How can I show the relationship between two progress/health bars?

There are a number of different types of information you are trying to represent/present to the user, and the key is to create a consistent and coherent set of visual signals so you can convey the key information correctly and clearly.

From what I can see, these are the key elements:

• Current available speed (that can be used)
• Maximum speed point available (that can be accumulated)
• Current available endurance (that can be added next turn)
• Maximum speed point available next turn (once endurance is added to speed)

So I suggest the following changes:

• Combine endurance with the speed bar since its value is only added to the speed bar (and it is also confusing for the user to have to do the calculation themselves
• Change the labeling for Endurance (+ ) so that the user knows it is something added to speed
• Create visual styling to show the connection (e.g. using same type of colour but different shade) between current and future speed points

I think each of these examples show how the design indicates both current and future speed points as you progress through your turn quite clearly, and can be applied to any other attributes that work in a similar manner.