ABSTRACT
Este trabalho tem o objetivo de avaliar a quantidade de radiacao eletromagnetica a que o fisioterapeuta esta submetido quando utiliza equipamentos de ondas curtas no tratamento de pacientes, em clinicas de Fisioterapia de Presidente Prudente, SP. Para isso, foram medidas densidades de potencia em alguns lugarres proximo ao paciente e ao equipamento, durante um procedimento-padrao de tratamento de coluna lombar. O paciente foi colocado em decubito dorsal e foram usados eletrodos (ou aplicadores) de placas. Os locais escolhidos para medidas foram: 1) acima do painel do equipamento, 2) ao redor do cabo dos aplicadores e 3) na altura do abdomem e dos olhos do paciente. As medidaas foram feitas usando um medidor de densidade de potencia (mW/cm) NARDA, com um sensor para a faixa de frequencia de 10 a 300 Mhz. Os resultados mostram uma queda exponencial da intensidade, em funcao da distancia ao ponto escolhido. Alguns equipamentos apresentam valores da densidade de potencia de ate 20mWcm, proximo dos cabos e dos aplicadores. Acima do painel de controle do equipamento os valores variam de 0,5 a 4,0 mW/cm em distancias de ate 30 cm. Proximo aos olhos do paciente o valor medido e da ordem de 2,0 mW/cm. Esses resultados indicam que em alguns locais o fisioterapeuta esta sujeito a riscos de exposicao acima dos valores recomendados pelos orgaos internacionais
Subject(s)
Diathermy , Occupational Risks , Physical Therapy Specialty , Radiation, Nonionizing , Radio WavesABSTRACT
PURPOSE: Others have reported preferential recruitment of fast motor units in muscles during performance of eccentric contractions and there is evidence that fast muscle fibers are more susceptible to eccentric contraction-induced injury. We tested the hypothesis that during a second bout of maximal eccentric contractions 1 wk after the first, there would be a reduction in the electromyographic (EMG) median frequency (MF) with minimal change in the EMG root-mean-square (RMS), indicating greater reliance on slower motor units. This could provide an explanation for the enhanced resistance to eccentric contraction-induced injury after a single bout of eccentric exercise. METHODS: Human subjects performed 50 maximal voluntary eccentric (N = 10) or concentric (N = 10) contractions of the anterior crural muscles on two occasions separated by 1 wk. To determine whether MF changes during the second bout could be a consequence of injury to fibers in fast motor units, the anterior crural muscles of mice were electrically stimulated to perform 50 maximal eccentric (N = 10) or concentric (N = 9) contractions on two occasions separated by 1 wk. In both the humans and mice, torque production and tibialis anterior muscle RMS and MF were measured during the two exercise bouts. RESULTS: In human tibialis anterior muscle, MF was 30% lower (P < 0.01) during the second eccentric bout although RMS was the same. In the mice, RMS and MF were unchanged at any time after the first eccentric bout despite torque deficits similar to those observed in the humans. CONCLUSIONS: The data indicate that with repetition of maximal voluntary eccentric contractions, there is an increased activation of slow motor units and a concomitant decrease in activation of fast units.
Subject(s)
Muscle Contraction/physiology , Muscle, Skeletal/physiology , Adult , Animals , Electric Stimulation , Electromyography , Female , Humans , Male , Mice , Mice, Inbred ICRABSTRACT
The objective of this paper was to analyse the activity of the longissimus dorsi and the iliocostalis lumborum muscles--components of the erector spinae muscle--in order to determine: their action potentials during the use of a plain and a tilt Roman table; 2) to compare the action potentials of the two muscles; 3) to verify if the action potential of these two muscles remain constant during the arc of movement--knee flexion and extension--divided into angle ranges, and 4) to compare the action potentials of the muscles in movements performed in a free manner and against resistance. Twenty-three young volunteers were studied electromyographically and each muscle received a needle electrode (Mise) and a surface electrode. The results showed that the table model did not determine any difference in the action potential of the muscles and that, on average, the iliocostalis lumborum muscle developed a slightly higher action potential than the longissimus dorsi muscle during the free flexion of knees on the plain table. In more than 70% of the cases, there was no difference between the action potential of the muscles over the various angle ranges of knee flexion and extension. Relatively higher action potentials were recorded during knee flexion and extension against resistance than during the same movements performed in a free manner. This shows that the paravertebral musculature responds better to an overload (8 kg) imposed on the knee flexor group, confirming the stabilizing role of the longissimus dorsi and iliocostalis lumborum muscles during knee flexion and extension on a Roman table.
