Genetic limitations of explosive capacity

[dmworking]

Rip,

In your article on www.t-nation.com titled "Is Olympic Weightlifting Strength Training?" you wrote:

"the capacity for explosion is controlled by the inherent quality of the neuromuscular system – it is genetically predetermined. The factors probably include both the ability of the nerves to send the signal efficiently and the ability of the muscle fibers to contract quickly."

This succinctly summarizes the thought that is old hat around these parts, that whatever percentage of your deadlift you can clean, that is dictated partially by an unchangeable genetically determined constant. The only alterable variable here is absolute strength. Go deadlift.

I have several questions on this topic, but they all depend on the first one: is the unalterable nature of explosive capacity an empirical observation, or has the underlying biology for why this is the case been identified?

I'm thinking the answer here is either:

A) I, Coach Rip, have never in my life coached a lifter who could meaningfully alter his or her capacity for explosion;
B) Neither has any other coach in the world;
C) This has been investigated, and you just haven't found the right article, you [insert colorful adjective for 'lazy' here] young man
D) This has been investigated, and I don't much care, because see A) and B)
E) Nobody really knows why this is the case

The reason I ask is that if explosive capacity (which as far as I understand has to key off near-simultaneous recruitment of motor units) has some flexibility outside of genetics, then could different muscle groups have different capacities? Or is explosive capacity an organism-wide constant?

Thanks for reviewing the question, and no, I'm not looking for an excuse to avoid getting my deadlift up. Just curious about the physiology.

--Dave

[Mark Rippetoe]

I am not a neuroscientist, so I'll get Stef to comment. It's an important question, and I answered it to the limit of my ability to be specific in the article. But you are correct with answers A and B. And I seriously doubt that a neurologically-dependent capacity such as this will show a muscle group-level variation. But again, I'm not the neuroscientist.

[stef]

Dave, the overall issue is the amount of plasticity that can occur at a particular point in development, the context if you will. "Genetic" is a limited term, it's both genetics (and other inherited factors) and development that have to be considered. Lots of things are quite variable in certain developmental windows and relatively stable outside them. There are many, many factors which affect excitability and those things have different periods of modification and extents to which they can be modified. If you look in the literature, you can easily be overwhelmed. Here are some examples:

channels
http://physrev.physiology.org/content/85/3/883.full.pdf

specific synapse types
http://www.ncbi.nlm.nih.gov/pubmed/10202544

fiber types
http://physrev.physiology.org/conten.../1447.full.pdf

(Note that the last two refs will probably be more interesting to you given your questions, #1 is mostly for example purposes)

To clarify: it is not that "explosiveness" cannot be modified, but that there is limited room for change using practical/training methods (note that provocations for adaptation in many of the studies are by drastic interventions such as removal innervation, rearranging innervation, transplantation and so forth). "Explosiveness" just doesn't have the same room for growth that general strength & mass have with training. Same is currently the case for administerable drugs.

[morbidlyfat]

Try contracting polio and see if that changes your explosive capacity.

[dmworking]

Thank you both for the replies and for the additional information.

Stef, to restate just so I understand: the issue is not that "explosiveness" is an unalterable constant, but that the degree to which it can be permanently changed (especially in an adult, trained population such as experienced olympic lifters) is negligible without resorting to rather radical surgical techniques.

I can't say I know much about metabolic conditioning, but I have long heard that an individual's VO2max is developable up to a "ceiling" that is genetically predetermined. It sounds like "explosiveness," as we're considering it here, operates along similar guidelines.

You're right, the literature is daunting. Thanks for getting me started-- looks like I'll have to dust off my biomedical engineering textbooks and remember the chemical basis of nerve function if I'm going to get anywhere with this.