August
15

Which Muscles are Really Used During the Pedal Stroke?

One of the most persistent myths in the mountain biking world surrounds the pedal stroke and goes something like this – without being attached to the pedals you can not use your hamstrings properly which forces you to rely too much on the quads the power the pedal stroke. By not being able to curl the knee joint during the upstroke of the pedal stroke you create muscular imbalances and tire out the quads faster, or at least that is what most of us have been told. However, this understanding of which muscles are used and how they are used during a pedal stroke is completely wrong and potentially dangerous over the long run.

When I ask why someone thinks that the muscles are used this way during the pedal stroke I am invariably led to some variation of this picture/ chart:

The myth we re told about what happens during the pedal strokeAccording to this theoretical model of muscles used during the pedal stroke the hamstrings are used maximally from 8 o’clock to 10 o’clock position while the glutes and quads are responsible for the downstroke part of the pedal stroke. This paints a completely false picture of the situation and leads a lot riders to assume that the hamstrings are only there to flex the knee joint on the upstroke, which would be impossible to do if you weren’t attached to the pedals. This, of course, would mean that it would be impossible to optimally pedal without clipless pedals, which is where the faulty logic that tells rides that it is impossible to pedal optimally without them stems from.

The problem with this whole notion is that this chart is completely theoretical and based on how the muscles work in isolation from each other. Unfortunately, the reality of how the muscles work together to create the actual pedal stroke movement is much different than the what this chart tells us. The model this chart is based on also assumes that all muscles that cross a joint are there primarily to flex that joint, as if the muscles on the front side mirror the actions of the muscles on the backside.

The human body is not set up so that the muscles are mirror images of each other – the hamstrings are not the “backside” quads. The hamstrings are made to powerfully extend the hips while less powerfully flexing the knee, the quads are made to powerfully extend the knee while less powerfully flexing the hip. Together they both work with and counteract each other to produce lower body locomotion. Train the hamstrings to flex the hips and stabilize the knee and the quads to flex the knee and help stabilize the hip joint – that is how those muscles function in real life and how we should train them, not based on the old model of training each muscle that crosses a joint to powerfully flex it.

In fact, trying to have a rider curl their hamstring to produce force on the upstroke is unnatural and asks the knee to produce force in an unstable position. Your hamstrings are not made to produce power by curling at the knee and instead are made to produce power at the hips while helping to stabilize the knee joint. The idea that you need to curl your leg through the bottom and upstroke portion of a pedal stroke is simply wrong and based on old and faulty logic – you want to flex the hip to push the leg through the bottom of the pedal stroke, not flex the knee.

Just like when running you don’t want to produce power by flexing the knee, you simply use knee flexion to get the leg back into position for the next “push”. The human body is made to push, not to pull, and trying to apply pulling (curling the knee is a pull) to lower body locomotion isn’t the most effective thing to do.

You want to produce your power at the hips, not the knee joint. The reason that a lot of riders have the knee issues is because the knee joint lacks stability, not strength. On a side note this is why I am an advocate for standing up more to pedal because it forces the knee and hips joints to act and stabilize more naturally than seated pedaling does.

As an interesting side note, I came across this chart of a pedal stroke while researching this article. It looks like it was based on actual EMG readings, not a theoretical model.

The reality of what muscles are used during a pedal stroke.

As you can see the Biceps Femoris (fancy talk to hamstring) is most active on the downstroke and least active on the upstroke. In fact, where first chart shows the hamstring to be most active is actually the place it is least active according to the EMG in the second picture. In other words, the first chart is flat out wrong and in no represents what is actually happening during a pedal stroke.

Take another look at the second picture and you’ll see how the downstroke finds all of the muscle groups lighting up and the upstroke sees very little activity by comparison. This also underscores the findings in the Mornieux (et al. Int J Sports Med 2008; 29:817-822) and Korf (et al. Med Sci Sports Exerc 2007; 39:991-995) Cycling Efficiency Studies I have referenced in the Flat Pedal Revolution Manifesto.

