Figure 11.2 An example of an EMG recording during 10 seconds of VDU work showing principles of signal analysis. (A) The EMG signals were RMS converted in 0.2 sec windows and normalised in relation to the EMG amplitude recorded during a maximal isometric contraction. The broken line indicates the 0.5 per cent EMG level used for detection of EMG gaps. (B) An amplitude probability distribution function analysis was performed on the RMS amplitudes shown in (A) and the static (p = 0.1), median (p = 0.5) and peak (p = 0.9) levels are indicated with broken lines. (C) An exposure variation analysis of the RMS amplitudes shown in (A) is shown in a three-dimensional graph. Here, the time spent within the indicated exposure levels and time period lengths are indicated.

DOI link for Figure 11.2 An example of an EMG recording during 10 seconds of VDU work showing principles of signal analysis. (A) The EMG signals were RMS converted in 0.2 sec windows and normalised in relation to the EMG amplitude recorded during a maximal isometric contraction. The broken line indicates the 0.5 per cent EMG level used for detection of EMG gaps. (B) An amplitude probability distribution function analysis was performed on the RMS amplitudes shown in (A) and the static (p = 0.1), median (p = 0.5) and peak (p = 0.9) levels are indicated with broken lines. (C) An exposure variation analysis of the RMS amplitudes shown in (A) is shown in a three-dimensional graph. Here, the time spent within the indicated exposure levels and time period lengths are indicated.

Figure 11.2 An example of an EMG recording during 10 seconds of VDU work showing principles of signal analysis. (A) The EMG signals were RMS converted in 0.2 sec windows and normalised in relation to the EMG amplitude recorded during a maximal isometric contraction. The broken line indicates the 0.5 per cent EMG level used for detection of EMG gaps. (B) An amplitude probability distribution function analysis was performed on the RMS amplitudes shown in (A) and the static (p = 0.1), median (p = 0.5) and peak (p = 0.9) levels are indicated with broken lines. (C) An exposure variation analysis of the RMS amplitudes shown in (A) is shown in a three-dimensional graph. Here, the time spent within the indicated exposure levels and time period lengths are indicated.