Some recent reading and self experimentation has led me to this idea: are there effective alternatives to standard VO2 Max intervals?
It all started with a video about short intervals by Dr. Stephen Seiler.
“The Rønnestad” Workout
Dr. Seiler gave examples of shorter interval workouts designed to reach various outcomes. The first one he mentioned was the Rønnestad. At its core, the intervals are 30 seconds on/15 seconds off. The sets are quite long; 13 reps in this case. It’s similar to a Tabata style workout, except rather than all out it’s a VO2 effort. The workout came from the study: Superior performance improvements in elite cyclists following short-interval vs effort-matched long-interval training
What Did the Study Find?
In short, the study compared an improvement in power of cyclists doing 3 sets of 13 x 30-second efforts with 15-seconds recovery versus riders doing 4 sets of 5-minute efforts with 2.5-minutes of recovery. The efforts were done at or near VO2 Max. The length of the study was 3 weeks, with three sessions per week (nine sessions in total).
I found the end result to be very interesting.
At the conclusion of the study, the short interval group achieved a greater improvement in power during a 20 minute max effort test. The short interval group saw a 4.7% improvement versus the long interval group, who saw a 1.7% reduction in mean power. The short interval group also achieved a greater percent-wise change in power at 4 mmol/L lactate (an approximation of anaerobic threshold). Furthermore, the short interval group displayed a greater improvement in watt max (mean power during final 60 seconds of VO2 max testing).
Interestingly, VO2 max did not change in either of the groups. That being said, there was an increase of 2.6% in the short interval group and 0.9% in the long interval group.
A Practicality to Shorter VO2 Max Intervals
When it comes to training, I’m a robot. I can do the same workout week-in week-out with little to no progression. Usually, I do a three week build of VO2 Max intervals culminating with two sets of 3×5 minutes with 2:30 rest between intervals and 10 minutes between sets. I can do this week after week, after week. Mentally and physically I just settle in and smash them out.
For many though, this can get boring. While there is an aspect of mental toughness and general suffering in cycling, happiness and variety are just as important. I can almost guarantee that many successful cyclists would look at some of my training blocks and cringe. If there’s another, potentially better, workout that produces the same physical adaptations without the boringness of a metronome, why not give it a shot?
More importantly, this workout led me to thinking about practicality and specificity. In my area there are virtually no races with climbs of 5 minutes. Looking back at the last road race I did, the longest climb took a little over two minutes. Even then, my average power was just above threshold.
The last lap featured a “wall”, which again only took about two minutes to climb. Because of its position in the race and the steepness of the climb it was a full on VO2 Max effort. Combine this with the punchy-ness of an amateur bike race and I have to ask, what’s the point of a steady 5 minute VO2 Max effort?
Trying the Rønnestad Workout
Recently, I did the Rønnestad workout in an effort to compare it to my standard VO2 Max workout. While this wasn’t 100% scientific, I decided to do my standard 2 sets of 3×5 and a week later tried The Rønnestad. The goal was to see how the workouts compared in terms of RPE and time spent at VO2 Max for both heart rate and power. The RPE of both workouts was tough, especially at the end of each set. Therefore, I would consider that metric to be similar.
Which VO2 Max Intervals Produce More Power?
When you get to these types of maximal efforts, I think it’s almost more important to look at HR than power. When the winning move goes away, it doesn’t matter how many watts you’re putting out, you’ve just got to go with it. However, if your HR is at max, you can only go so hard until your body says “no mas”. With that said, power is obviously one of the key metrics when it comes to cycling. So, let’s dive in!
As I mentioned, this is not a very scientific study. In hindsight, I should have tweaked the 3×5 from two sets (of 3×5) to three sets of 2×5. That would have made it a more apples-to-apples comparison. Instead, there’s three sets of intervals for the Rønnestad workout and two for my traditional 3×5.
Intensity, Average and Normalized Power
Perhaps the most interesting and remarkable thing about the 3×5 workout is the consistency. The numbers for both sets are practically identical. I really like to look at Average Power for these types of intervals, but as you can see, the Normalized Power (NP) is identical to the average. In the Rønnestad workout, clearly I went out way too hard. The numbers show a drastic difference from the first set to the last.
When you compare the averages from the two workouts, the IF and NP are higher in the Rønnestad. However, the Average Power is higher in the 3×5. In my opinion, repeatability and consistency is key, so I would give the edge to the 3×5 workout.
