Motor unit plasticity is currently incorporated into many professional and collegiate training regiments. Motor unit plasticity can be measured in many ways, the most important of which being neural firing frequency, EMG amplitude, muscle force output, pre-synaptic inhibition, and synchronization. Firing frequency is defined as the number of neuronal signals sent per second on one motoneuron. This frequency is measured in Hertz. Maximum firing frequency in humans typically ranges from 100–200 Hz. Studies incorporating electromyography have proven that adaptation mechanisms occurring as a result of resistance training can drastically increase the maximal firing frequency of a motoneuron. Firing frequency has been shown to
Vibration white finger short time. The duration of use of the tool is measured as trigger time, the period when the worker actually has their finger on the trigger to make the tool run, and is typically quoted in hours per day. Vibration amplitude is quoted in metres per second squared, and is measured by an accelerometer on the tool or given by the manufacturer. Amplitudes can vary significantly with tool design, condition and style of use, even for the same type of tool. In the UK, Health and Safety Executive gives the example of a hammer drill which can vary from 6m/s²