Don’t “do the machines”
The authors again speak out against isolating your muscles when working out. Their main problem with workout routines that follow a circuit around the machines is that nothing mimics a squat, and there is only one or two exercises that mimic a deadlift. Nothing mimics a lunge, and the pushing machines are unnatural. They do like pulling machines, however. Their two general problems with most of the machines are that they can force your joints into unnatural ranges of motion and make it easy to injure yourself, and that most of them prevent your body from doing the most important and useful muscle-building movements.
There are times when I have a lot of time that I can spend in the gym and that I “do the machines.” In general, I only “do the machines” when I am resuming weight training after time off, and I want to spend a few weeks getting my muscles used to the motions of lifting again. Otherwise, I do tend to stick to using free weights or cable machines.
If you are going to use machines, then be sure to always adjust them properly. If you are unsure how to do so, there are usually directions on each machine, and most gyms have trainers available who can help you.