Have you ever noticed that you may have a power difference when riding indoors vs. outdoors? Or potentially efforts at the same given intensity feel harder when you’re on your indoor trainer? Well, you’re not alone. This is where cycling dynamics come in place. Many cyclists find that they are unable to produce the same power indoors as they do out on the roads. Before you go on blaming the trainer, it is important to take a step back and try to evaluate why you may be producing less power indoors comparatively.
Understanding your why can help you address and identify specific areas that may be weaknesses for you – and that are holding you back.
Why Can I produce Higher Power Outdoors?
There may not be a clear black or white answer to this question, as this will differ for every rider. While some may see a clear difference between outdoor and indoor power, others may not have a numerical difference at all.
That being said, when you ride outside your bike is able to move freely underneath you. When does this affect us the most? Full out sprints! You are using not only your legs, but your upper body as well when you dance on the pedals and feel the bike moving back and forth beneath you. While many can assume that this added power from riding outdoors sprints can come from your upper body movement when you pull on the bars, it is not the only factor that is at play.
While not always your friend when ascending steep climbs, gravity helps you to produce those high wattage numbers when it comes down to a sprint! Think about it, when you’re in a full-on attack, all of your body weight is being added to the pedal pressure instead of being supported by the saddle as it normally is. When you stand, the gravity that is typically being applied to the saddle is now being applied to the pedals. In order to maximize this advantage, you want your center of gravity to be over the pedal you are pushing down on. This is why it is advantageous to rock the bike back and forth when attacking!
Joint alignment of your feet, knees, and hips is crucial for power production when you find yourself out of the saddle. When we rock the bike back and forth we are able to not only utilize our friend, gravity, but we are also able to utilize proper alignment through dynamic movement. Yes, you can also stand up on the trainer and utilize gravity, but you will be missing optimal alignment of your major lower limb joints since the bike is unable to move beneath you.
When the interval intensity decreases and you transition from out of the saddle to seat efforts, most cyclists will begin to see greater power differences. Most of the time, those with the greatest differences can be visually seen when watching them ride outdoors. Individuals who may fall under the “weave or bob,” category (those who rock their body back and forth with each pedal stroke) may see the most power differential when compared to indoors. Many people who fall under these categories have some form of weak hip stability. This instability can be caused by issues such as limited hip flexibility/mobility and weak glute muscle recruitment. Typically if someone has one of these issues, the other follows.
This type of body positioning is allowing riders to gain proper joint alignment when they are seated. If you have an unstable hip, the power you push into the pedals will be transferred through your hip and can throw your pelvis off-kilter. Therefore, most of the time individuals who bob and weave are unconsciously aligning the rocking of their pelvis with the rocking of their bike.
If you compound weak hips with a weak core, then the movement of the bike increases to utilize gravity as much as possible. What does this all mean for indoor riding? When the ability to move the bike beneath you is restricted as it is indoors, then your ability to produce the power you do outside is also restricted.
The joys of riding outside include feeling the wind in your hair…which is why indoor riding may potentially seem that much harder. You are generating far more heat with little to 0 airflow to cool you down! Heat and dehydration are well documented to cause declines in your performance, especially during longer durations. How to combat this? Bring on the fans and lots of them!
It is no secret that the motivation factors you encounter outside can drastically boost your performance versus solo indoor training. Having decreased motivation will have an effect on your overall performance where you may not be able to eke out every watt from yourself as you typically could outdoors. Smart trainer programs now allow riders to virtually see others on-screen to help not only boost motivation but to find those extra watts to simulate group riding. If not hooked up to any of these programs, indoor riding helps to build your own personal mental fortitude to help you get closer to your goals when the going gets tough.
What if your Outdoor Power is Different from Indoors?
Fear not. The first step would be to try to identify why your power is different. Are you suffering from hip mobility? Could you use a boost in your core strength? Or is the heat bogging you down?
From here you can begin to increase your mobility patterns to try to unlock your tight hip flexors or take time to increase your core strength to help see improvements indoors.
If you do have a power difference, and it is a large difference, then be sure to address your indoor and outdoor FTP. Depending on each FTP, your workouts will be altered to suit your individual needs. If you are someone (or a coach) who uses accumulated fatigue numbers to track fitness/progress, using an FTP number that is either too high or too low will alter your accumulated fatigue scores for each workout.
If not using power, then being in tune with your own RPE (relative perceived exertion) can help you to make adjustments to workouts both indoors and outdoor.
Mac Cassin is the Chief Cycling Physiologist at Wahoo Sports Science. He holds a degree in Integrative Physiology from the University of Colorado-Boulder and has won multiple National Championships. The experience of juggling athletic goals with collegiate and career responsibilities has taught Mac that peak performance is achievable even for those who cannot focus exclusively on training. While concentrating on exercise physiology in an academic setting, Mac competed at the World Championships, Pan American Championships, and World Cups on both the road and track.