Substituting Bike/Run for Long Run?

Triathlon Forum
1

I’m training for a stand alone marathon later in the year but there’s a half-ironman that I’d like to do that falls on a long run (23 miles) training day. Could the half-iron be an acceptable training substitute? I’d like to clock a decent time in the marathon.

Thanks.

2

just do the run leg twice =)
.

3

honestly though the point of marathon training long days is to get your muscles, bones, and joints adapted to the stress of a long run. A half ironman triathlon isn’t going to do that for you, even if it puts a similar stress on your cardiovascular system.

It isn’t your cardio system that is going to be in trouble at the end of a marathon, its your legs, hips, knees, ankles and feet.

4

I don’t think it’ll make much difference as long as you have been training consistently for the marathon. However, the thing you want to be careful of is going too hard in the half IM and not being able to fully recover for your marathon. That WILL hurt your performance.

5

Missing ONE long run shouldn’t make or break your marathon, especially if you are doing a half IM in place of it.

It’s not the same training effect, but one could make an argument that you’d be better off doing the half. It could simulate a marathon paced workout.

Be careful not to do this too close to your race.

6

Thanks everyone for your advice. Much appreciated.

7

a 1/2 IM is definitively not going to replace a 23 miles run when training for a marathon from a specificity perspective. but one in a while a change is needed.

However, assuming this is not your only long run nor the last one, I believe the 1/2 IM may have the same if not more benefit that your long run.

Firstly, it will be a change in your routine that your mind and body will greatly appreciate.
Secondly, racing once in a while is an important part of your training as it allows to simulate race conditions and/or push/shock your body.
Thirdly, while you will only run 13 miles, you will have biked 56 miles before which is not negligible on your legs (while preserving your joints, etc.) and swam 2 miles which will work your core!!

Cheers,
Fred.