The Four Minute Workout
Four minutes. To good to be true?
The whole workout might take a bit longer than four minutes, but it only requires 3 to 4 minutes of actual hard work made up of 6-8 x 30 second sprints. I love this workout for two reasons: First, you can do ANYTHING for thirty seconds: about the time the effort starts to get really uncomfortable, you're done. Second, even though the work portion of this workout is short, the body experiences a training stress equivalent to a significantly longer steady-state workout. The only caveat: during each 30-second interval you must pedal at absolute maximum; so hard, that it’s impossible to sustain that level longer than thirty seconds.
A growing body of research shows short, maximum-effort bursts of work not only raise anaerobic capacity, but also our aerobic performance. In fact, workouts like this have been shown to create the same aerobic gains as a significantly longer steady-state ride.
How To Do It
Do an effective 10-15 minute warmup, including high-cadence pedaling and at least one effort of 60-90 seconds at threshold. On E-Motion Rollers, I prefer to warm up in a low resistance setting, then set the resistance to its max and only change gears during the workout. This is one workout where I don't think it makes sense to use a trainer in "smart" mode. Doing so creates an arbitrary target power and can prevent an athlete from hitting their full capability.
Begin in a relatively hard gear and focus on quickly accelerating (110+ RPM’s) for each sprint. Don't spend the first 10 seconds ramping the power up. Stomp on the pedals, shift and continue to spin through gears until reaching maximum capable output. Hold that until the 30-second mark. Then drop to your lightest gear and spin easy for 4-5 minutes until you feel completely recovered and ready to hit full-intensity again.
Repeat until you are no longer able to perform full-power sprints.
● 10-15 minute warmup - including high cadence and tempo/threshold efforts. ● 6-8 x 30s maximum effort sprints (175-250% FTP) ○ 4-5 minute recovery between sprints - spin in an easy gear for recovery. ○ If you're recovered before 3 minutes, it's because you can sprint harder during the intervals! ● 5-10 minute cooldown - Easy spinning after last sprint
Above is a power file from this workout completed on Inside Ride rollers. The athlete performed six sprints right around 250% of FTP. This is damn good power to make sprinting in your living room in the late winter!
Why does this work?
Common thinking often views the aerobic and anaerobic systems as mutually exclusive with the aerobic pathways shutting down whenever we “go anaerobic” - as if some sort of switch gets flipped. In truth, our aerobic system never stops working, even during short-duration, maximum-output bouts of exercise. We simply reach a force/power requirement that our slow-twitch (aerobic, high-efficiency) muscle fibers can't achieve on their own. When this happens, our fast-twitch (anaerobic, high-force) fibers begin firing in order to contribute to the collective effort. and all of our energy systems are activated.
This workout's all-out, cross-eyed-hard sprints aim to recruit as many muscle fibers and energy systems as possible. Though you will only just begin breathing hard by the end of the sprint, there is a large oxygen debt created, which can take a couple minutes to go away. This debt creates signals that trigger the body to adapt and increase aerobic pathways (oxidative enzymes, mitochondrial density and others). Taxing the neuromuscular system triggers changes in the neural networks that control the firing of our muscles. Improvements here allow us to produce more force and to do it faster, which is the essence of increasing power
From a Training Stress Score (TSS) standpoint, looking at the Normalized Power (NP) of this workout yields some interesting insights. If an athlete hits 200+% of their FTP during the sprints, the NP of their entire workout will come out to their Sweet Spot power (90% of their FTP). That means if the ride takes 40 minutes, the body experiences the same training stress as if the ride was 40 continuous minutes at Sweet Spot!