No, MSP doesnâ€™t stand for “My Secret Pal”, nor does it stand for “Momâ€™s Special Potion”, and Iâ€™ll stop right there before this gets really silly. MSP stands for Maximum Sustainable Power. It is the level of power once can sustain for a specific time interval. When you are referencing an hour interval (measured and estimated with 20 minute tests), most elite cyclists who train with power refer to this as FTP or Functional Threshold Power.
I prefer to reserve the term “Threshold” for that unique metabolic event that takes place with respect to the production of energy; the “cross-over” process between the aerobic and non-aerobic energy production systems. In my opinion, this term should be reserved for cardiovascular training (it has been used and researched with this term as the agreed upon nomenclature for years before power meters even existed). Therefore, to avoid confusing heart rate and power training terms, I do not refer to threshold with respect to power, but instead reserve its use solely to reference ones heart rate when this metabolic event occurs.