Patrick Skov Tricep Press

tech_wreck47

tech_wreck47

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Frenchise said:
Wow...have any of you been in a weight-room? There are slots you put feet or thighs under when moving a load heavier than you. Now, I agree that 390 on this machine is not really 390, but it's not 50% of 390. His feet are braced.

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I go to the gym pretty often and most tricep push down machines don't have that, those are more of Bo flex type machines.

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Northeast Stinger

Northeast Stinger

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I think what happens is this. As he pulls down on the 390 pounds the force of gravity moves the earth closer to the weight. So with each pull, even though he would be lifted off the ground ordinarily, the ground is moving to meet the the 390 pounds thus maintaining contact with the bottom of his feet the whole time.
 
GTJason

GTJason

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dressedcheeseside said:
Not really seeing your point. See below:

"The mechanical advantage of a pulley system is determined by the number of ropes hanging on the sides of all pulleys that are working against gravity. A single fixed pulley uses only one rope, where the load is lifted by the same distance as the other end of the rope is pulled down. In a 1:1 mechanical advantage, the applied force is the same regardless of the pulley being used."

http://www.ask.com/science/mechanical-advantage-single-fixed-pulley-7a9e86e6f908f748

The advantage of a single fixed pulley is it changes the direction of the input force, it doesn't multiply it.
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It's not the pulley system at all. As I said it's where his weight is in relation to where the force is being applied. His forearms are the short lever arm and his humerous/chest is the long lever arm where his elbows are the fulcrum. It's a simple machine, just not a pulley
 
dressedcheeseside

dressedcheeseside

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GTJason said:
It's not the pulley system at all. As I said it's where his weight is in relation to where the force is being applied. His forearms are the short lever arm and his humerous/chest is the long lever arm where his elbows are the fulcrum. It's a simple machine, just not a pulley
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I get that, but he still has to generate 390 lbs of effort force, right?
 

Declinometer

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Please stop! He can't push down 390 lbs! The machine doesn't even go up to 390. Each plate is 10 lbs so the max is 200 lbs.
 
tech_wreck47

tech_wreck47

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dressedcheeseside said:
Ahhhh, but this machine has a movable pulley attached to the stack creating a 1:2 mechanical advantage. If Skov's machine is like this, he is only moving 195 lbs which is less than his body weight.
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So it's only 50%? I thought it was more like 70% they were actually lifting on machines like that?
 
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Dottie1145

Dottie1145

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tech_wreck47 said:
I don't even consider him doing 420, his form is awful and not even doing the right range of motion.
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Yeah. I agree, but look at the weight that he added to the machine. I was just pointing out that Skov wasn't pulling down 390, at the most it's 260
 
ilovetheoption

ilovetheoption

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Changing the vector actually does matter in this instance, as it allows the horizontal friction between his feet and the floor to act as an anchor against which to pull, no?
 
ilovetheoption

ilovetheoption

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Also, look at the distance the weights travel against the distance his hands travel. The hands travel way further, thus we can conclude that the pully system is indeed providing an advantage, and that it's not 390 lbs to him.
 
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