Patrick Skov Tricep Press

[GTJason]

How do you push down 390 when you only weigh 2 something?

Some of the weight is absorbed by the tension in the rope including the split at the end of the cable and some of it is absorbed by the pulley system which is acting as a fulcrum in this case. In short the weight absorbed by all of those items is not nearly enough to account for the weight discrepancy. The biggest factor here is torque (moment) as his center of gravity (for simplicity at his hips) is away from the biological fulcrum (his elbows.) Also his center of gravity is farther away from that fulcrum than his hands which are handling the weight. So think of it as a lever, a smaller weight with a long lever arm can lift a large one with a short arm. Also you have to be an f'n monster to move that 390 lbs. I'd be willing to bet he could grab hold and hang on that rope, but put him a few inches away and his body weight is more than enough to anchor him.

*Source: Me and 2 other engineers arguing for 30 minutes and drawing stuff on a whiteboard until we were satisfied

 

[dressedcheeseside]

Some of the weight is absorbed by the tension in the rope including the split at the end of the cable and some of it is absorbed by the pulley system which is acting as a fulcrum in this case. In short the weight absorbed by all of those items is not nearly enough to account for the weight discrepancy. The biggest factor here is torque (moment) as his center of gravity (for simplicity at his hips) is away from the biological fulcrum (his elbows.) Also his center of gravity is farther away from that fulcrum than his hands which are handling the weight. So think of it as a lever, a smaller weight with a long lever arm can lift a large one with a short arm. Also you have to be an f'n monster to move that 390 lbs. I'd be willing to bet he could grab hold and hang on that rope, but put him a few inches away and his body weight is more than enough to anchor him.

*Source: Me and 2 other engineers arguing for 30 minutes and drawing stuff on a whiteboard until we were satisfied

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.

 

[UgaBlows]

No, if you're pushing on a load and you weigh less than the load, you're gonna move not the load. Unless you're braced somehow like on a bench press or squat and you're pushing off the ground.

Mechanical advantage because of the pullies involved?

 

[33jacket]

The load vector is vertical in this instance. See above for pully.

No its not. Its a rope pull out. I have done these all my life. Its part down part out. You split the weight on the way down out.

But u know. I dont. Lets all move on

 

[jwsavhGT]

 

[dressedcheeseside]

Mechanical advantage because of the pullies involved?

Single fixed pulley, MA is 1:1

 

[Frenchise]

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.

 

[dressedcheeseside]

No its not. Its a rope pull out. I have done these all my life. Its part down part out. You split the weight on the way down out.

But u know. I dont. Lets all move on

I don't think that matters, actually. The effort force (Skov's force) must still be equal to the load (weight of the plates) regardless of the angle formed by the ropes over the pulley.

 

[dressedcheeseside]

Wow...have any of you been in a weight-room? There are slots you put feet or thighs under when lifting 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.

I said if you're braced you can do it.

 

[Dottie1145]

He's obviously a super human. Case closed.

 

[FightWinDrink]

Well I know how much people on here love Stanford, so maybe we need a Stanford grad like Skov to come explain it.

 

[UgaBlows]

Single fixed pulley, MA is 1:1

In the video it looks like there are 3 pulleys, like the cable goes up, down, then up again, and his feet are def not braced imo

 

[dressedcheeseside]

If the tricep machine is set up like this:

Then you only have to push 1/4 the actual load. Maybe this is how the machine is set up.

 

[Frenchise]

If the tricep machine is set up like this:

Then you only have to push 1/4 the actual load. Maybe this is how the machine is set up.

Then it isn't a 390lbs pulldown....it's a 97.5lb pulldown.

 

[33jacket]

I don't think that matters, actually. The effort force (Skov's force) must still be equal to the load (weight of the plates) regardless of the angle formed by the ropes over the pulley.

Ok. Yes.. Exactly. The force must equal the load. But if the force for the load is over angles that are not pure up down including lateral then something 200 or 300 or whatever is not just one way. Its up down. Left right based on pull angle therefore you can do more than your standing weight due to angles and pulleys. Just look up how the egyptians did it.

Point is the 390 is a vector pulley 390. He not doing a pure one direction 390

 

[nod]

How come, when I try 390 it won't move? That's what I can't figure out.

 

[IronJacket7]

Only on a GT forum could a topic of Triceps weight displacement be dissected to this degree. GEEZ. Start season! Please start!

 

[tech_wreck47]

A tricep machine is typically a single pully not a block and tackle, no mechanical advantage.

There actually is an advantage, a pully system helps keep it balanced. It's not like free weight where you are also struggling to keep everything even and balanced.

 

[MonroeJacket]

Only on a GT forum could a topic of Triceps weight displacement be dissected to this degree. GEEZ. Start season! Please start!

Something, something, offseason.

 

[AE 87]

smh. weight machines measure how much force you are exerting, not how much you are lifting with the assistance of the machine

I suspect that the answer @dressedcheeseside seeks is in torque equilibrium. How much torque would you have to exert to lift Skov by his hands with his elbows locked against his side? If Skov's goal was to lift his body weight, the downward push (pull) on ropes acts as the downward push of a lever with the fulcrum almost right at the same point. It actually puts you at a mechanical disadvantage meaning that moving the weight would happen before moving your own body.