What makes this girl so strong?

July 2, 2007 9:58 PM

What are the factors that control/limit human strength?

I've been reading about Varya Akulova the Ukranian girl who is incredibly strong, and I've become very curious about how she might be different than a typical human.

From pictures, you can see that she has very well developed musculature, however her strength seems to far exceed what you would normally expect from muscles that size. Other things you can tell from pictures are that her tendons are very large in relation to her muscles, and they seem to attach much farther from the joint than in a typical human.

Are these factors enough to explain her strength? Or are there other factors in the muscle tissue itself?

How much weaker than possible is ordinary human muscle tissue, and what mutations or genetic changes make it stronger?

What are the tradeoffs in tendons attaching farther from the joint? Would she be measurably slower at some tasks? I think I remember reading that this was one of the main reasons apes are so much stronger than humans. What evolutionary reasons are postulated for our current joint-tendon setup? Why have we traded off strength, and what does it get us, evolutionarily?

posted by lastobelus to science & nature (12 comments total)

What evolutionary reasons are postulated for our current joint-tendon setup? Why have we traded off strength, and what does it get us, evolutionarily?

My guess for this part is that the 'strongest' ones couldn't outrun predators, and couldn't catch prey. The 'fastest' ones could. But you know, that's based on vague ideas gathered from exactly three Biology courses ever. So there's a solid chance i'm entirely wrong.
posted by The Esteemed Doctor Bunsen Honeydew at 10:56 PM on July 2, 2007

What are the factors that control/limit human strength?

Here's a publication in the Journal of Applied Physiology titled, "Gender- and height-related limits of muscle strength in world weightlifting champions."

Here's some interesting excerpts:

The principal conclusions of this study are that muscle strength and height are related by a common factor and that muscle strength approaches absolute maxima at heights of ~183 cm for men and ~175 cm for women, at least using current training techniques. Another conclusion is that the ratios of weight lifted to cross-sectional area in heavier athletes decline above a specific threshold, possibly because of an increasing percentage of noncontractile tissue contributing to body weight. A final conclusion is that these ratios in women are a constant fraction of the ratios in men when proper adjustment is made for gender differences in the thresholds at which the fraction of noncontractile tissue starts to increase.

The analysis here depends on the consideration that strength is ultimately determined by the cross-sectional area of the contractile tissue. In this construct, contractile tissue is defined as the contractile myofilaments, so that the weight lifted depends on the number of myofilaments arranged in parallel. A major object of training, therefore, is to maximize contractile tissue in the cross section. It has been shown, however, that individual muscle cells achieve an upper limit of size that cannot be increased by additional training. This finding suggests a reason for the relationship between height and strength. In athletes who have achieved maximum muscle fiber size, strength is determined by the numbers of cells in parallel.
posted by junesix at 11:14 PM on July 2, 2007

Another biggie is the rate at which your lungs can put oxygen into the blood.
posted by rhizome at 11:27 PM on July 2, 2007

There was a question a while ago that this reminds me of, something along the lines of "If I was strong enough, could I rip off my own head?" Many of the answers, however, dealt with the limits of human strength, and one of the biggest factors is pain.
posted by Brittanie at 11:37 PM on July 2, 2007

the thing is, although she has the cross-sectional area of, say, a quite athletic 16-17 year old boy, she seems to be considerably stronger than 16-17 year old boys with that much muscle.

I mean, she weighs 85 pounds but can hold 3 adults on her back, one of whom is very muscular.

There has to be something about her muscles that is unusual beyond just their size.
posted by lastobelus at 11:55 PM on July 2, 2007

Are these factors enough to explain her strength?

This doesn't get right at the heart of your question, but her feats of strength look less-than-superhuman upon close examination.

While she is likely quite strong, from looking at her site, the circus-style feats of strength on display here (e.g. lifting her family and such) have more to do with intelligent uses of leverage than anything else. The claims of being able to lift 350 kg should also be taken with a grain of salt -- exactly what lift are we measuring here? The evangelical personality Pat Robertson claimed to be able to lift 2,000 pounds ... in a leg press. Also, she's 13-14 years old, which actually puts her into the prime pound-for-pound strength age for women -- witness the Olympic-level gymnastic feats of 16-year-old Mary Lou Retton and Nadia Comaneci at the 1984 and 1976 Games, respectively.

Or are there other factors in the muscle tissue itself?

A fun comparison is looking at the relative strength levels of a human vs. a chimpanzee. Chimps are smaller than humans, but anecdotally much, much stronger. Denser bones and bone levers set at different angles account for much of the differences.

Yet another fun comparison is how some Paralympian's with advanced prosthetics get accused of cheating, because their artificial limbs are longer than allowable -- again, the leverage advantages of longer limbs make for a "stronger" human.
posted by Cool Papa Bell at 12:03 AM on July 3, 2007

you should research steroids (and post the results here so i dont have to...)
posted by white light at 1:13 AM on July 3, 2007

Varya's genetics, diet and training regime accounts for her strength. That and kettlebells.
posted by the cuban at 2:11 AM on July 3, 2007

I would distrust strength claims from a circus performer. Undoubtedly she is strong for her age, but I believe most children that age can lift an adult off the ground. What is much less likely is the ability to squat lift or curl that kind of weight. Not collapsing under a load is not the same thing as actually lifting a load. If you want to see an uberman, look for someone with myostatin deficiency.

Cross sectional muscle area is probably the biggest factor in strength, followed by muscle fiber type, and V02 max. However, mental will is definitely a factor, especially I would say among people without much strength training.
posted by BrotherCaine at 2:38 AM on July 3, 2007

Thanks, the link on myostatin deficiency was interesting. One thing they mention is that there can be differences in how densely the muscle fibres pack together.
posted by lastobelus at 3:49 AM on July 3, 2007

It's about muscle, yes, but also about levers. That's what the Pat Robertson "Leg Press" is alluding to.

Strength is often confused with "work".
If I move 1200 pounds one inch, the work is the same as if I move 100 pounds 12 inches.

Additionally, the moment arms (in this case her legs), when nearly straight, are mostly resting on the structure (her bones) vs. her muscles. She certainly could not squat to the floor with her family resting mostly on her hips where are sitting right about her straight legs. Her skeleton is doing most of the work work.

So, yeah, she's strong, she's also using physics to her advantage.
posted by filmgeek at 11:57 AM on July 3, 2007

For God's sake, man, don't trust carnies.
posted by stavrogin at 11:49 PM on July 7, 2007