EMG stands for electromyography. Muscle fibres generate tiny electrical currents prior to the production of muscle force. These currents are generated by the exchange of ions across muscle fibres membranes, a part of the signalling process for the muscle fibres to contract. EMG is the signal made, it can be measured by applying conductive elements or electrodes to the skin surface, or invasively with the muscle. When using EMG, tiny devices named electrodes are used to transmit or detect electrical signals.
Three factors that may influence its accuracy:
1. The placement of the electrode on the skin, overlying the muscle.
2. ¬¬¬The electrode shape and size.
3. Physiology mind set of the character of EMG.
Results …show more content…
It is a double-headed muscle, meaning it has two points of origin in the shoulder area. The long head origin is just above the should joint, it is at the supraglenoid tubercle. The insertion of the long head is at the radial tuberosity. The short head of each bicep brachii originates at the top of the scapula, at the coracoid process. The bicipital aponeurosis to the fascia on the medial side of the forearm is the insertion for the short head. The biceps brachii helps to control the action of two different joints, the shoulder and elbow therefore it is a bi-articular muscle. It causes flexion at both the elbow and shoulder and forearm supination. Its flexion at the elbow is essential for the lifting of the forearm, we can see this by reflecting back to our results where the flexion raw results had the highest mean value. We also know that supination occurs because where they insert on the radius (biceps tuberosity) more so the EMG results back it up however the muscle is much less involved in the supination compared to the flexion. In our results we can see that pronation does occur but only slightly, due to the fact muscles in the forearm (pronator teres and pronator quadrates) work together to achieve pronation, this makes the bicep brachii much less