In them you see that a powerful downstroke with the lead leg and a more passive return of the trail leg was the most powerful and efficient way to pedal. You shouldn’t be worrying about trying to create power on the upstroke, which means that you can create the most powerful and efficient pedal stroke without being attached to your pedals.

So what does this mean for you?

1 – You can (and should) be able to pedal your bike very effectively with flat pedals. This myth is one of the most common ones I hear from riders as to why they don’t want to try flat pedals when in fact flat pedals will actually clean up and improve your pedal stroke. I have written extensively about this on my site and before you assume that I hate clipless pedals I suggest you read the article Just Because I am Pro-Flats Doesn’t Mean I am Anti-Clipless.

2 – You should train your legs to produce a powerful downstroke using the hips as the primary power source, not the knee joint. This means that leg curls and leg extensions are bad exercise choices since they reinforce this “knee powered” pedal stroke. Exercises like single leg deadlifts and single leg squats are much more effective since they train the legs to drive from the hips, not the knees.

3 – When riding don’t worry about “spinning circles” or “keeping equal pressure on the pedals”. Do not try to curl the hamstring through the return portion of the pedal stroke. While a good, efficient pedal stroke may feel like you are spinning circles the reality of what your muscles are doing to produce that feeling are much different. Your body has one way to optimally produce lower body locomotion and you simply want to apply it to the pedal stroke.

The idea that you can not optimally use your hamstrings during a pedal stroke without clipless pedals is based on faulty logic and theoretical models. Now that we have a more accurate insight into what is actually happening we see that models like the first picture/ chart need to stop being used as a way to think about pedaling our bikes. The hamstrings are one of the more important muscles used during the pedal stroke but it is how they work in concert with the other muscles of the lower body on the downstroke – not by themselves on the upstroke – that form the reality of pedaling your bike.

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  1. Scott B says:

    Trying to pull up will just pull you hip out of alignment and cause pain and diminished riding over time. Push down hard…forget circles…
    As a side note: all the Olymic lifting and power lifting are based on explosive power generated by pushing and extendeding the body.

    Reply • August 15 at 10:05 am
  2. Rob Lawrence says:

    Hey there
    Your information on foot placement when using flat pedals is very useful, and raises the obvious question: why not use that same positioning when being cliped in on a mountain bike?

    “sitting and spinning” is a far smaller part of MTB riding than for the road where clips came from, so it does make sense, if a person wanted to be clipped in on an MTB, to have their foot placed further forward relative to the axle than would normally be assumed?

    This would seem epsecially relevent to “enduro” riding, which is what most of us would love to do if we had a day out on our MTB.

    cheers

    Rob

    Reply • August 15 at 3:18 pm
  3. Tepi says:

    I have been using clipless for 18+ years and just bought my first flats for my Turner 5spot (and shinpads for safety). Looking forward for the weekend. Thanx for the post about the foot placement with flats.

    Reply • August 16 at 11:45 am
  4. ED BIRCH says:

    TURNER BIKE, 5/10 SHOES, FLAT PEDALS AND JAMES WILSON BLOG………………GOTTA LOVE MOUNTAINBIKING!!

    Reply • August 17 at 12:28 am
  5. Cindy says:

    I have been flipping back and forth from flats to clips for at least 12 years now. I like clipping in when I race but prefer flats when riding new technical trails or teaching skills to new riders.
    I have to admit that I have injured myself more when clipped in. That not only comes from not unclipping fast enough but also from pulling up on the pedal too much. I also have to admit that for years I have always used an inexpensive skate shoe for riding my flats. It was only recently that I finally broke down and bought myself a pair of Five Ten shoes. Wow, what a difference. So much better. I’m sorry I waited so long.
    I would also like to add that I do have my clips placed further back on my mountin bikes shoes and my road bike shoes. It does feel much more efficient. Thanks for all the great information James.

