Training: What is VAM?
By Sean Burke, Crank Cycling
4/9/12 - Cyclists, even riders that don’t necessarily consider themselves climbers, almost always love a good hill. The other things that cyclists love are gear and data. As power meters and GPS units have become cheaper and more ubiquitous, a typical cyclist has more data available to them than ever. This article will discuss one particular metric that can be measured using a GPS: VAM.
VAM was a term first popularized by Italian cycling trainer Michele Ferrari. VAM is the Italian acronym for “velocità ascensionale media” which basically translates as “average ascent speed”. Just think of VAM as vertical meters climbed per hour. VAM is typically measured in meters per hour (M/H), but you could theoretically use feet per hour, as well. What makes this metric so useful is the fact that when climbing, most of the power the cyclist applies to the pedals goes to pushing the cyclist upwards, rather than forwards. So VAM can be used as a proxy for power to weight, as well as to compare performance on say an 8% grade, to that of a 10% grade. If an athlete is climbing at a VAM of 100 (M/H), it will take the athlete 1 hour to get to the top of an 8%, 10% , or even a 15% climb of 1000M. The VAM metric can therefore be used to compare different climbs to each other. You can tell if a performance is a good one or a bad one based on the VAM you achieved on the climb.
In the absence of a power meter, VAM can be an excellent way to gauge an effort, or even a great tool to build a workout. For example, if a rider has a power meter, I might have him do a 20 minute time trial, and then take 95% of his average power as his threshold power. If the riders doesn’t have a power meter, I can have him do a 20 minute hill, and record the VAM. If he does a VAM of 1000, I can assume that at threshold power, he climbs at 95% of 1000, or 950 M/H! So, if I want this athlete to do 4 X 10 minute intervals at threshold power, but he doesn’t have a power meter, I can tell him to do 4 X10 minute hill shooting for an average VAM of 950! There are plenty of online tools out there such as Garmin Connect and Strava that allow you to upload your rides, and look at your VAM along with other metrics, and most GPS computers will allow you to view your VAM as you ride. So there you go, VAM is a great tool to compare climbs of with similar vertical ascent, and can also be used as an inexpensive alternative to a powermeter.
Sean Burke is a Cycling Coach in San Diego, CA. You can contact him with questions, or suggestions for training articles via his website http://crankcycling.com.
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