Test Your Lactic Threshold

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The reason coaches enjoy talking about Lactic Threshold (LT) is because it is so highly trainable. The key to everything in cycling is the balance between the rate of lactate production and lactate absorption. During light and moderate exercise, concentration of lactate in the blood remains low. The body is able to absorb lactate faster than the muscle cells are producing it.  As intensity increases, there comes a point at which lactate removal cannot keep up with the rate of lactate production. This inflection is called "lactate threshold". This is the beginning of the end of high intensity exercise. The bad news is that nobody can go above this level for very long. The good news is that through proper training you can raise your LT to new heights!

One of the important things you need to know about your body what your LT is. You don’t need a laboratory for this.  It’s easy.

Find a flat or slightly uphill stretch of road (avoid traffic lights, undulations or rolling hills). I go to an unused outdoor velodrome to do this. It’s perfect.

  • Warm up for at least 10-15 minutes
  • Ride a thirty-minute time trial and give it your best. You should finish with nothing left.
  • If using a HR monitor or power meter, record the last twenty minutes of your ride . – Your average heart rate or wattage over this period will estimate your HR or power at LT

I have both a power meter as well as a HR monitor. Both are quite accurate for measuring a long steady effort like this LT test.  Here’s the graph from my power meter on one of my LT tests (no world records broken here).

With your new found personal lactic threshold limit, you have an excellent benchmark where all your training intervals can be based on. Raising your LT will mean that "recovery" will be achievable at a higher power output.

After you’ve found what your LT is, a great workout to increase your lactic tolerance is "Over Under’s" . You basically ride slightly under your LT and then slightly over your LT.  These will hurt!

Overview: Warm-up for a solid half hr, then do 2x15min Over Under intervals with 5 min. recovery between each interval.  For this workout it’s best to find a flat road or steady gradual climb.  Even better to do if you’re stuck on an indoor trainer.

What to do:

  • 15min Over/Under interval: Ride at 95% of your LT and then every 2 minutes ramp it up to 120% of your LT for 30 seconds. Then recover back to 95% of LT (not below this). You’ll have 6 of these in total to complete the 15min interval. Take 5 mins recovery with an easy spin. Do this 15 min interval again.
  • Finish off with two VO2 max intervals at 2 X 5mins. This needs to be at 110-120% of your LT heart rate or power output. 5 minutes rest between each.

If using a HR monitor for these, remember not to go too hard right off the gun just to get your HR up. There is a good 30 second delay between your heart responding to your effort and the power actually being produced by your legs. This is not an ideal workout to be done with a HR monitor because by the time a 30sec interval is complete your heart will just start to respond.  You’ll have to go on your perceived effort at what 120% of LT feels like.  This is one of many reasons why a power meter is such an incredibly important tool.

This is one of many workouts that you can do to increase your LT.   If you think about it, this workout isn’t all that different from rolling turns with about 5-8 other cyclists in a group ride.  You go hard for 30 seconds and then drift back for some recovery in the draft.   Mix it up, keep it fresh, and most importantly have fun (and smash your mates while you’re at it!)

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