But I don't know what enthalpy means!!!

You're giving up too easily. You have been asked about musclular activity, ATP usage and heat gain. The units given for enthalpy include joules (j) that I would hope you all know is the unit of energy.

That really ought to tell you that this tells you how much energy is associated with the hydrolysis of each Mole of ATP.

So you don't actually need to remember what enthalpy means.