    Reply • August 17 at 9:02 am
  6. Mike says:

    James you are awesome! I stumbled upon your website last week, and immediately felt defensive over my use of clipless pedals. But I stuck with you. I read every one of your articles, and I have to conclude that I have never come across such clear and well reasoned information when it comes to cycling. You convinced me, and I’ve already begun making the switch to flat pedals. I just need you to convince my wife to let me spend $100 on some five ten’s, and I’m all set. I’ve been doing body weight exercises for years, but yours provide the direction and the focus that have been missing from my routine. Thank you so very much for providing the information that you do. You’ve already made a huge difference in my entire attitude about riding.

    Reply • August 28 at 7:47 am
    • bikejames bikejames says:

      Thanks a lot for the feedback, I am really glad you were able to give the info a chance to speak for itself and decide for yourself. The angle I take with mine is that if I don’t have good shoes I could slip of the pedals and get hurt and she never seems to argue with that, might work with your wife as well…

      Reply • August 28 at 1:38 pm
  7. David says:

    James, I guess this is the right topic to post a question which exercise(s) might help with my knee problem. It is probably an injury caused by running not being warmed-up. The occasional pain restricts me also when mountain biking (which is my mains sport activity). I feel the pain in muscles in the front side, just above the knee, on the outer side of the knee and at the back just bellow the knee, in the upper part of the calf. I guess those are the points, where muscles are attached to bones. The pain is also stronger when biking in colder mornings/days. I have noticed that marching knee huggers and calf stretch help to some extend. Could you suggest some specific exercise(s), from your extensive repertoire, which might help with the described problem. I would really appreciate that.

    Reply • November 16 at 1:49 am
    • bikejames bikejames says:

      First of all I have to say that you need to get that checked out and make sure there isn’t something serious going on. If that is not the case then it sounds like you are probably tight in the hips and not using them effectively to power movement. That puts a lot of stress on the knees. You need to strength train and do some mobility work. The Low Back Pain Solution post on this site is good for knees as well since it loosens up the hips and the Top 3 Kettlebell Exercises post will show you the exercises you should focus on with strength training.

      Reply • November 16 at 10:57 am
  8. Ed says:

    Interesting post,

    I think there are benefits to be gained for clipless pedal riders riding flats for a short time. The enhanced feeling of balance and oddly, security you get riding flats helps develop skills and movements that you can then apply when using clipless pedals again.

    I feel your diagrams are misleading because there is no way of telling at a glance what the differences are between the two if you aren’t savvy in anatomy. I may be dense but the diagrams are like comparing apples with oranges, the diagrams share colours but not the labels or legend, which is a shame because it makes it more difficult for people to understand your message.

    Reply • April 8 at 12:47 am
    • bikejames bikejames says:

      That is the problem I am trying to point out – the first chart is “made up” and has no basis in the reality of movement and the second chart does. It is comparing apples to oranges but only one chart is the right way to look at the pedal stroke for riding and it isn’t the first one. Thanks for your insights into the subject, hopefully as more riders see charts like the second one the first chart will go away and we won’t have to worry about comparing it to anything.

      Reply • April 8 at 7:55 am
  9. Dave says:

    You’re a big advocate for standing pedaling for extra power in climbs and I’m wondering if you can describe that position a bit more. Are you vertical or just rising a couple of inches in a crouch over the bike?

    Reply • April 18 at 2:51 pm
  10. Bokesy says:

    Interesting though to debate over pedal types is, there is no black/white answer. With flats I tended to dab more and therefore lost momentum. With clipless I was less confident and unclipped before anything that looked remotely tricky to ride.
    What really made the difference for me was night riding through the trees. With only the pool of light in front from my Hope 4, you have less distractions and not a great view of what is coming up. This led to a greatly increased feel for the trail, and a greater flow with the bike. Eventually I found that the greater security and connectedness to the bike that I got from clipless pedals meant that I was dealing with unexpected slips and slides over roots and other obstacles that would have had me dabbing with flats. With my clipess pedals, the lack of forward vision at night meant that I did not anticipate and unclip in advance of obstacles and I found myself dealing with obstacles at night that I would unclip for during the day. Now that I have developed that feel and flow, I don’t think it really matters what pedals i’m using.

