Fernando Amâncio Aragão

Mini-trampoline exercise related to mechanisms of dynamic stability improves the ability to regain balance in elderly

Falls have been described by several studies as the major cause of hip and femur fractures among the elderly. Therefore, interventions to reduce fall risks, improve dynamic stability and the falling recovery strategies in the elderly population are highly relevant. This study aimed at investigating the effects of a 14-week mini-trampoline exercise intervention regarding the mechanisms of dynamic stability on elderly balance ability during sudden forward falls. Twenty-two elderly subjects participated on mini-trampoline training and 12 subjects were taken as controls. The subjects of the experimental group were evaluated before and after the 14-week trampoline training (exercised group), whereas control subjects were evaluated twice in the forward fall task with a three-month interval. The applied exercise intervention increased the plantarflexors muscle strength (∼10%) as well as the ability to regain balance during the forward falls (∼35%). The 14-week mini-trampoline training intervention increased elderly abilities to recover balance during forward falls; the improvement was attributed to the higher rate of hip moment generation.

Reliability and differentiation capability of dynamic and static kinematic measurements of rearfoot eversion in patellofemoral pain

BACKGROUND Excessive rearfoot eversion is thought to be a risk factor for patellofemoral pain development, due to the kinesiological relationship with ascendant adaptations. Individuals with patellofemoral pain are often diagnosed through static clinical tests, in scientific studies and clinical practice. However, the adaptations seem to appear in dynamic conditions. Performing static vs. dynamic evaluations of widely used measures would add to the knowledge in this area. Thus, the aim of this study was to determine the reliability and differentiation capability of three rearfoot eversion measures: rearfoot range of motion, static clinical test and static measurement using a three-dimensional system. METHOD A total of 29 individuals with patellofemoral pain and 25 control individuals (18-30 years) participated in this study. Each subject underwent three-dimensional motion analysis during stair climbing and static clinical tests. Intraclass correlation coefficient and standard error measurements were performed to verify the reliability of the variables and receiver operating characteristic curves to show the diagnostic accuracy of each variable. In addition, analyses of variance were performed to identify differences between groups. FINDINGS Rearfoot range of motion demonstrated higher diagnostic accuracy (an area under the curve score of 0.72) than static measures and was able to differentiate the groups. Only the static clinical test presented poor and moderate reliability. Other variables presented high to very high values. INTERPRETATION Rearfoot range of motion was the variable that presented the best results in terms of reliability and differentiation capability. Static variables do not seem to be related to patellofemoral pain and have low accuracy values.

Reduced knee flexion is a possible cause of increased loading rates in individuals with patellofemoral pain

BACKGROUND Stair ascent is an activity that exacerbates symptoms of individuals with patellofemoral pain. The discomfort associated with this activity usually results in gait modification such as reduced knee flexion in an attempt to reduce pain. Although such compensatory strategy is a logical approach to decrease pain, it also reduces the normal active shock absorption increasing loading rates and may lead to deleterious and degenerative changes of the knee joint. Thus, the aims of this study were (i) to investigate whether there is reduced knee flexion in adults with PFP compared to healthy controls; and (ii) to analyze loading rates in these subjects, during stair climbing. METHOD Twenty-nine individuals with patellofemoral pain and twenty-five control individuals (18-30 years) participated in this study. Each subject underwent three-dimensional kinematic and kinetic analyses during stair climbing on two separate days. Between-groups analyses of variance were performed to identify differences in peak knee flexion and loading rates. Intraclass correlation coefficient was performed to verify the reliability of the variables. FINDINGS On both days, the patellofemoral pain group demonstrated significantly reduced peak knee flexion and increased loading rates. In addition, the two variables obtained high to very high reliability. INTERPRETATION Reduced knee flexion during stair climbing as a strategy to avoid anterior knee pain does not seem to be healthy for lower limb mechanical distributions. Repeated loading at higher loading rates may be damaging to lower limb joints.

Vertical Ground Reaction Forces are Associated with Pain and Self-Reported Functional Status in Recreational Athletes with Patellofemoral Pain.

Individuals with patellofemoral pain (PFP) use different motor strategies during unipodal support in stair climbing activities, which may be assessed by vertical ground reaction force parameters. Thus, the aims of this study were to investigate possible differences in first peak, valley, second peak, and loading rate between recreational female athletes with PFP and pain-free athletes during stair climbing in order to determine the association and prediction capability between these parameters, pain level, and functional status in females with PFP. Thirty-one recreational female athletes with PFP and 31 pain-free recreational female athletes were evaluated with three-dimensional kinetics while performing stair climbing to obtain vertical ground reaction force parameters. A visual analog scale was used to evaluate the usual knee pain. The anterior knee pain scale was used to evaluate knee functional score. First peak and loading rate were associated with pain (r = .46, P = .008; r = .56, P = .001, respectively) and functional limitation (r = .31, P = .049; r = -.36, P = .032, respectively). Forced entry regression revealed the first peak was a significant predictor of pain (36.5%) and functional limitation (28.7%). Our findings suggest that rehabilitation strategies aimed at correcting altered vertical ground reaction force may improve usual knee pain level and self-reported knee function in females with PFP.

