[Bored chemist]

Many British scientists are already aware of this.
It seems that you are not.

Science is mainly British.

Thank you.
I think the Americans would disagree and the Chinese would laugh.

[Bored chemist]

I can see how it is obviously wrong: I could lie on my stomach on a concrecte block for a minute without pain with my weight 70 kg, however the opposite is also true I can put a rock of 70 kg on my stomach with the same area of contact without any damage or pain. Obviously wrong concept.
I thought I discovered basic biomechanics, how stupid I am.
Thank you
Let this idea die out who cares.

Yes, your concept is obviously wrong. It's also worse than you thought.
Let's imagine you lying down on a concrete floor.
And now, let's imagine slicing you up with a chainsaw.
First, we cut off your head.
Since it was already resting on the ground, removing it does not affect the load on your stomach.
Then we cut your legs off.
Again, they were already resting on the ground so their weight was already supported.
So removing them adds no additional load to your stomach.
We can do the same with your arms.
There's no additional weight on your stomach, because your stomach wasn't holding your arms up.
Finally, we can cut your torso in half.
Your chest still supports itself, just as it did before.
So  we finally see that your stomach is only supporting itself- far less than 70 Kg.
So its absurd to compare that it it supporting an additional 70Kg of rock.


Well, that's a bit messy, so let's imagine putting you back together again.
And let's imagine that, in the fullness of time you end up married and in bed with your wife.
Are you going to tell her it's not possible for her to support 70Kg of you lying on top of her?

Or are you going to accept that your position was always absurd?

[Bored chemist]

I can see how it is obviously wrong: I could lie on my stomach on a concrecte block for a minute without pain with my weight 70 kg, however the opposite is also true I can put a rock of 70 kg on my stomach with the same area of contact without any damage or pain. Obviously wrong concept.
I thought I discovered basic biomechanics, how stupid I am.
Thank you
Let this idea die out who cares.

I should probably have said this first but...
Well done.

It's hard to change your mind, and even harder to admit it.

[paul cotter]

Well done Yahya!, enlightenment is a very rare occurrence on "new theories". OOPS! it's not new theories I am on, my error but the relevant praise remains.

[Yahya A.Sharif (OP)]

I'm sorry, but I just wanted to know if the scholars here might be biased against my idea. I've struggled for many years to accept that it might not be true, even though I know people here are knowledgeable. Maybe my idea seems illogical or unnecessary ? like claiming that muscles cannot  carry a relatively massive weight. Anyway, I plan to access a good lab to measure the maximum calf push force to confirm its validity once and for all, and then discuss it with researchers there.
Thank you very much for your time. I apologize for any inconvenience.

[Bored chemist]

OK, so the implication of your post is that there are researchers who have the  equipment used to measure the forces exerted by the human body- and there are physiologists and ergonomists- but that without your input, they will somehow not notice that the forces don't add up.

That's special.

[alancalverd]

I plan to access a good lab to measure the maximum calf push force to confirm its validity once and for all,

No need. We have all sorts of lifting and jumping contests with well-recorded results.

The greatest weight ever lifted by a human being is 2,422.18 kg (5,340 lb) for two cars with drivers on a platform backlifted by Gregg Ernst (Canada, b. 30 September 1961), performed and notarized at South Shore Exhibition, Bridgewater, Nova Scotia, Canada, on 28 July 1993.

and for a  straightforward olympic deadlift, around 450 kg, so about 225 kg per leg.

[Bored chemist]

and for a  straightforward olympic deadlift, around 450 kg, so about 225 kg per leg.

Plus about 100Kg per leg for the athlete himself.

[Yahya A.Sharif (OP)]

I plan to access a good lab to measure the maximum calf push force to confirm its validity once and for all,

No need. We have all sorts of lifting and jumping contests with well-recorded results.

The greatest weight ever lifted by a human being is 2,422.18 kg (5,340 lb) for two cars with drivers on a platform backlifted by Gregg Ernst (Canada, b. 30 September 1961), performed and notarized at South Shore Exhibition, Bridgewater, Nova Scotia, Canada, on 28 July 1993.

and for a  straightforward olympic deadlift, around 450 kg, so about 225 kg per leg.

Human muscle strength varies from individual to individual. It depends on gender, age, health, and training, so there is a big difference between an average 80-year-old person and a 25-year-old athlete. Consider an 80-year-old individual who lifts their own 70 kg body weight using their thigh muscles, compared to the same person attempting to lift an additional 40 kg of external weight.

[Bored chemist]

Consider an 80-year-old individual who lifts their own 70 kg body weight using their thigh muscles, compared to the same person attempting to lift an additional 40 kg of external weight.

I did the comparison.
It turns out that lifting 110 Kg is harder than lifting 70.

You seem to have missed this
OK, so the implication of your post is that there are researchers who have the  equipment used to measure the forces exerted by the human body- and there are physiologists and ergonomists- but that without your input, they will somehow not notice that the forces don't add up.

