I think that they are just an expensive 'pick me up.' There is no clinical research that I'm aware of to substantiate the marketing claims. It's all anecdotal. I suggest to clients to drink a glass of water and eat a banana. It's a great pre-workout ingestion.
Good answers. I favor the neck in neutral posture throughout the movement. Looking down can definitely affect balance. Neck extension, looking up, puts an overload on muscles extraneous to the exercise.
I think that squats are a great exercise. I don't know that you actually asked a question, but I recommend that for most of your clients squats to 90 degrees of knee flexion are the best. The post-patellar pressure past 90 degrees of flexion isn't worth it.
I agree with the responses given. The, as you call it, subjective assessment is the foundation on which you develop the program design for your client. The types of exercise have to be matched to your client's skills and preferences.
Great responses. Choosing depends on your client. Rowing (low impact) is relatively easy on the body, with the possibility of significant cardiovascular overload. Skipping rope (high impact) can be intense but if your client is able its a great addition to the cardiovascular regimen.
It is high risk. You can write a policy that climbing always has to be supervised, but you know that it will be taken with little weight. I would suggest that unless you can have someone always supervising the ropes take them out.