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icegirlclaire
06-06-2011, 12:42 AM
If you have ever participated in a spinning class at your local fitness center or YMCA, or have had the privilege of using the more advanced bikes from Keiser or Expresso, then you know that these products allow you to capture a variety of performance data as you ride.

You can see how far you have ridden and perhaps how many calories you have burned, or watts you have generated, or what your average revolutions per minute were – and from that information you may be able to derive what sort of progress you’re making while devoting those hours of blood, sweat and tears to improving your leg muscle efficiency and your cardiovascular condition.

What you don’t get, however, is insight as to how those muscles in your legs are interacting, how they contribute to the ride, the rate at which they fatigue, and perhaps how they respond to hydration or nutrition.

It was with that goal in mind that Tim and Sara decided to tackle the Keiser stationary bikes at the Island Health & Fitness Center in Ithaca, NY last week. They decided to ride at a fixed gear with reasonably high rate of resistance – 18 on the Keiser scale – maintaining a constant cadence (65-70 RPMs) for five minutes while they remained firmly in the saddle. A later test will explore the difference in muscle contribution between saddle riding versus standing.

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They strapped vibromyography sensors to their vastus lateralis and vastus medialis muscles on both legs to enable the MyoWave muscle assessment device to calculate the amplitude of effort generation throughout the ride.

MyoWave collects about 60 data points per second so the amount of data that had to be analyzed over that 5 minute period was rather substantial. MyoWave spent about 2 seconds generating a report after the ride was stopped. The results demonstrated that there is an opportunity to use MyoWave to analyze individual muscle contribution and muscle balance in a dynamic exercise over a protracted period of time.

Since bicycle riding causes muscles to exert a varying degree of effort as the leg spins through each cycle we focused on the overall average amplitude of muscle effort. However, MyoWave does permit the user to zoom in on individual sections of the data so it would be possible to analyze each section of the stroke and consider the ratio of peak effort between Muscle A and Muscle B.

So what did this data tell us?
http://www.apkziwei.com/wp-content/uploads/2011/05/tim-spin-resized-600.png
Tim’s dominant leg is his left. From the data, it appears that as the five minute test progressed, he relied more and more on only one muscle - the vastus medialis - to carry the predominant load. This was a surprise - we did not expect to see such single muscle dominance.

The left vastus lateralis, that had performed virtually equally from the outset, really diminished in effort as time passed and it seemed clear that an imbalance between the two medialis muscles was evident.
http://www.apkziwei.com/wp-content/uploads/2011/05/sara-spin-resized-600.png

Sara, on the other hand, used both vastus lateralis muscles to carry the load and their output remained quite constant throughout the entire exercise. It would appear that fatigue showed, as evidenced by the decline in both of her vastus medialis muscle fiber contractions over time. This is a distinct difference between VMG and electromyography, which counter-intuitively tends to show increased amplitude as muscles fatigue.

Bottom line – we learned that MyoWave can digest data from lengthy exercises which opens the tool up to be used in a broader range of activities. For example, serious biking enthusiasts might learn a great deal about their performance and be able to tailor training regimens to their own specific muscle balance metrics. For racers, this will provide a wealth of data that can translate into valuable training edges.

Since we have architected the device to try to minimize the effect of impact spikes, one of our next experiments will be on the treadmill. Imagine evaluating running styles with different shoe types, body position, etc. The world is now that much bigger.

For more information, please check our website: www.sonostics.com (http://www.sonostics.com)