Track Cycling Concepts: Power (Watts)
This blog is the second in a series that discusses the concepts behind peak power and how to train for it - If you haven’t read the first post covering training for peak torque, then be sure to do so. A lot of this information can be found in sport science publications, which are not always easily accessible to athletes. For this reason, this series is written in a detailed yet relatable manner so that riders can apply the concepts to their own training, knowing more about what they are doing - and why.
What is power, why it matters, and how to train it.
Power (measured in watts) is the measure of work over time - this means that watts can go up by doing the same work in less time, doing more work in the same time, or a combination of both!
Almost every cyclist is familiar with the idea of power on the bike, with the abundance of power meter availability, power-based training programs, smart trainers, zwift, etc. This blog entry will address peak power and how to train it.
We will see the highest power numbers during accelerations/sprints, because we are doing a lot of work in a short period of time. In our torque blog entry, we used the example of a standing start to demonstrate the difference between torque and power: “the highest torque values occur in the first few seconds of the acceleration, after which the torque values start dropping precipitously. The inflection point for this drop-off is around 30-55rpm, though it will be different for everyone.” That inflection point when torque starts dropping is the same as when power is rising and on its way to a peak. This is because the RPM increases as we go further into the standing start effort. When we measure power by work over time, the “time” is the time between pedal strokes (rpm): increasing work (force into the pedals) with decreasing time (less time between each pedal stroke) will equal a higher power output (watt).
We want power, but what is the best way to get it?
In the last post, I mentioned that “one of the important principles of sprint training is to target the intended systems as specifically as possible without compromising the intensity or quality as the efforts progress. This means that doing too few efforts in a session will leave adaptations (and therefore trainable speed) on the table. At the same time too many efforts will start to impact the wrong mechanisms and create fatigue, impacting the rest of the session - and possibly the rest of the week’s training.” In short, its important to find a good balance to optimise your training potential.
For training peak power, staying within the target adaptation system range means avoiding the torque phase (high force/low rpm). In a sprint effort, accelerating from a very slow speed (like a standing start), the athlete first needs to pass through the high torque environment to reach peak power. This leaves fewer metabolic resources available for training the peak power effort, therefore under-training the system we’re trying to target. So our strategy for training peak power to the fullest is to find training drills that allow us to hit peak power while skipping as much of the torque phase as possible. This is the same idea as our torque training approach: time spent training peak power in an effort takes away from the ability to do repeated high torque efforts, and conversely time spent at high torque in an effort takes away from the ability to do repeated quality peak power efforts.
To get as quickly into your peak power developing range as possible, a faster entry is required: this avoids the high torque environment of accelerating from slower RPMs, resulting in the athlete having more energy/resource for developing peak power. When training on a velodrome, a dropdown acceleration works great. A dropdown acceleration is a simple drill that can be done solo: the athlete starts by riding slowly at the fence rail, then takes a steep drop down one of the turns, resulting in a high but passive speed. Performed correctly, there should be little to no effort on the way down the track- letting gravity do the work to accelerate the bike up to an ideal rpm. Once the athlete reaches the bottom of the track/sprint lane, they should be moving 70+ rpm, allowing the bike to quickly move through the high torque phase and quickly get into a high-power environment. A similar training drill can be done on the road by rolling down a hill, or using another rider for a gradual lead out/draft before the effort.
The goal for these efforts is to quickly get into the high power environment, but also to stop the effort when that high power environment stops; this avoids fatigue that will compromise subsequent efforts in a set. 3-4x sets of 2-4x 50m or 100m efforts is a good all-around protocol for peak power production. Three minutes recovery between efforts is a good goal for these highly anaerobic efforts, based on how quickly the body can make sufficient anaerobic resources available again for the next effort. Rest between sets should be a minimum of around fifteen minutes.
Gearing for these efforts should allow for a peak rpm in the 120-150 range when doing a maximal effort: too much faster and you should go up in gear; too much slower and you should gear down. This rpm range will ensure that you don’t go too big and can get up to speed quickly enough to make it a peak power developing effort, while also making sure you don’t go too small and fall out of peak power rpm range before the effort is over.
A rolling entry is used to 'skip' the torque max point at the beginning of the graph, and skip to the second blue data point, which is in range of our peak power. This allows us to have more time and more efficacy in peak power range for optimised power training.
How does the gym fit into power development for the bike?
Track sprinters perform on the track, but are built in the gym. let’s look at some simple peak power development for the gym. We touched on power requiring both force and speed, so finding movements with the right ratio of load (weight) to acceleration is important. Most of these movements will be jumping and/or explosive in nature.
It doesn’t require a lot of weight to reach peak power, and too much will actually cause the athlete to reach a lower peak power value. For example, a typical heavy back squat will be in the .2-.5m/s range for speed. At that speed, and a heavy 155kg on the bar, the athlete would only produce 800w of power. However, at a bodyweight of 80kg, an athlete performing a box jump is likely to be around 1950w; this is why acceleration relative to the load is more important that overall load when talking about peak power development.
The box jump is a great tool, but ubiquitous, so let’s look at two different exercises we can use for power development. First is the hex bar hang-jump, which can be done with a hex bar or with dumbbells/kettlebells in the hand. The athlete will use around 25% of bodyweight (give or take 5%), lower down into the hang position with the knee just about 90º, and then explosively jump. It’s preferred for the athlete to softly land, and reset before the next repetition, rather than doing these continuously (or cycled). If using dumbbells, take the 20% and split it into 10% in each hand.
An example of the hex bar hang-jump. Notice that the bar is empty, facilitating explosive movement. Too much weight will bring down the peak power of the movement, as discussed earlier.
Another great tool for unilateral power development is the single leg press throw. The same movement quality is applied here: lower the sled until the knee is just past 90º, then explosively press the sled up, enough for the sled to leave the foot and “float” up the leg press, then softly ‘catch it’ with one or two legs. If you are someone with a speed sensor for lifting, we’re looking for over 1.5 m/s on these; for everyone else, a good rule of thumb is that the weight shouldn’t “grind” when pressing, and it should leave the foot a few inches, but not all the way to the end of the machine. This ensures that the weight is light enough to accelerate quickly through the whole lift, but also requires enough weight so that the sled doesn’t just fly into the top of the machine. Each leg press has a different design, so keeping your second leg out of the way is going to be individual to your equipment (this is important to plan for, to make sure you avoid injury).
This used to be a favorite of Anna Meares (ex world and Olympic sprint champion from Australia). You need to be careful with this movement (and all dynamic lifts), as it can be dangerous if your training hasn’t prepared you for higher force movements.
This is an example of the single leg press throw. The distance of the sled off the foot is right around what an athlete should aim for when dialing in the weights for an effective effort.
For volume (reps/sets), both of these exercises can be put into a workout in reps with a max of about 18 reps total. These can be in sets of 2-6 reps each, e.g. 5 sets of 3. In general sets of fewer reps are preferable, with ~3min rest between sets.
That is peak power for (sprint) cyclists in a nut-shell! The goal is to give the reader insight into why, what, and how to train for peak power production (in the gym, and on the bike). The next blog post will be about match sprint tactics…
This blog is authored by BJ Olson in collaboration with Dave Bernard (author of Older Stronger Faster) and Glenn Catchpole of Velobike
Coach BJ is the head coach of Performance Cycle Coaching, and is an Elite Cycling and Strength and Conditioning coach. He has worked with the US Olympic Development Program, Asian games Kierin athletes, among others. If you’re interested in 1-on-1 coaching, or training guidance, you can reach out to Coach BJ at bj@cyclecoaching.net and at www.cyclecoaching.net