Five Reasons to Add Stim2Go to Your Passive-Active Bike If You Have MS

Multiple SclerosisFES Cycling
Written By Derek Jones

We first started to work with FES cycling around 17 or 18 years ago now. We were told that many people with MS would be our clients. Actually that hasn't been the case, largely because the cost of most FES cycling systems were unaffordable. We couldn't help them. As we've started to work with the Stim2Go, we've found many more of our clients now have MS. They've been able to use the Stim2go for FES cycling and much more.

Most people with MS who own a motorised passive-active bike did not start out with one. They started with an ordinary exercise bike, and at some point it stopped being usable. They could no longer get on the upright one. The standard bike became unusable because they could not generate enough momentum. Their feet would not stay on the pedals, or a heel kept catching the frame, or tone made the whole thing impossible. A MOTOmed or a THERA-Trainer, with a motor that moves the legs when they will not move on their own, was the answer to that problem, and for many people, it has been a good one.

The question this article answers is whether the electrical stimulation you may have seen on a bike in a rehabilitation gym can be added to the bike you already have at home, and whether it is worth it. The Stim2Go, a very flexible yet powerful stimulator, is not tied to any bike. Let's look at what the evidence supports.

FES already means something else to most people with MS

If you have looked into FES before, you have almost certainly been looking at a foot-drop stimulator such as the Odstock stimulator, which lifts the foot as you walk. That is what the MS Society's evidence pack covers, what the MS Trust's information page covers, and what NHS funding, where it exists, is for. The MS Society's own survey found that around one in five people with MS would like FES, that fewer than half of those were getting it, and that around one in three had not heard of it. All of that, in any case, concerns a muscle stimulator targeting walking.

FES cycling uses the same fundamental electrical stimulation principle for a different job. Electrodes on the thigh and lower leg make the leg muscles contract in time with the pedals, so the muscles do the work of cycling even when you cannot ask them to. It is not on the NHS pathway for MS; NICE's 2022 guideline encourages exercise and says nothing about it. People reach it through a private assessment or, occasionally, a case-managed package.

One more piece of vocabulary. If exercise leaves you wiped out for days, or your legs turn to jelly once you warm up, that has a name: Uhthoff's phenomenon. Damaged nerve fibres conduct worse as body temperature rises, by as little as half a degree. I have written about the mechanism, and about why FES cycling sits differently in the body from ordinary exercise, on our fescycling.com site, and will not repeat it here. The point is that FES cycling exercise tends to be tolerated well.

Reason 1: your bike, whatever the make, can become an FES bike

Until recently, the stimulator was tied to the bike, either by cable, as with the RehaMove, or built into the ergometer, as with the RTI models. If you owned a different bike, the answer was a new bike, and for someone paying from their own pocket, that usually ended the conversation.

The Stim2Go from Pajunk takes a different route. It is a 185-gram unit that straps to the thigh and contains motion sensors. It identifies the pedal cycle from the movement of your leg and fires each muscle channel at its programmed point in the stroke. Nothing physically connects it to the bike. As far as I can establish, no other commercially available system synchronises stimulation to the pedal cycle without a physical connection to a specific validated trainer.

So a MOTOmed, a THERA-Trainer or another passive-active bike that you already own can be the base of an FES cycling system. The bike ideally needs controllable pedal resistance, so the stimulated contraction has something to push against for the best exercise effect. It should have secure foot fixation, because a stimulated leg will otherwise leave the pedal, and spasm handling, which the main ones have built in. If your bike came second-hand, or through a hire-to-buy arrangement, it doesn't matter as it is still the bike you can add FES to. The cheap motorised pedal exercisers sold online will run with the stimulator, but the common ones lack adjustable resistance, don't support the leg properly, and rely on straps that reviewers report breaking. I would not recommend one.

Reason 2: more than passive, less than voluntary, for the same felt effort

This is the reason that is specific to MS, and it has two halves that belong together.

The first half comes from a 2018 study by Edwards, Motl and Pilutti at the University of Illinois, in eleven people with MS who needed help to walk. In a single session, adding stimulation to cycling took the exercise from passive to what the researchers classed as moderate-to-vigorous: oxygen uptake at around 64 per cent of the individual's peak, heart rate at around 76 per cent of peak, and a work rate of 27 watts, all significantly higher than passive cycling on the same bike. Passive movement is movement, but electrically stimulated cycling is exercise.

