterapia na excitabilidade reflexa e atividade voluntária de sujeitos hemiparéticos: um estudo controlado aleatorizado cruzado

BACKGROUND: The disorder of reflex and motor function in patients affected by stroke causes negative impact on the performance of movement patterns and affects the functional activities. OBJECTIVES: To investigate the immediate effects of transcutaneous electrical nerve stimulation (TENS) and cryotherapy interventions on the spinal reflex excitability and in the voluntary electromyography (EMG) activity in people with chronic stroke. METHOD: Randomized crossover trial. The maximum H-reflex (Hmax), the H-reflex latency and the maximum motor response (Mmax) of the soleus muscle and also the EMG of the tibialis muscle where evaluated before and after the application of TENS, cryotherapy and control conditions. RESULTS: The Hmax/Mmax ratio was statistically significant higher (p=0.0245) and the H-reflex latency was statistically significant lower (p=0.0375) in the soleus muscle of the affected limb. The EMG amplitude of the tibialis anterior was reduced in the compromised limb (p<0.0001). After the use of the TENS, a reduction in the Hmax/Mmax ratio (p=0.0006) was observed leading to lower reflex excitability. However, after the cryotherapy intervention an increase of the Hmax/Mmax ratio was observed, which was accompanied by an increase in the H-reflex latency (p=0.0001). The EMG amplitude has not changed by any of the interventions. CONCLUSIONS: Our findings suggest that TENS may be a choice for immediate reduction of reflex excitability, whereas cryotherapy intervention may increase reflex excitability in hemiparetic subjects. However, none of the changes mediated by either intervention were able to modify the electrical activity in the antagonist muscle of the spastic muscle.

CONTEXTUALIZAÇÃO: O distúrbio da função motora e reflexa em pacientes acometidos por acidente vascular encefálico (AVE) causa impactos negativos na realização de padrões motores, comprometendo as atividades funcionais. OBJETIVOS: Investigar os efeitos imediatos da estimulação elétrica nervosa transcutânea (TENS) e da crioterapia na excitabilidade reflexa e na atividade voluntária de sujeitos vítimas de AVE. MÉTODO: Estudo Crossover. O reflexo H máximo (Hmáx), a latência do reflexo H e a resposta motora máxima (Mmáx) do músculo solear e a eletromiografia (EMG) do músculo tibial anterior foram avaliados antes e após a aplicação de TENS, crioterapia e em condições de controle. RESULTADOS: A razão Hmáx/Mmáx estava significativamente aumentada (p=0,0245) e a latência do reflexo H significativamente diminuída (p=0,0375) no músculo solear do membro afetado. A amplitude do sinal EMG do músculo estava significativamente reduzida no membro comprometido (p<0,0001). Depois da TENS, houve uma diminuição da razão Hmáx/Mmáx (p=0,0006). Porém, após a aplicação do gelo, houve um aumento da razão Hmáx/Mmáx, acompanhado por um aumento da latência do reflexo H (p=0,0001). A amplitude do sinal EMG não foi alterada por nenhuma das intervenções. CONCLUSÕES: Nossos achados indicam que a TENS pode ser uma escolha para redução imediata da excitabilidade reflexa, enquanto a crioterapia pode aumentar a excitabilidade reflexa de sujeitos hemiparéticos. No entanto, nenhuma das alterações mediadas por qualquer um dos tratamentos foi capaz de alterar a atividade elétrica do músculo antagonista ao espástico.

Immediate effects of TENS and cryotherapy in the reflex excitability and voluntary activity in hemiparetic subjects: a randomized crossover trial.

BACKGROUND: The disorder of reflex and motor function in patients affected by stroke causes negative impact on the performance of movement patterns and affects the functional activities. OBJECTIVES: To investigate the immediate effects of transcutaneous electrical nerve stimulation (TENS) and cryotherapy interventions on the spinal reflex excitability and in the voluntary electromyography (EMG) activity in people with chronic stroke. METHOD: Randomized crossover trial. The maximum H-reflex (Hmax), the H-reflex latency and the maximum motor response (Mmax) of the soleus muscle and also the EMG of the tibialis muscle where evaluated before and after the application of TENS, cryotherapy and control conditions. RESULTS: The Hmax/Mmax ratio was statistically significant higher (p=0.0245) and the H-reflex latency was statistically significant lower (p=0.0375) in the soleus muscle of the affected limb. The EMG amplitude of the tibialis anterior was reduced in the compromised limb (p<0.0001). After the use of the TENS, a reduction in the Hmax/Mmax ratio (p=0.0006) was observed leading to lower reflex excitability. However, after the cryotherapy intervention an increase of the Hmax/Mmax ratio was observed, which was accompanied by an increase in the H-reflex latency (p=0.0001). The EMG amplitude has not changed by any of the interventions. CONCLUSIONS: Our findings suggest that TENS may be a choice for immediate reduction of reflex excitability, whereas cryotherapy intervention may increase reflex excitability in hemiparetic subjects. However, none of the changes mediated by either intervention were able to modify the electrical activity in the antagonist muscle of the spastic muscle.

