Sport Tracks Training Load Explained

Somewhere between the first and second month of using Sport Tracks I discovered the “Training Load plugin”.  The immediate response was, “Oh my god, you can track all of that?”  At first glance, the graph is just a big mess with all kinds of bars, lines, shaded areas, and acronyms that don’t mean much. Once you look under the hood a bit, you see that the graph is very simple and can be quite useful in determining you current fitness level, how rested you are, and tapering for a race.


To dig in, you’ll need to know a couple of simple definitions:

TRIMP – Training Impulse: This is an arbitrary score given to each training event.  This is based on your HR and duration for each given activity.  You can set up your HR training zones in Sport Tracks or leave them at their default.  Each HR zone is given a factor as you can see below.  So for example, my Bike for the day was 3:03:30, or ~ 183 min, with an Avg HR of 142.  The factors are incremental, so you wouldn’t have 1.8 for the entire HR range of 139 – 150.  The result is a factor of about 1.73.  So, 183 minutes multiplied by 1.73 gets you a TRIMP score of 316.  Same holds true for running. With Swimming you’ll get a 0, unless you’re using a HR monitor that works under water(nothing is perfect). You don’t need to make any of these calculations as this is all done for you with the plugin.  I just added it because I’m sure someone would ask.


CTL – Chronic Training Load: In Blue, is a measure of your Fitness based on your activities over the longer term like 45 days.

ATL – Acute Training Load: In Red, is a good measure of your current level of fatigue.  This is more of a measure of your current training load over the past 10 days or so.

TSB – Training Stress Balance: This is basically the difference between your most recent activities vs. over the longer term.  You can see below prior to 5/1, I went into negative TSB fairly consistently.  This was during the month leading up to a 70.3 race, so I had some longer rides, longer runs, etc.  A negative TSB means you’ve been doing more recently compared to what you were doing.  Positive TSB on the other hand indicates less work recently.

For those of you who want to know all the details about how this is calculated go Here.


Now, if you slide the graph over to the left a bit, you can project into the future.  I’m writing this on 7/17, so if I just kept my training relatively light, I would be set for a maximal effort ~ Aug5th.  However, if you do absolutely nothing, you can see how your fitness level is projected to plummet as well.

To choose a race date in the future, just click on the date on the calendar column on the left hand side .  Then under Training Load, Choose “Set Taget Date”.  Over on the far right-hand side you will see your Current Training Status. So my race is 11/6 and I suspect my last really long workout will be around 10/7.  Full Tapering will be about 10 days out.  Pretty cool, eh?

Cal Target_Date

Oh and I totally forgot the best part.  Sport Tracks is FREE!! The Plugins are FREE!!  Some of the plugins have a button where you can donate some money to the developer who created the plugin.  Some of the plugins are definitely worth a donation for the creativity.  To check out a full list, go to the Plugins Catalog page.

So, what Training Log software does everyone else use?  What is the best thing you like about it?

This entry was posted in How To, Ironman, Running and tagged , , , , . Bookmark the permalink.

5 Responses to Sport Tracks Training Load Explained

  1. Pingback: Training Logs for Triathletes | Jeff Greene

  2. Eric says:

    I started using this in SportTracks because of this article. But I’m curious about it for swimming. I’ve just manually entered an average HR of 130 on the summary page for the workout. That seems to do the trick. Is that it basically? I took my pulse twice after 500m, seemed to be an ok estimate. I only swim once a week so it’s not a huge deal, but would like those workouts to “count”.

  3. Jeff says:

    Hi Eric,
    Unfortunately, that is the downside. I tried doing the same thing by trying to figure out my average HR, but it just became too cumbersome with doing drills, intervals, pyramid sets, etc. Trying to remember all of that while counting laps seemed to not work out too well. So I just track the Bike and the Run, which is ok since you’re not likely to get ‘overtrained’ from swimming too much.

    I’ve pretty much been doing only swim drills for the last month since IMFL, so my graph looks like I’ve been slacking.

  4. the5krunner says:

    great article.
    re: swimming TRIMP

    I use 3 trimps per 100m with a wetsuit and 4 without. That is probably a little too HIGH.
    it’s good to see the overall load but I’m not sure that the inclusion of swimming helps (even tho I do it) as the load experienced when swimming is not the same as run/bike and by that I mean that 1 swimming trimp is not the same as 1 running trimp EVEN IF YOU HAVE HR Zones for each sport (which I do).

    here is another take on your article that I wrote:

  5. David Iott says:

    Jeff, thanks for the information here I have found it very helpful. I am just starting to use Sporttracks Training Load plugin to ST3 and also the Mobi browser version about one month ago. This tool is exactly what I’ve been looking for. I think that I understand ATL, CTL, TRIMP and TSB concepts and calculations based on the great info that you and others have provided.

    I just completed the Iceman Cometh mountain bike race in Traverse City MI this weekend. The Training Load plugin calculated a TRIMP of 450 for the race. I went into the race with a Performance score (Mobi) of 241. I completed the race successfully, hitting my time goal of 2:23, my average heart rate was 153, and I average 159 for over an hour of the total time (I’m 62 so I was working pretty hard) to achieve this time. One question that comes to mind — what is the appropriate Performance score for a given anticipated TRIMP? Should I have had a score much closer to the 450 TRIMP?

    Appreciate your thoughts on this as I would like to use the tool for plan and complete training for several races next year.

    Thanks very much,

Leave a Reply

Your email address will not be published. Required fields are marked *