RESUMO
A study was conducted to investigate muscle fatigue during isometric contraction of the indicis proprius using EMG analysis (BIMUTAS Ver. 2. 1) .<BR>The subjects were 8 healthy men (ranging in age from 19 to 42 years) .<BR>Plummets (ranging from 300g to 600g) were placed on the distal knuckle of the index finger to create loads on the indicis proprius muscle. EMG was recorded until the plummet dropped, and the total time required was divided into 10 equal parts. In each part, the EMG record for the first 1000 ms was picked out. Then the mean power frequency (MePF) and median power frequency (MdPF) of the power spectrum were calculated.<BR>The results were as follows:<BR>1) Both MePF and MdPF showed shits to lower frequency bands.<BR>2) Integrated values of the EMG power spectrum increased with time.<BR>3) The time courses of the MePF and MdPF in each EMG sample for the 8 subjects were determined by the 3-point moving average method.<BR>A break-point was observed in each MePF and MdPF diagram.<BR>It was considered that two-break points observed in the time courses of the EMG record were valid as an objective index of local muscle fatigue.
RESUMO
To visualize skin temperatures during the dynamic and static arm exercises, a monochromatic thermograph was used.<BR>The thermoviewer JTG system presented a 5-monochromatic step-thermal display in centaral temperatures of 34.5 or 34.0°C and a temperature range of 2°C. The temperature resolving power of the system was 0.2°C. A 35 mm camera was used to take a synchronous thermogram of 2 sec scanning time.<BR>The experiments were carried out in August in an experimental room with an air temperature of 27.3±0.6°C, and a relative humidity of 50.5±4.3%.<BR>The skin temperatures of the forearm, upper arm and chest for five male subjects (18-25 yr) were observed before, during and after 5 min exercise on an arm ergometer at work intensities of 0, 2, 3 and 4 kg (dynamic exercise : a rate of 40 contractions/min as timed with a metoronome) .<BR>The following results were obtained.<BR>1) Changes in skin temperatures were observed in detail and over a wide area during the dynamic and static exercises.<BR>2) The upper arm skin temperature increased as soon as that of the shoulder fell immediately after the beginning of dynamic exercise.<BR>3) The decrease in skin temperatures on the chest, shoulder and upper arm appeared with static exercise.<BR>4) The fall in skin temperature increased and spread from forearm toward chest with the incresse in static work intensity.