Let’s face it! If you’re a dirt bike rider then you have experienced arm pump before! You may not have known what it was at the time but we’ve all felt the debilitating effects of arm pump while riding a motorcycle. There are many causes of arm pump and unfortunately there is usually a combination of factors that contribute toward the problem. Let’s take a closer look at some of the causes and more importantly how to fix the problem and move forward.
What is arm pump!
Arm pump is when a rider’s forearms are filled to their maximum with a combination of blood and lactic acid. This causes a major downturn in fine motor-skills which are needed to operate the throttle, clutch and front brake. It’s quite similar to the feeling a 100 metre sprinter feels in their legs at the end of a run.
What happens is the muscle expands to its maximum size where the outer muscle sheath won’t allow it to expand anymore, followed by a feeling that your muscle is about the burst like a balloon. Once the muscle has pumped-up it can take quite a while to get it back to an efficient working unit. As you can imagine, this can be quite a dangerous situation when a rider is trying to jump a 20 metre triple and land centimetre perfect or make their way through a rough section of a track.
For me personally I have been one of the lucky ones over the years to have rarely suffered from arm pump! But every once in a while I did get it and can understand what the fuss is all about. It almost feels as if the bike is on auto pilot and has a mind of its own. The messages that your brain sends to your hands seem to almost be in slow motion, or even worse get scrambled along the way. Some riders choose to be smart and slow down, while others choose to ride through it which usually ends up in a cartwheel.
Arm pump causes!
Let’s have a look at some of the classic causes of arm pump for dirt bike riders. Arm pump is always caused from holding on to the bike too tight with your hands but it’s the actual cause of the rider holding on too tight that we want to take a look at.
The percentages game!
All riders have their own style, technique and body position. That is what makes us unique. However the higher percentage rate that you grip with your legs the less chance you have of getting yourself arm pump. Here’s an example:
Leg grip- 0% Arm grip- 100% = certainty of arm pump
Leg grip- 30% Arm grip- 70% = high probability of arm pump
Leg grip- 50% Arm grip- 50% = possibility of arm pump
Leg grip- 70% Arm grip- 30% = low probability of arm pump
Leg grip- 100% Arm grip- 0% = zero chance of arm pump
Of course, we all know that it is not possible to ride the bike just using your legs while using 0% of our arm strength. But we need to get down around the 70% to 80% mark with those legs to ease the load off your arms. You can have the best suspension in the world and be a super fit athlete but if you don’t get your percentages right you’ll pump up immediately!
One of the most common causes of arm pump in riders that I have witnessed is poor body position. If a rider has a squatted standing position then their legs don’t do enough work to grip the bike. This leaves the arms to do all the work. When in your standing position your legs should cover your air box and grip extremely tight inwards on the bike.
Hard on the equipment
One of the biggest tell-tale signs that a rider is going to get arm pump is how quickly they go through grips and gloves. Riders that grip too much with their hands will always trash their grips and gloves very quickly while also quite often getting blisters on their hands. A set of soft compound grips will generally only last a few days of riding when a rider is death gripping the bike with their hands. When you successfully loosen off your hands you will minimise arm pump, blisters on your hands, tearing up your grips and tearing up your gloves.
For a lot of riders out there that don’t get the opportunity to practice during the week, race day can bring arm pump. Particularly in practice while the rider finds their rhythm once again. Make sure you take your time to warm up and stretch before practice. Don’t go flat out in your first couple of laps, but ease your way into it.
Bump it up a notch
A lot of riders who are knocking on the door to get their first factory ride tend to practice at a different pace to what they do on race day. They ride all week long at different practice tracks and suffer no arm pump until race day. The cause here is normally a combination of two things – anxiety on race day, along with the extra speed needed on race day to perform at your best. To increase your intensity of practice sessions during the week try getting your mechanic to record some of your sprint lap times and set these as your lap time goals for weekly practice sessions. If your mechanic or dad can swing off the pit board for you during the week this will help you keep up your intensity. Also try to ride with other fast riders to get that adrenaline flowing.
If there is one part of our sport that seems to bring on the arm pump it is Supercross! Mainly due to rider comfort, a rider will tend to ‘death grip’ the bike a lot more on a Supercross track than an outdoor Motocross track. It’s all about comfort! If you’re comfortable then you won’t hold on so tight. If you don’t hold on tight, you won’t get arm pump. The more you practice Supercross, the more comfortable you will be and the looser your hands will grip the bars.
A poor diet will also help trigger arm pump. Simple sugars are proven to speed up the lactic acid process which is a key factor in arm pump. It sounds too easy but drinking plenty of water not only minimises arm pump in the first place, but also helps flush the lactic acid out of the system once it is in there. If you can’t bring yourself to have a healthy diet all week long, then at least watch what you eat a couple of days before an event. Keep off sugary, sweet food and fried goods while trying to eat a fair bit of unbleached grains. Two litres of water per day is a bare minimum.
If a rider is lacking in leg strength and fitness they will eventually tire in the legs and the standing position will sacrifice, causing the rider to have to grip a lot tighter with their hands, the end result being arm pump. Make sure you increase overall fitness and leg strength so you can keep your good form through the entire race. The arms and hands have enough work that they are supposed to be doing rather than taking on extra work that the legs are supposed to be looking after.
This is one of the only cases where the rider isn’t really at fault. The rider may have perfect technique, be extremely fit and ride regularly but still suffer from arm pump due to poorly set-up suspension. Typically you will find that forks set up too stiff will be the main cause of arm pump in the suspension department due to constant chattering of the arms, but suspension set up too soft will also cause arm pump. Take the time to learn about suspension setup and constantly monitor your own settings. Don’t be scared to get the screwdriver out and have a play with the clickers during the week.
Go get ‘em
Well as you can see, it isn’t as simple as putting your finger on one problem that will solve all of your arm pump problems. And just when you think you have it sorted, something else might pop it’s head up and cause you to hold on too tight. Get yourself a checklist of things that you know have the possibility to cause you arm pump because at any time it can come and bite you on the bum when you least expect it.