How to Avoid (and Reduce) Arm Pump When Mountain Biking

We’ve all been there -  hands cramping, forearms throbbing, fingers stuck in the shape of a claw that needs to be pried off the handlebar. Unable to maintain a decent grip on the bars, you're questioning whether getting back on the lift for another run was a good idea, but you don't want to cut your riding vacation short.

It's the dread arm pump and you've got it bad. Arm pump, death-grip, hand pump, forearm fatigue, "the claw", whatever you call it, the clinical term for the unbearable hand fatigue you're feeling is Chronic Extertional Compartment Syndrome, or CECS for short.

What causes Arm Pump?

The pain from CECS is attributed to the swelling of the muscles in the forearms. As blood flow to these muscles is decreased, oxygen levels drop, and so goes the grip strength in our hands. It is believed that the combination of vibrations in addition to forced grip exertion is responsible for these symptoms. Logic dictates that if we’re able to reduce vibrations as well as grip exertion, arm pump will no longer be an issue. 

Here are a few options for addressing the symptoms of arm pump that might just help salvage what’s left of what was supposed to be an epic riding vacation.

Dealing with Arm Pump Symptoms

If you’re on a trip and you’re stricken with a bad case of Death-grip, here are a few things you can do:

• Ice your forearms
• Ibuprofen or other over the counter NSAIDs
• Rest
• Review your bike setup

Since the pain of arm pump is caused by swelling and inflammation of the muscles, our priority is to reduce the inflammation.

Icing the affected area as well as Ibuprofen can help with the immediate symptoms. Massage can be helpful in restoring blood circulation as well.

If it's still early in the day and you're hoping to get more use out of a bike park ticket, one remedy is to change it up. If blasting through braking bumps on rough trails is destroying your arms and hands, taking a break from the high-speed trails creating those high-frequency vibrations might mean retaining enough energy/grip strength to finish out your day.

At Whistler, we like to mix it up, hitting some of the slower speed, technical trails in between high speed runs down flow trails.

Rest is generally prescribed for the symptoms of arm pump. Taking a break from the activity causing the issue is always a good idea, though it can certainly put a damper on a riding vacation. (during trips to the Whistler Bike Park we often take a break from the park to ride the trails in nearby Squamish.)

If you haven't been riding a lot and have a big riding trip planned, working to increase your grip strength and conditioning yourself in advance is always recommended. And the best preparation for a big riding trip? More riding!

Crosstraining by doing activities — like rock climbing —that increase grip strength is helpful as well.

Long term effects

Arm pump is no joke — prolonged exposure to vibration in the hands and forearms can have some scary long term effects. The swelling can develop and grow worse over time. For some, surgery is the only option.

Whereas CECS is attributed to riding, (moto riders often get it the worst) prolonged exposure to vibration can result in Hand-arm vibration syndrome (HAVS). HAVS is a well-documented disorder widely recognized as a potential occupational hazard for those working with vibrating power tools. Bottom line, these vibrations are bad, and if you’re experiencing arm pump regularly, taking steps to treat and prevent it can prevent long term nerve damage.

Of course, that doesn’t help you if you’re currently 2 days into an MTB dream vacation at the Whistler Bike Park. In the short term, here are a few other things you can do to reduce forearm exertion and minimize the symptoms of arm pump.

Reviewing your bike setup

Taking a second look at the angle of your levers may be helpful. Your brake levers should be adjusted for an optimal position while in an attack position, standing on your pedals with your elbows out. If you’re having to make a major effort to reach your brakes, that could increase muscle fatigue, and therefore the effects of arm pump. If you’re not already running powerful brakes with large rotors and a high degree of stopping power, you may be exerting yourself excessively as well. Remember, our strategy here is to minimize the amount of effort required to hold on to your grips/bars.

Another thing to consider is raising your bars. Reducing the weight you apply to your hands may conserve the energy you have for maintaining your grip.

Is your suspension dialed? 

Make sure you’re getting the most out of your suspension, especially your fork. Excessive compression damping means you’re feeling more of the terrain, and your fork isn’t doing as much as it can to damp impacts, making your grip tighter. 

Friction is the enemy of fork and shock seals, which is why a regular lower leg service interval is recommended in order to keep those sliders working at their best. Any excessive friction means your suspension isn’t performing as well as it should, which means more vibrations are being transmitted to you.

Are you and your riding dialed?

It takes energy to grab the brakes, and if you’re braking excessively, your grip strength will be affected. It takes even more energy to brake in the rough stuff, so planning your braking points with purpose while riding as well as sighting further down the trail could be helpful and conserve energy. In the same vein, avoid clenching the bars too tightly, and try relaxing your grip and forearms when possible. 

 

Larger grips

A lot of riders prefer the feel of narrow grips, but they often require additional grip strength. During a recent trip to Whistler, I tested this theory, riding one day with the narrower 30mm SPANK Spike Grips and the Spike 33 grips the next day. After running the larger grips, I kept them on for the remainder of the trip and am still running them today.

SPANK Spike 33 grips have a bit of extra padding as well as a relief area where the rubber floats, which offers a bit more in the way of shock absorption. 

While I used to prefer my grips on the thinner side, after my day of A/B testing with the larger diameter grips, I found I retained my grip strength and I haven't gone back.

Grips are relatively inexpensive — the SPANK Spike 33 grip sells for $25.90, (and there’s nothing like a fresh set of grips on the bike) and if it saves a riding trip, it's a more than worthwhile investment!

We've also heard reports from some riders that switching to thinner grips is what worked for them — we're all different, so experiment with what works best for you!

You can certainly spend more — a number of brands have created products to take on the problem of hand/arm fatigue. Suspension grips and flexing bars are just some of the products developed for bike and motocross riders suffering from arm pump.

As fans of gravity riding, SPANK Industries has dedicated a significant amount of time and energy into developing a solution to address the vibrations that cause forearm fatigue: the SPANK Vibrocore collection.

Vibrocore™

We really hate arm pump, and Spank Industries has made significant investments in tackling this problem head-on. This research and development resulted in the patented Vibrocore™ technology, which is lab and rider tested and proven to reduce the short term effects of hand-arm numbness and fatigue, and reduce the long term risk of arm pump.

Vibrocore is featured in SPANK Industries Vibrocore handlebars and SPANK Vibrocore rims. Learn more about it here.

 

Spank Vibrocore Explained. You can also read the results the the Frequency Analysis of the Vibrocore Test here.