4 Brick Walls of Cycling

There are basically four brick walls in cycling (or any other sport for that matter).  These walls are hit when you go all out.  You hit the first wall during the first 10 seconds of an all out sprint.  Your legs just won’t go faster and the your power drops off quickly.  Your body is using an energy system that can gererate lots of power but only for a 7-10 seconds.  This energy system needs at least 5 minutes to be replenish before it is topped of again.  There is not too much immediate pain associated with this wall.  Your heart and lungs don’t react very quickly to this short of an effort (assuming you were to stop now).  If you keep the effort going, you will run into the second wall.  This is the wall that starts to hurt.  As you keep your all out sprint going for 60 to 120 seconds, you will feel the lactic acid building in your legs and down into your fingers.  As the lactic acid builds your power levels drop off.  As some point before 120 seconds you just can’t get your muscles to work and and you must slow down below your lactate threshold in order to recover.  Also, as this point you have reached your maximum heart rate and your lungs are struggling hard to get more air.  The next wall happens when have slightly recovered and are trying to go hard again but you just can go much go above your lactate threshold.  You can try to go above your lactate threshold but your body will hit this wall (more like a ceiling) again and have to back off a little to keep going.  The final wall happens when you have burned up all of your stored carbohydrates and you bonk out.  You will have trouble turning a pedal and seeing colors.  All of these walls have different levels of pain, but most importantly, each wall has training methods that allow you to hit the wall harder (i.e. generating more power when you hit the wall) and to move the wall slightly further away so that it takes longer to hit the wall.  

 

This is not a perfect way to think about it because the each energy system is on all of the time but the relative contribution depends upon what you are asking your body to do and what you have already asked your body to do.  In fact, the power that you are producing at any point in time is using a combination of Creatine Phosphate system (ATP/CP), Anaerobic Glycolysis system and Aerobic energy systems.  The Lactate Threshold wall is really the limit of your aerobic system to buffer lactic acid.  Each of these energy systems have specific pathways for how the energy is made available to your muscles.  The key fact to understand is that energy system for short term sprints and anaerobic efforts get replenished when you are exercising below your lactate threashold.  Based on my post from other day, I can see that my training last year allowed me to develop some serious short term power numbers before I hit the walls, but I did not spend enough time ensuring that my lactate threshold ceiling was high enough.  I was not able to let these two systems replenish during my races because I was always racing right at my lactate threshold.   So, even though I was able to develop, in training, high power levels from these systems, I was not able to use this power in my races.  If I had a higher lactate threshold, i.e. I was able to generate more power aerobically but under my lactate threasold, then these energy systems could replenished and be available for use during the race.  The higher your lactate threashold the less the Anaerobic and ATP energy systems will be used until you need them.  The more times you use your ATP and Anaerobic system in a race the higher the fatigue levels will be.  The greater your power at lactate threshold the more often you are able to attack in a race and recover faster then someone with a lower power at lactate threashold.   The theory about the number of matches you have to burn is related to this.  With higher power at lactate threashold, you will be not burning as many matches as the rider who has a lower power at lactate threashold.   In addition, you need to be below your lactate threshold in order to replenish your ATP and Anaerobic systems, so if you can burn matches but recover quickly, you will be able to attack and attack.  So basically, this last year I had built a high tolerance for lactic acid in my muscles and the ability to generate a lot of lactic acid but I did not work my aerobic system hard enough to help me recover.  Criteriums are all about being able to attack and recover, and do it again.       

Ride Hard     

Steve