Virtual Trainer: Arm Pump

By Dr. Dale Macdonald and Tim Crytser 09/20/04

In an effort to bring Racer X Online readers the best information available regarding MX fitness, postings on this website are open to anyone with a specific and proven expertise in the fitness field. Dr. Dale Macdonald, a chiropractor and Certified Strength and Conditioning Specialist in private practice in Calgary, Alberta, Canada, certainly has the knowledge and experience to be considered an expert. A former intermediate / local pro motocross racer, he is the Chief Health Care Coordinator of the CMRC Canadian Pro Motocross National Series. If you follow the Canadian Nationals, look for the good Doctor at each and every round. If you have any specific question don’t hesitate to stop by the booth at the track or drop him a line at drmacdonald@elitesportperformance.com.


Arm Pump – The Silent Killer


If there are two words that strike fear into the hearts of motocross racers, its “arm pump,” that mysterious ailment that comes on near the end of your moto, makes your arms feel like concrete blocks and your hands go numb and fly off the grips. Arm pump has been responsible for countless crashes and lost positions over the years. As a former racer, I remember getting arm pump so badly I couldn’t pull the clutch lever, couldn’t pull the brake lever, couldn’t hold onto the grips and—worst of all—couldn’t shut the throttle off!

Arm pump ranges in severity from slightly annoying to completely debilitating. One would think that an ailment that affects almost every rider at some point in their career would be thoroughly researched by the motocross and medical communities and a solution common knowledge. Unfortunately, that has not happened and folklore at the race track runs rampant as to how to prevent getting rock-hard forearms. This article will attempt to boil arm pump down to the simple basics, separate fact from fiction, extinguish the folklore and offer some basic, factually driven solutions.


Layman’s Description

Arm pump is academically known as chronic exertional compartment syndrome (CECS). At its most basic: arm pump is the failure of blood to leave your forearm fast enough. New blood is constantly coming into your forearm, and if the old blood is not removed, backpressure builds up. The forearm compartment is not elastic, so when the pressure does build up, other structures such as nerves and muscles get compressed and lose their ability to function properly. (Picture stepping on a garden hose….) This compression of important structures is what causes the loss of sensation and inability to contract your muscles.

It is important to remember that not all forearm pain is caused by arm pump; you may think that your pain is a result of arm pump when in fact it may be from something else entirely. Many other factors can cause forearm pain including carpel tunnel syndrome, epicondylitis (golfer’s or tennis elbow), arthritis, shoulder and neck problems, fractures and previous injuries. If you suspect any of these other ailments, see you doctor for a full medical evaluation. In the interest of this article we will deal with forearm pain from arm pump only.


Technical Description

To fully understand arm pump, let’s first take a short lesson in muscle anatomy. Muscles are often found together in what are called “fascial compartments.” Fascial compartments contain muscle wrapped in a layer of fascia. Fascia is the stuff that gives muscles their form, much like the casing that wraps a sausage. Although fascia is very strong, it is not elastic. Since the fascia compartment is so inelastic, any increase in volume will cause pressure increases within the compartment. During intense exercise, muscles require large amounts of oxygen-rich blood to keep the muscle performing at peak levels. This increased volume engorges the muscle within the inelastic fascia, resulting in increased pressure within the compartment. Since we all remember that fluids are incompressible, and blood is most certainly a fluid, the increased pressure buildup within the fascia makes the muscle feel hard as a rock. When the compartment pressure builds up high enough, blood vessels can collapse, which restricts or stops the flow through the vessel. Veins typically have a lower internal pressure and have thinner walls than arteries. Because of this, veins will collapse from external pressure long before arteries. When this happens, venous flow reduces while arterial blood continues to enter the fascial compartment but is restricted from leaving. This restricted outflow increases the compartment pressure and is what causes the muscle to feel hard. If the compartment pressure rises high enough, even the capillaries and arterial vessels can collapse, resulting in a painful condition of oxygen deprivation. Acute compartment syndrome is the rare worst-case scenario of a compartment syndrome. A medical emergency, acute compartment syndrome is often the result of trauma (i.e. a hard crash). Acute compartment syndrome can afflict any muscle in your body, and should be suspected if the area becomes increasingly more painful, swollen, red and hot in the few hours after an injury.


Why the Inequality in Blood Flow?

The previous paragraph outlines the discrepancy between blood coming into your forearms versus blood leaving your forearms. Why the difference? The amount of used blood that you can effectively remove from a muscle is called your “venous return” and is a measure of your cardiovascular fitness. The more cardiovascularly fit you are, the better job your body does at removing used blood from muscle and returning it to the lungs (where it gets loaded up with fresh oxygen). If your cardiovascular fitness is not as good as your muscular strength (i.e. holding on to the handlebars with a death grip for two 30-minute motos), you will have problems.


