Why Do Some Machines Feel Heavier Than Others?
Have you ever changed gyms and tried to do your usual workout, only to find that the machines were much more difficult or perhaps much easier? Before you start questioning your strength or training, there’s something you need to know: You can’t trust the numbers on a weight stack, and you shouldn’t expect them to be consistent from gym to gym, or even from machine to machine.
What do the numbers on the weight stacks mean?
When you look at a cable machine or any other strength machine with a stack of rectangular weights, each plate probably has a small sticker with a number on it.
Sometimes these numbers are expressed in pounds and represent the weight of the plate itself. If you were to take a 10 pound plate from a machine and weigh it, it would weigh 10 pounds. (Probably.) Sometimes they are measured in kilograms. Unless it’s specified what it is, there’s no easy way to know for sure. It also doesn’t really matter for reasons I’ll explain below.
And sometimes there are no weight markings on the stacks of plates at all. You just know that if you are strong enough to operate the plate that says “5”, you are stronger than if you could only use the machine on the “4” setting. How many pounds do you lift? That doesn’t say much, and frankly, it doesn’t matter.
Pulleys and levers change the feeling of heavy weight.
Even if the numbers on the machine are accurate, they are useless. Let’s say there’s a stack of cables, each plate weighs 10 pounds, and you can use 5 plates for a particular exercise. You are moving 50 pounds of iron.
But are you really applying 50 pounds of force to move that iron? Not necessarily. As you may remember from your school days, pulleys and levers can make moving heavy objects easier or more difficult. If you perform crossovers on the LifeFitness Signature Series dual-adjustable pulley machine shown below, you get a 4:1 mechanical advantage. When you place a pin in a stack that says 52.5 pounds, you can lift 52.5 pounds, but you only need about 13 pounds of force to do it.
Cable machines are simple enough that a company can publish their ratio, as LifeFitness did. (A few more examples: The Rep Athena pulley system has a 2:1 ratio, so 20 pounds feels like 10 pounds, while their lat pulldown has a 1:1 ratio, so 10 pounds feels like 10 pounds.)
But when it comes to other types of machines, there may not be a simple answer. A given gym equipment may have a combination of pulleys, levers, and other devices, and they can provide different assistance depending on how you set up the machine or what exercises you perform.
Machines have different designs (and maintenance schedules)
With all of this in mind, you now know that the weight you feel like you’re moving is different from the weight listed on the stack. But what does this tell us about comparing one car to another?
Machines may have different designs, especially if they are different models or from different manufacturers. One gym may have a 4:1 cable machine, while another has a similar machine with a 2:1 ratio. At one gym the leg press might be horizontal with a weight stack, while at another it might be an angled leg press that you load with plates from the free weights section. Don’t expect 200 pounds on one to feel like 200 pounds on the other.
Even if two gyms use the same brand and model of exercise equipment, one may be more difficult to move than the other. Perhaps Gym A has an old machine that’s a little rusty, and Gym B has a newer model that just got oiled yesterday.
How to track your progress as you train on different machines
Now that we know that every car is unique and the labels don’t necessarily mean what they say, how do we deal with this?
Unfortunately, there is no simple solution. If you alternate between two gyms, it’s best to keep records separately for each. In your notebook or strength training app, simply track “Planet Fitness Leg Press” separately from “Crunch Leg Press.” (Most apps allow you to duplicate and edit exercise recordings.)
If you go to various mystery gyms (maybe you travel a lot), try programming your workouts using RPE. Instead of doing four sets of 12 reps with a weight of 70 pounds, imagine four sets of 12 reps with a difficulty of 8 out of 10. That might be 70 pounds in one gym, 65 in another, and 72.5 in another, but it’s not matters. You’ll still get a good workout in all three cases.