The second half comes from the same group in 2026, this time in eighteen wheelchair users with advanced MS, average age 61. Each did fifteen minutes of arm cycling, fifteen minutes on a recumbent stepper, and fifteen minutes of FES cycling, all at the same perceived effort, "somewhat hard" on the standard scale. All three modes reached the training zone, between 58 and 68 per cent of peak oxygen uptake. But at that matched effort, FES cycling produced significantly lower oxygen uptake, heart rate and work rate than the other two. The authors' own summary was that FES cycling "may provide a less demanding aerobic stimulus" for the same perceived exertion.

If we read those two findings together, we see that stimulated cycling gets you into the training zone, unlike passive cycling. And for the same feeling of effort, it costs the body less than exercise you drive yourself.

For someone whose limits are central fatigue and heat, that is the whole point. It also means a smaller training dose than arm cycling, and that has to be said in the same breath. FES cycling is not the most powerful exercise available to you, but it is the one that many people with advanced MS can tolerate.

KEY POINT: Adding stimulation turns passive movement into moderate exercise, measured by oxygen uptake and heart rate. At a matched perceived effort, it costs less than arm cycling or stepping, which is what makes it tolerable for people whose fatigue and heat sensitivity rule out ordinary exercise. That is a gentler stimulus, not a stronger one.

Reason 3: it is well tolerated at the severe end of the disability range

The MS studies of FES cycling recruited people whose mobility had gone well past the point where most exercise advice stops applying, and the tolerability findings are consistent.

The most useful is a 2020 study by Williams and colleagues at the Shepherd Center in Atlanta. Ten people with MS, scoring 6.5 to 8.5 on the disability scale, which means a wheelchair for most of the day and often full time, tried three or four different FES cycling protocols over six to eight sessions. All ten completed the protocols, and there were no serious adverse events. Two people had a brief drop in blood pressure after a session that used the bike's motor assist; both resolved within ten minutes. Spasticity was lower or unchanged after 70 per cent of sessions, and where pain rose during a session, it was back to baseline by the next one 91 per cent of the time.

The finding I would like to draw your attention to concerns the bike's motor. Half the group could cycle for the full thirty minutes. The other half could manage under three minutes of continuous stimulated cycling. Those five reached thirty minutes by using the motor to fill the gaps, cycling in short stimulated intervals with motor-assisted recovery between them, and over the sessions their active cycling time rose by an average of 400 per cent. That pattern is only possible on a passive-active bike. The bike you already own is not just compatible with stimulation; it is the right kind of bike for it.

Backus and colleagues, at the same centre, found no adverse events in fourteen non-ambulatory people over a month of sessions in 2017, and none in a twelve-week randomised study in 2020. The 2026 randomised trial discussed below also reported none. More broadly, a 2014 systematic review by Pilutti and colleagues pooled 26 exercise studies and 1,295 participants with MS and found a lower relapse rate in those who exercised than in controls, 4.6 per cent against 6.3 per cent.

The counterweight is that dropout in these small studies is high. Scally and colleagues, in a 2020 systematic review from the University of the West of Scotland, found a pooled dropout of 26 per cent, and ten adverse events across 36 participants. In the Edwards pilot trial, all six mild adverse events were in the stimulated group. Tolerable does not mean effortless, and not everyone stays the course.

Reason 4: fatigue and quality of life, in small studies

Fatigue is the symptom people with MS most want help with, and it is the outcome where the FES cycling studies point most consistently in one direction. The effects are small, though.

Backus 2017 reported that fourteen people completed a month of thirty-minute sessions, two or three a week. The physical and psychosocial scores on the Modified Fatigue Impact Scale both improved significantly. Muscle strength and clinical spasticity scores did not change. Backus 2020: twelve weeks, randomised, six people per arm at the end, all scoring 7.0 to 8.5 on the disability scale. The stimulated cycling group showed moderate to large improvements in fatigue, depression scores and physical quality of life compared with a control group that did no cycling at all. Pilutti 2019, the secondary outcomes of the pilot trial by Edwards and colleagues: four people per arm, stimulated against passive cycling for 24 weeks. Fatigue severity improved with a large effect size, pain improved, and cognitive processing speed improved by an amount the authors called clinically meaningful.