Comparison of frequency and time domain electromyography parameters in women with patellofemoral pain.

BACKGROUND Despite its high incidence, patellofemoral pain etiology remains unclear. No prior study has compared surface electromyography frequency domain parameters and surface electromyography time domain variables, which have been used as a classic analysis of patellofemoral pain. METHODS Thirty one women with patellofemoral pain and twenty eight pain-free women were recruited. Each participant was asked to descend a seven step staircase and data from five successful trials were collected. During the task, the vastus medialis and vastus lateralis muscle activities were monitored by surface electromyography. The data were processed and analyzed in four variables of the frequency domain (median frequency, low, medium and high frequency bands) and three time domain variables (Automatic, Cross-correlation and Visual Onset between the vastus medialis and vastus lateralis muscles). Reliability, Receiver Operating Characteristic curves and regression models were performed. FINDINGS The medium frequency band was the most reliable variable and different between the groups for both muscles, also demonstrated the best values of sensitivity and sensibility, 72% and 69% for the vastus medialis and 68% and 62% for the vastus lateralis, respectively. The frequency variables predicted the pain of individuals with patellofemoral pain, 26% for the vastus medialis and 20% for the vastus lateralis, being better than the time variables, which achieved only 7%. INTERPRETATION The frequency domain parameters presented greater reliability, diagnostic accuracy and capacity to predict pain than the time domain variables during stair descent and might be a useful tool to diagnose individuals with patellofemoral pain.

Q-angle static or dynamic measurements, which is the best choice for patellofemoral pain?

BACKGROUND The elevated Q-angle seems to be one of the most suggested factors contributing to patellofemoral pain. Females with patellofemoral pain are often evaluated through static clinical tests in clinical practice. However, the adaptations seem to appear more frequently in dynamic conditions. Performing static vs. dynamic evaluations of widely used measures would add to the knowledge in this area. Therefore, the aim of this study was to determine the reliability and discriminatory capability of three Q-angle measurements: a static clinical test, peak dynamic knee valgus during stair ascent and a static measurement using a three-dimensional system. METHOD Twenty-nine females with patellofemoral pain and twenty-five pain-free females underwent clinical Q-angle measurement and static and dynamic knee valgus measurements during stair ascent, using a three-dimensional system. All measurements were obtained and comparisons between groups, reliability and discriminatory capability were calculated. FINDINGS Peak dynamic knee valgus was found to be greater in the patellofemoral pain group. On the other hand, no significant effects were found for static knee valgus or clinical Q-angle measurements between groups. The dynamic variable demonstrated the best discriminatory capability. Low values of reliability were found for clinical Q-angle, in contrast to the high values found for the three-dimensional system measurements. INTERPRETATION Based on our findings, avoiding or correcting dynamic knee valgus during stair ascent may be an important component of rehabilitation programs in females with patellofemoral pain who demonstrate excessive dynamic knee valgus. Q-angle static measurements were not different between groups and presented poor values of discriminatory capability.

Effects of Russian current and low-frequency pulsed current on discomfort level and current amplitude at 10% maximal knee extensor torque

Background: Low-frequency pulsed current (LFPC) and Russian current (RC), a type of kilohertz-frequency alternating current, have been frequently used for muscle strengthening in rehabilitation programs. Despite the popularity of these current types, it is unclear which is most effectively able to generate a similar submaximal torque with minimal discomfort and current amplitude. Objective: To compare discomfort and current amplitude between LFPC and RC to achieve a knee extensor torque of 10% of the maximal isometric voluntary contraction (MIVC). Methods: Twenty-two healthy subjects were subjected to three electrically elicited knee extensor submaximal contractions (10% MIVC) that were sustained for 10 seconds. The current amplitude required to achieve 10% MIVC and subjective discomfort were assessed directly by the electrical stimulator and with the Visual Analogue Pain Scale, respectively. A paired t-test was used to determine differences between the electrical currents (α = 0.05). Results: LFPC required significantly lower current amplitude (15%) and a lower discomfort level (50%) to achieve 10% of MIVC compared to RC. Conclusion: LFPC current seems to be more effective than RC with respect to discomfort level and current amplitude to produce 10% of MIVC.

