Power Meters: A Beginners Guide – Part 2 – Putting It To Use

Written by: Editor in Chief

Now that you have a basic understanding of the terms used in conjunction with a power meter, it is time to determine your threshold power.  Understanding your threshold power is one of the first step to effectively utilizing your new power meter in training. There are essentially two effective ways in which to obtain your threshold power 1) by performing a laboratory blood lactate test or 2) by performing a field test for which many protocols exist.

What The Difference?

Taking a blood lactate sample
Taking a blood lactate sample

Blood Lactate Test

A blood lactate test measures the concentration of lactate in your blood drawn typically via pick on the end of your finger or ear lobe taken at increasing levels of power or exercise intensity.  Lactate threshold is usually defined as 4.0 mmol/L of lactate, which is a measurement of the concentration of lactate in the blood. Lactate threshold is essentially the point above which lactate begins to accumulate exponentially, and is produced much faster than it can be cleared away.  Blood lactate test typically run anywhere from $100-200 depending on your location – though your mileage may vary.  These are often the most accurate but given that you should test every 6 weeks, they can become prohibitively expensive over time.

Field Testing

Field testing is generally the accepted for of testing for the majority. It is usually performed in real world conditions, is repeatable in training, and has little to no cost involved.

Here’s a quick and easy way to calculate your FTP:

20 min Time Trial average wattage X .95 = FTP.

For example: your 20 min average power is lets say 300w.  Now we know 300*0.95 = 285.  So we now know we have an FTP equivalent to 285w. Now that we have a baseline we can begin to piece together our training zones. We also want to note the average HR for the last 15mins of the time trial as this correlates well to threshold heart rate.

You might be asking if FTP is the power one can sustain for an hour, why do we use a 20 min TT figure as opposed to 60 min? Effectively completing a 60 min time trial isn’t feasible for many of us, or easily repeatable on a regular basis. Using the 20 mins 5% methodology is much easier, fairly accurate, and repeatable. Also, for many of us it’s much easier to find an open 20min road or climb than a 60min stretch of road. However, if you do have power numbers from a 60 min TT  during a race please use that.

Power Zone Calculators

Most of the common sites used to track riding have calculator built in to them.  Here are some screenshots where you input the information with quick directions to get your zones setup.

TPZones
Click to View

TrainingPeaks

Go to Setting > Zones > Power > Input your Threshold Value (20min Test Average x .95)

Then select Auto Calculation > Threshold

Then select Method > Andy Coggan

Calculate

StravaPowerSettings
Click to View

Strava 

Go to Setting > My Performance > Input your Threshold Value (20min Test Average x .95) into field atbottom.

Power Based Training Levels (Coggan Power Zones) developed by Andy R. Coggan, Ph.D.

Level Name Average Power Average HR Perceived Exertion Description
1 Active Recovery <55% <68 <2 “Easy spinning” or “light pedal pressure”, i.e., very low level exercise, too low in and of itself to induce significant physiological adaptations. Minimal sensation of leg effort/fatigue. Requires no concentration to maintain pace, and continuous conversation possible. Typically used for active recovery after strenuous training days (or races), between interval efforts, or for socializing.
2 Endurance 56-75% 69-83% 2-3 “All day” pace, or classic long slow distance (LSD) training. Sensation of leg effort/fatigue generally low, but may rise periodically to higher levels (e.g., when climbing). Concentration generally required to maintain effort only at highest end of range and/or during longer training sessions. Breathing is more regular than at level 1, but continuous conversation still possible. Frequent (daily) training sessions of moderate duration (e.g., 2 h) at level 2 possible (provided dietary carbohydrate intake is adequate), but complete recovery from very long workouts may take more than 24 hs.
3 Tempo 76-90% 84-94% 3-4 Typical intensity of fartlek workout, ‘spirited’ group ride, or briskly moving paceline. More frequent/greater sensation of leg effort/fatigue than at level 2. Requires concentration to maintain alone, especially at upper end of range, to prevent effort from falling back to level 2. Breathing deeper and more rhythmic than level 2, such that any conversation must be somewhat halting, but not as difficult as at level 4. Recovery from level 3 training sessions more difficult than after level 2 workouts, but consecutive days of level 3 training still possible if duration is not excessive and dietary carbohydrate intake is adequate.
4 Lactate Threshold 91-105% 95-105%(may not be achieved during initial phases of effort(s)) 4-5 Just below to just above TT effort, taking into account duration, current fitness, environmental conditions, etc. Essentially continuous sensation of moderate or even greater leg effort/fatigue. Continuous conversation difficult at best, due to depth/frequency of breathing. Effort sufficiently high that sustained exercise at this level is mentally very taxing – therefore typically performed in training as multiple ‘repeats’, ‘modules’, or ‘blocks’ of 10-30 min duration. Consecutive days of training at level 4 possible, but such workouts generally only performed when sufficiently rested/recovered from prior training so as to be able to maintain intensity.
5 VOMax 106-120% >106% 6-7 Typical intensity of longer (3-8 min) intervals intended to increase VO2max. Strong to severe sensations of leg effort/fatigue, such that completion of more than 30-40 min total training time is difficult at best. Conversation not possible due to often ‘ragged’ breathing. Should generally be attempted only when adequately recovered from prior training – consecutive days of level 5 work not necessarily desirable even if possible.Note: At this level, the average heart rate may not be due to slowness of heart rate response and/or ceiling imposed by maximum heart rate)
6 Anaerobic Capacity >121% N/A >7 Short (30 s to 3 min), high intensity intervals designed to increase anaerobic capacity. Heart rate generally not useful as guide to intensity due to non-steady-state nature of effort. Severe sensation of leg effort/fatigue, and conversation impossible. Consecutive days of extended level 6 training usually not attempted.
7 Neuromuscular
Power
N/A N/A *
(Maximal)
Very short, very high intensity efforts (e.g., jumps, standing starts, short sprints) that generally place greater stress on musculoskeletal rather than metabolic systems. Power useful as guide, but only in reference to prior similar efforts, not TT pace.

 

There you have it.  The third and final installment will have some threshold bumping workouts for you.  Thanks for reading.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s