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→Electrical Stimulation and Wound Healing
[[File:EMS VMO.jpg|right|thumb|300px|Using EMS on the [[VMO]].]]
Electrical Muscle Stimulation is the direct of stimulation a muscle using an electric current that is applied via electrode patches on the skin. EMS may be useful in the treatment of [[Knee Pain]], preventing muscle atrophy after injury, and as an addition to regular training.
=What EMS Can and Can't Do=
Like any technology, it's important to understand what it can and can't do.
* '''Does not cause discomfort.''' EMS is generally well tolerated and does not cause discomfort<ref name="EMSBrod11"/>. (EMS units have intensity controls, and increasing the intensity too high can be painful.)
* '''Does Increase strength. '''Many studies have shown that EMS can increase strength<ref name="EMSBroch05"/><ref name="EMSMaff00"/><ref name="EMSGond05"/><ref name="EMSMaff01"/><ref name="EMSMart93"/>. For instance one study showed an increase in quad strength by over 20% in untrained subjects<ref name="EMSStrength1983"/>. (As an aside, this study trained only one leg with EMS, and the other untrained leg gained 15% strength. This effect, where training one limb increases the strength in the other, has been known about since at least 1894 and is called the Contralateral Strength Training Effect<ref name="EMSCarr06"/>. )
* '''Does Increase [[Muscle|Muscle Recruitment]]. '''Studies indicate that EMS increases muscular recruitment and that this may be the underlying mechanism for some of the strength gains<ref name="EMSGond05"/><ref name="EMSMaff01"/><ref name="EMSMart93"/><ref name="EMSRecruitment"/>.
* '''Does Increase Blood flow.''' EMS can increase the flow of blood to a muscle<ref name="EMSZico95"/><ref name="EMSBrod11"/>. (Lower frequencies of around 7-9Hz seem to be optimal<ref name="EMSBrod11"/>.)
* '''Does Not Reduce Weight.''' EMS does not help with weight reduction or fat loss<ref name="EMSFda"/><ref name="EMSPorc05"/>. In 2002 the FTC charged three companies with false claims about weight loss [[Weight Loss]] from EMS devices<ref name="EMSFtc"/>.
* '''Can Cause DOMS.''' It's not a surprise given that EMS is a form of strength training, but EMS can cause [[Delayed Onset Muscle Soreness]]<ref name="EMSCauseDOMS"/>. (EMS may also help relieve DOMS - see below.)
* '''Endurance - Unclear'''. They are few studies on the use of EMS for endurance. A study of sedentary subjects showed a 10% increase in [[VO2max|V̇O<sub>2</sub>max]]<ref name="EMSBane05"/>, but this study used an unusually large level of EMS over an unusually large area. I found no studies of endurance benefits for trained athletes. A study did show a doubling of the number of abdominal curls that could be performed after EMS training<ref name="EMSPorc05"/>, but this is not "endurance" in the sense a runner would mean.
* '''Can Help with [[Knee Pain]].''' Studies have shown that EMS of the [[VMO]] (part of the quad near the knee on the inside of the thigh) can help reduce [[Knee Pain]]<ref name="PFClinical"/>. The recommendation is for eight weeks of EMS consisting of 20 min. sessions twice a day (18 sec stimulation and 25 sec rest)<ref name="PFClinical"/>.
* '''May improve muscle recovery.''' There is some limited evidence that EMS may help with recovery from [[Delayed Onset Muscle Soreness|DOMS]], probably due to increased blood flow<ref name="EMSDoms"/>.
=Why use EMS?=
The main reasons to use EMS are around injury treatment and rehabilitation. EMS may be able to directly help with [[Knee Pain]] (see above), as well as reducing the loss of muscle strength (atrophy) that can occur while injured. EMS may be a beneficial supplement to regular training, but I have not found sufficient guidelines or studies that would define the optimal usage pattern.
