Pulleys on cable exercises

[Konitz]

Why do they put 150lbs. on a pulley machine when there are two pulleys that form a snatch (Peter's laugh) block that effectively cuts the weight in half; they should label it 75 lbs. Am I correct or am I missing something?

[alwaysgrowing]

I believe they simply go by the total of the weight if placed on a scale. Pulleys be damned

[alwaysgrowing]

Although it is funny when people bench or curl with cables and then go braggin about their "weight"

[Konitz]

Although it is funny when people bench or curl with cables and then go braggin about their "weight"

Exactly, you are not curling 150lbs; you are curling 75lbs lol

[Scrumhalf]

No, you are still lifting 150lbs. Of course, the compound pulley has a Mechanical Advantage of 2, so it cuts the effort in half (of course there is no free lunch, so you end up moving the weight through half the distance).

Needless to say, one can't claim to have lifted 150lbs unassisted because of the mechanical advantage ratio that the compound pulley provides. It is the equivalent of using a car jack to change your tire and then claiming that you lifted your car. :)