Arm pump and back pain: it's not the bike's fault

I always like to describe the handlebar as a delicate conductor's baton that wants to be handled with feel and tenderness. It's a sensor and a control element, not a grab handle and not a climbing frame. If you have no tension in your core, you hang on your arms, and if you hang on your arms, you cling to the handlebar. But that's not the end of it – that's just where it starts. A handlebar that's being pulled and pushed no longer gives any feedback, because it's constantly busy dealing with the rider's body weight instead of with what the front wheel is actually doing.

This turns into a chain reaction every one of us knows. Tense arms produce a wooden line, the wooden line produces discomfort, and the discomfort produces even more tension. Because the hands are permanently squeezing, the forearms eventually just can't keep up. The physics behind it is simple: braking and acceleration forces have to get from the rider into the vehicle somehow, and the only question is whether they go through the weak arms or through the strong core. It's not the handlebar's fault that your abs are missing, so it shouldn't have to pay for it either.

So we don't stay vague: arm pump isn't an imaginary problem, it's a mechanical one. Medically, it's called chronic exertional compartment syndrome of the forearm, and it occurs very frequently in motorcyclists. The muscle works, swells and sits inside a fascial sheath that can't stretch along with it. It's diagnosed using dynamic pressure measurement in this muscle compartment. In motocross riders, the measured forearm pressure at rest was around 15 mmHg and rose to around 78 mmHg under load. In 70 to 100 percent of cases both arms are affected, which fits the cause nicely – people rarely cling on with just one side.

What I find remarkable is how little known this is. In a survey by the French Motorcycling Federation, 29 percent of the licensed riders who responded had never heard of the condition at all, and more than a quarter of those affected had seen at least two practitioners before getting a diagnosis. In racing, stubborn cases are treated by surgically splitting the fascia; in professional motorcycle racers, pain on the visual analogue scale dropped from a median of 53 to 7 and stayed stable for over five years. It never has to come to that for a touring rider. But it shows that nothing here is imaginary, and that the cause lies in the grip, not in the handlebar diameter.

When it comes to the back, the picture is even clearer. Since 1990, low back pain has been the world's leading cause of years lived with disability. In 2020, 619 million people were affected, and 843 million are projected for 2050. That's not a motorcycling issue, that's a human issue. It's just that on a bike we do quite a lot to make it worse: sitting, soaking up vibration and channelling forces through a passive upper body. Anyone who already has a weak trunk will find ideal conditions on a bike to notice it.

What's meant by the core is often reduced to the rectus abdominis, which is why many people start with sit-ups and feel nothing. It includes the transversus abdominis, the multifidus along the spine, the obliques and the rectus abdominis, the erector spinae, the pelvic floor and the diaphragm. The transversus abdominis is considered the primary stabiliser of the lumbar spine and activates before any movement of the limbs – before an arm or a leg even gets going. And the research points in a clear direction: core stabilisation training reduces pain intensity and functional limitation in non-specific chronic low back pain and improves activation of the deep trunk muscles.

And now comes the part I wasn't so clear about before this trip. The Colorado Backcountry Discovery Route is officially 745 miles long; for us it was around 1700 kilometres, and most of it unpaved. Off-road, standing on the pegs is the default position, because the legs work as suspension, the centre of gravity moves lower and you get a better view ahead. In practice that means standing – for hours, for days. No gym in the world prepares you as honestly for this question as a week on loose ground.

The Aprilia Tuareg 660 showed me how cleanly ergonomics can support this – and at the same time, that it doesn't do the work for you. 860 mm seat height, a consistently slim seat, 240 mm of suspension travel at both ends and wide off-road pegs make for a silhouette that stays narrow when standing, so the knees can find grip. Still, the core did the work. On Cinnamon Pass at around 3850 metres, loose rock above the treeline, steering happened almost exclusively through the legs and feet, through light inputs on the pegs and through where I was looking. My hands were practically unemployed. That's exactly the state in which nothing hurts.

What made this trip especially honest was the altitude, because it immediately bills you for every wasted bit of muscle effort. Without acclimatisation, maximum oxygen uptake drops by a good six percent per 1000 metres of ascent; at 3100 metres it's around 21 percent below the sea-level value. Acclimatisation only gets part of that back – you never regain your home level up there. On top of that, above 2500 metres there's acute mountain sickness, assessed using the Lake Louise score, which increases with every additional 1000 metres of altitude. You notice it immediately and unspectacularly: strapping luggage onto the bike and being out of breath.

Here lies the real reason why core strength matters more on the road than at home. When the oxygen supply shrinks by a fifth, every unnecessary bit of muscle work becomes expensive, and anyone clinging to the handlebar is burning oxygen for nothing. The second factor nobody accounts for on tour is vibration. Epidemiologically, sustained whole-body vibration is considered a risk factor for the frequency and intensity of back pain in professional drivers. A week of gravel is vibration exposure! And a serious amount of it. You can dampen it by riding standing up! Then the spine no longer takes the vibrations directly through your backside, but somewhat filtered through your arms and legs.

The foundation is your feet, and that's the fix with the best effort-to-effect ratio. The balls of your feet belong on the pegs – not the arch, and certainly not the heel. As soon as the ball of your foot is on the peg, tension rises throughout the whole leg, and part of your weight goes through the pegs into the vehicle instead of through the seat into your lumbar spine. The second fix is the spine itself: actively lengthen it a little in the saddle instead of leaving your trunk and head to gravity. It sounds more strenuous, but in the long run it isn't, because the weight then rests on muscles rather than on intervertebral discs.

The third point is a check, and it's the most honest self-diagnosis I know. When traffic is calm, try flapping your elbows once in a gentle lean. If that's easy, your grip is fine and the forces are going through your core. If it isn't, you're hanging on your arms and you know where your aches in the evening come from. It takes three seconds and is more incorruptible than any self-assessment. In a dynamic system, the calm, comfy seated position isn't the most relaxed one – the active one that moves with the bike is.

I don't train for the bike, I train so the bike doesn't hurt. That's a small difference in motivation, but it lasts considerably longer than any resolution to get fitter. Twenty minutes of core work, twice a week, for six weeks before a bigger trip is enough to notice a difference on day three. On tour itself, a ritual that costs nothing helps: every half hour, consciously open your hands and let your shoulders drop. If you can't do that without the bike getting unsettled, you've already got the answer to the question of what's causing it.

Gear plays a smaller role than muscles, but not an unimportant one – mainly where it allows or prevents movement. A suit that pulls at the shoulders when you're standing pushes you back into the passive posture this entire article argues against. The iXS Venture-Air 1.0 suit with its two-layer ripstop stretch went along with the movement rather than restricting it; the jacket and trousers are AA-certified and fitted with Level 2 protectors. And the Cardo Packtalk Edge was the unsung hero of this trip, because we could coordinate ruts, grazing cattle and camera positions without having to stop.

The trip itself came from Colorado Motorcycle Adventures in Golden near Denver, including both Aprilias, the programmed tracks and the complete logistics. If you're heading there, pencil in twenty minutes of core training per week, starting six weeks beforehand. It's cheaper than any handlebar adapter, works more reliably than any new seat, and it's the only part of your bike you can't buy as a replacement.

• Colorado Motorcycle Adventures
• Jacket used
• Trousers used
• Cardo Packtalk Edge
• Helmet: Arai Tour-X5
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• More reports from travel partner Clemo:
• Used and new Aprilia Tuareg 660s