Why do some horses “sway” during FES treatments to their lumbosacral or thoracic regions?

Typically this sway is due to extensive asymmetry in the lumbosacral region, but can also be a result of lumbothoracic or cervicothoracic regional asymmetry. Therefore, when you are treating with FES and you obtain functional movement, you will see the asymmetrical lateral movement through the pelvis during the flexion and extension of the pelvis. If you watch carefully during riding of these horses, you will also typically see this asymmetrical movement when they are asked to “engage” their hindquarters more. For example, at the base of a fence watch as the horse gathers to spring. In addition, when you question the rider, many times the rider will tell you that these horses drift to the same side as the sway during riding. It is harder to see the asymmetry when the rotation is more subtle, so during walking, for example, you may not notice it initially.

What I have found clinically, for example if the horse sways to the left, then typically the right side musculature of the lumbosacral region is hypertonal pushing the lumbosacral region to the left. Of course this is a simplification, and most likely there is a combination of hypertonal and hypotonal musculature on both sides of the spine which causes this abnormal movement during hindquarter rotation. However, I do find that if I start by simplifying my focus, so to speak, to lengthen the musculature on the concave side of the sway, the horses decrease their level of sway. FES works to increase tone in hypotonal regions as well as decrease tone in hypertonal areas to produce symmetrical functional movement when the stimulus is placed symmetrically over the spine. Therefore, it can be harder to determine rhetorically if it is the improvement in hypo or hyper tone which is the most important aspect to produce the improvement that you see. Most likely it is the combination of the increase in tone of some muscles together with the decrease in tone of other muscles that improve the symmetry, and therefore reduces the sway.     

If there is no noticeable twist in the lumbosacral area, then this sway can be more of a systemic issue dealing with proprioception. You can see this in horses with advanced Lymes, EPM or other systemic issues such as systemic muscle diseases. The neuromuscular connection is not being made appropriately, and the “sway” reaction is a very normal feeling for these horses when lumbosacral movement is initiated either by their own neuromuscular connection or by FES. It is very interesting to observe these horses because in most situations the horses do not exhibit any discomfort, even when the sway becomes severe and the horse is at risk of loosing their balance.

The improvement in rotation, and therefore reduction in the sway pattern, typically happens progressively over time with the use of FES, for horses that have a asymmetrical muscular development with no systemic muscle disorders, and in 3-4 treatments to the thorax and si regions you should observe at least a 50% reduction in sway. If you do not see an improvement after 3-4 treatments to the thorax and si regions, then I suggest to discuss with the attending veterinarian any suspicions of a neuromuscular muscle disorder.

Below is a typical symmetrical pelvic rotation in response to FES (gray horse).

The chestnut horse shows is a typical sway pattern observed in some horses showing  an asymmetrical muscular development. This sway resolved over a sequential FES treatment protocol of 5 treatments to the si region and 5 treatments to the thoracic region over a period of 3 weeks.

Cable tail position

The cable tail is used as a quick release so if the cable and/or pad gets pulled abruptly, the tension on the connector will be at the cable tail rather than at the front panel. This could help to avoid a front panel connector break which is always a good thing. It’s much easier to get a new cable tail than it is to send in the system for a front panel connector repair. Below is the correct placement of the cable tail.

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This cable tail below has been incorrectly pulled straight up which will put considerable tension on the connector and could eventually loosen the wires into the connector.


When are the connectors getting old and in need of replacement?


The connector holes are lined with gold plate (which is why they are so expensive…) This gold plating will wear out and then the quality of your connection to the cable is not as strong. This can result in an uneven conductivity reading for your channels. If you notice one channel is constantly showing a lower conductivity value than the other two channels, then check the connector to see if the gold sleeves around the holles of the are in good shape.

The below connector is an old connector that is due for replacement soon.


In contrast, this below connector still has lots of good use left in it.


And finally, this is what a new connector looks like


MacGyver fix for a broken connector

I recently had a horse shake extremely hard during a treatment and knock the cable into to the side of the bag causing the connector sleeve on the unit faceplate to break. I had several horses to still treat that day and the cable would not stay tight into the connector. I still had all the parts of the connector so I was able to tape them together to make the connector sleeve tight enough to hold the cable in place. Here is how I did it.

Broken connector can ruin your day….


I borrowed some electrical tape from the barn I was at and cut the tape so that I had a piece which was the same height as the connector.


If you can’t find electrical tape, then you can use a piece of your white tape that you have to hold your self-stick electrodes in place. Both tapes are stretchy and that is what is important so you can pull the pieces of the connector tightly back into place so the cable will stay firmly into the connector.

Pull the tape tightly around the connector so you get the plastic sleeve back to the same diameter it was before it broke.  This fix lasted me for several days before I was able to get the system in for repair.


The broken connector pictured below will be hard to fix because some of the pieces from the sleeve are missing. But it is still worth a try.


