Specific Adaptations to Imposed Demand

Written by Patrick Sherrod. Patrick is an ACE Certified Personal Trainer, RRCA Certified Running Coach and StretchMed CST.

Why does my training plan mostly detail running slow when I want to run fast?

It may sound crude but I’ll declare because Coach S.A.I.D. so!

The SAID principle is an acronym from the strength and conditioning world which simply means: “Specific Adaptations to Imposed Demand.” In other words, the body will adapt and become more efficient in accordance with the training demands placed upon it.

“But I want to run FAST!” Sheesh, don’t we all!!

But what are the specific adaptations that will occur when we train fast to run fast? Leg muscles may get stronger, produce more power, and turn over at a faster cadence but this type of training can only be done in short bursts and therefore would not be a specific adaptation that is conducive to distance running.

By running at an easier pace for longer durations, the benefits experienced are increased endurance, durability, fat utilization and oxygen efficiency. Training below one’s aerobic threshold builds capillary pathways that deliver oxygen to your muscles and carries lactate away from the muscle, which is the key to running efficiency! This is a specific adaptation that would serve distance runners!!

However, running when it feels foolishly slow or unproductively easy takes much patience. You may even find that, based upon heart rate, you may need to incorporate walking breaks to stay below your aerobic threshold. The key is to make your training feels easy so that you can work that much harder on race day!

If you still don’t believe me, take a look at how the best in the world devotes his training:


Happy miles, Striders!





Leave a Reply

Your email address will not be published. Required fields are marked *