It’s almost an ingrained behaviour, and certainly one that seems to be the talking point amongst cyclists. If you haven’t turned yourself inside out and virtually collapsed then you didn’t do a worthwhile training session. While pushing hard might feel beneficial, and event satisfying, low-intensity training can have greater benefits to your top-end performance. It may not sound as macho, hard core or heroic… but if you want results then here are some ideas.
The benefits of high-intensity interval training (HIIT) are profound. Research has well documented the benefits of HIIT for improving VO2 max, Functional Threshold Power (FTP), lactate buffering capacity, and many other adaptations. And certainly for multi-sport athletes, then using the bike for intensity sessions is MUCH safer from an injury prevention perspective than maximal running sessions.
While HIIT is an essential component of any training program and should be incorporated regularly, more is not always better. For many cyclists, the best way to continue improving is likely to increase training time at lower intensities. While it may not seem like it, low-intensity training has significant benefits, including ironically improving your FTP and top-end performance.
Harder isn’t Better
It seems logical that to increase your FTP, you would need to train at high intensity, I get that. The line of thinking is that to get fast you’ve got to go hard as often as you can. After all how will your body know how to go “fast” in a race if it hasn’t experienced it in training.
It’s important to understand that every training session has a cost-to-benefit ratio. The cost of a workout is the physiologic strain that it places on your body and the time you take to recover. The benefit is the total fitness and adaption you can gain from the session. So clearly what we are looking for is the greatest benefit (adaption) at the lowest cost (recovery time and injury / illness risk).
Interval training has a huge benefit but also comes at a significant cost. If you do too many intervals, you may see short term improvements; but over the long term, you may end up overtrained, plateaued, or worse still injured. This is why intervals should be used with caution. They work, and they have a roll to play, but need to be used appropriately for the phase of training, the athletes age and condition, as well as the overall goal that is being sought.
Comparatively, Zone 2 training also has a huge benefit to your fitness, but at a much smaller cost. Training within Zone 2 can be repeated daily with little risk of overtraining, and regularly exposing yourself to this training load over time will deliver great results. How does it work?
Zone 2 to improve FTP?
So how does low-intensity training improve your performance? To understand this we need to think about how our bodies work in a little detail. Exercising at low intensity for prolonged periods of time instigates repeated muscle contraction, which increases calcium levels within the muscle. This activates a specific pathway for aerobic adaptations.
When this pathway is activated, many adaptations occur, including the creation of new mitochondria. Mitochondria are responsible for aerobic metabolism at a cellular level, and with more of them, your FTP can increase because you are getting more oxygen to where it is needed – in the cells producing energy to fuel your muscle.
In my own training I have found that increasing the amount of zone 2 running and cycling has produced significantly better increases in sustainable fitness for endurance sport than adding a couple of extra “hard” sessions. Similar results have occurred with a cross section of athletes I coach and other coaches have reported similar.
You should note that the pathway described above can be activated by both low-intensity and high-intensity training. Thus, it is important to include a combination of both modes of training in your program. However, since low-intensity training is much less taxing than high-intensity training, and carries less risk, you can improve your fitness further by adding significantly more low-intensity volume with almost negligible risk. Therefore eliciting much greater adaption and performance improvement.
Building more Zone 2 into your plan
If you were to compare a professional cyclist’s training to that of an amateur cyclist, you’d find that many amateur cyclists do more total minutes at high intensity than a pro. Only 5-15% of a pro’s total training time is spent at higher intensities — the rest is spent almost entirely within the low-intensity zones. This might equate to an average of only one to two hours per week of total time at high intensity. Clearly, riding at low intensity is an effective way to train even if it doesn’t come with bragging rights at the local cycle club.
Current evidence suggests that there is no added benefit in doing more than a couple of high-intensity sessions per week, as anything beyond that will not create any additional beneficial adaptations but can, in fact, increase the risk of fatigue and injury. Therefore, perhaps the best way to continue improving is by adding volume in Zone 2.
For example, consider two scenarios in which you do the same 3 x 15-minute FTP workout twice weekly for five weeks. In the first scenario, you add Zone 2 training time to your interval workouts to equate to six hours per week of training. In the second scenario, you do the same exact intervals, but add Zone 2 miles to your training to total 12 hours per week.
In which scenario do you think you will improve the most? Even with the same amount of intensity, you will clearly see much more improvement with additional time in Zone 2.
For the time-poor cyclist, this may not be what you want to hear, but there is no magic interval workout that can replace time on the bike. Every athlete should take a look at their training distribution to make sure they are training enough within Zone 2. Ideally, approximately 80% of your training sessions should be low-intensity Zone 2 sessions, similar to that of runners.
If you are looking to further your cycling fitness, one of the best ways to do so is by increasing your training volume by adding Zone 2 riding. This will allow you to make additional gains with little risk.
Combined with appropriately programmed interval workouts, adding low-intensity volume to your training will yield beneficial results in every aspect of your cycling, including your top-end fitness. While it may seem contradictory, similar to run training, riding slow will help you race fast.
