Thursday, March 11, 2010

Aerobic Heart-Rate Workouts to Increase Endurance (then Speed)


I am NOT a skilled professional, but it is my amateur understanding that there are 30+ years of studies which show that exercise keeping the Heart-Rate 0-10 BPM below the Aerobic Threshold (AeT) builds (typically over several months) the endurance base required for all other running/cycling/swimming fitness. Typically over 95% of the energy used for endurance sports (events lasting more than a few minutes) comes from the aerobic system.
- A simple non-laboratory Maximum Aerobic Function (MAF) Test can be used to measure AeT improvements. One possible MAF test is to run+time 3 or 5 constant distance "intervals" (taking perphaps 10-15 mins each) at 180-minus-age constant AeT Heart-Rate (each interval will be slightly slower than previous one). Over many weeks the total time will decrease (speed will increase) and eventually level off.
- The AeT can be laboratory measured, or it can be reasonably estimated using “180 minus age” for fit individuals (there are +/- adjustments for some fitness factors).

The studies also show that the Lactate Threshold (LT, where more lactic acid builds up in your muscles than there is oxygen to carry it away) then becomes the major factor for extended endurance performance. Once the Aerobic base is established and stabilized, then Tempo+Interval+Fartlek exercise can be used to improve the Lactate Threshold as well as building short-term speed and power.
- The laboratory Conconi test can be used to accurately measure LT, or it can be reasonably determined with a simple non-laboratory Lactate Threshold Test running 10mins warmup then 30 mins constant Distance/Speed (measure HeartRate for each 10 min interval).  If each of the 2nd and 3rd HeartRates are almost identical that HR is your LT.  Otherwise run next weeks test slower or faster.
- NOTE: Initial training LT-HR will likely be 20 bpm below AeT,  somewhere around "Recovery-HR" in the table below. Much later, after Aerobic and Lactate training, it should get to around 20bpm above AeT as shown in the table  below:

Aerobic Threshold:

There are a lot of articles to do with "Maximum Aerobic Function" that strongly claim that FIRST you need to build your Aerobic Threshold (AeT) endurance ("slow twitch muscle", energy burning fat) which is the basis for most energy consumed during medium and long events (Carbohydrates stores are smaller and run out much sooner).
- At bottom of AeT (80% of LT) your energy typically comes from burning 75% fat (everyone has a large storehouse), about 20% from carbs, about 5% from protein (muscle)
- by actual AeT (89% of LT) you typically burn 50% or less fat, 45% is quickly consuming your much more limited store of carbs, and 5% from protein
- by actual LT you are typically burning 75% or more carbs and 10% protein (muscle), and less than 15% fat
- fat supplies around 38kj per gram whereas carbohydrates and protein supply 17kj per gram, so we burn more but get less energy as we shift through and past the Aerobic heart-rate zone, and there are also smaller stores available.

As your Aerobic energy efficieny improves, performance will improve (until you maximize Aerobic capacity). THEN you can build your Anaerobic power ("fast twitch muscle", energy burning carbohydrates) and start to increase your Lactate Threshold and your bodies maximum physical endurance. The focus on AeT seems to be widely agreed for any sort of endurance running. For example, see the following:
The above papers describe in detail the 180-age (+/-fitness) calculation to determine Heart-Rate to use for AeT improvement.

As well, some coaches are strong believers in walking intervals (during training and races):

Heart-Rate Zones (some different ranges and definitions):

Lactate Threshold:

Once you have Aerobic endurance maximized and want to increase your Lactate Threshold and speed+power, there are articles covering adding Tempo and Interval and Fartlek training to your distance/endurance base, such as:

What am I doing in my personal training?

  • I have carefully read various articles to understand the details, and have my doctor's approval for this activity.
  • I have stopped doing training based on the old-school "220 minus age" Maximum-Heart-Rate (train at 60-80% of MHR)
  • I am now doing all my training runs trying to keep Heart-Rate 0-5 BPM below Aerobic Threshold
  • I am recording the average speed/pace over that constant distance run (plotable as my personal MAF)
  • I expect to see improvements over the next 1-3 months, then (sometime) level off
  • I will then add in Tempo/Interval/Fartlek work to increase LT
  • RESULTS: Results are shown in a more recent (June) post

Comments Appreciated

- Have you tried this? Any comments or suggestions would be appreciated.
- I think additional/separate non-Aerobic activity is OK, it just wont help build the Aerobic base.

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