all clients that ever came to me did so because they wanted to change something. In order to help people get there, you need to know where they are.
That’s what the fitness assessment is for; establishing this starting point.
I agree with Ariadne. If you don’t know your client’s starting point and current fitness level, it will be very difficult to design a program that’s safe and effective. A fitness assessment is a great way to determine the starting point and it, along with the health history, will help you design a safe fitness program for the client.
Having baseline data allows you to track progress from beginning to end.
Having a clear picture where they begin lets you set that progress on track in a safer and more effective way.
Going through the process of measuring baseline data, like taking a health history, helps you catch health risks, or just weaknesses that must be addressed.
Going through the process also helps create bonding with the client, letting you each understand and trust each other, and presents you as a careful science based professional.