 This connector is probably hopeless to try and fix unless you can find the missing pieces…..


FES and horse shows

I rarely treat a horse, that has never had FES previously, the week of a horse show. If I have never treated the horse in the past with FES, I want a minimum of two weeks to see how they respond before they would show. Sometimes the horses just change too much and they need some time to restabilize. If I throw a horse show at them, during the early stages of muscle work, then they can either perform really well or not perform well, and it is too much risk to take, I think.

I have never treated a horse the day of the competition, but it could be an option for the right type of horse. I work almost exclusively with jumpers and dressage horses where they need more “explosive” types of movement. Maybe a western pleasure horse would really benefit from FES right before they compete, but I have no experience with that protocol.

As far as treating horses immediately before a horse show, it really depends on how they have responded to the FES in the past. If they are an excitable type of horse, I have found treating them the evening before the competition relaxes their muscles and relaxes their mind and they have a better chance of performing well. If the horse tends to be more laid back, then treating them the night before the show can relax them too much and the rider doesn’t get the “snap” they may need at the show.

I base my decisions on what is the best use of FES before a show on the way the horse has responded to the rider after previous FES treatments. I add together information from the rider, as well as my impressions of the horse’s response to the FES, to determine what is the best format to follow with the FES treatments during the show season.

So…. I don’t have a solid recommendation, other than if I am uncertain, I do not FES the horse the night before the show. I will FES a horse at least 12-24 hours before a horse show with a horse I have previously treated, as long as that horse has also had a minimum of 2 weeks of exposure to FES treatments. In that situation we can most likely have enough information to determine how the horse responds under saddle after the FES work, and therefore determine how to best use the FES before a horse show.

What does it mean if the screen goes blank or black?

This is not good news, but not perhaps as bad as you might think. Typically, the problem is either the switch that turns the system on and off. First, try to turn the system on and off several times to see if it will reset. If you have only pushed the on/off toggle switch part of the way down, this will sometimes cause the screen to turn solid blue because the connection with the display was not made. Turning the system off and then on again will solve the problem.
If you have to turn the switch on and off several times then most likely the switch is going bad. You can continue to treat your horses for the day, just don’t turn off the system until you are done for the day. You can charge the system during treatments if necessary or charge the system without turning it off with no damage to the system.
Why the switch goes bad can be due to moisture getting into the switch, or the switch can just be going bad with use. The moisture problem can occur if the system is exposed continuiously to high humidity or if water unintentionly gets into the switch. Sometimes the spray systems in stalls will coat the top of the system with moisture and could be another reason the switch may fail. Pull the flap over the system if the spray comes on or cover the top with a washcloth to keep moisture off the top of the system.
The switch will need to be replaced if you must turn the system on and off several times to get the screen to dispay.

If the screen displays similar to the below picture then typically the problem is the display and must be sent in for replacement.

Is this harness worth fixing?

If the pin has pulled loose from the harness wire and the harness is still new, then this harness would probably be worth getting fixed.
Check to see that the pins are still gold colored and not silver colored on the harness to further determine if this harness is worth fixing. If the gold plating has worn off, then the harness is getting fairly old and may not not worth the time and money to get it fixed.
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Trouble shooting when conductivity values are inconsistent

When one of the channels is showing a lower number than the other channels, or no value at all during treatment, this could indicate there is a problem with the connection between the system and the horse. The system software itself is working, it is just the hardware connection between the equipment and the horse that is not functioning correctly.
One of the following problems is typically the issue:

The connection between that channel’s electrodes and the horse is not made
The harness wires for that channel are broken
One or both of the cable connectors are broken
One or both of the cable tail connectors are broken
The connector at the top of the unit is broken

First, just double check that the connection between the electrodes and the horse is well gelled and there is no air space between the skin and the electrode. With heavy coated horses this may mean that you have to use the tip of the gel bottle to work some gel down onto the skin itself.

Second, to test if the harness is the problem, remove the pins of the harness from the electrode.
Hook up the harness directly to the front panel of the system to determine if it is the connector to the system or the harness is the problem.
Turn the system on and set the voltage at 8 or 9. Touch the pins together like shown below which make up one channel.
A channel is: red and black wires
B channel is: brown and blue wires
C channel is: white and green wires
Make sure you wait for the therapy light to come on. Watch and see if the conductivity values display on the screen for the channel you are testing. If the conductivity value shows up, then that set of wires is good. Be very careful that the wires you touch together must be the correct ones for each channel.
The picture below shows that the B channel wires are not working.
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To make sure the problem is not the connector, hook up another harness (i.e. leg or neck harness) and test in the same way. If the conductivity values all show up equally, then the problem is the initial harness you were testing. If, with a new harness the same channel shows zero, then it is the connector that is malfunctioning.
Now, sometimes I have had a channel consistency show a conductivity value but that channel is slow to register and then typically that wire goes bad in the near future. There are lots of thin copper wires inside the colored casing of each harness wire in the harness and those thin copper wires can get damaged just through use or bending. When enough of these thin copper wires break then the harness wire will finally not make a connection. I make sure I have an extra harness on hand and typically I just replace the harness at that point so I don’t have to worry about inconsistent contact.

