We’ve all heard it. We may even have said it. “That lactic acid burn… lactic acid is building up and it makes me sore… lactic acid slowed me down…”
Well, lactic acid, or better referred to as lactate is actually an energy source which is critical to conditioning and performance. Lactate builds up in our blood stream as a result of exercise. Muscles actually love lactate for energy. When it can’t use all that is produced it spills over into the blood stream. The point at which it builds up at a rate faster than it is used by our muscles for energy is called the lactate threshold (LT). This occurs somewhere around 60-80% of your vVO2max (the minimal speed at which you hit maximum oxygen uptake). A pretty large range huh?
So, this first means lactate threshold which is commonly confused with anaerobic threshold are obviously completely different. Lactate threshold is most definitely an aerobic process.
There is something else which is very important to note. The way that so many coaches have espoused to improve your lactate threshold is to run for various lengths of time at your LT pace. This is not true! In fact, you have to run at a pace faster than your LT pace in order to improve your LT!
What does this mean to you? All you have to do is run your quality workouts at a pace that is at least at 90% of your vVO2max.
How do you know your vVO2max? Run a time trial of between 1600-2000 meters (6:00-7:00 of running all out). This will work for most age group runners; elite runners will run closer to 3000 meters. Now calculate your pace. That is your vVO2max pace.
Now, take your time and divide by .90. That will give you 90% of vVO2max pace. That pace or faster is ideal for improving your LT. Example: Time trial of 6:00 for 1600. That is 1:30/400. 1:30 divided by .90 = 1:40. LT workouts should be anything 1:40 and faster (all the way up to sprints).
You will find variations in finding your optimal LT enhancing pace. The key is to realize it has to be faster than your LT pace. LT pace for a well trained runner will be close to their 15k (9.3 miles) pace. Therefore, to enhance your LT you have to aim for 10k pace or better. This also means the typical “tempo” run will not enhance LT because it is most often run too slow. A proper “tempo” run should be just about 10k pace.
Bottom line, if you really want bang for the buck, running a variety of fast paced workouts (from your vVO2max pace to sprints) will not only enhance LT, it will enhance economy and vVO2max.
Now, for that lactic acid burn issue. Lactic acid is not a cause for slowing down. It is also not a cause for soreness. It actually appears that soreness in muscles appears to mostly be due to the three following things:
• Neuro-transmitters (chemical) issue
• Muscle membranes damaged
• Inflammation which irritates nerves
So, if you want to improve powerful markers of performance (LT & vVO2max & economy) run fast!