[Yahya A.Sharif (OP)]

Consider an 80-year-old individual who lifts their own 70 kg body weight using their thigh muscles, compared to the same person attempting to lift an additional 40 kg of external weight.

I did the comparison.
It turns out that lifting 110 Kg is harder than lifting 70.

How much harder is it? The point is to understand the extent of the difference. For example, compare lifting 70 kg to lifting 90 kg (i.e., 70 kg plus an additional 20 kg). Is the increase in difficulty truly proportional to adding 20 kg to the original weight?

Why is it that a child aged 12 years, weighing approximately 40-45 kg, can lift their own body weight by pulling up on a bar, yet cannot lift a rock of equivalent weight (40-45 kg) using a rope and pulley, even though both actions appear to involve the same muscle groups?

[alancalverd]

Depends on the rope and pulley! If you add a handlebar, so you can pull with both hands and optimum grip, I think the laws of physics apply, but pulling directly on a rope involves slightly different muscle alignments and a weak grip.

[Bored chemist]

Why is it that a child aged 12 years, weighing approximately 40-45 kg, can lift their own body weight by pulling up on a bar, yet cannot lift a rock of equivalent weight (40-45 kg) using a rope and pulley,

It's not a real question.
Ignore the child's muscles.
Imagine I get a rope and a pulley and a 40Kg weight I tie the weight to the rope, thread it over the pulley (which is fixed to the roof or whatever) and tie a stick to the other end,
I lift the child up and tell them to hold onto the stick. Then I let go of them.

If they weigh more than 40 Kg then they fall, and the weight rises.
If they weigh less than 40Kg then they just hang off the stick.

If they then pull down on the stick, they may be strong enough to lift themselves, and they may not- depending on their musculature.

[Bored chemist]

You deem to have forgotten to answer this again. Why is that?
 
OK, so the implication of your post is that there are researchers who have the  equipment used to measure the forces exerted by the human body- and there are- physiologists and ergonomists- but that without your input, they will somehow not notice that the forces don't add up.

[alancalverd]

Come to think of it, at the age of 12, most of my cohort could do a chinup to the bar, but only a few gifted gymnasts could climb a rope hand-over-hand without using their feet.

[Yahya A.Sharif (OP)]

You deem to have forgotten to answer this again. Why is that?
 
OK, so the implication of your post is that there are researchers who have the  equipment used to measure the forces exerted by the human body- and there are- physiologists and ergonomists- but that without your input, they will somehow not notice that the forces don't add up.

I have not found any references providing experimental data on the maximum force generated by the toes and calf muscles during a push-off in non-athlete individuals, particularly young children.

[alancalverd]

The minimum force required to leave the ground is the weight of the child, by definition. The additional force required to leave the ground  at a given initial velocity is time-dependent: in a standing jump the maximum probably occurs on rotation to the ball of the foot. I'm sure that elite sports departments (try Loughborough university) and athletic or ballet shoe manufacturers have plenty of data for teenagers upwards, and maybe for juniors too. If not, you can measure it yourself with a strain gauge or a maximum-recording weighing machine - a simple modification of a bathroom scale.

[Bored chemist]

You deem to have forgotten to answer this again. Why is that?
 
OK, so the implication of your post is that there are researchers who have the  equipment used to measure the forces exerted by the human body- and there are- physiologists and ergonomists- but that without your input, they will somehow not notice that the forces don't add up.

I have not found any references providing experimental data on the maximum force generated by the toes and calf muscles during a push-off in non-athlete individuals, particularly young children.

You have that data.
You just do not understand it.

Children can walk up stairs, and they even sometimes do so while carrying a dog or a friend.
In doing so, they exert a force rather larger than their own weight and they do it with each foot in turn.
So it's a fair guess that they can (if using both feet) deliver about 3 or 4 times their weight.
It's called muscle.
No magic required.

[Yahya A.Sharif (OP)]

You deem to have forgotten to answer this again. Why is that?
 
OK, so the implication of your post is that there are researchers who have the  equipment used to measure the forces exerted by the human body- and there are- physiologists and ergonomists- but that without your input, they will somehow not notice that the forces don't add up.

I have not found any references providing experimental data on the maximum force generated by the toes and calf muscles during a push-off in non-athlete individuals, particularly young children.

You have that data.
You just do not understand it.

Children can walk up stairs, and they even sometimes do so while carrying a dog or a friend.
In doing so, they exert a force rather larger than their own weight and they do it with each foot in turn.
So it's a fair guess that they can (if using both feet) deliver about 3 or 4 times their weight.
It's called muscle.
No magic required.

Three or four times their body weight? How realistic is that? For example, could a child weighing 40 kg actually carry 120 kg or even 160 kg while walking up a flight of stairs? I am not referring to lifting or carrying another person, I am specifically asking why this would not apply to an inanimate object, such as a rock or a small refrigerator. Anyway that is not numerical data.

[Bored chemist]

Three or four times their body weight?

Like I said, you have the data (a child might be expected to carry his twin brother) but you do not understand it.
You are essentially trying to claim that 2 times 2 equals four is not numerical.