Training Speed

Q: How do I know how fast to train?

Q: What’s the difference between an aerobic and anaerobic workout?

Q: Which one is better?

To answer this, we need to understand how our bodies produce energy.   We have two primary energy systems and three basic ingredients that run these systems.  The three basic ingredients for producing energy are oxygen, fat and carbohydrates. The two basic energy systems are our slower Aerobic system and our faster Anaerobic system.  Aerobic means with oxygen and Anaerobic means without oxygen.   Our slower aerobic system is extremely efficient as long as this system has both oxygen and fat.   This system can be trained to last for an incredible length of time. (think, iron man and ultra races)   Now, if your looking for speed to PR in your next 5K your going to want to train your anaerobic system as well.     When you pick up thrunner_croppede pace from your comfortable aerobic zone you enter our faster anaerobic zone.   In this zone you’ll start burning through a much higher percentage of Carbs and not much fat.  This faster zone is also going to create an oxygen debt and build up lactic acid in your muscles.  The results are a limited time of speed before we have to slow down.   The more we train in our anaerobic zone the more efficient our bodies become at speed.   The more we train in our aerobic zone the more our efficient our bodies become at endurance.
There are countless varieties of training runs we can perform to improve both our aerobic and anaerobic energy systems.  I’m going to break things down into three basic type of runs.   The long runs, tempo runs and speed work.    Each of these run has a very specific goal and trains a different energy system.
Long Run
During the long run we use our extremely efficient aerobic energy system.   Arobic means ‘with oxygen’.  These runs are run at a comfortable conversational pace.  If you are gasping for air you’ve left the aerobic zone.   Our goals in this run workout to train the body to burn fat as fuel, store more glycogen and increase mitochondria all of which are going to make as a more efficient runner.     When we run too fast during these runs we’ll change energy system and no longer be able to accomplish our goals for this type of run.
The aerobic training zone is the most effective means of aerobic development.    I know it can be frustrating to run this slow, but this is where you will build your aerobic endurance .  Once you enter the anaerobic zone, you are no longer building your aerobic system of energy.
Tempo Run
This run is faster than your long run pace but slower than speed work pace.     The tempo run balances right between the aerobic zone and the anaerobic zone.  This is called your Lactic threshold pace.   Once you cross over into the anaerobic zone your body quickly builds lactate acid in your muscles.   Your lactate threshold pace should feel like what some coaches call “comfortably hard”.   During a race you’d be able to maintain this pace for almost an hour.   Greg McMillian says your lactate threshold pace is the most important determinate of a runners performance.  We need to incorporate these types of workouts into our training plan in order to increase your lactate threshold point.
Speed Work 
 Speed work is run in the anaerobic energy system.  These workout are run at maximal oxygen combustion otherwise know as VO2Max.  This is a less efficient yet very powerful system.  You’d only be able to maintain this speedy pace for around 10 minutes before the lactate acid builds up caused you to slow down.   Training intervals at this pace helps our body get efficient at processing oxygen and lactate acid.
To explain it another way, when you start increasing your pace you’ll change over from the aerobic system to the anaerobic system.    At this point the aerobic system can’t keep up with the demand for energy and the anaerobic system kicks in.   Basically it skips a couple steps to make quick energy.    The effects are a lactic acid build up and oxygen debt.    The benefit is that you can run faster, but only for a limited amount of time.  Start your workout too fast at the front end and your going to fatigue and slow down on the back end.
The good news is you can train your body to increase its aerobic threshold, lactate threshold, and anaerobic threshold.
Aerobic Threshold is typically around 65% of VO2 max
Lactate Threshold is typically around 75%- 90% of VO2 max
Anaerobic Threshold is typically around 90-100% of VO2 max
Most people have one speed when the go out on a training run.   They don’t run slow enough on long endurance days and don’t run near fast enough on the tempo or speed work days.   The take away from this article is that you need train your body at different paces.  Each workout you perform should have a specific goal behind it.   Your aerobic days should feel slow and easy improving your endurance.   Save the hard work for your tempo runs and speed workout days which will be improving your anaerobic system.      Training at different paces is a much more effective way of training.   If you want to improve your speed and endurance lets train at the appropriate paces!

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