James: On page 22 of the Oct 2011 issue of Bicycling magazine talks about using knee extensions to improve your ability to turn a crank. A new study found that three weeks of thrice weekly strength training for the knee extenders improved torque by 17% among older cyclists. Since I’m approaching 70 this month and still an avid mountain biker, (so much fun to ride these spouts into the ground)… I seem to remember that you felt knee extensions were not worth while. Let me know what you think.

Gregg/OMR (Old Man Riding)
Warriors Society
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Gregg,

Thanks for posting this question, I think that it highlights a couple of points that are good to raise. There are three things you need to consider to when looking at that study…

First, everything works for a few weeks, especially for people that have never strength trained. I don’t have the reference for the study to check (post it and I’ll be happy to take a look at it) but I’d be willing to bet money that the subjects were largely inexperienced strength trainees. You can do almost anything with someone who has limited strength training experience and produce some results.

You also have to look at how they were tested and what that really means. They may have increased power output in the lab but what does that really add up to on the bike? You have to know the subjects and the testing procedure to really have any idea of how applicable that 17% increase really is.

Second, there is a difference between performance and durability. Many things that can result in a short term performance increase can also lead to overuse injuries in the long run. What if the increase in torque is also coming with more stress being placed on the knee by teaching the body bad movement habits that rely on knee extension and not hip extension? What’s the trade-off in the long run? If your knees are taking a pounding then are the performance increases worth it? I’d argue that they are not.

Lastly, the fact that some strength training increased pedaling torque isn’t a newsflash, we’ve known that for a while (why the lab guys like to study the same stuff over and over is beyond me). What would have been more interesting is looking at knee extensions vs. a better exercise. I guarantee you that a well executed deadlift or kettlebell swing would have lead to even better results. I like to get the most bang-for-the-buck with my exercises and so I pick the most effective exercises like deadlifts and avoid the junk exercises like knee extensions.

When you all these points into consideration you can see why knee extensions are still on my list of 4 Exercises Every MTB Rider Should Avoid. There are better exercises that will result in more real world performance increases with much less stress on the knee so it is largely a waste of time. Hope this helps…

-James Wilson-

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