RPM2 cycling power meter shoe insole insert

While PowerTap may have experimented with insole-based power meters, RPM2 put their foot down and stepped into production.

They make versions for both cycling and running as well as a combo unit for triathlon/multisport use, and the cycling features make it fairly unique among power meter options. Garmin’s recent software update for its Vector pedals added a simple foot pressure balance measurement, showing if you were putting more pressure on the inside or outside edges of the pedal. Presumably, this data let you know if you’re feet could be better centered over the pedal for more efficient power transfer.

RPM2 takes this a step further (or closer?) by measuring both left/right and fore/after pressure, letting you see exactly where your feet are pressing the hardest against your shoe’s sole. This provides more specific and exact data that can be used to correct cleat placement, fit and alignment.

Of course, it also provides standard total power output for each leg, along with cadence and where in your pedal stroke your power is being applied…

RPM2 cycling power meter shoe insole insert

Depending on the type of workout you’re going to do, the RPM2 app (iOS, Android) has specific tests available to measure things like pedal stroke efficiency and power pressure over time. The latter shows how your form breaks down over time, which can show help illuminate things like muscle imbalances, poor form and alignment issues that could lead to decreased performance or overuse injuries.

RPM2 cycling power meter shoe insole insert

It captures and displays power, peak power, cadence, pronation, supination and bilateral equivalence (aka separate left versus right leg power output). They recommend weekly tests to gauge improvement, and that you use your standard insoles during regular training, putting the RPM2 insoles in mainly for testing purposes.

For runners, it measures gait along with impact forces and position, helping you determine if you’re striking in the heel, mid or fore foot. It also shows pronation and supination, how hard you’re landing and how your form changes over the course of a run. Olympian Michael Johnson has just signed on to endorse them and help with development.

RPM2 cycling power meter shoe insole insert

The insoles top off their batteries using the included inductive charging pad, just rest them on top of it. Running and cycling versions are sold separately for $599 and $619 respectively, or get the combo triathlon model for $649. They come in six different sizes from women’s 3US to men’s 15US, each one accommodating a 1.5 to 2 shoe size range by trimming them down within the guidelines.

RPM2.com

 

16 COMMENTS

  1. I can’t imagine longterm durability would be very good on an insole powermeter. I mean usually you wear insoles out in a couple of years…

  2. @nightfend – The measuring element could probably be swapped, though that isn’t visible in the pictures.

    @simon – I think this is the real question…

  3. Power on an upstroke is a myth. in reality, when spinning at normal cadence, you can’t get your foot our of the way of the pedal fast enough to even start to pull up. You’re actually still pushing down on your upstroke. it’s been proven in many university labs including Ray Browning at CSU

  4. Who ever can come up with a power meter to put in any shoe will be a game changer for sure. The research potential for “in the field” human performance would be staggering, think NFL, NBA, NHL, etc. Agree with Myke, this price is much to low to be accurate and/or repeatable.

  5. I’m willing to bet that the bottom of someone soles are useless when it comes to providing accurate power measurements, especially given how susceptible to bias human sensory perception is.

    I’m not sure that the cost/benefit analysis of a power meter designed into what is likely a high wear item favors said power meter.

  6. Let me tell you a story…In late 2010 I worked out the design of this exact same product. I purchased a Nordic Semiconductor dev kit and started piecing the communications portion together. I chose Nordic as they own the ANT/ANT+ protocol used in cycling. I pitched this idea to their development team that was supposed to establish an ANT+ profile to accommodate power readings from both feet. Unfortunately Nordic is owned by Garmin and all of a sudden—no return calls no nothing. I go to file provisional patents and it’s gone. First lesson, never ever discuss your concepts with any OEM without first seeking an NDA unless it is open source.
    Now, This device works in a couple ways..It uses force sensing resistors in the insole to measure Ft/lb’s. The Phone app pairs with the Insoloe, a Cadence meter and a speedometer. With those three values and some basic math you can come relatively close to approximating watts. There is an “offset applied to compensate for the lack of monitoring the force on the upstroke. For the “Sneaker” version you only have to couole the force sensing ressitors with a 6 axis accelerometor and you can derive watts. NOW…..I’ve pulled back the curtain on the wizard of Oz and he’s just a greedy old man. BTW…all the parts for this cost $69.00 and it can be done with an Arduino micro.

  7. Hi. Am a below knee amputee cyclist. Would these work with an artificial foot? Am trying to get something which would measure my power output in my legs as I am trying to build this up on my weakest leg. Thanks.

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