Contribution of altered hip, knee and foot kinematics to dynamic postural impairments in females with patellofemoral pain during stair ascent

BACKGROUND Altered hip, knee and foot kinematics have been systematically observed in individuals with patellofemoral pain (PFP). However, less attention has been given to the altered dynamic postural control associated with PFP. Additionally, the relative contribution of kinematic impairments to the postural behavior of subjects with PFP remains an open question that warrants investigation. The aims of this study were: i) to investigate possible differences in hip adduction, rearfoot eversion, knee flexion and displacement area of the center of pressure (COP) in individuals with PFP in comparison to controls during stair ascent; and (ii) to determine which kinematic parameter is the best predictor of the displacement area of the COP measured during the stance phase of the stair ascent. METHODS Twenty-nine females with PFP and 25 asymptomatic pain-free females underwent three-dimensional kinematic and COP analyses during stair ascent. Between-group comparisons were made using independent t-tests. Regression models were performed to identify the capability of each kinematic factor in predicting the displacement area of the COP. RESULTS Reduced knee flexion and displacement area of the COP as well as increased peak hip adduction and peak rearfoot eversion were observed in individuals with PFP as compared to controls. Peak hip adduction was the best predictor of the displacement area of the COP (r(2)=23.4%). CONCLUSIONS The excessive hip adduction was the biggest predictor of the displacement area of the COP. CLINICAL RELEVANCE Based on our findings, proximally targeted interventions may be of major importance for the functional reestablishment of females with PFP.

Efeitos da corrida em esteira em músculos sóleos de ratos encurtados por imobilização

The aim of this work was to compare weight and length adaptations of the soleus muscle of male Wistar rats as well as estimation of the total number of serial sarcomere and mean sarcomere length, when they are submitted to remobilization on treadmill. 18 Wistar male rats were used and divided in the three following groups: CG - left soleus (LS) muscle immobilized and remobilized free in the cage; G10 - LS muscle immobilized and remobilized in speed of 10 m/min on treadmill; and G12 - LS muscle immobilized and remobilized in speed of 12 m/min. The right muscles (RS) of each animal were used for comparison. The results showed the following variations, muscular weigh: CG -22.35% (p = 0.0089), G10 -12.52% (p = 0.0623), G12 -12.07%, (p = 0.0004); muscle length: CG -5.47% (p = 0.0120), G10 -3.31% (p = 0.2868), G12 0.41% (p = 0.8987); estimation of number of serial sarcomere: CG -15.42% (p = 0.0047), G10 -10.87% (p = 0.0193), G12 -4.97 (p = 0.2409); sarcomere length: CG 11.16%, (p = 0.0142), G10 9.31% (p = 0.1270), G12 5.58% (p = 0.1327). It was concluded that G12 presented the best effectiveness after immobilization period since it presented greater similarity with the non-immobilized soleus.

Reliability of electromyography parameters during stair deambulation in patellofemoral pain syndrome

A reprodutibilidade e essencial para todos os aspectos da medida, uma vez que mostra a qualidade da informacao e permite conclusoes racionais no que diz respeito aos dados. Alem disso, os resultados sao controversos sobre parâmetros eletromiograficos avaliados durante a subida e descida de escada em individuos com sindrome da dor femoropatelar (SDFP). Portanto pretende-se determinar a reprodutibilidade de parâmetros eletromiograficos nos dominios do tempo e da frequencia em ambos os gestos em mulheres com SDFP. Foram selecionadas 31 mulheres com SDFP. Os dados dos musculos vasto lateral e vasto medial foram coletados durante a subida e a descida de escada. Os parâmetros selecionados foram: o onset automatico, frequencia mediana, bandas de baixa, media e alta frequencia. Determinou-se a reprodutibilidade atraves do coeficiente de correlacao intraclasse e do erro padrao da medida. As variaveis no dominio da frequencia apresentaram boa reprodutibilidade, com a subida apresentando os melhores indices, e o onset mostrou-se inconsistente. Os resultados sugerem que a subida de escada e mais confiavel do que a descida da escada para avaliar individuos com SDPF na maioria dos casos.La reproducibilidad es esencial para todos los aspectos de la medida, ya que muestra la calidad de la informacion y permite conclusiones racionales con respecto a los datos. Ademas, los resultados son controvertidos en parametros electromiograficos evaluados durante el ascenso y descenso escaleras en las personas con sindrome de dolor patelofemoral (SDPF). Por eso tenemos la intencion de determinar la reproducibilidad de los parametros electromiograficos en el tiempo y la frecuencia en ambos gestos en mujeres con SDPF. 31 mujeres com SDPF fueron seleccionadas. Se recogieron datos del vasto lateral y medial durante ascenso y descenso de escaleras. Los parametros seleccionados fueron: inicio automatico, frecuencia mediana, bandas de baja, media y alta frecuencia. La reproducibilidad se determino mediante el coeficiente de correlacion intraclase y el error estandar de medicion. Las variables en el dominio de la frecuencia mostraron buena reproducibilidad, el ascenso presento los mejores indices, y el inicio demostro ser inconsistente. Estos resultados sugieren que el ascenso de la escalera es mas confiable que el descenso para evaluar individuos con SDPF en la mayoria de los casos.