"Why do I make less power (fewer watts) standing, then when I'm seated, John?"
A great question from one of the riders in yesterday's Performance Cycle class. An observation that shows he's paying attention + it gives me the chance to clear this up, so you can properly explain this anomaly to your participants.
The short answer is you don't* If resistance and cadence remains the same, in or out of the saddle doesn't matter. The amount of power/watts you are creating doesn't change... because it can't.
The bike decides the right amount of power
You know that Power = Force x Cadence. So let's assume this participant is riding seated and pedaling @80RPM. Their resistance is set to a level that results in the console display showing 150 watts.
Our legs create the perfect amount of force required to get the job done, which in this instance is overcoming the resistance to pedal @ 80RPM. If your resistance setting on the cycle requires "X" amount of force to push down the pedal, your muscles will create exactly "X" - no extra force is created and no less. The combination of that force, multiplied by a cadence of 80 RPM results in the power meter showing 150 watts.
In fact there's an actual law of physics that says that it's impossible to get the same amount of power out of a machine with a reduced amount of power added into it - which is why I'm saying the amount of power/watts you are creating stays exactly the same, if you make no change other than to stand and ride out of the saddle.
"But then why does the power meter show my watts lower, when I'm standing."
My response was; "you're right it does and there's a simple answer why...**[wlm_private 'PRO-Platinum|PRO-Monthly|PRO-Gratis|PRO-Seasonal|Platinum-trial|Monthly-trial|PRO-Military|30-Days-of-PRO|90 Day PRO|Stages-Instructor|Schwinn-Instructor|Instructor-Bonus|28 Day Challenge']
Let me begin with the basics. I teach at a Life Time Fitness Athletic Club and we ride FreeMotion S11.9 with the Carbon Drive belts. FreeMotion's measure power only through the left crankarm as you can see here.
Yes, the meter shows a drop in power...
Many of us who teach or ride on this Indoor Cycle have noticed that the power meter will show a lower wattage number when you transition out of the saddle, without giving any thought as to why. As I explained above, it shouldn't > the wattage number should remain the same. Again; Power is equal to force times cadence. If you didn't change the resistance setting, and you're maintaining the same cadence, the power meter should continue to show the same wattage... but it doesn't because >>>> your legs aren't the same strength.
Your dominate (stronger) leg does more work
The force required to pedal is divided between your two legs - but not equally. Because many (if not all) of us have one leg that's stronger than the other, our brains automatically proportion the amount of force from each. Remember: our legs only create exactly what's needed. Unless you consciously choose otherwise > more force is unconsciously asked from the stronger leg and the opposite leg adds what's left, equaling the total required.
Some quick research showed me that it's very common for one leg to be stronger in most people. Your dominant/stronger leg is typically the same as your writing hand. Since ~90% of people are right handed, the majority of your class will be seeing lower wattages when the come out of the saddle > because they are doing more work with their right leg. The FreeMotion's left hand power meter sensors are seeing a lower amount, of the total amount of work, as coming from your left leg.
Because this IC can only sense force on the left side, when you stand your stronger leg carries a greater percentage of your body weight = the wattages appear lower.
So standing or seated at the same cadence, you continue to create the exact same amount of power. It's just that the power meter doesn't see all of it and displays the reduced amount = the misperception that we create less power standing... which you now understand isn't true 🙂
Make this a feature (not a bug) in your class
Since the Freemotion can show leg strength disparity, why not use it as a training tool?
Novel idea, right?
Start by teaching everyone which leg is their stronger/dominate leg. The simplest way I know is by doing Step-Ups on a box or step raised to the proper level as shown in this short video.
This exercise was eye opening to me, when we did them in Boot Camp. Learning that my right leg is considerably stronger, I'm now really focusing on making my left leg do more work. Hopefully over time, a stronger left leg will result in me having a higher FTP and greater overall muscular endurance.
I suggest having your riders do this as an after class activity > or you could bring a box into your studio and have everyone take a turn.
Using a pair of reasonably sized dumbbells, perform 8-12 reps all on one side and then the other. It should be quickly apparent which (or if) they have a leg strength disparity.
We'll explore drills to exploit this feature and help riders train their weaker leg in future posts! [/wlm_private]
* I'm not referring to pedaling efficiency here, which is a completely different subject.
** Please let me know if this isn't clear, if I've confused you or you have an alternate method of explaining this.
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