Surgical Approach to a Solution

Pro riders have sometimes taken drastic measures to reduce the pressure that causes arm pump. Fasciotomy is a surgery that releases the compartment that houses the muscle, blood vessels and nerves. Little research exists regarding the effectiveness of surgical fascial release for chronic exertional compartment syndrome; however, conservative estimates place its effectiveness at just over 50%, meaning that nearly every other rider who gets this procedure done has no noticeable improvement. (Also note that surgery is very successful and in fact necessary for acute compartment syndromes).

Further complicating the recovery is the formation of scar tissue over the area that was just released. Scar tissue can actually make the symptoms of arm pump worse than before the surgery. Several top pro riders can vouch for this. In North America, as we have become accustomed to modern medicine providing the passive, easy fix for us. Popular culture is full of solutions to just about any ailment you have just by taking a pill. Bladder problems? Take a pill; Memory loss? Take a different pill; high cholesterol? Take three pills! In a day and age when we all want a drive-thru solution to what ails us, it’s no wonder that so many are seeking a solution to arm pump through surgery. If you take the time to read and understand the mechanism that causes arm pump, you can most likely eliminate this beast from your life and save yourself the time and pain that comes with surgery. Unfortunately, there is no simple, one sentence solution.


The Tough Solution

The first and most important thing you can do to eliminate arm pump is to ride, ride, ride, and then keep riding! There is no better sport-specific exercise for MX than just riding. If you are a normal weekend warrior and don’t always get to ride, then the most important thing you can do is to improve your cardiovascular fitness through supplemental training. (See the Racer X archives section for several complete workouts). Doing substantial amounts of endurance training will promote the growth of more small veins in the body (a process called neovascularization). More veins equal more pathways for used blood to leave a muscle (forearms in this case). Please take note that the types of exercises that are most beneficial are total body exercises, NOT isolation exercises like arm curls or squeezing a tennis ball. You must use total body exercises to condition your body to become efficient at delivering oxygen rich blood to muscles and to remove byproducts (like lactic acid) more efficiently. This can only be done with total body, cardiovascular exercises. Running is a personal favorite of Dr. Macdonald’s, as it gives a great cardiovascular challenge and can be tailored to mimic race day (for example – try running 2 x 35 minutes at a “tempo” pace (75 – 80% of your maximum heart rate), with the same length of rest as you get between motos. (For information on how to calculate maximum heart rate, visit elitesportperformance.com.) So remember, to increase your chances of eliminating arm pump, you must improve your total body cardiovascular fitness.


Race Day Solutions

There are also some things that can be done while you are at the track. A very thorough warm-up prior will help kick start your circulation. In fact, going for a moderate run (20 minutes) will warm you up to the point where you begin to sweat. This amount of warm-up will ensure that your venous return is working well; allowing you to get rid of used blood more efficiently. Don’t worry about being a little tired from your warm-up – you can finish your warm-up 30 minutes before your first moto and still reap the benefits. Most riders suffer from arm-pump worse in the first moto than the second, primarily because their venous return is not up and running before they get on the track: When it comes to arm pump, it is better to be a little tired than a little cold. Besides that, since you trained so hard to improve your cardiovascular fitness, a 20-minute warm-up should do just that; warm you up not tire you out.


Riding Solutions

Riding technique will also help tremendously. Learning to squeeze the gas tank with your knees will allow you to loosen your grip on the bars. Remaining relaxed on the bike is also a key point. Forearm muscles only get blood flow when they are relaxed, which may explain why some people pump up more on race day than on practice days.


Non-surgical Solutions

Soft tissue treatments such as Myofascial release (of which Active Release or A.R.T. is a form) are often used to minimize adhesions between muscles and their fascia. This helps. These techniques are uncomfortable, but can be quite effective in improving the mobility of these compartments. To learn more about this technique, contact Dr. Macdonald.


Other Solutions (the power of Placebo)

There is also a class of solutions that I consider to be less effective at reducing arm pump. They include things like suspension set-up, bar position, lever position, grip size, steering dampers, type of bars (anyone remember the bar snake?), seat grippers, and nutritional supplements. This is the point where the science of arm pump management leaves and the art of bike set-up begins. Just remember, the placebo effect can be a powerful tool!


The Bottom Line

So there you have it, there is no magic solution to arm pump, only a number of small steps that you can take to minimize your odds of getting it. Remember, arm pump is linked to your overall cardiovascular fitness so if you are not in top condition for your riding ability, then your chances of getting arm pump are high. Good luck and as always please email Virtual Trainer at crytset@comcast.net with any questions or comments. Also, don’t forget to check out the Racer X archives section for all your MX fitness needs.