Gray's metabolic power approach and comparison with Di Prampero's one

Approaches and level of analysis of the physical demonstration of professional soccer players. Level 6 (part 5).

Today I'll introduce the Adrian Gray metabolic power approach (Gray and col. 2011. Energetic analysis of running demands in australian football using global positioning systems technology. PhD Thesis), to which I have had the fortune to have access to it (thank you Adrian!).
This alternative metabolic power approach, that has not yet been extensively applied (done that the more important international GPS systems based brands are using the Di Prampero approach), has its own characteristics that are essentially different from that of Di Prampero.
Gray propose an approach based on the calculation of mechanical work to obtain the the metabolic power, basically horizontal and vertical work, work against air resistance and limbs work. But what it's really interesting is that both approaches, with so different ways of calculating, gives very similar average data when applied to a specific task analysis. In fact, Gray uses the same metabolic power zones.

After the short introduction, and in order to better understand the differences that each approach "offers", I present you a graph in which you'll see the metabolic power data of both approaches applied to a game action, also with velocity and acceleration data.
In this action, in which the player perform 3 consecutive CoD with some sprints of different duration, you will be able to distinguish and understand the differences of each approach, that basically are related to the "weight" that each one puts to acceleration and velocity portion of the sprint.

Enjoy,