Weight Lifting Exercises for Beginners : Leg Extension Exercise Weight Lifting Exercise for Beginners

depend on your bodytype. Low reps but heavy can cause hypertrophy if you are skinny while high reps not. There's no formula really.

Legs First then Upper Body

How do you do this at home if you don't have a machine like this?

I hear you can tie ankle weights and just do it in a chair.

You can sit on a chair and strap weights to your ankle. The weight affects the muscle more as you raise it using this method, since the weight always pulls towards the ground. You are probably best doing squats without added weight at first. Works basically all leg muscles and more, especially as weight is added. This machine simply isolates the quads which is important for body building more than anything as you don't want a muscle being limited by other tired muscles in an exercise.

yo do squats (far superior exercise too)

It's a good exercise if it's done right...slow and non explosive. Explosive power with this exercise can blow a knee out.

Is this bad for your knees?

No... not bad for your knees... just don't over do it if you are a beginner.