Few things stay the same for long in the sport of cycling. In days gone by, perceived exertion gave way to heart rate monitors, and they too soon gave way to power meters. With that shift came new ways of quantifying performance; new language arose, and watts per kilo became the topic of conversation from the coffee stops to the mountain tops. Watts per kilo and power to weight ratios transformed the approach to riding among the pro peloton to the amateurs alike. Here’s what you need to know about this all-important metric.
WHAT IS POWER TO WEIGHT RATIO AND WHY DOES IT MATTER?
Power to weight ratio is one of the most useful concepts in all of cycling. It provides us with a way of quantifying rider performance in relative terms and is particularly useful in predicting how fast a rider can climb. It normalises the number of watts that a rider can produce for their body weight.
Cyclist’s bodies come in all shapes and sizes; some are small and light, others strong and powerful. On the flat, cyclists with higher absolute power numbers will always go faster, but on the hills it’s a different story. When the road kicks up, the force required to maintain a certain speed on the bike is dictated by the power they produce relative to their weight. In such cases, those with a higher ratio will always go faster.
To calculate your power to weight ratio, simply divide your average power output during a hard effort over a given period by your bodyweight in kilograms. The higher the value, the faster you’ll climb.
WHY POWER TO WEIGHT ALSO MATTERS INDOORS
Power to weight doesn’t only matter out on the road; it matters indoors too. In the quest to provide ultimate realism, platforms like Zwift take rider weight into account. This means that when the road kicks up, power to weight ratio has a direct effect on rider speed.
Power to weight takes on added significance in e-racing, where the ratio has as much importance in the virtual world as it does on the road. One of the drawbacks of online platforms is that it’s all too easy for a rider to lie about body weight. In cases where there’s prize money at stake, riders are often required to compete in person, while for other events, the Zwift Transparency Facebook Group ensures that all riders honestly report their weight.
Given that power to weight ratio has such a dramatic effect on cycling performance, how can you go about improving yours?
HOW TO IMPROVE YOUR POWER TO WEIGHT RATIO
There are various ways to increase your power to weight ratio. They involve losing weight, improving strength, or ideally, both.
When it comes to reducing weight, one option is to lighten your bike. Carbon wheels and lighter frames may well make you faster on the climbs, but remember that every 100 grams dropped in bicycle weight equates to approximately $100 — and that’s not a particularly good return. It’s much better to focus on losing bodyweight and increasing strength, economy, and efficiency on the bike before forking out for new equipment.
While some cyclists do carry a spare tyre around their waist, the truth is that most active cyclists don’t have a huge amount of body weight to lose. In many cases, losing additional weight will result in lost power due to muscle loss. The most effective strategy for increasing power to weight ratio is often to increase your power numbers. When done correctly by training smart, most cyclists will invariably shift the weight they need to.
In many cases, even minimal losses in weight coupled with moderate increases in power can lead to substantial increases in power to weight ratio. By way of example, a rider who drops from 78 to 74 kg, while increasing FTP from 225 to 240 watts, will gain a substantial increase in power to weight ratio from 2.88 W/kg to 3.2 W/kg.
TARGET POWER AND STRENGTH NOT WEIGHT
By incorporating some training to increase absolute power levels, you help ensure maximum gains. HIIT sessions are best for this. By repeatedly and consistently taxing your power zones at threshold and above, you’ll quickly bring about beneficial adaptations. Over and under sessions where you alternate at 5% above and below threshold can be very helpful, as are prolonged efforts at threshold.
Power to weight isn’t always about threshold though. Where time trialists and triathletes are concerned purely with threshold, road racers are just as concerned with their power to weight ratio during short and intense efforts from 30 seconds to 5 minutes in particular. Anyone competing in road racing should ensure they train each zone specifically to meet the requirements of their event.
INCREASE STRENGTH TO COMPLEMENT POWER
To complement the targetted training, try performing regular weight training. Heavy resistance training and the conditioning of key muscle groups such as the quads, hamstrings, buttocks, calves, and core will help prevent muscle loss during periods of high training loads.
WHAT’S A GOOD POWER TO WEIGHT RATIO?
Power to weight ratios vary enormously from amateur cyclists to the pros. Average club cyclists generally have 5-minute power to weight ratios of 4 W/kg or more, and have a ratio of approximately 3.5 W/kg at their Functional Threshold Power (FTP). The top pros of the modern era will comfortably produce over 7 W/kg for 5 minutes, and 6 W/kg at threshold for between 20-60 minutes.
While losing weight and increasing power output will improve power to weight ratio, psychology still plays an enormous role in how effectively we can reproduce what we’re capable of. At its core, cycling is still a game where those who succeed are those who are prepared to suffer most. And unlike our technological and linguistic advancements, this doesn’t seem set to change any time soon!