Making FES Cycling system adjustments

How to get more out of using an FES bike

The RehaMove FES Cycling system (sometimes known as an FES bike) is widely used by clients to allow them to exercise paralysed muscles actively. There are many benefits of doing this following a neurological condition such as a spinal cord injury. This video may be of general interest, but will be particularly useful to existing users of our FES Cycling system who wish to get more from using the product. The video is around 15 minutes long and it addresses three commonly asked questions

• Why should I use an FES bike?

• When and why should I change the stimulation settings?

• How should I make these changes?

The video distinguishes between training for a goal and general exercise and looks at a useful structure to think about how to train, The effect of changing each of the stimulation parameters is considered. You might want to term on subtitles when viewing the video.

If you dont want to watch the video - here is the text along with a timestamp.

RehaMove 2 FES Bike combining FES unit and MOTOmed

[00:00:00] In this video, we are looking at making changes to the stimulation settings of a Rehamove FES bike. This video might be of general interest, but it's really intended to be of value to clients of anatomical concepts who have been using a bike for some time. A Rehamove FES cycling system is a popular product used by many clients at home and in the clinic.

It's pretty easy to use, but not everyone will have the same goals. The goals of a user will inevitably influence how they use the bike. So let's get started and look at what is involved in making changes. In our experience, there are three questions that come up quite frequently. One question, certainly before purchase of a bike, and the other two when asking how to make best use of it.

First question, obviously, why use an FES cycling system at all? Second question, when should we change the stimulation settings? How often is it necessary to [00:01:00] change settings? And the third question is how to accomplish these changes to the settings. So let's take some time and review these questions one by one.

So, but why use an FES cycling system? I'm thinking now of persons who have a neurological condition such as a spinal cord injury. There are a number of good reasons that have emerged from research studies over the years and certainly the ability to exercise paralyzed muscles despite this paralysis is a big factor in making such systems worthwhile.

They can contribute to long term cardiovascular fitness. They can help keep muscle, bulk and muscle quality as high as possible. These systems can help to preserve range of motion at the joints and they can help preserve bone density, which is obviously very important. Generally, they're also contributing to better health and reducing the risk of complications.

Now let's talk about when to change settings. There are two main reasons [00:02:00] why you want to change things. First of all, you've got a goal and you want to train towards that goal rather than just exercise. And the second reason might be you haven't changed settings for a while and aren't quite sure whether you need to or how to do it.

So let's take a look first of all at the first question about training. There is a difference between training and exercise that isn't often realized. Training is about aiming to achieve a particular goal, so you'll have a target and you've got to work systematically to achieve it. Exercise is actually what most people do when they go to a gym.

Maybe they don't record the sessions. Maybe they don't systematically approach their exercise in a way that involves achieving a goal. So both are worthwhile, but having a goal and thinking of what you're doing as training can often be more motivating for some people. In both situations, it will be a good idea to make some stimulation setting changes from time to time.

When you're setting training goals, I think it's important to make them [00:03:00] specific to using the bike so that they're easy to measure. For example, cycling actively in gear 6 for 30 minutes would be a goal that you can easily identify when you've achieved it, or something like achieving 10k of active cycling in 3 days.

Again, that might be a worthwhile training goal. It's about having something specific and definite to work towards. Now, previously, we've written articles on our website about the philosophy of training, and we talked about these six success steps that you can see here. I'm just going to highlight the first three, which are listed in order of importance.

The first step towards success in training is adherence, or in other words, the art of sticking at it. It should be pretty obvious, but unless you can consistently carry out regular exercise, you're not going to progress towards a training goal. So that remains the most important thing. And certainly when we first started to offer these bikes, our biggest concern was would people use [00:04:00] them consistently?

Would they actually be happy to do that? Second in the list of success steps is what I've shown here as volume, intensity and frequency. Not to get confused with frequency in an electrical stimulation sense. Volume is the amount of work you might carry out in a particular session, such as the length of a session.

