2

Recently I encountered a leg press machine that works in the reverse direction than a typical leg press machine. Instead of pushing the weights forward with your legs you push your seat backwards which is attached to weights. It is more like a calf raise machine but it was clear from the instructions on the machine that it is for leg press. I am avoiding squats because I have spine issues (yes the jury is still out for the leg press machine on that issue as well but that’s not related to my question at the moment).

Basically this machine works like a horizontal squat with a seat. My question is considering various types of leg muscles and glut involved does it matter which direction you are pushing? Probably the same question can be asked for other devices such as pull-ups vs dumbbells for biceps, etc. What I noticed in the past was pull-ups built a lot more of my brachioradialis than my biceps. That’s why I am skeptical that the distribution of muscles affected will be the same for two different leg press machines as the movement direction seems to build the muscle more that is attached to the bone that remains static as opposed to the one attached to the bone in motion. Or at least the percentages will be different if both bones are moving.

I am looking for some references to studies on this matter.

Improve this question
2
  • With all due respect, do you really need studies on something that is evident by understanding physics as fundamental as Newton's third law of motion?
    – Philip Klöcking
    Commented Apr 22 at 14:03
  • 1
    @PhilipKlöcking Ceteris paribus, it may be a physically symmetric situation. However I learned not to assume anything in life.
    – Cagdas Ozgenc
    Commented Apr 22 at 16:47

1 Answer 1

Reset to default
2

There is no difference in the muscles used between a leg press with a fixed seat and moving foot pad, vs one with a moving seat and fixed foot pad. It's the exact same movement either way, just that in the latter variant you're moving your bodyweight in addition to the external weight, so you shouldn't expect to use the same weight with one style as you would with the other. But with all different types of loading available in leg press machines (45° sled, cable-and-weight-stack, vertical sled), you can't expect the weight you can lift to be the same between any two types of leg press machine.

For other cases, like pull-ups vs dumbbells for biceps, those are very different movements (since you don't move your shoulders in a bicep curl), and use different muscles.

Improve this answer
2
  • 1
    When I was mentioning pull-ups I was talking about the effects on biceps specifically. What I noticed in the past was pull-ups built a lot more of my brachioradialis than my biceps. That’s why I am skeptical that the distribution of muscles affected will be the same for two different leg press machines as the movement direction seems to affect the muscle more that is attached to the bone that remains static as opposed to the one attached to the bone in motion. Or at least the percentages will be different if both bones are moving.
    – Cagdas Ozgenc
    Commented Apr 22 at 9:33
  • What changes is also the difficulty to setup: in the horizontal leg press you start at the bottom (legs fully bent) which is the hardest part, while in the 45º leg press you start with the legs extended.
    – Luciano
    Commented Apr 22 at 13:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.