EMG Fatigue Analysis

Tracks median and mean frequency over time to assess muscle fatigue. Decreasing median frequency indicates fatigue due to reduced motor unit conduction velocity. The signal is divided into overlapping windows and the power spectral density is computed via FFT for each window.

Usage

emgFatigue(x, window_sec = 1, overlap = 0.5, assay_name = NULL)

Arguments

x

A PhysioExperiment object with EMG data.

window_sec

Analysis window in seconds (default: 1.0).

overlap

Overlap fraction between windows (default: 0.5).

assay_name

Input assay name (default: first assay).

Value

A data.frame with one row per channel per window, containing columns:

channel

Integer channel index.

window

Integer window number (1-indexed).

time_sec

Start time of the window in seconds.

median_freq

Median frequency (Hz) at which 50 percent of the spectral power is below.

mean_freq

Power-weighted mean frequency (Hz).

rms_amplitude

Root mean square amplitude of the window.

References

De Luca, C.J. (1984). "Myoelectrical manifestations of localized muscular fatigue in humans." Critical Reviews in Biomedical Engineering, 11(4), 251-279.

Merletti, R. & Parker, P.A. (2004). "Electromyography: Physiology, Engineering, and Non-Invasive Applications." Wiley-IEEE Press. doi:10.1002/0471678384

See also

emgFatigueIndex() for a summary fatigue metric, emgSpectralMoments() for spectral moment analysis, emgEnvelope() for amplitude envelope extraction