I am making an exercise for physics students about the first law of thermodynamics, burning heat and evaporation heat. So my idea is to use cycler which runs on fats and sugars where proportion determined by respiration quotient. The amount of evaporated sweats would be determined from inefficiency of using the fuel. Unfortunately I am unable to find efficiency data to form the exercise.
So what are typical efficiencies to run skeletal muscles on either fat or sugar molecules?
EDIT
Assuming respiratory quotient measured at the time of cycling is 0.7 so all energy is obtained from oxidizing fats: $$ C_{16}H_{32}O_2 + 23 O_2 -> 16CO_2 + 16 H_2O + \Delta G$$ what part of the $\Delta G$ can do mechanical work $A$ or simply what is typical value of efficiency coefficient: $$\mu = \frac{A}{\Delta G}$$