Intensity is how hard you're making the muscles work, how much resistance you're working against, and the third point, frequency relates to how often you're training. It's those three things together that reflect your workload and the means that you're using to progress in your training. Progression is important as well, and this is really the heart of what we're going to be covering in this video.

This is about how to make changes, how to progress with your training, so that you can achieve something that's worthwhile in terms of a training goal. So if you were just interested in exercising and you're not working towards a specific goal, what does that actually mean? What would you be doing? [00:05:00] You can still exercise regularly, you still want to be exercising your muscles actively, but you might say, okay, I'm just going to exercise on the bike each day or three times a week, whatever's convenient for you.

Even if you're just exercising without a goal in mind, you might still want to make changes every few months and you might want to make sure that as far as possible you are actively cycling so that you've got strong muscle contractions every time you use the bike. And again, think from time to time of adjusting the duration of your exercise, maybe how often you carry that out, and maybe making small changes so that the strength of contractions are improved.

When we talk about intensity of stimulation in electrical stimulation terms, we are referring to three things. Frequency, pulse width and current, because collectively these three things have an effect on how hard the muscles work. If we were able to visualize the electricity being delivered to the muscles, [00:06:00] it would look like this diagram here.

FES Cycling stimulation parameters - how they affect intensity

So you can see there are regular pulses with a positive part and a negative part. Then there's a bit of a gap, and then that pattern repeats. So frequency is a description of how often pulses repeat, and that's measured in Hertz. And typically we might be using something like 30 Hertz or 35 Hertz. The width of a pulse is measured typically in microseconds, and can be up to 500 microseconds with the system that we're using.

Finally, current reflects the height of these pulses, and the maximum current we can work with is 130 milliamps. So it's the combination of these three things, frequency, current and pulse width, that affects ultimately how hard your muscles work. Let's now consider the effect of changing stimulation frequency.

When we set up a bike for the first time, we normally will look to start everyone with a frequency of around 35 Hz. That's 35 pulses in a second. [00:07:00] The reason for that is it's a bit of a compromise. We can get a strong muscle contraction, but without causing too much fatigue. If you were to increase the frequency closer to 50 Hz, then you can produce a stronger muscle contraction, but it will tend to fatigue a little bit faster.

If you reduce the frequency, then we can get better endurance, even if the strength of contraction isn't quite strong. There are also some quite interesting effects you can get from changing frequency that are beyond the scope of this video. When it comes to changing current, we have a maximum current available to us of 130 mA, but quite often we're not going to be anywhere near that level.

What we're going to be doing whenever we set a program is setting the individual current levels for each muscle group that we are using, and we are going to aim for a good and strong, visible muscle contraction, with the default pulse width set at around 250 microseconds. During a session, we can [00:08:00] manually adjust these current levels to make the muscle work harder or less hard, if necessary.

Bear in mind that when we're cycling, it's the quadriceps muscles which have the biggest effect on active cycling power. They're the ones that will contribute most to pushing the pedals and generating power in cycling. Let's look at changing pulse width. If we are using what is called adaptive stimulation, to some extent, the pulse width values can be adjusted automatically.

Once the program is running, what we might want to do is increase the maximum pulse width above the default value of 250, but we've got to do it in small steps, gradually increasing the strength of contractions. The maximum pulse width is 500 microseconds, but don't feel you always need to go as high as that.

It's the combination of those three parameters, frequency, current, and pulse width, that contribute to the intensity of a contraction. So you don't need to adjust everything to maximum, that's [00:09:00] for sure. If we are using adaptive programming, the bike will always try to automatically adjust the pulse width to get the user to exercise at a target cycling speed.

When you start the program running, what you would do is manually set the passive cycling speed shown as this line on the chart here. You would also be expected to set the gear, which represents the resistance to pedaling. Over time, you would increase the gear that you are using so that you're working against more resistance.

