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There’s 5 kilometers to go and you’re sitting 20th wheel, tucked inside the bubble, saving your energy for the sprint. A four-rider breakaway is up the road with just a few second’s gap, but the field is chasing and you’re confident that it will all come back together. But before the final sprint, there is a major obstacle standing in your way. At 3km to go, there is a short, sharp climb – about 900m long at an average of 6 percent. It might only take two minutes, but its proximity to the finish means that attacks will be flying. All of the climbers and time trialists will be going full gas up the climb in an attempt to drop the sprinters (read: you).
This is going to hurt.
You hit the lower slopes with the goal of just hanging on. But even at 450 watts, the peloton is starting to slip away. One meter becomes two, two turns into five, and by the top of the climb, you are well and truly dropped. So close, yet so far.
What happened? You have a good sprint and a decent threshold, but during those two- to three-minute efforts, you simply suck. These are VO2 Max intervals when the muscles beg for oxygen and the lungs deliver as best they can. They’re too long to be an all-out sprint, but too short to settle into a steady state-type effort. While a 15-second sprint may be the difference between winning and losing, a VO2 Max interval determines whether you will be there at all.
What is VO2 Max?
VO2 Max is the maximum amount of oxygen that your body can take in at a given time. Oxygen is then used to break down nutrients – carbohydrates, for example — and utilize them for energy. Generally speaking, the higher your VO2 Max, the faster you are on a bike.
In wattage terms, VO2 Max is the maximum power output an athlete can sustain for about five minutes. Depending on the athlete, this usually works out to 110-120 percent of their functional threshold power (FTP) which is the athlete’s theoretical maximum one-hour power. In order to improve your VO2 Max power – and avoid getting dropped – you need to increase your above threshold power output. Here’s how:
Increasing your VO2 Max power
VO2 Max workouts typically fall into two categories: long (LI) and short-duration (SI) intervals. SI’s are comprised of short work intervals lasting less than a minute, while LI are typically longer — two to six-minute — work intervals. Here are some examples:
A classic LI session is 4 x 5 min at 110-120 percent FTP with 2.5 minutes recovery at 45-55 percent FTP. This workout doesn’t beat around the bush – straight into five minutes at VO2 Max, five repeats. Simple as that.
But these sessions are tough, really tough. While effective, LI workouts are also extremely demanding, both physically and mentally. Here’s the good news: Recent research suggests that very short work intervals may be even more effective at improving your VO2 Max power than longer intervals.
A personal favorite of mine is this SI session: 3 x 13 x 30s:15s. Translated: three sets of 13 repeats of 30-second intervals at 110-120 percent FTP, followed by 15 seconds at 45-55 percent FTP, with three minutes rest in between sets.
Popularized by a study of 18 elite cyclists by Bent Rønnestad and his colleagues at the Inland Norway University of Applied Sciences, this SI workout was shown to significantly improve peak aerobic power output, fractional utilization of VO2 Max at 4 mmol L-1 (blood lactate levels), and a relative increase in power output when compared to LI. Another translation: The SI group saw greater improvements in cycling economy and physiological efficiency than the LI group.
In summary, do the SI workout. And when you’re bored of that, try the LI workout.
The key to the complicated SI workout is that it allows the athlete to accumulate more time at 90-100 percent VO2 Max power (~115 percent FTP) compared to more traditional LI workouts.
It is important to note that SI intervals are best done when using a heart-rate (HR) monitor to put a cap on the physiological workload. During each of the three sets (which last 9.5 minutes), the athlete’s HR should plateau at ~90 percent HRmax. If the athlete’s HR exceeds 93-95 percent HR Max, they’ve gone too deep and won’t be able to complete another set of quality intervals.
This brings us to our final note and oft-heard cliché: Focus on quality over quantity.
The biggest fitness — VO2 Max — gains come from consistent training and quality workouts. Go too deep one day and you’ll pay for it the next. By sticking to the plan and nailing your workouts, you’ll avoid burnout and see bigger fitness gains than ever before.
Rønnestad BR, Hansen J, Nygaard H, Lundby C. Superior performance improvements in elite cyclists following short-interval vs effort-matched long-interval training. Scand J Med Sci Sports. 2020;30(5):849‐857. doi:10.1111/sms.13627