Efecto de la práctica mental kinestésica en la fuerza y actividad mioeléctrica del bíceps braquial, luego de un periodo de inmovilización de codo en adultos-jóvenes sanos / Effects of kinesthetic mental practice in strength and myoelectric activity of the brachialis biceps due to an elbow immobilization period in healthy young adults

RESUMEN: El objetivo de este estudio fue determinar el efecto de la práctica mental kinestésica (PMK) en la fuerza y actividad eléctrica muscular (AEM) del bíceps braquial, luego de un periodo de inmovilización del codo en un grupo de personas adultos jóvenes sanos. Un total de 14 personas (18,64 ± 0,92 años de edad) participaron voluntariamente del estudio, a las cuales se les evaluó la fuerza muscular de prensión y la AEM del bíceps braquial utilizando un dinamómetro de mano y un equipo de electromiografía, respectivamente, antes y después de un periodo de inmovilización del brazo no dominante, y se asignaron aleatoriamente a uno de dos grupos: grupo control (GC) o experimental (GE). El GE realizó PMK: tres series de 15 repeticiones con un minuto de descanso entre series, tres veces al día durante los seis días de inmovilización, mientras que el GC no realizó PKM durante su inmovilización. Al aplicar una prueba de ANOVA de dos vías, no se encontraron diferencias significativas en la fuerza ni en la AEM. Sin embargo, la fuerza del GC disminuyó en 23,75%, mientras que la del GE aumentó en 33,19%. Los resultados sugieren que un periodo de inmovilización del codo de seis días no fue suficiente para que la fuerza ni la AEM disminuyan significativamente, lo que supone que la PMK realizada no es necesaria en periodos menores a seis días.

ABSTRACT: The aim of this study was to determine the effect of kinesthetic mental practice (KMP) on the strength and muscular electrical activity (MEA) of the brachial biceps, after a period of immobilization of the elbow in a group of healthy young adults. A total of 14 volunteer participants (18.64 ± 0.92 years of age) were part in the study. The muscle strength and the AEM of the brachial biceps were assessed using a hand dynamometer and an electromyography equipment, respectively, before and after a period of immobilization of the non-dominant arm. After the pretest, they were randomly assigned to one of two groups: control group (GC) or experimental group (GE). The GE performed 3 sets of 15 repetitions with one-minute rest between sets, three times a day of PMK during the 6 days of immobilization, while the GC did not perform PKM during its immobilization. A 2-way ANOVA test (group x measurement) indicated non-significant differences in strength or AEM. However, the strength of the GC decreased by 23.75%, while increased by 33.19% in the GE. The results suggest that a period of immobilization of the elbow of 6 days was not enough for the strength or the AEM to decrease significantly, which means that the PMK is not necessary in periods of immobilization of less than 6 days.

Long-term strength and functional status in inclusion body myositis and identification of trajectory subgroups.

INTRODUCTION: Objective information on longitudinal disease progression in inclusion body myositis (IBM) is lacking. METHODS: Longitudinal dynamometry and functional status data were collated from a cohort of IBM patients. Annual change was calculated by means of linear modeling. Trajectories of change in grip, knee extension, IBM Functional Rating Scale (IBM-FRS) and Neuromuscular Symptom Score (NSS) were identified by means of latent growth mixture modeling. RESULTS: Data were collated from 75 IBM patients (348 person-years follow-up). Annual strength loss was greatest for pinch (-10%) and knee extension (-4%). Functional deterioration was greatest for males. Three distinct trajectory groups were identified. Rapid deterioration trajectory for grip strength was associated with younger diagnosis age. Rapid deterioration for knee extension strength was associated with older age of diagnosis. DISCUSSION: This study has quantified strength change in IBM and identified distinct trajectory groups, which will aid prognostication and stratification for inclusion into future clinical trials.

Analysis of three different equations for predicting quadriceps femoris muscle strength in patients with COPD.

OBJECTIVE: To compare equations for predicting peak quadriceps femoris (QF) muscle force; to determine the agreement among the equations in identifying QF muscle weakness in COPD patients; and to assess the differences in characteristics among the groups of patients classified as having or not having QF muscle weakness by each equation. METHODS: Fifty-six COPD patients underwent assessment of peak QF muscle force by dynamometry (maximal voluntary isometric contraction of knee extension). Predicted values were calculated with three equations: an age-height-weight-gender equation (Eq-AHWG); an age-weight-gender equation (Eq-AWG); and an age-fat-free mass-gender equation (Eq-AFFMG). RESULTS: Comparison of the percentage of predicted values obtained with the three equations showed that the Eq-AHWG gave higher values than did the Eq-AWG and Eq-AFFMG, with no difference between the last two. The Eq-AHWG showed moderate agreement with the Eq-AWG and Eq-AFFMG, whereas the last two also showed moderate, albeit lower, agreement with each other. In the sample as a whole, QF muscle weakness (< 80% of predicted) was identified by the Eq-AHWG, Eq-AWG, and Eq-AFFMG in 59%, 68%, and 70% of the patients, respectively (p > 0.05). Age, fat-free mass, and body mass index are characteristics that differentiate between patients with and without QF muscle weakness. CONCLUSIONS: The three equations were statistically equivalent in classifying COPD patients as having or not having QF muscle weakness. However, the Eq-AHWG gave higher peak force values than did the Eq-AWG and the Eq-AFFMG, as well as showing greater agreement with the other equations.

