Charazterization of biceps brachii muscle activity during contractions using surface electromyographic signal analysis

Analysis of surface electromyography (EMG) signal, measuring electrical activity of muscles, is one of the key areas of recent interest to understand the appropriate muscle characteristic during its activation. EMG signal on skeletal muscle provides a high correlation between muscle force and contraction. Among all the upper extremity skeletal muscles, the biceps brachii (BB) is most commonly responsible for causing pain, disability, weakness, tenderness and dysfunction due to overuse of upper arm movements. Therefore, proper understanding of the muscle function and characteristics of BB is essential from the biomedical and biomechanical perspective. Thus, the purpose of the present thesis is to investigate the EMG signal amplitudes to understand the BB muscle activities during static and dynamic contractions produced by load and grip force, and forceful sports movement. The thesis also aims to provide a hand-held tablet computer based EMG feedback device that can fit into the single muscle. The thesis is divided into three phases. The first phase presents the BB muscle activity, during the contractions produced by both load and grip force in terms of sensor placement locations, range of elbow joint angle and anthropometric parameters. Phase II investigates the BB muscle activity, function and fatigue during contractions generated by two active sport activities (namely, arm wrestling and cricket bowling). The EMG signals were compared on the basis of sensor placement, anthropometric parameters, performance parameters and various arm mechanics. The last phase discusses the design and development process of a portable EMG data acquisition (DAQ) system and obtained results from the system were analyzed to characterize the BB muscle activity. Twenty four healthy subjects (male: 21 and female: 3) participated in the entire experiments. The recorded root mean square EMG signal amplitude was normalized to the amplitude observed during the maximal or sub-maximal voluntary contraction (MVC) over a certain period of time. A number of mathematical and statistical analyses were performed to evaluate and compare the muscle activity as well as the relationship among different parameters. Finally, the thesis presents the effective characteristics of BB muscle determined from testing of EMG signal during production of force and contraction. The results indicate that EMG signal amplitudes 'Cliffer depending on the type of muscle contractions, sensors placement procedures, range of elbow angle, different anthropometric and performance parameters. The thesis also successfully completes a reliable EMG DAQ system, where signals are accessible graphically and stored in text form. The results from this thesis may play a pivotal role in initiation of BB muscle-specific guidelines and treatment protocols to decrease muscle damage or fatigue, develop better rehabilitation programs, arid improve the intense exercise performance under different conditions.