So there's long been a battle between which is better -- machines or free weights? There's passionate opinions on both sides of the fence, much differing approaches and even more confusion.
Trainers of the functional bent generally hate with undying passion all machines. Their charge is that machines are unnatural that reenforce faulty and limited movement patterns. I won't argue with that.
Machine defenders love the way machines can truly isolate muscle groups with heavy weights. Bodybuilders love machines. As do I.
Some trainers think machines are safer and easier to use for beginners. Other think beginners should learn how to move and control their own bodies with free weights before, if ever, using machines.
Now, I won't pretend to have the final word on this debate but let me share my own approach.
Yes, when it comes to overall general fitness free weights are best -- given you know how to use good form. You'll incorporate more of those stabiliser muscles and the skills you learn from lifting free weights will better translate into real life applications. You'll learn to move your whole body better.
When I start training a beginner I will assess and correct their movement and posture. All my clients begin their workouts with mobility warm ups to ensure they can move with full range of motion. If they are particularly weak and uncoordinated I will start them off mostly on machines; I find the ease of use of machines is less intimidating to beginners and helps build up base strength. After a couple of weeks I'll slowly ween them off and introduce more free weights.
When it comes to my own workouts, I definitely use a good combination of both. I find machines are great when you want to isolate a muscle group with heavy weights. Bar squats are a fantastic lower body workout that also tax the core. However, I can leg press 5 times more weight than I can squat. So when I really want to kill the legs, I love the leg press.
Typically, in each of my workouts I'll start with machines for heavy weights and ease into free weights, elastics and pulleys towards the end. I'll also usually start with bilateral moves (using both legs or arms at the same time) and progress into unilateral moves (one side at a time) to really make sure everything is even.
So, a leg day might look something like this:
Leg press (machine, bilateral)
Leg curl (machine, bilateral)
Bench step ups (free weights, unilateral)
Single leg swiss ball curl ins (Bodyweight, unilateral)
Weighted clamshells (free weight, unilateral)