Dear Saeed,
The following publications describe a method to record EMG under water:
1-
Electromyogr Clin Neurophysiol. 2009 Mar-Apr;49(2-3):103-8.
A novel signal processing method using system identification for underwater surface electromyography.
Uehara S1, Muraoka Y, Tanabe S, Ota T, Kimura A.
Author information
Abstract
PURPOSE:
Currently, to record underwater surface electromyography (EMG), electrodes are covered with waterproof tape. For short-term measurement, waterproof tape prevents electrical leakage. However, during long-term measurement, water or sweat can contact the electrodes, changing the measurement conditions and gradually affecting the EMG data. The purpose of present study was to devise a novel method for prolonged underwater EMG recording, which estimate dry-land EMG from underwater EMG recorded by non-waterproofed electrodes using system identification techniques.
METHOD:
One healthy male participated in this study. System identification was used to convert underwater EMG signals to the estimated dry-land signals. Transfer functions were derived using two pairs of surface recording electrodes on the same muscle in parallel. System input was the EMG recorded using non-waterproofed electrodes; the output was the signal recorded underwater using waterproofed electrodes (supposed to be the same as dry-land signals). To examine the validity of the present method, three experiments were conducted.
RESULT:
There was a high positive correlation between the estimated dry-land EMG based on the non-waterproofed electrodes and the EMG obtained using waterproofed electrodes. To test the validity of long-term recording using the novel method, the estimated dry-land EMG signals were measured during 30 minutes of underwater stepping and were stable.
CONCLUSION:
The novel method using non-waterproofed electrodes with system identification techniques eliminated the effect of changes in measurement conditions and appears effective for long-term, underwater surface EMG recording.
http://www.ncbi.nlm.nih.gov/pubmed/19400405
2-Journal of Neuroscience Methods 134 (2004) 37–43
A method for positioning electrodes during surface EMG
recordings in lower limb muscles
A. Rainoldi a,b,∗, G. Melchiorri b,c, I. Caruso b,c
a Electronic Department, Bioengineering Center, Polytechnic of Turin, C.so Duca degli Abruzzi, 24. 10129 Torino, Italy b Physical Medicine and Rehabilitation, University of Tor Vergata, Rome, Italy c Don Gnocchi Foundation—Onlus, Rome, Italy
Received 4 July 2003; received in revised form 24 October 2003; accepted 27 October 2003
Abstract
Purpose: The aim of this work is to provide information about the degree of inter-subject uniformity of location of innervation zone
(IZ) in 13 superficial muscles of the lower limb. The availability of such information will allow researchers to standardize and optimize
their electrode positioning procedure and to obtain accurate and repeatable estimates of surface electromyography (sEMG) signal amplitude,
spectral variables and muscle fiber conduction velocity. Methods: Surface EMG signals from gluteus maximus, gluteus medius, tensor faciae
latae, biceps femoris, semitendinosus, vastus medialis obliquus, vastus lateralis, rectus femoris, tibialis anterior, peroneus longus, soleus,
gastrocnemius medialis and lateralis muscles of ten healthy male subjects aged between 25 and 34 years (average = 29.2 years, S.D.= 2.5
years) were recorded to assess individual IZ location and signal quality. Results: Tensor faciae latae, biceps femoris, semitendinosus, vastus
lateralis, gastrocnemius medialis and lateralis showed a high level of both signal quality and IZ location uniformity. In contrast, rectus femoris,
gluteus medius and peroneus longus were found to show poor results for both indexes. Gluteus maximus, vastus medialis obliquus and tibialis
anterior were found to show high signal quality but low IZ location uniformity. Finally, soleus muscle was found to show low signal quality
but high IZ location uniformity. Conclusions: This study identifies optimal electrode sites for muscles in the lower extremity by providing
a standard landmarking technique for the localization of the IZ of each muscle so that surface EMG electrodes can be properly positioned
between the IZ and a tendon.
© 2003 Elsevier B.V. All rights reserved.
Keywords: Electromyography; Electrode positioning; Lower limb muscles; Innervation zone; EMG variables; Standardization
http://www.udel.edu/bioms/students/Courses/BMSC867-Intro2EMG/Readings/Rainoldi_JNeurosciMethods2004_EMGplacement.pdf
3- Monopolar electromyographic signals recorded by a current amplifier in air and under water without insulation
ARTICLE in JOURNAL OF ELECTROMYOGRAPHY AND KINESIOLOGY 24(6) · SEPTEMBER 2014
ABSTRACT
It was recently proposed that one could use signal current instead of voltage to collect surface electromyography (EMG). With EMG-current, the electrodes remain at the ground potential, thereby eliminating lateral currents. The purpose of this study was to determine whether EMGcurrents can be recorded in Tap and Salt water, as well as in air, without electrically shielding the electrodes. It was hypothesized that signals would display consistent information between experimental conditions regarding muscle responses to changes in contraction effort. EMG-currents were recorded from the flexor digitorum muscles as participant’s squeezed a pre-inflated blood pressure cuff bladder in each experimental condition at standardized efforts. EMG-current measurements performed underwater showed no loss of signal amplitude when compared to measurements made in air, although some differences in amplitude and spectral components were observed between conditions. However, signal amplitudes and frequencies displayed consistent behavior across contraction effort levels, irrespective of the experimental condition. This new method demonstrates that information regarding muscle activity is comparable between wet and dry conditions when using EMG-current. Considering the difficulties imposed by the need to waterproof traditional bipolar EMG electrodes when underwater, this new methodology is tremendously promising for assessments of muscular function in aquatic environments.
https://www.researchgate.net/publication/265415771_Monopolar_electromyographic_signals_recorded_by_a_current_amplifier_in_air_and_under_water_without_insulation
Hoping this will be helpful,
Rafik
Article Monopolar electromyographic signals recorded by a current am...
drar Saeed Arsham
i hope next research help you
http://cdn.intechopen.com/pdfs-wm/25872.pdf
https://www.biopac.com/knowledge-base/emg-underwater-measures/
http://repository.supsi.ch/2741/
http://www.ncbi.nlm.nih.gov/pubmed/19400405
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4129181/
Dear saeed
Generally you can use a type of water proof tape tp isolate electrods. Note that you must process aquired data differently, due to new artifacts. To do this you can wavelet (Matlab).
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