* Frequency range: 1-150Hz
* Pulse width: 50-400us
* Wave Form: Square Wave. (Sine wave would be better<ref name="Bennie-2002"/>)
Different devices had two to eight electrodes (one to four channels), and some devices had a TENS mode for pain reduction. Some devices had preset programs for different body parts or for different effects, while others allowed you to set the specific parameters such as current, frequency, pulse width.I looked a wide variety of devices and eventually settled on the [http://go.fellrnr.com?id=35454X937677&xs=1&url=http%3A%2F%2Fwww.overstock.com%2FHealth-Beauty%2FInTENSity-Twin-Stim-III-TENS-and-EMS-Combo%2F6017593%2Fproduct.html InTENSity Twin Stim III]. This device provides full control of all parameters with the widest range of settings I found, comes with an AC adapter (useful as EMS devices have a reputation for eating batteries), and was available for only $50. So far I've been remarkably happy with it.
[[File:IntensityEMS3.jpg|none|thumb|300px|The [http://go.fellrnr.com?id=35454X937677&xs=1&url=http%3A%2F%2Fwww.overstock.com%2FHealth-Beauty%2FInTENSity-Twin-Stim-III-TENS-and-EMS-Combo%2F6017593%2Fproduct.html InTENSity Twin Stim III].]]
=Replacement Pads=
The sticky electrode pads are reusable and last for 5-20 uses. The sticky on the pads degrades quite slowly, so how many times you use them may depend on the location you're trying to stick them to. Flat, smooth locations like the quad are easy to stick to, where attaching them to the end of the [[VMO]] requires a little more adhesion. I ordered these [http://go.fellrnr.com?id=35454X937677&xs=1&url=http%3A%2F%2Fwww.amazon.com%2Fdp%2FB001TZJYXE replacement pads from amazon.com] and they were $25 for 40 pads, so the running costs are quite low.
* Do not apply to the chest area if you have any heart conditions.
* If you have a pacemaker, do not use EMS anywhere on your body.
* Do not apply EMS to the [http://en.wikipedia.org/wiki/Carotid_sinus Carotid sinus] area of the neck, as this could affect heart rate [[Heart Rate]] or blood pressure.
* Do not apply through your head.
* Do not apply through cancerous tissue.
If you have any doubts or concerns contact a healthcare professional.
=EMS and Intermittent Hypoxic Exposure=
There has been little research on combining EMS and [[Intermittent Hypoxic Exposure]] (IHE), but there is a suggestion some evidence that the two may be synergistic in some way<ref name="EMSIHE"/> and may have unique benefits when combined<ref name="Viscor-2009"/>.
=InTENSity Twin Stim III Settings=
It's not clear how the settings for EMS change the effect. Here are the settings I use, based on a little trial and error. Don't consider these a recommendation, just some extra information.
* On Time 6 seconds
* Rest Time 6 seconds
=Electrical Stimulation and Wound Healing=
There is some good evidence that electrical stimulation can improve wound healing<ref name="woundsinternational.com"/><ref name="McCaig-2005"/>. The mechanism may be the electrical potential of ~23 mV (10-60mV) that exists in the skin, known as the "[http://en.wikipedia.org/wiki/Transepithelial_potential_difference transepithelial potential]". A skin wound causes this potential to collapse (0 mV) and an "[http://en.wikipedia.org/wiki/Current_of_injury injury current]" is created (~10-100 µA), which may attract or repel nearby healthy cells<ref name="Kloth2005"/>. As the wound heals, different types of cells are required which have different polarization<ref name="Kloth2005"/>. A review of the research into Electrical Stimulation for Wound Healing<ref name="Balakatounis-2008"/> indicated that the effective range is 200 to 800 µA, with underlying studies using 130 Hz, 130 μs for >30 minutes/day. The general recommendation is to apply the negative electrode close to the wound and the positive electrode proximally. One study reversed the polarity after 3 days if no infection was seen. If infection did occur than polarity was reversed 3 days after infection had subsided. After that, polarity was reversed each time healing reached a plateau. (NB, EMS devices have current in the 1-100 mA range, so the lowest setting is 1 mA or which is 1,000 µA.)
