I've been working out with a trainer at a local gym. He's had me doing (among other things) leg presses on an inclined machine. You sit on a seat on an inclined ramp and put your feet against a platform directly in front of you and push. So you're lifting part of your own weight plus whatever weight you have the machine set at. He had me doing 100lbs on the machine (15 reps x 3 sets), which is doable without stressing my muscles too much. I don't have any knee or muscle pain during or after the exercise.
Yesterday he had me do the exercise using just one leg at a time. He said to set the machine at 10lbs. I was like, what? I can do 100lbs with both legs, why not 50lbs with one leg? But he was right, 10lbs using one leg at time was pretty tough.
Why is that? Why is 10lbs using one leg so hard when I can do 100lbs using both legs? Is it because I'm using more of my core muscles when I use both legs?
