Every program should start off with a proper assessment. If you don't have a starting point, you'll never know when you've made progress. At Nunn's Performance Training, we do a movement screen (overhead squat and single leg squat), bodyfat test (or circumference measurement), bodyweight measurement, and a nutritional and lifestyle analysis. Most fitness centers will do a pretty good job of the bodyfat, bodyweight, and lifestyle analysis, but they neglect the movement screen part. This is mainly do to ignorance on the trainers part. They probably don't understand the process of the screen or what to do with what they find during the screen. During the movement screen, the trainers responsibility is to identify movement dysfunction so they can put a proper plan in place to address this and minimize injury to the client. When doing the screen, the trainer should be identifiing which movement patterns they will have to regress for the client. It is important for the trainer to realize that our job is first and foremost to NOT INJURE PEOPLE! If a client is injured, they cannot train. If they cannot train, they cannot get results, and anyone in this business will tell you that getting results is where the money is.
Here's an example of what a trainer may find during the initial assessment:
Posterior Pelvic Tilt
Notice in this picture, the client presents a posterior pelvic tilt. She may be asymptomatic at the time, but it doesn't mean that she won't be in the future. When the hips tuck under like that, the ligaments in the lumbar spine are stretched and more likely to cause pain and injury (i.e. herniated disc and/or stenosis). Initially, squatting would not be a good choice for someone who presents this.
The posterior tilt is just one of the many things that can be found during the screen.