That is the fatigue evidence from three studies and two research groups, with between four and fourteen people per arm. The direction is positive every time. The research suggests FES cycling is beneficial to MS fatigue, but in a formal sense the studies were small and more research is needed to establish this as a benefit.

KEY POINT: Every study that has measured fatigue after FES cycling in MS has found it improved, including the one comparison against passive cycling. Every one of those studies had fewer than fifteen people per group. Encouraging is the right word. Proven is not.

Reason 5: keeping the legs working when they will not work for you

Passive cycling keeps the joints moving and the blood flowing. What it cannot do is make the muscles work, and there is one small study showing what happens to MS muscle when stimulation does. Reynolds and colleagues, in 2015, measured how much oxygen the thigh muscle consumed in eight non-ambulatory people before and after twelve sessions of FES cycling over four weeks. It rose by 47 per cent. Eight people, four weeks, no control group, and the only muscle-level finding in MS. But it is the same direction as the far larger spinal cord injury literature, where a 2021 systematic review of 92 studies rated the evidence for muscle health as high.

Tone is the other half of this reason. In the spinal cord injury literature, the one direct comparison, by Krause and colleagues in 2008, found that a single stimulated session freed the leg to swing more than a matched passive session did, in five people. In MS, there is a single case report from the same group. Backus's 2017 study found no change in clinical spasticity scores over a month, although participants reported feeling less stiff after individual sessions. My own experience matches that: people often feel looser for a day or so after cycling, and it builds with regular use. In seeing hundreds of people, I've yet to find anybody whose spasms or tone absolutely stop them from using an FES bike. Changes to stimulation parameters, a period of passive cycling before the stimulation starts, and the bike's own spasm handling are the tools for managing it.

The plainest version of this reason is feasibility. The Williams and Backus studies recruited people at 7.0 to 8.5 on the disability scale and got them cycling with their own muscles. For a group with almost no other way to exercise their legs, that is a really positive outcome, and it needs no efficacy claim attached.

The trial that found no difference

In May 2026, Simpson and colleagues at Johns Hopkins published the first randomised trial comparing FES cycling with passive cycling in secondary progressive MS. Fourteen people completed the trial, scoring 5.0 to 7.0 on the disability scale, eight on stimulated cycling and six on passive cycling, for twelve weeks. The primary outcome was walking speed over 25 feet.

There were no significant differences between the two groups on any measure. The stimulated group trended towards faster walking, but not significantly. The passive cycling group, not the stimulated one, showed a significant improvement in the timed up-and-go test. No adverse events were reported in either arm.

It is a small trial, it lasted twelve weeks, and the authors say themselves that longer interventions may be needed. But it is the most recent randomised comparison of exactly the question this article is about, and you will find it if you look. Two things follow from it. Passive cycling on the bike you own is worth doing in its own right. And the case for adding stimulation in MS rests on the exercise intensity, the tolerability and the fatigue signals above, not on walking.

While I am listing what the evidence does not support: there is no study showing FES cycling slows MS progression or reduces relapses, none that measured a change in disability scores over time, and none at all on bone density or muscle size in MS. Gains may taper as the disease progresses, which is a reason for realistic goals rather than a reason not to try. And as with spinal cord injury, the benefits depend on continuing to use the systems. Stimulated cycling is a commitment to exercise, not a course of treatment.

KEY POINT: The one randomised trial of stimulated against passive cycling in progressive MS found no difference between them over twelve weeks when walking was the outcome examined. It is small and short, and it should be read alongside the tolerability and fatigue findings rather than instead of them. It is also the reason this article does not promise you anything about walking.

What it costs

When NICE looked at the RT300 FES cycling system in 2019, the company's own figures were £14,995 for a six-channel leg cycle, £495 for delivery and set-up, £495 a year for servicing and £528 a year for electrodes, all excluding VAT, with an expected eight-year life. The current UK price is unknown to us but is likely higher now. It's an integrated system, so it includes a bike.

If you already own the passive-active bike, you won't pay for that part again. The Stim2Go is around £7,500 at the time of writing, with everything you need, including support to get you going. We don't anticipate annual service and similar costs. We will give a formal written quotation to anyone who asks. Electrodes are a running cost on every system, ours included.