    Reply • July 18 at 4:37 pm
  11. […] stroke, check out the article about muscle use in your pedal stroke written by James Wilson by Clicking here. Clipless pedals are a great ENHANCEMENT to your riding but that is what they should be. They […]

    Reply • September 2 at 8:13 pm
  12. Eva says:

    Hey James,

    Any data that shows the type of contraction during the pedal cycle, eg concentric contraction/ eccentric contraction? I suspect the glutes are acting eccentrically during hip flexion, storing passive energy for the push down phase. This is probably a very important point for training off the bike and again highlights one of the (many) reasons that traditional strength training rarely translates to improved performance on the bike. Also, suggests that length/tension becomes very important and highlights the importance of good bike set up.

    Love your work!

    Eva

    Reply • September 20 at 2:03 am
    • bikejames bikejames says:

      I have not seen any data on it but I suspect that you are right in that the glutes and hamstrings (a.k.a. the hips) are storing some elastic energy while they are shortening, that is how we run and how our lower body is set up to produce locomotion. It is also another reason I like standing pedaling as it allows a more natural range of motion and use of this stored energy.

      However, I also think that your Starting Strength (ability to overcome inertia with no elastic energy helping) is very important on the bike as well. We have to start creating force at the pedals sooner than you do when running and your leg is at a mechanical disadvantage when it does. Plus, the slower the RPM the less this elastic energy will help.

      Since mountain biking requires both I like to use slow eccentrics and pauses to take out that elastic energy in addition to using faster speeds and highlighting that eccentric component.

      Thanks for sharing your thoughts, hope this makes sense…

      Reply • September 20 at 8:25 am
  13. James says:

    How does this relate to road riding where you have to pedal seated for the majority of time.

    Reply • December 2 at 1:16 am
    • bikejames bikejames says:

      Who says you have to stay seated most of the time? Plus, seated pedaling and standing pedaling are powered the same way. Pretty sure that EMG was done with seated pedaling as well.

      Reply • December 2 at 9:21 am
  14. Vio says:

    I’ve got some pain in the quadriceps tendons. Is that caused by the fact that the saddle is too low?

    Reply • January 22 at 5:24 am
    • bikejames bikejames says:

      No, more than likely there is a larger movement issue behind it. Besides, you should be standing up more so saddle height is a bit overblown for MTB. Once you stand up all that leg extension stuff gets taken care of and it might actually help your pain since you are likely overusing the quads by sitting too much.

      Reply • January 22 at 11:08 am
  15. […] some interesting graphs showing just what muscle gets used during which part of the pedal stroke:  http://www.bikejames.com/strength/which-muscles-are-really-used-during-the-pedal-stroke/    All that said, he admits they may have a place in racing. NO!!! When I told people I’d […]

    Reply • February 22 at 8:22 pm
  16. […] some interesting graphs showing just what muscle gets used during which part of the pedal stroke:  http://www.bikejames.com/strength/which-muscles-are-really-used-during-the-pedal-stroke/ All that said, he admits they may have a place in racing. NO!!! When I told people I’d […]

    Reply • February 22 at 8:25 pm
  17. […] some interesting graphs showing just what muscle gets used during which part of the pedal stroke:  http://www.bikejames.com/strength/which-muscles-are-really-used-during-the-pedal-stroke/ All that said, he admits they may have a place in racing. NO!!! When I told people I’d signed […]

    Reply • February 22 at 8:40 pm
  18. Simon says:

    My 1991 Kona Cinder Cone had BioPace rings which were oval to enable a more fluid motion through the power stroke…

    I always believed that pushing hard on the down stroke while pulling the other foot up on the up stroke gave more power. But what I found was that I simply could not do this consistently. It just seemed to require physical coordination which I am not capable of – I am also a lousy dancer…

    But I do find that on a hard climb when dropping down a gear is not an option, pulling up on the upstroke pedal while driving down on the power pedal and riding out of the saddle gets me to the top of the climb. Which is one reason I always ride with clips…

    Reply • June 26 at 8:24 pm

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