phonomyography

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| name = Phonomyography

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| purpose =measure force of muscle contraction

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| synonyms = Sound myography

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Phonomyography (PMG) (also known as acoustic myography, sound myography, vibromyography, and surface mechanomyogram){{cite journal | doi = 10.1007/s00421-003-0924-1 | pmid = 12923643 | quote = It is important to underline here that the term "surface mechanomyogram" was suggested during a CIBA Foundation Symposium in 1995 to overcome the terminological confusion caused by the habit of identifying the phenomenon with the electrical signal produced by different transducers (microphones, accelerometers, piezoelectric transducers, LVDs, etc.) instead of with its mechanical origin | volume=90 | issue = 3–4 | title=The surface mechanomyogram as a tool to describe the influence of fatigue on biceps brachii motor unit activation strategy. Historical basis and novel evidence | journal=European Journal of Applied Physiology | pages=326–336| year = 2003 | last1 = Orizio | first1 = Claudio | last2 = Gobbo | first2 = Massimiliano | last3 = Diemont | first3 = Bertrand | last4 = Esposito | first4 = Fabio | last5 = Veicsteinas | first5 = Arsenio | s2cid = 6031573 }} is a technique to measure the force of muscle contraction by recording the low frequency sounds created during muscular activity.

Although, until recently, less precise than the more traditional mechanomyography, it is considerably easier to set up. The signal is measured using condenser microphone elements, piezoelectric sensors, accelerometers, or a combination of sensors attached to the skin. Hydrophones have also been used to measure muscles immersed in water. Improvements in microphones and contact transducers (piezoelectric devices), as well as recording systems, has meant that they have become available in a size and of a quality that enables them to be applied to a normal daily setting outside the clinic and the laboratory setting. These new possibilities provide a clinical tool for the assessment of patients with musculoskeletal complaints during daily activities, or assessment of athletes in terms of efficiency in use of muscles.{{citation needed|date=December 2021}}

The sound created by muscle movement can be heard with the ear pressed up to a contracting muscle, but most of the energy is low frequency, below 20 Hz, making it inaudible infrasound.

Electromyography signals are typically bandpass filtered from 10 Hz to 500 Hz, by comparison. PMG signals are limited to 5 Hz to 100 Hz in some experiments.{{Cite web |url=http://www.uta.edu/faculty/jcramer/KINE5328/5328_4_Spring05.ppt |title=Archived copy |access-date=2009-09-07 |archive-date=2011-06-04 |archive-url=https://web.archive.org/web/20110604170347/http://www.uta.edu/faculty/jcramer/KINE5328/5328_4_Spring05.ppt |url-status=dead }} Orizio states that the low-frequency response of the sensor is the most important feature, and should go as low as 1 Hz.

Images of PMG waves are available in this creative commons-licensed document, "Mechanomyographic amplitude and frequency responses during dynamic muscle actions: a comprehensive review".{{cite journal |last1=Beck|first1=Travis W. |last2=Housh|first2=Terry J. |last3=Cramer|first3=Joel T. |last4=Weir|first4=Joseph P. |last5=Johnson|first5=Glen O. |last6=Coburn|first6=Jared W. |last7=Malek|first7=Moh H. |last8=Mielke|first8=Michelle |title=Mechanomyographic amplitude and frequency responses during dynamic muscle actions: a comprehensive review |journal=BioMedical Engineering OnLine |volume= 4|issue=1 | page=67 |doi=10.1186/1475-925X-4-67 |pmid=16364182 |pmc=1343566 |date=19 December 2005 |doi-access=free }}{{open access}}