=References=
<references>
<ref name="woundsinternational.com">Electrical stimulation in wound care; Supplements; Wounds International, http://www.woundsinternational.com/supplements/electrical-stimulation-in-wound-care, Accessed on 27 November 2013</ref>
<ref name="McCaig-2005"> CD. McCaig, AM. Rajnicek, B. Song, M. Zhao, Controlling cell behavior electrically: current views and future potential., Physiol Rev, volume 85, issue 3, pages 943-78, Jul 2005, doi [http://dx.doi.org/10.1152/physrev.00020.2004 10.1152/physrev.00020.2004], PMID [http://www.ncbi.nlm.nih.gov/pubmed/15987799 15987799]</ref>
<ref name="Kloth2005">L. C. Kloth, Electrical Stimulation for Wound Healing: A Review of Evidence From In Vitro Studies, Animal Experiments, and Clinical Trials, The International Journal of Lower Extremity Wounds, volume 4, issue 1, 2005, pages 23–44, ISSN [http://www.worldcat.org/issn/1534-7346 1534-7346], doi [http://dx.doi.org/10.1177/1534734605275733 10.1177/1534734605275733]</ref>
<ref name="Balakatounis-2008"> KC. Balakatounis, AG. Angoules, Low-intensity electrical stimulation in wound healing: review of the efficacy of externally applied currents resembling the current of injury., Eplasty, volume 8, pages e28, 2008, PMID [http://www.ncbi.nlm.nih.gov/pubmed/18552975 18552975]</ref>
<ref name="EMSFtc">FTC Charges Three Top-selling Electronic Abdominal Exercise Belts with Making False Claims http://www.ftc.gov/opa/2002/05/projectabsurd.shtm </ref>
<ref name="EMSCarr06">Contralateral effects of unilateral strength training: evidence and possible mechanisms http://jap.physiology.org/content/101/5/1514.full </ref>
<ref name="EMSMaff01">Activation of human plantar flexor muscles increases after electromyostimulation training http://jap.physiology.org/content/92/4/1383.full </ref>
<ref name="EMSMart93">European Journal of Applied Physiology and Occupational Physiology, Volume 67, Number 5 - SpringerLink http://www.springerlink.com/content/w42n8tn66421416r/ </ref>
<ref name="EMSZico95">[Effect of the frequency of neuromuscular electri... [J Mal Vasc. 1995] - PubMed - NCBI http://www.ncbi.nlm.nih.gov/pubmed/7745364 </ref>
<ref name="EMSBrod11">Patient tolerance of neuromuscular electrical s... [Med Eng Phys. 2011] - PubMed - NCBI http://www.ncbi.nlm.nih.gov/pubmed/20926329 </ref>
<ref name="EMSFda">Consumer Products > Electronic Muscle Stimulators http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/HomeHealthandConsumer/ConsumerProducts/ucm142478.htm </ref>
<ref name="PFClinical"> Clinical classification of patellofemoral pain syndrome- guidelines for non-operative treatment, Erik Witvrouw, S. Werner, C. Mikkelsen, D. Van Tiggelen, L. Vanden Berghe, G. Cerulli </ref>
<ref name="EMSContra"> Contraindications and Precautions to Electrical Stimulation http://faculty.uca.edu/fletcher/electro/unit1_TENS/Contraindications%20&%20Precautions%20to%20E-Stim.pdf </ref>
<ref name="Bennie-2002"> SD. Bennie, JS. Petrofsky, J. Nisperos, M. Tsurudome, M. Laymon, Toward the optimal waveform for electrical stimulation of human muscle., Eur J Appl Physiol, volume 88, issue 1-2, pages 13-9, Nov 2002, doi [http://dx.doi.org/10.1007/s00421-002-0711-4 10.1007/s00421-002-0711-4], PMID [http://www.ncbi.nlm.nih.gov/pubmed/12436266 12436266]</ref>
<ref name="Viscor-2009"> G. Viscor, C. Javierre, T. Pagès, JL. Ventura, A. Ricart, G. Martin-Henao, C. Azqueta, R. Segura, Combined intermittent hypoxia and surface muscle electrostimulation as a method to increase peripheral blood progenitor cell concentration., J Transl Med, volume 7, pages 91, 2009, doi [http://dx.doi.org/10.1186/1479-5876-7-91 10.1186/1479-5876-7-91], PMID [http://www.ncbi.nlm.nih.gov/pubmed/19874615 19874615]</ref>
</references>