Surface EMG alterations induced by underwater recording.
OBJECTIVE
This study aims to verify if amplitude and spectral characteristics of surface EMG signal are modified due to recording in a wet environment.


METHODS
Isometric contractions of the biceps brachii muscle of ten subjects were performed in several different set-up combinations, both in dry (D) and in water from hydrotherapy pools (PW), with (PWM) or without moving the pool water and with (T) or without water-resistant adhesive taping.


RESULTS
In PW condition the amplitude of the recorded signal is reduced to 5-10% of the corresponding signal recorded in D condition. In PWM the power spectrum is drastically reduced and altered by the water movement that introduces an increase of spectral power in the frequency range 0-20 Hz. The use of T modality allows to record signals with both amplitude and spectral frequencies comparable with those obtained in the D conditions.


CONCLUSIONS
This work demonstrates the need for water resistant taping when EMG signals are recorded in water. Signals recorded without such a protective film are strongly affected in their amplitude and frequency characteristics by the conductivity and the movement of water.
Rainoldi
A
A
Centro di Bioingegneria, Dipartimento di Elettronica, Politecnico di Torino, Turin, Italy. alberto.rainoldi@eln.polito.it
Cescon
C
C
Bottin
A
A
Casale
R
R
Caruso
I
I
D000328:Adult; D016477:Artifacts; D001458:Bandages; D004566:Electrodes; D004576:Electromyography / Q000295:instrumentation* / Q000379:methods; D019544:Equipment Failure Analysis / Q000379:methods; D006801:Humans; D007101:Immersion; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water
D014867:Water