Mountain biking’s bursty power is primarily a function of terrain. Rocks, roots, ruts, short steep climbs, switchbacks, obstacles and more all contribute to the highly variable power demands of mountain biking. It’s essential to mountain bike racing to be able to produce these efforts in order to clear the technical terrain and maintain your speed up, over, and thru the terrain.
Conversely, you’ll also notice that preceding most of these efforts are periods of zero wattage (highlighted in blue). This indicates that the terrain was fairly technical and I had to stop pedaling temporarily to clear a section of trail but then was back on “the gas”. When I started pedaling again I went from 0 to 300 watts to keep the momentum going. It’s these short burst efforts and the subsequent changes in wattage or cadence that truly distinguishes mountain bike racing from road racing.
Cumulatively, these efforts add up to a big ‘ol physiological demand. Once or twice is nothing, but 88 times (like in a race) will absolutely bring you to stop.
If you reach that "capacity" in a race you’ll have no choice but to slow down. However, if you work on raising your anaerobic capacity in training, you’ll have an extra gear to race faster. Much MUCH faster.
How to Raise your Anaerobic Capacity
In summary, mountain bike power is bursty as illustrated by the tempo climb above. Mountain bike power is even more bursty when racing flat out with your heart rate pegged at 180bpm. Therefore an athlete’s ability to perform zone 6 level efforts over and over during a mountain bike race is critical. Having a huge aerobic engine is important too but having both is a lethal weapon.
At FasCat Coaching, we like to have mountain bike athletes perform Tempo Bursts Intervals. These structured intervals are performed at normal tempo wattage, but every 2-4 minutes, the athlete jumps up out of the saddle for 10-30 seconds at 125% or greater of their threshold power. After the burst, the athlete returns to their tempo pace/wattage until the next burst. Here is an example tempo burst workout:
· Tempo Bursts: 3 x 9 minutes ON 9 minutes OFF b/w 224 – 266 watts w 10 seconds > 357 watts @ 3, 6, & 9 minutes
As the athlete progresses, tempo can be replaced with Sweet Spot and even FULL GAS Threshold work/wattages. Another example would be:
· Sweet Spot Bursts: 4 x 10 minutes ON 10 minutes OFF b/w 245 – 286 watts w 15 seconds > 357 watts @ 2, 4, 6, 8
& 10 minutes
The Sweet Spot Burst workout above is more advanced and much harder than the first tempo burst example. The most advanced workout is to perform bursts during a threshold interval. In other words, going harder when you are already going as hard as you can.
· Threshold Bursts: 2 x 20 min On 10 min OFF b/w 268 – 310 watts w 15 seconds > 357 watts @ 5, 10, 15, 20 minutes
As a side note this is an excellent workout for a time trialist racing over a variable and hilly course like the Tour of Missouri or jumping out of corners and accelerating on a course like the USPRO TT in Greenville this past year.
At FasCat, we reserve the Threshold Burst Intervals only for the 2 – 3 weeks pre-A race competition.
These bursty intervals force the physiological adaptations required for the constant start/stop pedaling and short bursty anaerobic power that are necessary to ride fast over technical mountain bike terrain.
An Example Anaerobic Capacity Interval workout
Lastly, to work exclusively on your anaerobic capacity, there’s the old tried and true Zone 6 workout. Here is an example:
· Zone 6: 2 sets of 4 x 1 min On 1 min OFF, Full Gas > 357 watts; 5 min inb/w sets
This workout contains 8 minutes (2 sets of 4 x 1 minute) of anaerobic capacity work. We adjust the total workload duration for the athlete on an individual basis between 5 and 25 minutes with never more than 7 intervals per set. 1 minute is a good middle of range anaerobic capacity duration but 30 – 90 seconds may also be used.
If you want to take your A game up to an A plus game this season on the mountain bike, these mountain bike specific intervals are just the ticket.
Copyright 2010, FasCat Coaching, LLC
Jason Hilimire is an Apprentice Coach with FasCat Coaching. He can be found out on the trails around Boulder, perfecting his short burst power. To find out more about his coaching services, please contact him by email Jason@fascatcoaching.com