EMG Fatigue Index

Computes a fatigue index as the ratio of final to initial median frequency. Values less than 1 indicate fatigue (frequency decrease). The signal is internally analyzed with emgFatigue() using 0.5-second windows at 50 percent overlap, then the initial and final portions are compared.

Usage

emgFatigueIndex(x, initial_pct = 0.2, final_pct = 0.2, assay_name = NULL)

Arguments

x

A PhysioExperiment object with EMG data.

initial_pct

Percentage of signal used for initial estimate (default: 0.2).

final_pct

Percentage of signal used for final estimate (default: 0.2).

assay_name

Input assay name (default: first assay).

Value

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

channel

Integer channel index.

fatigue_index

Ratio of final to initial median frequency. Values less than 1 indicate fatigue.

initial_mdf

Mean median frequency (Hz) in the initial portion.

final_mdf

Mean median frequency (Hz) in the final portion.

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

emgFatigue() for detailed windowed fatigue tracking, emgSpectralMoments() for spectral moment analysis, emgEnvelope() for amplitude envelope extraction