Abstract:
The project aims to investigate the relationship and effect of stress induced by the physical work of muscle between the cardiovascular system and musculoskeletal system in the lower body. Such investigation was conducted by simultaneously monitoring the subjects’ electromyogram (EMG) and electrocardiogram (ECG) while they performed several stress tests. The stressed muscle would contracted and caused the muscle to be in tension and taut state, and depending on the severity of the stress, the effect of stress on muscle could range from fatigue, cramps and other muscle related ailments. The effect of physical stress to the cardiovascular and respiratory systems were interrelated with each other, as stress caused the heart to work faster and harder, elevated the blood pressure and heart rate while the lung will be forced to perform respiration faster to supply the increased demand on nutrient to tissues as well as the whole waste removal and gaseous exchange process to the whole body.
In order to investigate the relationship of stress between the muscle and the heart, biosignal amplifier circuits were constructed from available resources to enable the detection and recording process for the subjects while they performed about three level of stress tests. Considering the nature of those hand-built circuits that ehavior general-mill electronic components, the performance in detecting those signals under such circumstance was adequate enough to obtain usable signal outputs and able to produce some commendable outcomes, but they still behind the capabilities of professional, medical-grade monitoring equipment.
From the obtained results, as expected the heart rate did increase dramatically with the increase of burden in the stress test. It still depended on the athletic capability of subjects, because the stress test did not put much burden to the athletic subjects compared to normal subjects as their heart rate was higher. As for the stressed muscle, some subjects indicated some strange ehavior in their leg muscles as they did some sequential contraction consisting of two discrete contraction that differed in strength and force.
