If you train with weight machines, you'll get stronger on those same machines better than if you trained a different way — it really helps to practice the exact move you're being tested on.

If you train using weight machines and then test your strength on machines, you’ll get stronger than if you trained with free weights — but only because the test matches the training. It’s like practicing basketball shots from the free-throw line and then being tested there: you’ll do better than if you practiced elsewhere.

If you're already fit, you might get stronger faster using gym machines like the chest press than doing classic lifts like squats or bench press — at least over 9 weeks — maybe because you're already used to the free weights.

If you want to get stronger at lifting weights like dumbbells or barbells, training with those same free weights will help you gain more strength than using machines — because your body gets better at the exact movements you practice.

If you're already used to lifting weights, using free weights or machines won't make a noticeable difference in how much stronger you get or how fast you can push the weight after 8 weeks of training.

When it comes to building upper-body strength, machines might give you a little more gain than free weights, but for your legs, both work about the same.