For people with MS, funding is almost always personal. VAT relief depends on HMRC's test of whether an item is designed solely for use by a disabled person, which a programmable stimulator meets more clearly than an exercise bike does, so ask the supplier rather than assuming. The MS Society's national grants programme has closed, although some local groups run their own. A personal health budget is possible when the local NHS team agrees that the equipment meets an identified need in your care plan, but in my experience, that is rare for exercise equipment.

Any cautions

Heat first. The evidence that people with MS stop exercising at a very small rise in core temperature is clear: in a 2021 study by Chaseling and colleagues, those who stopped early did so at a rise of only 0.2 to 0.5 degrees. FES cycling is less demanding than voluntary exercise at the same effort, but it still raises body temperature. Start in a cool room with a fan, at a few minutes rather than thirty, and watch for symptoms for the rest of the day. That is how the published protocols built tolerance, and it is how we would prefer to run a first session.

If you have preserved sensation, and most people with MS do, the stimulation may be uncomfortable at useful intensities. That is something to find out at an assessment, not after a purchase. Two people in the Williams study had a brief drop in blood pressure after motor-assisted sessions, so the first sessions should not be done alone. Skin under the electrodes needs a look after every session; in our experience, at the energy levels these stimulators use, any redness dissipates quickly once the session stops. People with a pacemaker were excluded from almost every trial.

One boundary is worth stating plainly. Standard FES works through the nerves to the muscle. If your weakness comes from damage to the peripheral nerves themselves rather than from MS, the muscle may not respond to this kind of stimulation, and a different device is needed. The 2022 guidelines from the chartered physiotherapists' neurology group make the same point, and add that anyone with a condition affecting the upper motor neurones, which includes MS, should be eligible for an FES assessment regardless of diagnosis.

In conclusion

If you have MS, own a passive-active bike and are wondering about adding stimulation, three things are worth doing with your own clinical team first. Ask your neurologist or MS nurse, and your physiotherapist if you have one, whether stimulated cycling is appropriate for you and whether there is anything in your history that argues against it. Tell them about your heat tolerance and how long your recovery takes after exercise, because that shapes how a first session should be run. And if you have already found that passive cycling helps you, keep doing it; nothing in this article argues against the bike you have.

What we do at Anatomical Concepts is assess before we recommend: a conversation about your MS and your goals, a look at your bike, and, where practical, a trial session in a cool room at a modest starting dose, with the electrodes adjusted to your tone. If it makes sense to go ahead, we set the stimulation programmes to your legs and your bike's spasm settings, train you or your carer to run it, and come back after about six weeks. For people who do not have a bike, the THERA-Trainer Tigo models are the ones we typically supply and train on, but a key point of this article is that you can use other bike models too.

Decisions about treatment sit with your clinicians, and I would always rather you went to them first.

If you would like to talk it through, with no expectation that it leads to a purchase, please get in touch. Sometimes the answer is that your bike and a stimulator would suit you well. Sometimes it is "not yet, the priority is something else." Either is a useful answer.

Further reading

MS Society UK. Functional electrical stimulation (FES): treating foot drop in MS. FES Evidence Pack, May 2022. https://www.mssociety.org.uk/sites/default/files/2022-05/FES%20Evidence%20Pack%20V3.pdf

MS Trust. Functional electrical stimulation (FES). A to Z of MS. https://mstrust.org.uk/a-z/functional-electrical-stimulation-fes

National Institute for Health and Care Excellence. Multiple sclerosis in adults: management. NICE guideline NG220. June 2022. https://www.nice.org.uk/guidance/ng220

Edwards T, Motl RW, Pilutti LA. Cardiorespiratory demand of acute voluntary cycling with functional electrical stimulation in individuals with multiple sclerosis with severe mobility impairment. Applied Physiology, Nutrition, and Metabolism 2018;43(1):71-76. https://doi.org/10.1139/apnm-2017-0397

Edwards T, Chaves AR, Awadia Z, Ludgate J, Walker LAS, Reed JL, Pilutti LA. Cardiorespiratory response to different aerobic exercise modalities in people with advanced multiple sclerosis. Multiple Sclerosis and Related Disorders 2026;108:107065. https://doi.org/10.1016/j.msard.2026.107065

Williams J, Moldavskiy M, Bauer K, et al. Safety and feasibility of various functional electrical stimulation cycling protocols in individuals with multiple sclerosis who are nonambulatory. Archives of Rehabilitation Research and Clinical Translation 2020;2(2):100045. https://doi.org/10.1016/j.arrct.2020.100045