To determine if the cable is the problem, next hook up the cable to the system and to the harness to see if the conductivity values are the same for all channels. If there are one or two channels that show zero when the treatment light is on, then the cable is the problem.

Test the cable tail in the same way.

Care and feeding of your self-stick electrodes

The issue with the self-stick electrodes is they are designed for single use on humans. We try to modify them to be able to get the most use out of them for our use in equine practice. We have to use the Lubrivet gel between the skin of the horse and the gel pad of the electrode to make the contact we need, so we don’t have to clip. Due to this addition of gel, the gel pads gets too wet and if they are not dried out between uses, the gel pad can separate from the electrode itself. If this separation occurs, the electrode can still be used but, you should then remove the gel pad from all 6 electrodes so that the signal has the same level of resistance for all channels. The problem with the removal of the gel pad is that the electrodes don’t make as good of an overall contact with the skin which is necessary to spread out the signal, ideally in an equal manner over the entire electrode. Therefore, trying to keep the gel pad “healthy” is typically worth the effort.

First, never place the electrodes back into the package and close them up. I just stick them to the outside of the plastic package they came in and put 3 electrodes on each side of the plastic bag and then leave them out to dry as seen below.


I’ll flip the package so all electrodes have their equal time in the sun 🙂 Many times I will place them in the windshield of the car so the sun can get to them and help dry them. If they are really wet and the gel pad is thick and loose, then I take them off the plastic bag and turn them upside down individually in the sun and let them dry with the gel pad facing up. Once I get to the next client they are typically dried out and ready to go again.
But also make sure the fabric side of the electrode is dry as well or the tape won’t stick. Below is a picture of well-used-dried-out-correctly electrodes.

Sometimes the gel pad is not evenly spread out over the electrode so I just reposition the gel pad so it is centered over the electrode itself. If you loose some of the gel pad, no worries. Again, just so the majority of the gel pad is still on the electrodes so that the signal has about the same resistance for each electrode.

The tape we sell can be used to hold the electrodes in place, especially as they get older. I will sometimes cut the tape in half (fold at least 2 pieces over so that the paper side is up or you won’t be able to cut through the adhesive without the tape sticking to the scissors) I will use one piece on the top of the electrode and one piece on the bottom of the electrode on my really old ones to hold them in place. Of course make sure the skin is dry or the tape won’t stick. Also if the client uses a silicone or oil-based fly spray or coat conditioner, the tape won’t stick so you will have to remove the spray first. Usually a good rub down works.

The other option is you can actually just use the black carbon electrodes that are in your back pad for the neck and lateral electrode placements. They don’t stick as well but once you put the gel on it really helps to get them to stick. You hold them on the skin with the tape. I prefer the gel-backed electrodes because they adhere more evenly, even when they get old. But, you may find if you have lots of people that don’t care for the electrodes properly it might be less of a hassle to use the black carbon electrodes.

The length of time I get out of my electrodes basically depends on how many times I use the electrodes before drying them out. If I am only using them once and then drying them out, I can get a good 20-25 uses out of the electrodes. The only other issue that could possibly reduce the life span of the electrodes is the type of gel you use. I only use the LubiVet lube so if you use another type it could break down the gel pads faster.IMG_7555

Here are some pictures of electrodes:
This electrode has been used 5 times and the gel pad is starting to get too soft. If you dry the gel pad out you will get another 5 uses before you need to dry it out again. Turn it upside down like you see here. I set it on the hood of the truck. IMG_3809
This electrodes has been used 10 times and the gel pad is very thick and starting to separate from the black carbon electrode. You might be able to save this electrode by drying it out. It will get super stickey when the gel dries and will turn light brown IMG_3822
These electrodes have the gel pad completely separating from the carbon electrode. You can reposition the gel pad and let it dry and still get a few more uses out of it.
This gel on the below electrode is basically dead. IMG_2349However, you can remove the gel pad and just use the black carbon electrode but remember to remove the gel pad from all the electrodes on your harness so the resistance to the electrical signal is the same between all channels.

IMG_6928You will have to use two pieces of tape to tape the gel-free electrodes in place. I just cut the tape in half and use one piece on the top and one piece on the bottom of the electrode to keep it in place as shown below.

The electrodes will eventually wear out and when this happens you will typically notice that one channel will always show a lower conductivity than the another channels. In this case it is not the harness or connectors that have gone bad, it is the electrodes.  Switch out the electrodes and test and if the change results in the “new” channel being slow to connect then it is time to throw out the entire batch of electrodes. When one goes bad the rest will follow shortly.