I am following the daily suggested workouts for an upcoming race using heart rate. The workout suggestion is 143 bpm for a given time. I followed it closely and received an execution score of 95%. However, my training effect for this workout was very different from what the forerunner suggested it would be. The watch suggested a TE of 2.8 and the final TE for the workout was 3.5. I don't think I fully understand what, if any, link there is between execution score and TE. What would cause such a discrepancy?