Backus D, Burdett B, Hawkins L, Manella C, McCully KK, Sweatman M. Outcomes after functional electrical stimulation cycle training in individuals with multiple sclerosis who are nonambulatory. International Journal of MS Care 2017;19(3):113-121. https://doi.org/10.7224/1537-2073.2015-036

Backus D, Moldavskiy M, Sweatman WM. Effects of functional electrical stimulation cycling on fatigue and quality of life in people with multiple sclerosis who are nonambulatory. International Journal of MS Care 2020;22(4):193-200. https://doi.org/10.7224/1537-2073.2019-101

Pilutti LA, Platta ME, Motl RW, Latimer-Cheung AE. The safety of exercise training in multiple sclerosis: a systematic review. Journal of the Neurological Sciences 2014;343(1-2):3-7. https://doi.org/10.1016/j.jns.2014.05.016

Scally JB, Baker JS, Rankin J, Renfrew L, Sculthorpe N. Evaluating functional electrical stimulation (FES) cycling on cardiovascular, musculoskeletal and functional outcomes in adults with multiple sclerosis and mobility impairment: a systematic review. Multiple Sclerosis and Related Disorders 2020;37:101485. https://doi.org/10.1016/j.msard.2019.101485

Edwards T, Motl RW, Sebastião E, Pilutti LA. Pilot randomized controlled trial of functional electrical stimulation cycling exercise in people with multiple sclerosis with mobility disability. Multiple Sclerosis and Related Disorders 2018;26:103-111. https://doi.org/10.1016/j.msard.2018.08.020

Pilutti LA, Edwards T, Motl RW, Sebastião E. Functional electrical stimulation cycling exercise in people with multiple sclerosis: secondary effects on cognition, symptoms, and quality of life. International Journal of MS Care 2019;21(6):258-264. https://doi.org/10.7224/1537-2073.2018-048

Reynolds MA, McCully K, Burdett B, Manella C, Hawkins L, Backus D. Pilot study: evaluation of the effect of functional electrical stimulation cycling on muscle metabolism in nonambulatory people with multiple sclerosis. Archives of Physical Medicine and Rehabilitation 2015;96(4):627-632. https://doi.org/10.1016/j.apmr.2014.10.010

van der Scheer JW, Goosey-Tolfrey VL, Valentino SE, Davis GM, Ho CH. Functional electrical stimulation cycling exercise after spinal cord injury: a systematic review of health and fitness-related outcomes. Journal of NeuroEngineering and Rehabilitation 2021;18(1):99. https://doi.org/10.1186/s12984-021-00882-8

Krause P, Szecsi J, Straube A. Changes in spastic muscle tone increase in patients with spinal cord injury using functional electrical stimulation and passive leg movements. Clinical Rehabilitation 2008;22(7):627-634. https://doi.org/10.1177/0269215507084648

Krause P, Szecsi J, Straube A. FES cycling reduces spastic muscle tone in a patient with multiple sclerosis. NeuroRehabilitation 2007;22(4):335-337. https://pubmed.ncbi.nlm.nih.gov/17971625/

Simpson AC, Keller J, Shoemaker T, et al. Functional cycling ergometry with or without electrical stimulation in individuals with secondary progressive multiple sclerosis: a randomized controlled trial. Multiple Sclerosis and Related Disorders 2026;109:107095. https://doi.org/10.1016/j.msard.2026.107095

National Institute for Health and Care Excellence. RT300 for spinal cord injury rehabilitation. Medtech innovation briefing MIB169. January 2019. https://www.nice.org.uk/advice/mib169

Chaseling GK, Filingeri D, Allen D, et al. Blunted sweating does not alter the rise in core temperature in people with multiple sclerosis exercising in the heat. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology 2021;320(3):R258-R267. https://doi.org/10.1152/ajpregu.00090.2020

Bulley C, Adonis A, Burridge J, et al. Evidence based clinical guidelines for the use of functional electrical stimulation to improve mobility in adults with lower limb impairment due to an upper motor neuron lesion. Association of Chartered Physiotherapists in Neurology, September 2022. https://www.acpin.net/_userfiles/pages/files/2210%20QMU%20Report.pdf

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Articles on this site are researched and drafted with the help of AI tools, then checked, edited and approved by me. Every citation is verified against the original source before publication.

Derek Jones
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