Every cyclist has strengths and weaknesses. But uncovering whether your real talent lies in sprinting, time trialling or climbing is challenging for some. A power curve is an informative graph that’ll allow you to see just where you shine with one quick glance.
WHAT IS A POWER CURVE?
A power curve is a graphical representation of your power across time. With time on the x-axis and power on the y-axis, the graph shows the power that a rider can hold for a given period.
Because we can all hold a higher output for short periods, every curve will have higher power output at shorter time periods on the left with a gradual decrease as time increases.
The value of a power curve is its unique ability to enable cyclists to distinguish their strengths and weaknesses quickly. By identifying specific zones within the graph such as sprint power (≈30 seconds), VO2 max (≈ 3 to 5 minutes), and the endurance zone (extending out to several hours), cyclists can quickly see where they lie on the spectrum.
Almost all software solutions allow users to graph their power curve, and it’s simply a matter of accumulating time on the bike to acquire enough data to build up an accurate curve. It only takes a few weeks of hard training or competition across all zones, and you’ll be able to identify where your strengths lie and which areas need work.
HOW TO INTERPRET A POWER CURVE
Interpreting a power curve is surprisingly simple. Depending on your preferred discipline, you’ll be looking for strength in particular areas that meet those demands. For example, time trialists will look for a flat line that’s consistently high from 5 minutes up to several hours. In contrast, sprinters will be more concerned with the power output across shorter timeframes from 5 seconds to 30 seconds.
Before quantifying your curve, it’s important to understand the typical power output across different periods for cyclists of different abilities. The primary markers consist of 5-second, 1-minute, 5-minute, and 20-minute power. Here are where cyclists of differing ability commonly fall on the spectrum.
● Novice (Non-racer)- 10 Watts/kg
● Average Amateur – 16 Watts/kg
● Top Amateur – 20 Watts/kg
● World Class Pro – 23 Watts/kg
● Novice (Non-racer)- 6 Watts/kg
● Average Amateur – 8 Watts/kg
● Top Amateur – 9.5 Watts/kg
● World Class Pro – 11.5 Watts/kg
● Novice (Non-racer)- 3.5 Watts/kg
● Average Amateur – 5 Watts/kg
● Top Amateur – 6.5 Watts/kg
● World Class Pro – 7.5 Watts/kg
● Novice (Non-racer)- 2.5 Watts/kg
● Average Amateur – 4 Watts/kg
● Top Amateur – 5.5 Watts/kg
● World Class Pro – 6.5 Watts/kg
The profile of all-rounders is represented by a horizontal plot where all four time frames are within the same range. The all-rounder profile is commonly seen in novice cyclists who haven’t yet begun to specialise in one particular discipline and define themselves as a cyclist.
The true all-rounder is likely to be competitive across a broad range of disciplines, but unlikely to be at the upper end in any.
A cyclist with a solid sprint will always have a well-defined slope from left to right on their power curve. They’ll generate a power output well above average for their category from five seconds to one minute before trailing off considerably in the aerobic zones.
The good news for sprinters is that the aerobic zones are highly trainable. This means that by training the endurance zone, they can soon develop more all-round abilities, something that’s very important given that a sprinter must arrive at the finish line with something in reserve before they unleash their sprint.
The profile of a natural time trialist tends to remain relatively steady from five minutes to FTP. Many time trialists lack the neuromuscular power of sprinters, although they make up for it with their enhanced capacity at lactate threshold.
Time trialling is a very specific art form. It doesn’t require an ability to sprint but places a significant emphasis on steady-state power. Much of the training focuses on building FTP to reach one’s personal ceiling. Any time taken away from that pursuit in an attempt to improve sprinting ability is unlikely to result in improved time trial performance.
Pure climbers will also exhibit the characteristics of a solid time trialist. Punching well above average at FTP, the distinguishing factor will be their low body weight when compared to traditional time trialists. When factored into the watts/kg equation, it leaves them with a significant advantage when pushing against gravity.
Aside from high steady-state power, the power curves of punchy climbers also show a higher than average five-minute power. This zone represents a cyclists VO2 max, a useful metric in gauging a road cyclists ability to break away from a group before sustaining a high effort to the line.
Anyone with the physique and power profile of a pure climber may well benefit from training their five-minute power to enhance their ability to escape before relying on their natural ability to maintain a solid effort thereafter.
Pursuit specialists generally exhibit both high anaerobic and aerobic power. This ability commonly manifests as an inverted V-shape on their power curve, where 1-minute power is often remarkably high.
It should also be noted that this profile is relatively rare and is often present in untrained cyclists. Most cyclists exhibit an inverse relationship between neuromuscular power and lactate threshold, so before assuming you’re a track specialist, make sure that you’ve accumulated enough data!
CAN YOU TRAIN YOUR POWER CURVE?
Although power curves are highly trainable, there are genetic factors at play that separate the sprinters from the mountain goats.
Muscle fibres make us more adapted to a specific type of riding. Endurance cyclists have an abundance of what are known as Type 1 fibres. Also known as slow-twitch fibres, they don’t produce significant power, but instead, they fatigue slowly over time with steady efforts.
Type 2 fibres are known as fast-twitch fibres and are split into two distinct groups, type 2a and type 2b. Type 2a fibres power both aerobic and anaerobic efforts, while type 2b fibres only fuel short-duration anaerobic activity.
The secret to training your power curve lies in recognising that each fibre type is capable of more than one thing. Remember, no one is strictly limited by their genetic make-up, and if you see a notable dip in ability at some point on your curve, there’s no reason why some hard and focused training can’t fix that!