How can your calves act as springs without pushing off?

Discussion in 'Barefoot & Minimalist Running' started by Jaap Francke, Sep 26, 2018.

  1. Jaap Francke

    Jaap Francke Barefooters
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    Hi all,

    I'm still working on my form and this is one of the things I haven't quite figured out.
    One of the lessons is that you should not push off or toe off. Particularly when running on rough surface my bare feet confirm this lesson. Push off / toe off would simply hurt. So especially on rough surfaces I try to focus on lifting my feet and do that 'early'.

    The other thing I read about is that one's calves should act as a spring. To me, this seems to contradict the idea of lifting your feet: if you lift your feet - I don't see how that can be combined with the idea of a spring. If your calves are springs, that sort of implies pushing off.

    Thanks for your help!

    Jaap

    PS: After more than a year of barefoor running and wearing minimal shoes, I still have sore calves/achilles from time to time. I'm not sure what I'm doing wrong. Maybe I'm still overstriding? Maybe I should focus more on lifting my knees?
     
  2. Jon from PDX

    Jon from PDX Barefooters
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    As I understand it, there are two related parts to the spring question: one is about the mind/body connection and the other is about running efficiently. I’m a novice, though, so take this all with a big grain of salt.

    The spring behavior should happen automatically. Every time a foot lands, the body will absorb and dissipate those forces regardless of what we do; the goal of using a spring-like mechanism is to dissipate those forces downward to use this “free” energy to make running easier. In contrast, pushing off takes muscle activation, and there’s nothing free about that. Running easy and light will maximize the spring while pushing off will maximize overall effort. It isn’t about forces on the foot as such but rather about good, efficient form, and the about mental approach we have to take to get there. So many runners, especially new runners, seem to find satisfaction in how hard it is. It is hard, one way or the other, but our goal as runners should be to make it as easy as possible so that we can run further, faster, for more years, and feel better after each run. Talking about springs and pushing-off addresses that to some extent.

    Another way to look at it is from a purely mechanical perspective. The most efficient running gait — on a flat, smooth surface — would resemble a wheel in that there is nearly no braking force applied in front of the center of mass and so there need be nearly no acceleration force applied behind the center of mass in order to maintain velocity. Running at a constant pace is about keeping the body up in the air so that momentum can efficiently carry us forward. If you’re pushing off but also maintaining a current pace, then, by definition, you’re also applying about the same amount of braking force on every landing. So, if you can run at the same pace without pushing off, that means you’ve improved the efficiency of your landings.

    As far as sore calves go — again, I’m a novice, so who knows if this is wisdom or folly — I’ve found that my lower legs feel a lot better when my hips and glutes are carrying their full share of the running effort. The hips should be lifting the leg even as the foot is approaching the ground, both to soften the impact and to align the body for the upcoming stance phase; I think I’ve seen this described as “start lifting your feet before they even hit the ground.” Doing this will relieve the calves of much of their role as shock aborbers, allowing them to more easily perform the nuanced role of adjusting foot angle and placement while transmitting (rather than adding to) forces from the rest of the body. If nothing else, it never hurts the calves to focus on quicker, shorter strides with more deeply bent knees.

    I’m interested in others’ interpretations of this, too.
     
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  3. Christian Lemburg

    Christian Lemburg Barefooters
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    This is another example of cue (perceptual reality) vs. physics (measured reality) in an apparent contradiction, similar to this one: https://www.thebarefootrunners.org/threads/bend-the-knees-versus-running-light.21033/#post-191428.

    The contradiction disappears when you consider that "avoid pushing off" or "lifting your feet" are instructions to you as a runner, while the spring action of your calves is something physical that you actually can measure, but which you typically will not notice, since it is based on a passive reactive mechanism.

    "Avoid pushing off" or "lifting you feet" describe what you should focus on when you perceive how you run. They are cues, things a trainer will tell you. Your trainer chooses to tell you these specific instructions because they usually work, and describe things you can actually control, by giving you a useful mental picture of the action.

    The spring action of your calves (the composite complex of your muscles - mainly soleus and gastrocnemius - and your tendons - mainly Achilles tendon) is a physical phenomenon, part of your leg spring action, in which the whole leg is viewed as a spring. You are not able control this spring reaction as such, it will just happen, you can only control the stiffness of the spring by activating your leg muscles. You will actually do this involuntarily while running over changing terrain, like from a road onto grass or vice versa. Your calve muscles don't move you in the same way your legs move you in a squat. You contract the muscles mainly to adjust the stiffness of your leg spring, which will bounce due to its elastic properties, if you let it.

    In fact, "avoid pushing off" and "lifting you feet" are cues that should lead to a better spring action of your calves, by decreasing ground contact time and thus enabling the stretch reflex and tendon elasticity to do their work more effectively, propelling you forward with less active muscle effort.

    You can control how much work the different muscles in the leg spring have to do by varying your "stance" (cue again) in running - if you bend your knees more, you will engage the quadriceps and soleus to a higher degree, while with less knee bend, the gastrocnemius will bear a higher load. Try it out running in place, with nearly straight legs vs. in a crouch. You will feel it. Note how you will not be able to feel the spring action itself, apart from a "bouncing" feeling - it is too fast to control. That's why it is controlled by a reflex :) ...

    As for your soreness - if it is something you sometimes have and sometimes not, but not something regular, and you run regularly - I would guess it is mainly related to speed (running at a higher speed than you are used to) and/or downhill running. Or you are changing technique all the time?
     
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  4. trevize1138

    trevize1138 Barefooters
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    The other replies so far nailed it.

    I like to think of efficient running as consciously focusing on moving my legs quick enough to get "out of the way" of my springy tendons. If I move my legs too slow they get in the way and the spring of the tendons doesn't push you forward as well.

    You don't feel it compared to how you really feel it when you forcefully push off with muscle but it happens. If you want to witness it in action try running in place focusing on just lifting your feet quick and not pushing off. Then try to prevent your feet from losing contact with the ground.

    At 120 spm you'll discover it's quite easy to keep both feet on the ground at all times. Ramp that up to 180+ and it becomes increasingly difficult to prevent your feet from popping off the ground. That's your elastic tendons at work.
     
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  5. Tristan

    Tristan Barefooters
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    @Jaap Francke I too thought this early on. I was overly concerned about not "pushing off" since it was mentioned so much on the forums and such. But I found I could not really control this the way I originally thought, cushioning the landing with strength from the calves and leg muscles but somehow turning off this calf strength later in the cycle to not push off was just something I couldn't do that fast. Basically my calf strength was relatively constant for the landing and push off, only thing I could vary slight was staying off the toes and more onto the ball of foot, but this is dependent on how fast you are going. If you're sprinting a 400m/quarter-mile repeats you're going to be pushing off more and on the front of you foot more than a casual long run pace, I think this is natural. But I may not be doing it perfectly myself, as my calves and Achilles are still often sore & tight after harder efforts. They will likely never be as strong and resilient as they would be if I had been barefoot running my whole life, but after 30ish years of atrophy I think they are doing ok after easing in to barefooting since 2011.
     
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  6. Jaap Francke

    Jaap Francke Barefooters
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    Thanks for all the replies! Usefull stuff, I think, although I'll have to repeat reading it and experiencing my technique to really understand your remarks.
     
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  7. trevize1138

    trevize1138 Barefooters
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    Yes! Trying things out is crucial. I think that's the case with just about anything.

    "What do you guys think about doing [something here]?"

    Answer: "Give it a try and see what happens."

    Doesn't work well if [somehting here] is quite obviously a bad idea, of course. ;)
     

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