The job description reads as follows:
Design and run user studies related to cardiovascular fitness & energy expenditure, including calories burned, metabolic rate, aerobic fitness level measurement/tracking and other key physiological measurements.
Candidate will be knowledgeable about the physiological effects being measured and how to avoid potential inaccuracy and experimental error due DOE flaws and/or reference monitor (i.e. metabolic cart, etc.) usage issues.
The role will need to apply relevant knowledge to the design of products and their testing/validation through user studies.
The position was posted on February 6th; however, once it was noticed by the media, Apple removed the listing. You can find a screenshot below.
It's thought that Apple will release a new 'Healthbook' app alongside iOS 8 that will be able to monitor and store fitness statistics including steps taken, calories burned, and miles walked. More details here.