this really depends on the person. Most very overweight people are not looking forward to an ‘assessment’ only to learn how bad things are.
Many of the tests that are often part of an assessment are skewed if a person is very overweight, and bony landmarks are difficult to see. I may or may not do body composition. Since I use near infrared technology, it is not as invasive as calipers, and most clients are okay with that. I always check blood pressure. Even though most clients are on medication and are aware of it, I always want to make sure.
I do a musculoskeletal assessment as well as possible and use the wall test (from the BioMechanics Method) and/or the squat test per NASM. I tend to forego any strength endurance tests but look for range of motion in the shoulder and hips. I also try very hard to find something that is praiseworthy so that I can start my summary with a positive statement.
The main thing is to be flexible and sensitive to the client. And assessment is often the first encounter with a client, and I like to keep that on a positive note. If I sense anxiety on the part of the client, I just leave it out. Every subsequent workout will double up as a test anyway.