Why do endurance athletes suffer from shrinking arms and legs despite all that training? This is a very common complaint among all athletic types that visit our clinic - loss of muscle.
Now, there’s a lot of reasons why people lose muscle, but there’s a very specific reason in this group of people.After all, you’d think endurance athletes are made out of muscle. Well, yes and no.
There are several reasons why this group’s muscle mass is ‘at risk’ so to speak:
We don’t spend as much time in the gym lifting heavy stuff. That’s a no-brainer.
If we do go to the gym, we don’t lift very heavy, and, we’re tired from all the running, swimming, biking, etc!
Genetics. No, not everyone has the ability to lay on tons of muscle. And, endurance athletes tend to be leaner, that’s part of why we’re drawn to the sport.
Despite these issues, there’s an important major underlying physiological conflict between strength and endurance training adaptations that limits an athlete’s ability to put on (or hold onto) appreciable amounts of muscle.
And, that reason has to do with the hormone cortisol.
Endurance training of course involves tons of cardio training, and relatively little strength training.Add in life, work and the stressors of training, you’ve got chronically elevated cortisol levels.
Because cortisol is a stress hormone, one of its main jobs is to make sure we have energy ready to use. Think back to our ancestors, who probably went days or longer without a meal, yet still had to fight, run and think their way out of problems in order to survive. Where did that energy come from to do these things, if they hadn't had a meal in days?
That energy comes from cortisol.Cortisol makes energy by mobilizing amino acids from the skeletal muscle - those aminos are then delivered to the liver where under the process of gluconeogenesis, sugar is made.
This is the reason why endurance athlete’s struggle with putting on muscle, and holding onto it.Our ancestor’s stresses were of relatively short duration.We fought or ran, and it was over.Cortisol went up, then it came down when the threat was gone.
Our lives are much different though - we have never-ending daily stressors, our relationships are much more complicated, and we endure training for weeks and months at a time. All of these stressors keep our cortisol higher, and this amounts to a physiological 'push' against muscle building. Cortisol is a catabolic hormone that defies much of the strength training we attempt.
So, how do we fix this, short of quitting our sport?
Here’s a few ideas where you can start:
Shift your training focus: if you want to put some muscle on (that will withstand the rigors of racing season) you need to lift like you’re a body builder in the gym during the off season.This means: Low rep, high weight, and lift to failure.
Increase protein: Most endurance athletes we’ve seen in clinic just don’t get enough protein in. Blame it on restrictive diets, or just lack of a focused nutritional plan, this is how it goes. The Academy of Nutrition and Dietetics and the American College of Sports Medicine recommend 0.5 to 0.9 grams of protein per pound of body weight per day for athletes. This is covered in more detail in the video above.
Supplement: See our list of supplements below that help facilitate muscle gain.