30/30 intervals, which consist of alternating 30 seconds of intense effort followed by 30 seconds of easy pedaling, are a classic cycling training technique for improving VO₂max, or the body's maximum capacity to utilize oxygen during exercise. But not all cyclists benefit equally from this method. Depending on the type of rider, the effectiveness of 30/30 intervals can vary. Here's why and how to adapt this training to maximize its effects.
By Guillaume Judas – Photos: depositphotos.com
According to the most common training plans, 30/30s are programmed at an intensity of 125 to 145% of FTP (Functional Threshold Power, or functional threshold power), alternating 30 seconds of effort in the target zone with 30 seconds of active recovery. The goal of this type of exercise is to create a high oxygen demand, to force the heart to work at a rate close to its maximum, so as to stimulate the cardiovascular adaptations necessary to increase VO₂max. According to a study published in the Journal of Sports Sciences (2020), short high-intensity intervals such as 30/30 are effective in improving aerobic capacity, especially in athletes with a lower aerobic base.
For riders with high endurance but who lack a bit of punch, those who excel at long efforts but struggle with sprints or short accelerations, the 30/30 at 125-145% of FTP is intense enough to push them to the limit. These cyclists often finish these intervals out of breath, a sign that the aerobic stimulus has been reached.
However, For runners who benefit from high anaerobic power, these same intervals may seem too easy. An intensity of 125-145% of FTP is not enough to make them pant, which limits the impact on their VO₂max. Why? Because their physiology allows them to avoid the perceived difficulty of these efforts, relying on anaerobic rather than aerobic mechanisms.
Why 30/30 is easier for some
Runners with high anaerobic capacities benefit from three advancestagphysiological factors that reduce the effectiveness of traditional 30/30 to boost their VO₂max:
- Rapid regeneration of phosphocreatine (PCr) : their muscles rapidly regenerate ATP-PCr stores during the 30-second recovery period. This allows them to produce energy without fully engaging their aerobic system during exercise intervals. A study in Sports Medicine (2017) shows that athletes with high anaerobic capacity recover up to 50% of their PCr stores in 30 seconds, thus reducing oxygen demand.
- Better glycolytic buffering capacity : Type II muscle fibers, predominant in these runners, have a greater capacity (about 50%) to neutralize lactate and H⁺ ions. This delays acidosis, preventing the effort from pushing the aerobic system to its maximum, as explained in an analysis in Frontiers in Physiology (2019).
- Neuromuscular efficiency : they preferentially recruit fast-twitch fibers, which consume less oxygen per watt produced. As a result, they can maintain target power without reaching the heart rate associated with VO₂max, according to research published in the European Journal of Applied Physiology (2018).
In summary, if you finish your 30/30 feeling easy or enjoying exercise, chances are you're that type of runner. These intervals do not push you enough to generate the expected VO₂max stimulus, as opposed to a sustained 5-minute effort at the limit of your aerobic capacity.
How to adapt the 30/30
For runners with high anaerobic capacity, it is crucial to adjust the 30/30 so that they are truly challenging their VO₂max.To optimize them, increase the intensity to 150-170% of FTP or higher to maximize aerobic demand and fully engage the cardiovascular system. Reduce recovery periods to 15-20 seconds to limit phosphocreatine regeneration, thus maintaining a high aerobic demand, as recommended in HIIT protocols. Extend interval blocks to 8-12 repetitions per set, with multiple sets, to accumulate fatigue and force the aerobic system to activate. Finally, complete your training with sustained efforts of 3 to 5 minutes at 95-100% of VO₂max (approximately 110-120% of FTP) to maximize aerobic gains.
TestCreate your profile and adjust your training
To find out if you are a Diesel or a runner punchy, observe your feelings during the 30/30If you find them relatively easy and recover quickly, increase the intensity or change the structure of the intervals. If, on the other hand, you are out of breath after each effort, the classic protocol is probably suitable for you.
Un test A simple test recommended by many coaches is to compare your power output over a 30-second sprint to that of a 5-minute effort. If your power output over 30 seconds is significantly higher (e.g., 50% higher), you are likely a runner. punchy (Friel, J. (2021). The Cyclist's Training Bible. VeloPress).
Customize your 30/30 for optimal gains
30/30 intervals are a powerful tool, but their effectiveness depends on your physiological profile. For the diesel, the standard 125-145% FTP protocol is ideal. For more aggressive cyclists, you'll need to increase your effort and adjust your recovery to truly boost VO₂max. Tailoring these intervals to your physiology will maximize your progress, whether you're an explosive sprinter or an endurance climber.
