So in most triathlon training programs swims are distance based, and bike and runs tend to be time based. For example this plan

I am decently fast on the bike, but really slow on the run. In my HIM coming up I expect to complete the bike between 2:15 and 2:30 and this training plan has several bikes in this time frame, so no problem.

However, on the run, I am hoping that I can complete it in about 2:30, although I doubt I will. It will probably be close to 3 hours after the other two events. 11:27/mile gets it done in 2.5 hours, and the three hour mark would involve some walking.

Ignoring my slow speeds for a moment, this plan has the longest run of 1:30. To finish a half marathon in this amount of time, we are talking a pace of 6:52/mile, kind of blistering especially for a guy my age.

So my questions are:

Why are the runs for most tri training programs time based?

Why are the short in relationship to the bike?

Should I adjust up my running time or even do some distance based running?

What should be my long run when training for a HIM?

2 Answers 2


Most triathlon run training programs are time based, as that is the easiest metric to quantify. The generic plan doesn't care what pace you are at, it's just "go run X minutes". This makes it easier to coordinate different workouts and times. (Same holds true for bike segments, they are mostly time based as well). You will generally only have specific distances assigned when you have interval/threshold work to do. (Swimming is almost always distance based, however).

Runs are short in relation to bike training, because it takes longer on a bike to get the same results as far as training, and it reflects the emphasis on a distance in the triathlon. (There are always debates among athletes about changing distances to make them "equal" in importance, but they never lead anywhere). Simply put, it takes longer on a bike and it's easier for people to do.

If the time allows, I would absolutely bump up distances/times on all the segments. If you note, the training plan is to "complete" the triathlon, not "compete" it. There are much more aggressive programs out there. If you are comfortable on your bike training as it stands, then I would add in distance on the runs. I'd have to study the training plan to see where to fit them in, but more running hardly ever is a bad thing as long as you aren't sacrificing other workouts or adding too much intensity. (Also considering that you admit to being decent on the bike and poor on the run. Train your weaknesses).

If you are aiming at 2.5 hours for the run portion (Which is not shabby at all), then I would aim to have a long run of 1.5 - 2 hours. If you've ever done a half marathon before, that is enough. You will also get enough corollary training from the bike to help.

I've said it in other answers, but the best run training advice is "Run. Run lots. Mostly slow, sometimes fast." - The biggest mistake I've seen people make is to run too hard on easy days, and not hard enough on the tough days.

  • I am doing my first half marathon in about a month and will do a second one about four months, and about 2 months before the HIM.
    – Pete B.
    Commented Nov 8, 2018 at 19:31

So I have been reading a lot since I first asked this question and think I have found some answers. As JohnP said the example of the training plan is not very good and that needs to be considered.

Anyway here are the reasons, that I found, for time based runs over distance and why they tend to be shorter than the bikes relative to distance that needs to be covered.

Heart Rate Training

Currently there is much todo about heart rate training. That is most training should be done in Zone 1-2 or Zone 4. However most athletes tend to train in Zone 3, which is to hard for the easy portions of the workouts, and to easy for hard portions of the workouts. When reading about this there is quite a bit of research that found that athletes of all levels found it difficult to stick to heart rate zone targets when giving a distance goal, but easy when giving a time goal. This was found in the book 80/20 running.

Tri Runs Start with the Bike

I've read quite a few articles that state that in order to have a good tri run, you need to have really good legs. One article said that "in a tri, runs get ugly in the beginning not near the end". I have found this to be true. In my Sprint distance experience, the first quarter to half mile defined my run. The runs actually got easier as I moved past that point.

Bike rides help build run endurance, and are easy to recover

Some authors claim that biking is almost as good as running for building run endurance and does not lead to anywhere near the injury. I don't really buy this argument, one needs to run a lot to have good run fitness.

  • I think you are slightly misinterpreting what people mean by "the run starts with the bike", and the ugly comment in that if you don't have good biking legs/fitness you can't have a good run. :)
    – JohnP
    Commented Jan 2, 2019 at 19:45

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