3×5
IF | Avg Power | NP | |
1 | 1.09 | 348 | 348 |
2 | 1.09 | 347 | 347 |
Rønnestad
IF | Avg Power | NP | |
1 | 1.18 | 361 | 391 |
2 | 1.09 | 326 | 361 |
3 | 1.09 | 330 | 360 |
Average
IF | Avg Power | NP | |
3×5 | 1.09 | 347 | 347 |
Rønnestad | 1.12 | 339 | 371 |
Percentage of Time in VO2 Max Zone
Beyond the raw power numbers, I wanted to look at the time actually spent in the VO2 Max and Anaerobic zone. Because of the structure of the workouts, the 3×5 does not include the recovery periods since they’re so long. However, because of the structure of the Rønnestad workout, those periods are included in these numbers.
During the 3×5, I spent 80% of the time at VO2 Max or above. In the Rønnestad workout, it’s closer to 60%. However, I feel like the Rønnestad workout has the edge, because 55% of the intervals were spent above VO2 Max. Since this also includes roughly 3 minutes of rest (i.e. recovery zone), I would argue that the Rønnestad is more effective at producing max power.
3×5
VO2 Max | Anaerobic | Total | |
1 | 58.8 | 22.4 | 81.2 |
2 | 53.5 | 26 | 79.4 |
Rønnestad
VO2 Max | Anaerobic | Total | |
1 | 2.3 | 58.9 | 61.2 |
2 | 4.1 | 53.1 | 57.2 |
3 | 5.2 | 52.4 | 57.6 |
Average
VO2 Max | Anaerobic | Total | |
3×5 | 56.2 | 24.2 | 80.3 |
Rønnestad | 3.9 | 54.8 | 58.6 |
Which VO2 Max Intervals Are More Effective for HR?
For reasons I mentioned above, I think heart rate is a more effective measurement for VO2 Max intervals. I took a look at two different metrics to compare the two workouts. I looked at the percentage of time spent at VO2 Max and time spent at VO2 Max.
One quick note – when I pulled the HR data, the zones got a bit mixed. There was no anaerobic zone because, for some reason, VO2 Max was the top zone. Therefore, I’m calling it VO2 Max+.
Percentage of Time in VO2 Max Zone
As I expected, the Rønnestad workout produces a higher time at, or above, VO2 Max. The intervals feature significantly less recovery, so my HR never really has time to come down. As I noted in the power analysis, the first interval in the Rønnestad workout was significantly harder than the last two. However, the final interval did bring the HR back up above 90%.
3×5
VO2 Max+ | |
1 | 87 |
2 | 85.3 |
Rønnestad
VO2 Max+ | |
1 | 94.5 |
2 | 80.5 |
3 | 91.2 |
Average
3×5 | 86.2 |
Rønnestad | 88.7 |
Time in VO2 Max (plus) Zone
When looking at the HR total time at V02 Max+ the end result is very similar (as you can imagine from the previous tables). The Rønnestad workout produced about 30 seconds more time at VO2 Max+, but relatively speaking they’re pretty close. Not to sound like a broken record, but the second interval in the Rønnestad workout produced significantly lower HR values across the board.
3×5
Time (max 15min) | |
1 | 13:04 |
2 | 12:48 |
Total | 25:52 |
Rønnestad
Time (max 10min) | |
1 | 9:25 |
2 | 7:55 |
3 | 9:02 |
Total | 26:22 |
What does this all mean?
The research leans towards shorter intervals, as well as practicality and specificity. My own data and experience shows that the workouts produce nearly similar power numbers. The heart rate data shows that the Rønnestad intervals do produce more time spent at, or above, VO2 Max.
So, what am I going to do? Both of course. What kind of article would it be if I gave a simple answer?
After self experimentation and looking at the science, I feel like a more traditional build up of about two sessions of longer intervals, followed by one or two sessions of shorter intervals provide the perfect mix.
For me, I would start out with 2 sets of 2×4-minute intervals. The next week, I would bump it up to 2 sets of 3×4-minute intervals. Then, I would throw in the shorter intervals: 3 sets of 13 x 30/15 on/off. In addition to mixing things up, the shorter intervals provide better specificity than doing 2 sets of 3×5 minutes. This would be a solid mix of VO2 and more traditional threshold intervals. The threshold intervals would push my FTP, while the VO2 intervals would push it over the top.