During the session, you can manually adjust frequency and or current values to make the muscles work harder. But importantly, the system itself automatically adjusts the pulse width to try to get you cycling faster until you actually reach the target cycling speed. If you don't reach that target cycling speed, typically it's because your settings, frequency, current or maximum pulse width are not set high enough.

Alternatively, you might be trying to cycle against too much resistance. [00:10:00] When a user starts to use a bike, they may not be able to actively cycle against much resistance at the beginning. We find it's best to gradually build up the intensity, just as you would with any form of exercise. Things like preserved sensation can complicate things too.

Finally, let's get to the important issue of how to actually change the settings on your bike to reflect what you want to achieve. I am assuming that we are using an adaptive stimulation program. This is what we choose for the vast majority of our clients. For Now, when an adaptive program is started, you will first see a warm up screen, followed by the active session screen.

Generally, every program should commence with a warm up period. This is intended to move the legs passively, although it is possible to deliver some stimulation during this stage too. During warm up, you will see something like this. You'll see that there are really only two obvious buttons that you can press during the warm up stage.

One affecting the [00:11:00] resistance to cycling and one affecting the passive cycling speed. Once you press one of these buttons you can rotate the knob to set the value you want and then press the knob to fix the value. This use of the knob is common for all of the setting changes during the active session.

In this view we'll see whether we're actively cycling because the little bike icon will appear if it senses that you are generating power. You'll always see the yellow bar at the top of the screen when stimulation is being delivered to the muscles. You'll also see a black line that indicates the target cycling speed, and you'll see a green trace, which shows the evolution of your actual or present speed as it changes over time.

Now the bike is trying to get you to cycle at the target cycling speed, and is varying the pulse width in order to get you there, but it will only increase the pulse width as far as the maximum value that you've set. When this blue bar is completely covering that horizontal area, it means that the system is delivering the [00:12:00] maximum pulse width already.

So maybe you're achieving the target cycling speed, maybe you're not, but it's using the minimum and maximum values of pulse width to determine how hard your muscles are working. Now this view shows how you can change various aspects of performance. For example, by pushing this button, you'll get to change the resistance to pedaling.

Push this button to change passive cycling speed, this one to move straight to cool down. This button allows you to pin the current display. Otherwise, what happens is it pages through a number of different displays. I happen to like this one and would tend to keep this in place most of the time. This button is the key one, really, because this is the button that you press when you want to change the stimulation settings.

This one is quite useful as well. Pause stimulation enables you to continue moving your legs passively, but the stimulation will be turned off. Now, you might do that if you suspect that your muscles have [00:13:00] fatigued. Maybe when you started the session, the little bike was on and you were generating power and achieving the target cycling speed.

But after a minute or two, your speed dropped, the little bike disappeared, and basically this was an indication that your muscles were fatiguing. By pausing stimulation, and then re engaging it after a few minutes, you might find that the muscles revive. Once active cycling starts, you want to be aware of how to change your settings, and the key button is this one here.

Pressing that button reveals this screen, which gives you access to change all of the stimulation settings that we've discussed. Once you access the stimulation settings screen, you can push the button adjacent to the label, and then change the pulse width, current or frequency as you require. As shown here, you can change the minimum and maximum pulse width, for example.

You will be using the knob to increase these values, so remember to also push the knob to set the value you [00:14:00] selected. OK. On this screen, I have listed a number of points to note. These are, if you like, tips on using a bike effectively. I'm not going to read this out word for word. We can provide this as a download so you can print it out and look at this at your leisure.

FES Cycling usage tips

We've also got quite a number of videos. Typically these are short, perhaps 3 or 4 minutes, and they explain all aspects of making changes in a bit more detail than are shown in this particular video. So if you go to festcycling. com slash videos, you'll find everything available for you there.

Consumables such as electrodes and cables are available in our web store at this link. And of course, you can feel free to contact any of us in the office and we'll be glad to help you. If you have questions or would like us to record a video on any particular topic, please let us know.[00:15:00]