Analysis of three different equations for predicting quadriceps femoris muscle strength in patients with COPD / Análise de três diferentes fórmulas de predição de força muscular do quadríceps femoral em pacientes com DPOC

AbstractObjective: To compare equations for predicting peak quadriceps femoris (QF) muscle force; to determine the agreement among the equations in identifying QF muscle weakness in COPD patients; and to assess the differences in characteristics among the groups of patients classified as having or not having QF muscle weakness by each equation.Methods: Fifty-six COPD patients underwent assessment of peak QF muscle force by dynamometry (maximal voluntary isometric contraction of knee extension). Predicted values were calculated with three equations: an age-height-weight-gender equation (Eq-AHWG); an age-weight-gender equation (Eq-AWG); and an age-fat-free mass-gender equation (Eq-AFFMG).Results: Comparison of the percentage of predicted values obtained with the three equations showed that the Eq-AHWG gave higher values than did the Eq-AWG and Eq-AFFMG, with no difference between the last two. The Eq-AHWG showed moderate agreement with the Eq-AWG and Eq-AFFMG, whereas the last two also showed moderate, albeit lower, agreement with each other. In the sample as a whole, QF muscle weakness (< 80% of predicted) was identified by the Eq-AHWG, Eq-AWG, and Eq-AFFMG in 59%, 68%, and 70% of the patients, respectively (p > 0.05). Age, fat-free mass, and body mass index are characteristics that differentiate between patients with and without QF muscle weakness.Conclusions: The three equations were statistically equivalent in classifying COPD patients as having or not having QF muscle weakness. However, the Eq-AHWG gave higher peak force values than did the Eq-AWG and the Eq-AFFMG, as well as showing greater agreement with the other equations.

ResumoObjetivo:Comparar diferentes fórmulas de predição do pico de força muscular do quadríceps femoral (QF); investigar a concordância entre elas para identificar fraqueza muscular de QF em pacientes com DPOC; e verificar as diferenças nas características nos grupos de pacientes classificados com presença ou ausência dessa fraqueza de acordo com cada fórmula.Métodos: Cinquenta e seis pacientes com DPOC foram avaliados quanto ao pico de força muscular do QF por dinamometria (contração isométrica voluntária máxima de extensão de joelho). Os valores preditos foram calculados com três fórmulas: uma fórmula composta por idade-altura-peso-gênero (F-IAPG); uma por idade-peso-gênero (F-IPG); e uma por idade-massa magra-gênero (F-IMMG).Resultados: A comparação da porcentagem do predito obtida pelas fórmulas mostrou a F-IAPG com maiores valores do que os valores de F-IPG e F-IMMG, sem diferença entre as duas últimas. A F-IAPG apresentou concordância moderada com F-IPG e F-IMMG, enquanto essas últimas também apresentaram concordância moderada, mas menor, entre si. Do total de pacientes, a fraqueza muscular de QF (< 80% do predito) foi identificada por F-IAPG, F-IPG e F-IMMG em 59%, 68% e 70% dos pacientes, respectivamente (p > 0,05). Idade, massa magra e índice de massa corpórea são características que diferenciam pacientes com e sem fraqueza muscular de QF.Conclusões: As três fórmulas foram estatisticamente equivalentes para classificar pacientes com DPOC como portadores ou não de fraqueza muscular de QF. Entretanto, a F-IAPG apresentou maiores valores de pico de força do que F-IPG e F-IMMG, assim como maior concordância com as outras fórmulas.

Age and sex differences of controlled force exertion measured by a computer-generated quasi-random target-pursuit system.

OBJECTIVES: This study examined age and sex differences of controlled force exertion measured by a computer-generated quasi-random target-pursuit system in 207 males and 249 females aged 15 to 86 years. METHODS: The participants matched submaximal grip exertion of their dominant hand to changing demand values, appearing as a moving quasi-random waveform on the display of a personal computer. They performed the test three times with 1-min intervals (one trial was 40 sec). The total sum of the percent of differences between the demand value and the grip exertion value for 25 sec was used as an evaluation parameter. RESULTS: The errors in controlled force exertion tended to increase constantly with age in both sexes. Significant linear regressions were identified, but there was no significant difference in the rate of increase in both sexes. Analysis of variance showed nonsignificant sex differences among means, except for those in individuals older than 60 years; significant differences between means in the groups older than the 40 yr.-old age group and the 20-24 yr.-old group were found in both sexes. CONCLUSIONS: Controlled force exertion did not show a significant sex difference and decreased gradually with age in both sexes, but decreased remarkably after 40 years of age.

Validation of a pictorial rating scale for grip strength evaluation in 3- to 6-year-old children.

The present study aimed to validate a pictorial rating scale to evaluate the child's ability to produce grip forces. Thirty-seven children aged 3 to 6 years participated as subjects in this investigation. We used a tailor-made pictorial scale and a hand grip strength meter, as well as a Piaget's clinical interview aimed to gather information on the child's understanding of the rating scale. The sensitivity of the rating scale was measured by testing a 4-intensity-level hand grip effort with 3- to 6-year-old children. In addition, the reproducibility of this pictorial rating scale was investigated by a test and randomised re-test procedure. Statistical analysis revealed that no significant main effect (P>0.05) for test was observed in any child. In addition, no significant main effect (P>0.05) for intensity was found in 3-year-old children. However, in the 4-year-old children and over, a significant main effect (P<0.05) was found for intensity. The results also showed that 5- and 6-year-old children were able to produce four differentiated intensities of grip forces. These findings suggest that the pictorial rating scale for grip strength evaluation showed acceptable reproducibility and was sensitive to the age of the children tested. To conclude, this pictorial rating scale appears to be a valid tool to investigate accurately the child's ability to produce grip forces in young children from 5-year-old and over.