Is The "box Car" Analogy True?

Discussion in 'Hypertrophy-Specific Training (HST)' started by k_dean_curtis, Apr 3, 2020.

  1. k_dean_curtis

    k_dean_curtis Member

    Question mainly for Byran, but would like feedback from anyone that knows the actual science. Does hitting a muscle at multiple angles contribute to more growth? Specifically, does the "box car" analogy of sarcomers contracting along different sections of a muscle belly be innervated at different ranges of motion, really matter.

    I am not referring to joints that have multiple planes of movement such as the shoulder, but within a single plane of movement. Example is medial deltoid. Dumbell laterals hit the top ROM. A Nautilus machine supposedly hits all the points along the range. Is the latter better? Do we have to do leg extensions because leg press and squat do not hit the top? Etc.

    I know experience is valuable and should be respected, but I would like to know what the science actually says.
    Jester likes this.
  2. Bryan Haycock

    Bryan Haycock Administrator Staff Member

    Hi dean,

    The tissue itself does not know "angles", but the nervous system does. Because the tissue is simply being pulled from either end, it only knows degree of stretch. As you mention, I am not talking about muscle that have different segments, like lats, pecs, or delts. For this reason, its best to focus on training a muscle at different degrees of stretch, rather than holding the limb at a different angle. For example, triceps, because the long head of the triceps connects to the scapula, the long head is stretched as you move the upper arm forward and up. So, combining tricep push downs, and overhead tricep extensions makes sense. However, combining pushdowns with dips or close grip bench makes does not create a meaningfully different degree of stretch for the long head. Another good combination would be lying leg curls and sitting leg curls. Sitting puts the hamstrings into a stretched position, lying does not.

    So, why do this? Does it lead to more growth? It may, it might, it can. Training a muscle at a specific length will induce adaptation that will change the length of the muscle. If you always train a muscle in a stretched position, it will add sarcomeres serially in order to improve the efficiency of the cross-bridging between myosin and actin. Likewise, if you only train a muscle from a shortened starting position, over time it will reduce sarcomeres in order to improve cross-bridging. Granted, I doubt most people would ever be able to feel a change, except perhaps for a small increase in range of motion over time.

    In addition to this, the real stimulus for muscle growth is mechanical and metabolic stress. So anyone who creates enough of this type of stress to the tissue will see gains even if they don't actively try to train at both shortened and stretched positions. Likewise, someone who isn't training adequately (or has reached their genetic max) will not see gains even if they do train that way.

    Should you do it? My opinion is yes. I try to do it with as many muscle groups as I can. I wouldn't waste time with it if I thought it wouldn't help.
    Jester, NWlifter and _Simon_ like this.
  3. k_dean_curtis

    k_dean_curtis Member

    Thanks Bryan! Much appreciated.
  4. _Simon_

    _Simon_ Active Member

    Awesome, very insightful. @Bryan Haycock would you say in order to maximise the stimulus of training different angles, that you should:

    a) Train both exercises in the same session (eg couple sets of pushdowns + overhead extensions)

    b) Train both exercises on separate days, alternating basically (and slightly higher volume for each as it's the only primary exercise for that muscle group)

    c) Train for most of a cycle with the more midrange/shortened position exercise, and later in the cycle switch to only stretch position (I remember in the FAQ you said something about adding stretch position exercises later as like a sort of "progression")

    Or it does not really matter haha? Have read and trained alot using POF (Positions of Flexion) training but curious as to your thoughts.
    Bryan Haycock likes this.
  5. Old and Grey

    Old and Grey Super Moderator Staff Member

    Triceps is an excellent example.
    Bryan Haycock likes this.
  6. NWlifter

    NWlifter Active Member

    What is weird to me, is how/why some muscle fibers vary in type during their length. Andy Galpin has researched so much into muscle fiber physiology, characteristics and alterations and has found some really interesting things. The two things that when thought of together I'm meaning are..
    1) Fiber types change with training and can change pretty rapidly (weeks to months)
    2) A single fiber can have an area that's very fast leading to and area that's much slower

    So that seems like somehow part of the fiber was stimulated to be a different MHC , but how can that be when the fiber has 'one nerve', feels the same tension for it's length (or does it?), and is activated the same from end to end?
    Bryan Haycock likes this.
  7. Bryan Haycock

    Bryan Haycock Administrator Staff Member

    _Simon_, I don't think we know the answers to your questions about when or in what sequence or grouping for these exercises. There is a general principle based on the SAID principle that shows that when two difference stimuli or presented simultaneously, the adaptive response is a compromise between the two. The military did a lot of combined anaerobic combined with aerobic training to show that when a muscle is forced to do both strength and endurance at the same time, it get's a little better at both, but not as good at either as it does when only one stimulus is present.

    Growth can be a little different though...So I would guess...if I would to do this I would either do 6-8 weeks of shortened movements followed by 6-8 weeks of stretched movements. I think stretched represents another form of mechanical load so its a way of progressing the load. If I were to do them in the same workout I would do long first, for the mechanical load, then do shortened with lighter weight to increase metabolic effects. So, heavy overhead extensions followed by "burnout" sets of pushdowns. Just my opinion.
    _Simon_ likes this.
  8. Bryan Haycock

    Bryan Haycock Administrator Staff Member

    NWlifter, that is indeed interesting. Fiber types are driven by both neural activity, and I believe also by metabolic activity. Because our tissue isn't digital, meaning black and white but rather a bag of water with thousands of different chemicals floating around bumping into complex protein structures, it could be simple chance when the environment is not extreme one way or the other. Or in other words, the idea of tipping points in fiber type expression. Perhaps some sarcomeres hit the stimulus tipping point while others even in the same fiber don't. Very interesting....
    NWlifter likes this.
  9. NWlifter

    NWlifter Active Member

    good thoughts, gotta be something like that, ... it's so 'weird' still to me, it's like having a rope lifitng a load and one section is under more stress or gets 'used' more... seems impossible! yet...
  10. _Simon_

    _Simon_ Active Member

    Thanks Bryan appreciate it, yeah guess there's no hard and fast rule, but what you say makes sense.

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