No, MSP doesn”™t stand for “My Secret Pal”, nor does it stand for “Mom”™s Special Potion”, and I”™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.
Know Your MSP
From the foundational concepts of Stress & Adaptation, we know that we need to establish where our fitness level currently is, in order to set stress levels above that for adaptation. When we put that into the context of cycling power, we need to know what power numbers we can sustain for different periods of time before we can attempt to improve our power. Because power can be measured every second, just seeing a given number on your display screen doesn”™t mean a lot. We really must put it into the framework of a time interval, which should reflect the situation that might require that kind of power outside.
7 - 20 Minute Maximum Sustainable Power
In the eBook Power Training, these timed intervals are suggested within a range when we are discussing the Power Zones for Indoor Cycling. For riders new to power training or indoor cycling in general are just beginning their journey into power development, the Indoor chart is the best place to begin. These newbies are still building sufficient fitness to prepare the body to “work hard” and may not be able to sustain any power level above .5 Watts/lb for very long. These ranges of time then provide a method of scaling power tests for progressively longer attempts as the rider adapts and gets stronger over time.
Conducting a Power Test
The rider should have a structured warm up for at least 20 minutes prior to this test, or longer if desired. The rider should then choose a Watt level that they believe will be challenging but not impossible. They also need to choose a length of time for the test. It is recommended that a 7 minute test be done before any longer tests are attempted. Once the rider has mastered tests below 20 minutes with enough success, they can proceed to performing a complete 20 minute test.
Despite having success at less lengthy intervals with the same Wattage, if the rider can not hold this Wattage for 20 minutes, the rider should attempt the next power level down. It is likely that they experienced physical fatigue towards the end of the test, and that their fitness level may not be able to sustain that level of work for a full 20 minutes.
NOTE: Before you begin your test, make sure you know how to reset your bike in order to obtain the average power during the time interval you have selected. On the Keiser m3, you simply stop pedaling for 3 seconds, and then flip the gear lever all the way up and down 3 times to see all zeros across your display. Your time is set to zero (along with your power), and then when you”™ve ridden the number of minutes you”™ve set for the test, you simply stop pedaling, and your average power number will flash. Ecco fatto! as they say in Italy - that”™s it, done!
20 Minute MSP
When using the Power Zones for Outdoor Cycling, (the second chart in the Cycling Fusion Power Training System) the time intervals for each zone are no longer ranges, but they are distinct numbers. These are more in line with power training protocols used for elite and professional cyclists, and hence comparisons are more easily managed for those riders who have higher aspirations.
The 20 minute interval is often considered the norm for determining “Functional Threshold Power” or FTP as stated in most power forums and discussions. However, as noted above, we keep our “threshold” terminology straight by always referring to this as the 20 minute MSP. It is meant to reflect the sustainability for a complete hour, and in fact, FTP is typicallty estimated and considered 5% below what one can sustain for 20 minutes. This power level will be used for long and hard efforts; most notably time trial performance when discussing race scenarios. This may also be used during short races of 1.5 hrs or less, where a rider tries to stay at their “max” power for the longest time possible.
One other distinction about this level is the recruitment of slow twitch muscles that are required for sustaining an MSP over 20 minutes or more. Slow twitch muscles are used in endurance training, and they will be put to the test, even their limit to establish this MSP.
Just Do It
So there you have it, what MSP is, how to choose a time frame, and how to conduct a test to measure your own MSP. Now all you have to do is pick a power number and go!
- Indoor Cycling Power Research #7: Good News, Bad News - August 16, 2023
- Blog Post #10 Baseline& Performance Testing - June 29, 2023
- Keiser Tour de Power - April 18, 2023