What is necessary to establish a causal relationship?
Briefly explain how I would set up a research study to determine that a reduction in lean body mass is causing a decrease in max VO2.
(I am assuming that part of it could be that if there is a decrease in lean body mass there is less oxygen required)
So one key part in this is using the scientific method. (I know this sounds basic but it is a good first step to remember.) The question you asked is how would you set up the research, not the parentheses part about the reasons for the phenomenon- that's a different question. The four steps* are listed with basic statements of how they might apply to the V02 problem.
1. Observation and description of a phenomenon or group of phenomena.
(A PHYSICIAN NOTICES THAT HER PATIENT'S V02 LEVELS BEING MONITORED AS A PART OF ANOTHER CONDITION DECREASE AFTER THE PATIENT SUSTAINS A BROKEN LEG AND HAS STOPPED HIS EXERCISE ...
The expert determines what is necessary to establish a causal relationship.