Which workout is more aerobic, and which is more anaerobic: 12x400 45 sec rest, or 12x400 3 min rest?

When I watch Rui Silva, I see a runner who produces a lot of power from his feet and ankles. A runner with a very high VO2 won't produce the same elastic rebound.

J.O. wrote:

Huh? I'm talking about muscle tone produced by arousal levels, you know, nervous system control? Surely you must know about this?

And I'm talking about MUSCLE PHYSIOLOGY, which was the original topic of the discussion: what dictates O2 cost?

It has nothing to do with muscle "tone", "tension" or anything other than:

1. amount of fiber shortening

2. volume of active muscle

If by "arousal level" you mean the ability to activate a given volume of muscle (under nervous system control), then I refer you back to point #2 above. Arousal level does not influence muscle VO2 cost in any way, unless you want to talk about how nervous system control influences either of the two points mentionned above.

"Arousal level" as I think you're thinking about it is more appropriately termed "muscle activation" or the central nervous system's ability to stimulate and recruit the motor units required for the task. This does NOT influence muscle "tone" or "tension" in any way.

If you want to argue about what physiologists know about nervous system control, which I haven't stated already, I can sum it up very easily: the nervous system's role is to control activation of the required motor units in order to perform a given task, be it simple tasks like finger grasping or more complex tasks like running. When the nervous system activates a muscle fiber(s), this causes activation and subsequent generation of force via formation of hundreds of thousand of cross-bridges at the level of the sarcomere.

So, unless I have no idea what you're talking about when you refer to muscle "tone", I cannot see how activation of the central nervous system dictates muscle tension or O2 cost, unless you go about it from a roundabout way and eventually come back to my 2nd point as to what dictates muscle energy use.

jT

Without in any way offering support to JO, he sounds like he's trying to explain something similar to what Marius Bakken used to mention on his site years ago.

Bakken used to discuss the difference between showing up for a race/workout with a good amount of "spring" in the legs compared to showing up with "old man's muscles" and no bounce whatsoever.

Bakken (and now apparently, JO) referred to this as "muscle tone" and suggested it was the secret to fast racing and that he knew what workouts would bring your leg muscles to the race in ready-state; i.e. with bounce. (We all know the feeling he is trying to invoke).

Bakken did not do anything to define it as anything more than "muscle tone", and neither does JO.

JO can correct me if I am misinterpreting him.

Yes thanks, that is exactly what I am talking about, optimal muscle tone = more spring in the muscles maintained from the start of the race to the finish. So you either get a faster pace for the same effort, or less oxygen uptake for the same pace.

I have no idea why the concept of muscle tone would be so unfamiliar to anyone who considers themselve either a good coach or a good exercise physiologist, it's absolutely basic stuff.

J.O. wrote:

Yes thanks, that is exactly what I am talking about, optimal muscle tone = more spring in the muscles maintained from the start of the race to the finish. So you either get a faster pace for the same effort, or less oxygen uptake for the same pace.

I have no idea why the concept of muscle tone would be so unfamiliar to anyone who considers themselve either a good coach or a good exercise physiologist, it's absolutely basic stuff.

Sorry, but "muscle tone" isn't what you THINK it is. I encourage you to do a google scholar search on "skeletal muscle tone", see what comes up, and then convince me that what DOES come up is relevant to the O2 cost of exercise. Are you referring to "vasomotor tone" or "vascular tone" when you say "muscle tone"?

What I THINK you're referring to is muscle ELASTICITY. If so, I will tell you this: in human movement, muscle elasticity (stiffness, modulus or however else you want to measure it) makes very little difference in the energetic cost of contraction. However, what DOES play a large role is the TENDON elasticity. Specifically, the tendon's mechanical properties (primarily stiffness) needs to be optimally tuned in order for the muscle to operate most econimically. I encourage you to check out:

Changes in tendon stiffness and running economy in highly-trained distance runners. Eur J Appl Physiol. 110: 1037-1046, 2010.

Here, we show that tendon stiffness is altered depending on prior activity and this can either favorably or negatively affect your running economy. To sum it up, because the triceps surae (calf) muscles do not undergo a pre-stretch during the run cycle, a stiffer tendon allows the muscle to better transmit muscle force to the bone and it is more economical because muscle shortening is minimized. This affects the "optimal" regions of the force-length and force-velocity properties of skeletal muscle.

I am certain that this is what Marrius Bakken is/was referring to previously and it makes a lot of sense that he has found through trial and error the optimal workouts for his tendons to operate at an "optimal" stiffness. But, this is not muscle tone at all.

I apologize for the confusion in the vernacular; however, as an exercise physiologist, sometimes it needs to be clarified what you mean by "muscle tone" or "muscle tension" because it can mean very, very different things depending on your previous experiences and definitions.

jT

No, I'm not refering to vasomotor tone or vascular tone. Muscle tone or tonus is a medical definition of the state readiness of muscles to do work. You can also think of it as stiffness.

But isn't tendon stiffness influenced by the muscle? After all, the dimensions of the tendons don't change with training, and they are part of the skeletal muscles.

J.O. wrote:

But isn't tendon stiffness influenced by the muscle? After all, the dimensions of the tendons don't change with training, and they are part of the skeletal muscles.

No, the dimensions, morphology, mechanical properties of the tendon change very acutely and readily with training. The tendon acts in series with the muscle ("series elastic element", which also includes the aponeuorosis, and I would argue the properties of the tendon influence the behavior of the muslce's contractile responses.

For example, for a given joint rotation at the ankle, for a more compliant tendon, greater muscle shortening is required compared to the shortening required of a stiff tendon. Think of shutting a door with a long, compliant elastic band attached to the door handle vs a steel rod. Which will require a greater "tug of war" action to close the door?

Where the area of "optimal" tendon stiffness gets foggy is, for example, in the vastus lateralis tendon, where considerable stretch-shortening occurs during running. In this case, a more compliant tendon is optimal for energy conservation as a compliant tendon can absorb the force of landing without stretching the muscle fibers attached to it. This keeps the muscle fibers relatively isometric and they can thus again operate under optimal conditions as dictated by their force-length and force-velocity relationships. The lengthening requried from ground contact from touch-down to toe-off can be accomodated by the compliant tendon. If the tendon was too stiff, it would not be able to fully absorb the lengthening and the muscle fibers would have to lengthen. This causes greater shortening and greater O2 cost, and less than optimal contractile conditions (operating at a longer length, thus lower force, and operating at a higher velocity of shortening, again, lower force).

jT

Hi jT,

I've talked about muscle tone, not tendon stiffness when discussing the importance of muscle tone in running performance. Muscle tone is related to, but not the same as muscle elasticity. I actually did my masters paper in medical school on the intrinsic factors in the muscles that influences muscle tension(that is : factors entirely outside of the nervous system control)

I am certain that this has a huge influence on running performance, can quite easily be controlled and when actually looking into the more technical aspects of the literature, it is easy to understand why.

If you are who I think you are, I'm a big fan of your work - shoot me an email at marius.bakken (at) mariusbakken.com if you'd like a copy of that masters paper on muscle tone. Large parts of it is translated to English.

all the best,

Marius Bakken (now M.D.)

Bump.

It's threads like this that make LR what it is.

I find it strage that posters here are unaware of the term 'muscle tone' is it only in Europe that this term is used?

A very good post with Jack Daniels and I believe JO is Jan Olbrecht a very well respected exercise physiologists. Interesting read.

Sorry, I'm not Jan Olbrecht. Neither am I a fan of his.

And jtupper-ware isn't Jack Daniels either.