Generic Recording Setup

A generic setup for recording electrical potentials from surface electrodes would be as shown in the drawing. Signals are recorded by the electrodes and amplified before being linked into the A/D converter. The converted, now digital values, are then routed to the computer for analysis.

You can select each item by clicking on the component in the picture.

Electrode: To make a recording of the electical activity of striated muscle through the skin we use what are called surface electrodes. There are many types of electrodes. The picture below shows an electrode with two pickups that are encased in a plastic module compelte with a pre-amplifier. The preamplifier ensures that the signal that is conducted to the main amplifier is sufficiently large enough to be free from eletrical interference, or noise. Click on the picture to see other types of electrodes.

To record electrical activity from a muscle the skin and electrode must be prepared. The electrode is then positioned and attached to the skin over the belly of the muscle using double-sided adhesive tape Click on the picture for more details.

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Amplifier: The electrical signal recorded from the muscle via the electrodes is then transmitted to a main amplifier. The lab EMG amplifier allows seven input EMG signals, thus permitting simultaneous recording of EMG at seven locations on the body. Click on the picture for more details.

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AD Converter and computer system: To acquire EMG data we typially use an analogue-to-digital converter. This computer unit converts the analogue data stream that comes from the amplifier into a digital one that the computer system understands. Once these data have been sampled they can be processed in programs like Microsoft's Excel and then displayed on the computer monitor or onto a printer.

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