Functional and morphological changes in the quadriceps muscle induced by eccentric training after ACL reconstruction.

OBJECTIVES: The purpose of this study was to investigate the contributions of functional and morphological factors in the recovery of the quadriceps muscle after anterior cruciate ligament (ACL) reconstruction. METHODS: Nine subjects (31.3±5.8 years) underwent eccentric exercise sessions twice a week for 12 weeks. Quadriceps muscle function was evaluated using an isokinetic dynamometer (isometric and eccentric peak torque) and electromyography (RMS). Morphological changes were measured using magnetic resonance imaging. RESULTS: The initial evaluation showed a significant deficit in knee extensor torque in the involved limb and significant muscle atrophy along the length of the quadriceps. EMG activity was lower in all tested situations. Eccentric training significantly increased isokinetic torque (from 199±51 to 240±63, p<0.05, respectively) and quadriceps area, with the greatest hypertrophy in the proximal thigh region (from 169±27 to 189±25.8 cm², p<0.01). The EMG activity of vastus medialis increased after the first six weeks of eccentric training. The increased extensor torque was correlated with quadriceps cross-sectional area (r=0.81, p<0.01) and EMG activity (r=0.69, p<0.05). After twelve weeks of training, there was a correlation only between torque and cross-sectional area (r=0.78, p<0.01). CONCLUSIONS: 1) eccentric training proved to be a potent resource for the quadriceps recovery, both morphologically and functionally, 2) the contributions of functional and morphological factors varied according to the length of training.

Functional and morphological changes in the quadriceps muscle induced by eccentric training after ACL reconstruction / Alterações funcionais e morfológicas do quadríceps induzidas pelo treinamento excêntrico após reconstrução do LCA

OBJECTIVES: The purpose of this study was to investigate the contributions of functional and morphological factors in the recovery of the quadriceps muscle after anterior cruciate ligament (ACL) reconstruction. METHODS: Nine subjects (31.3±5.8 years) underwent eccentric exercise sessions twice a week for 12 weeks. Quadriceps muscle function was evaluated using an isokinetic dynamometer (isometric and eccentric peak torque) and electromyography (RMS). Morphological changes were measured using magnetic resonance imaging. RESULTS: The initial evaluation showed a significant deficit in knee extensor torque in the involved limb and significant muscle atrophy along the length of the quadriceps. EMG activity was lower in all tested situations. Eccentric training significantly increased isokinetic torque (from 199±51 to 240±63, p<0.05, respectively) and quadriceps area, with the greatest hypertrophy in the proximal thigh region (from 169±27 to 189±25.8 cm², p<0.01). The EMG activity of vastus medialis increased after the first six weeks of eccentric training. The increased extensor torque was correlated with quadriceps cross-sectional area (r=0.81, p<0.01) and EMG activity (r=0.69, p<0.05). After twelve weeks of training, there was a correlation only between torque and cross-sectional area (r=0.78, p<0.01). CONCLUSIONS: 1) eccentric training proved to be a potent resource for the quadriceps recovery, both morphologically and functionally, 2) the contributions of functional and morphological factors varied according to the length of training.

OBJETIVOS: O propósito deste estudo foi avaliar as contribuições dos fatores funcionais e morfológicos na recuperação da força muscular do quadríceps femoral após reconstrução do Ligamento Cruzado Anterior (LCA). MÉTODOS: Nove indivíduos (31,3±5,8 anos) foram treinados por meio de contrações excêntricas máximas, duas vezes por semana, durante 12 semanas. A função do quadríceps foi avaliada pela dinamometria isocinética (pico de torque isométrico e excêntrico) e pela eletromiografia (EMG). As alterações morfológicas foram mensuradas por meio de ressonância magnética (RNM). Na avaliação inicial, observou-se significativo déficit no torque extensor do joelho do membro acometido, com hipotrofia muscular de todo o quadríceps e redução na atividade EMG, quando comparado ao membro não-acometido. RESULTADOS: O treinamento excêntrico produziu aumento no torque excêntrico a 30º/s (de 199±51 Nm para 240±63 Nm, p<0,05) e no volume muscular, sendo que maiores hipertrofias ocorreram na região proximal da coxa (de 169±27 para 189±25,8 cm², p<0,01). A atividade EMG do Vasto Medial (VM) aumentou nas primeiras seis semanas de treinamento. O aumento no torque extensor demonstrou correlação positiva com o aumento no volume (r=0,81, p<0,01) e na atividade eletromiográfica (EMG) (r=0,69, p<0,05) nas primeiras seis semanas. Após 12 semanas de treinamento, houve correlação apenas entre o aumento do torque e do volume (r=0,78, p<0,01). CONCLUSÕES: 1) O treinamento excêntrico mostrou-se como potente recurso tanto na recuperação dos fatores morfológicos como funcionais do músculo quadríceps; 2) A contribuição dos fatores neurais e morfológicos varia em função do período de treinamento.