I run about 30 miles a week, far more than most people of my age, and I’d like to measure how hard and how much I’m working out. Specifically for my workouts, I want to monitor
a) the total expended energy (workout Load)
b) the average energy expended per unit time (workout Effort)
c) the peak energy expended per unit time. (workout PeakEffort)
d) work per mile or vertical distance
I want to do this without fancy equipment or lots of statistical analysis. Let’s look at each, but first let’s see how we measure workouts.
NB: I have a spreadsheet you can use if you like. ping me.
Workout Measurements
I use 4 metrics:-
a) Workout Effort
b) Workout Load
c) Peak Effort
d) Work rate (per min or mile or vertical distance) ... and inverses
e) Lactose Threshold
Inputs
You need to record only 5 things 1) average heart rate, 2) workout duration 3) maximum heart rate 4) distance 5) elevation gain
How hard was that workout? This you can measure from heart rate performance. If your heart rate stayed at the resting heart rate (Hr) then you didn’t work out, you slept instead. If you did a very, very short HIIT session then your heart rate was probably close to the maximum heart rate (Hmax). By the way, I do NOT do HIIT sessions (see “personal worst” above).
On a normal workout you need to measure your average heart rate (Hav). Then a greater Hav during of the workout means your Load was greater. Sure, but by how much? As we age, our hearts age, our fitness decreases and so an Hav of say 140 beats per minute (bpm) is quite low for a 25 year old but it’s absolutely knackering for a 66 year old like me.
So we really need a comparison. We need a measure of our possible heart rate range and this needs to change as we age. There’s a measurement called the Hrr, heart rate reserve, which is the difference between your resting heart rate your max heart rate. So Hrr is really a yardstick for your heart, it shows you what’s the range over which you can push your heart, and it’s linked to your age by your Hmax. You get Hmax from (220 - your age) or (206.9 - (0.67 x age)) - unless you have access to a sports physiology lab and piles of cash so you can get a proper test. You will also need your resting heart rate, Hr, which probably means you need to wear your fitness watch or monitor thing, to bed a few nights. Note that this will be lower than the heart rate you get just sitting around the house watching the telly or relaxing
Then the Hrr = (Hmax - Hr)
So now you can compare your workout’s average heart rate Hav to the possible range over which you can push yourself, your Hrr. Of course you need that as a relative amount (percentage) because your 25 year old heart could operate over a much wider range than your 65 year old heart (eg (195 - 60) > (155 - 60) ).
Workout Effort
As I’ve defined the Workout Effort as the average energy expended per unit time, the formula for this is
Effort = (Hav - Hr)/Hrr
Or, in English, how much above my resting heart rate did I keep my heart working during the workout, as a percentage.
Workout Load (or total effort)
As I’ve defined the Workout Load as the total expended energy during the workout, the formula for this becomes
Load = Effort x workout duration
Or, in English, for how long did I keep my heart rate working at this effort during the workout
NB: This is a relative load rather than an absolute load, ie how hard did I push myself compared to my absolute maximum (when Hav=Hmax).
Workout Peak effort
We can only get this from looking at minute by minute heart rates rather than the workout’s average heart rate. So, you can get this as Hpeak from Strava, probably most other apps, but it’s not in Apple Watch fitness, you need to go to the Apple Health (which is annoying). So we get,
PeakEff = (Hpeak - Hr)/Hrr
Work Rates
There are several ways to measure the work rate. per mile (and miles per work)
Work/min - W/min = load/duration
Work/mile - WpM = load/distance
Miles/unit work - MpW = distance/load
Work/elevation gain - WpV = load/vertical gain
These may sound arbitrary but in combination may be useful over the long term. For example, if MpW increases over the year that means you can go increasingly far without stressing your heart. However, this assumes your runs haven't changed! So, check that WpV and W/min don't change. So a good graph would be MpW and WpV and W/min over time. Actually, the WpV is less informative eg you can still work hard even if you have a net downhill - which is hard to graph - so we won't graph this.
Best long term Performance gauge: If you graph MpW and W/min then if your performance is improving then we'd expect to see MpW increasing and Work/min decreasing (or staying the same) over time.
Lactose Threshold
To train best you should train around your Lactose Threshold (I'll add stuff about this once I've done a calibration run to figure out what mine is). Apparently*** this is 80-90% of my max heart rate Hmax (so if Hmax=155 then LTR is 124 - 140 bpm).
These are the metrics I use, they’re all available from Strava or Apple Watch and can be put into a spreadsheet easily.
Best long-term Performance gauge
An even better gauge of long-term performance is to plot MpW and W/min. If your performance is improving then we'd expect to see MpW increasing and Work/min decreasing (or staying the same) over time. In the plot below, we can see that towards the end of the period I was covering slightly less distance but working harder.
Notes on Relative Effort, Zones, Trimps, RPE
There are other workout measurements. I don’t use them primarily because they’re too tedious and slow to calculate or they’re based on younger people or hidden algorithms. As Albert Einstein said, keep it simple but not simpler.
Workout zones - these are an artifact based to some extent on the lactose threshold of athletes. Firstly, they need to be calculated based on your resting heart rate, which is possible in Strava but I want custom zones due to my heart issue (which appears under load) and Strava doesn’t actually use custom zones.
Trimps is a way of using workout zones and comes in a variety of forms (eTrimp, iTrimp etc)
Strava has the Relative Effort. Its calculation is hidden but I think it accumulates previous days’ workouts and possibly Trimps. This is totally useless to me
RPE, the Perceived Rate of Exertion is more of a smeared out wishy washy way of doing my calculations, at least as far as running workout is concerned.
Maximum Heart rate, Hmax is either (220 - your age) or (206.9 - (0.67 x age). I use the former, not the latter (Borg calculation). This is because, while I have got up to the Borg Hmax value, I don’t want to have a heart attack just to prove a point. the (220-age) apparently underestimates Hmax but listen to your heart!
Enjoy your working out
no worries
Norm
Addendum
1. I forgot to mention, naps - take naps. They're good for you :)
2. Just to show you how utterly useless Strava's performance metrics are consider this snippet from my spreadsheet below.
Strava thinks the Releative effort os only 56 and 60 (rows 15 and 17) despite the runs being knackering with Peak Efforts near 100%, Loads of 99% and 104%. Whereas it reckons that row 9 has a Strava Rel Effort of 148 ... almost 3 times as hard! Crazy!
Specs details
i need the following program. inputs age (age) in years (a real number between 6 and 120), resting heart rate (Hr) in bpm (between 30 and 130), run duration (t) in minutes and workout average heart rate, (Hav) in bpm (between 30 and 230), workout peak heart rate, (Hpeak) (between (between 30 and 230). It outputs a blank line the maximum heart rate Hmax = (220- age), heart rate reserve Hrr = (Hmax - Hr) and Effort = (Hav-Hr)/Hrr. It also outputs the Load=Effort*duration/100 and the PeakEffort=((Hpeak-Hr)/Hrr). The Effort and PeakEffort are output as percentages It needs to run on a Mac laptop in python 2.7
4. Writing the workout calculator in a spreadsheet program is much easier. That's what I do as I want the history in any case.
5. Using AI to write an smartphone app to calculate the workout metrics is a bit harder. I'll do that later
6. the Chrome browser extension called Elevate gives you some extra performance details but I'm not convinced of their validity
References
*** https://marathonhandbook.com/average-lactate-threshold/
