Strength and levers

Guys,

would i be right in thinking that you need more strength to deal with loger limbs/levers?

If you have strength problems, is this exaggerated by having long limbs?

Thanks

Sort of…

If you want to use the term Lever
then:

2. Stabilize the fulcrum.

3. Max Strength stabilizes the fulcrum.

Toque is directly proportional to the length of the lever. So if you want to bicep curl 40lbs and your arms are 50% longer than someone else, you need to produce 50% more force around the elbow.

So do you guys fing that taller athletes usually have more strengthening requirements than shorter athletes who have shorter levers?

This is sort of related, but I can’t really figure out the science in my head. One of my friends is 6’3-4 and can clean 140kg, and another one of my friends is more like 5’9-19 and has cleaned 152.5kg. I would almost argue the 140 clean is more impressive due to the extra height and he could well be exerting more downwards force in order to lift the bar that much higher.

Thoughts??

Obviously there are technical issues that come into play here also.

I doubt it, but this one is beyond my limited experience. The end of these longer levers are also moving faster than shorter levers with the same rotational speed (or stride frequency as it relates to running).

I don’t think you can assume the 140Kg is more impressive automatically.

Let’s pretend for a moment that the following assumptions are true:
1)Your short and tall friends can produce the same amount of force in the pulling (deadlift) portion of the lift.
2)Your short and tall friends can produce the same amount of force on the bar (what little there is) while they are dropping under the bar.
3)Your friends’ technique is the same, in two ways. A) They both pull the bar until the bar reaches a certain percentage height of their body (say 40% of their height), and B) They both need the bar to reach a certain percentage of their height for a successful catch (say 60% of their height)

If this is true, the taller person will be able to clean more weight. The reason for it is that they have proportionally more length in which to pull the bar before they have to catch it, because the bar doesn’t start on the ground. Suppose one guy is 1m tall and the other is 2m tall, and the bar starts 0.2m off the ground - then the short guy can only pull until the bar height is 0.4m, while the tall guy can pull until the bar height is 0.8m (Using the 40% I’ve mentioned before. The actual % doesn’t matter). This gives the short guy 0.2m of pulling distance, and the tall guy 0.6m of pulling distance. This allows the tall guy to get more mass up to the vertical speed necessary to make the catch.

Yea, I see your point and understand your example. It was for similar reasons that I said obviously there are technical issues. But I was simply pointing out that my taller friend is causing a greater displacement of the bar than my shorter friend. I agree though, that doesn’t automatically asume it is superior, but it may well be.

This is like saying a taller lifter has an advantage in a squat because they will get a bigger stretch reflex from having longer muscles.

Fact of the matter is Work = force x distance. Being taller you do more work to lift the same amount of weight as someone who is shorter. Being tall is never an advantage in lifting.

As far as sprinting, all things equal tall people are worse starters than shorter people. Tall people are better at top speed though. Long lever takes time to get moving but once it is moving it will go faster and cover more distance.

In the end it doesn’t matter, sprinters of all sizes have reached the top.

My example is not at all like your squatting example. My calculations are based on the assumption that both lifters can produce the same amount of force. I’m avoiding the advanced bio-mechanics altogether because it’s simply much too complicated.

Yes, I understand the physics, and that the taller athlete has to expend more energy to get the mass to a greater height. However, work is not what we are comparing. I can do WAY more work than what it takes to clean 250KG - it will just take me longer to produce that energy that it will them :).

So am i right in thinking that for a taller person to achieve full extension they would need to produce more force that a shorter person?

I think I understand what you are saying, but my point is this. If both lifters produce the same amount of force, a shorter lifter will be able to lift more than a taller lifter. A taller lifter HAS to be able to produce more force in order to compensate for leverage disadvantages.

A tall lifter might have to expend 500N of force to lift a given weight while a shorter lifter might only need 250N. If they both have a max of expending 500N, the shorter lifter is going to lift more with other things staying equal.

Just look at the majority of successful powerlifters and weightlifters, they are short. Having to pull the bar a greater distance (as in a clean) and then squat it a greater distance(!)is never an advantage. Just think about the difference in displacement for a clean comparing a 5 foot person and 6 foot person.

The only time I could ever see being tall as helpful is if they were [b]extremely[b] deficient in their RFD whereby having greater time to produce the force would be of benefit. I still doubt that’s really much of a help though.

With other things staying equal, proportional body mass for example, yes. However, this doesn’t mean being tall is some huge disadvantage. If so, little people would be winning running events.

false dichotomy and there will be an OPTIMAL height for any given activity with some range/variation seen

and taller athletes, although they may carry more mass still tend to be at a slight disadvantage because muscle cross sectional area scales with the square of height and volume as the cube.

a taller athlete will have to carry exponentially more muscle/be capable of exponentially greater strength/power output for this reason.

About the last paragraph - if you use my initial assumptions, then being taller IS an advantage. If the bar started on the ground, then people who can produce the same maximum force would be able to lift identical amounts, if their techniques were identical - regardless of their heights.

I think we might be talking about force in difference ways. When I said they can apply an equal force, I meant they can produce that force to another object, and I wasn’t referring to the amount of force the muscle produces. In this case, a taller athlete will be able to clean more than a shorter one.

If we’re talking about the force their muscles can produce being the same, then it seems likely that the shorter athlete will have the advantage in most exercises (but the clean and the snatch are a bit complicated). The shorter athlete doesn’t have to oppose as much torque since their limbs are shorter.
However, the distance from the tendon to the fulcrum (pivot point of the joint) is larger for taller people, so if the muscles of a short and taller person can produce the same force, there is more torque about the taller person’s joint. I doubt this makes up for the fact that the taller person has longer limbs though.

Now I understand what you are saying, like you said we were thinking about force in different terms.

Isn’t this what I said? I stated if a taller person has proportionally more body mass in relation to them having more height, in comparison to a shorter individual, they will need more strength.

As far as exponentially goes, I have trouble with that. Are you saying Asafa Powell is exponentially putting out more force than Ben Johnson did considering Asafa is around four inches taller?

Taller athletes don’t always carry around more muscle and or more mass either.

I was responding simply to this statement
“However, this doesn’t mean being tall is some huge disadvantage. If so, little people would be winning running events.”

As far as exponentially goes, I have trouble with that. Are you saying Asafa Powell is exponentially putting out more force than Ben Johnson did considering Asafa is around four inches taller?

as noted, muscle XSA scales with the square of height, muscle volume with the cube. srength output is related to cross sectional area and to carry even the same muscle at 4" taller will require a lot more muscle.

this ignores nervous system stuff mind you.

how much does asafa weigh relative to ben, that’s the other part of the equation that’s missing. if he’s lighter despite being taller, that will cancel some of hte need for massive power increases because we are interested in power:weight more than absolutes

Taller athletes don’t always carry around more muscle and or more mass either.

see above: nervous system influnces this as well

Ok, we’re on the same page.

Ok great, im starting to understand now.
So is full extension much more achievable for one with short levers than long?

I ask this because i had no problems when i was 5,7" at 15yrs old but now dont achieve full extension at 6,4" and 21 yrs old. Does this sound like my body not being strong enough to handle its ‘new’ levers?

thanks