Examples of challenging in a sentence. 1  I find the job challenging and fun. 2  Teaching is challenging but rewarding work. 3  It's a challenging book that requires careful reading.  The slope was challenging for even the most experienced climbers.
Electromyography (EMG) is an electrical recording of muscle activity that aids in the diagnosis of neuromuscular disease. Muscles are stimulated by signals from nerve cells called motor neurons. This stimulation causes electrical activity in the muscle, which in turn causes contraction. This electrical activity is detected by a needle electrode inserted into the muscle and connected to a recording device. Together, the electrode and recorder are called an electromyography machine.
An EMG is the summation of action potentials from the muscle fibers under the electrodes placed on the skin. The more muscles that fire, the greater the amount of action potentials recorded and the greater the EMG reading. EMG recording: The EMG is recorded by using a electrode placed on the muscle. The electrical activity measured by each muscle electrode and the ground electrode are sent to an amplifier. The amplifier eliminates random voltages caused by electrical noise by subtracting the signal from the ground electrode from the muscle electrode, producing the raw EMG.