The Brick Run Conundrum

Since I began triathlon I’ve hated brick runs! Sometimes I’ve tacked on extra bike mileage as an excuse to avoid them. I wanted to state my prejudice before I wrote any more on the subject. I get the impression most triathletes love them and most Ironman athletes like them very long. I’m not about to suggest you avoid them, but question how much you do.

Specificity is a common theme of mine, it’s important how you train is relevant to your event and what could be more relevant than a brick session? I won’t devalue them for that, if you’re unfamiliar with the experience of running off the bike it’s worth practicing. My problem is with them as run training. Too often I’ve seen athlete’s blame disappointing run performances on insufficient brick sessions.

It would be a rare case where a lack of bricks was the cause of a poor run, yet they’re held in such high esteem. Perhaps a short course athlete has more to gain, but if you’re struggling with a marathon after a 112 mile bike you’re problem doesn’t relate to bricks. Run performance relates to your run and bike fitness and how you’ve paced the race, suitable training along with a well executed race plan deliver run results.

Given my dislike you may be wondering why previous posts have brick sessions in their plans. It’s a matter of time efficiency, especially when you see more than one in a week. Allocating time straight off the bike is usually easier than scheduling an entirely separate run. These brick runs aren’t key sessions, but they increase run volume and help time limited athletes develop run fitness.

In my early career time efficient run volume gains were the main reason I utilised bricks, but once full time I experimented further. Whilst living on the Gold Coast I tried running off every bike, over a month building from fifteen to forty-five minute runs. I’d added four hours run training to my week by the end of that block and the race that followed went well.

You can’t draw conclusions from a brief experiment, but the result wasn’t enough for me to adopt the practice. It’s impossible to tell if any impact in performance was specifically a result of brick running or simply because of additional volume. Periods of high run volume have yielded better results since so I suspect the increase wasn’t significant enough. I see advantages to running more, but little significance in whether extra running follows a bike ride or not.

For Ironman triathletes brick sessions can form a challenging training day and well executed are a good test of race pacing. An occasional four hour ride followed by an hours run makes for a solid day’s work (consider adding a swim too). My aim in these sessions is to build the effort on the bike and finish with a lot of race pace work then repeat that process over the course of the run. Building into race pace in both ensures this should be a tough session that gives feedback on race pacing.

I use these sessions sparingly, perhaps once a month and not at all over winter. My preference is to split bike and run over the day, it gives time to recover and eat so I run better later on. Learning to run on tired legs is often given as a reason to brick run lots, but I’m concerned too much reinforces poor run form. Rested legs will run better and the bulk of run training should be done with an emphasis on running well.

Fatigue is a natural part of the training week so you run on tired legs anyway. The long run delivers this experience, after an hour or two it takes effort to continue running well. A structured program should deliver enough run volume, but also enable some of those runs to be performed fresh. Brick sessions can fit in there, but shouldn’t dominate.

In training plans I tend to place the weekly brick run following a shorter threshold bike session. Logistically it’s easier to manage and the hard bike guarantees legs are in no fit state for running. A short well paced run after gives a good sense of leaving transition without too much impact on recovery. Those long brick sessions always concern me, if you push then the affects could carry into the next few days.

I’ve seen Ironman plans with serious brick workouts built around long bikes followed by two hour runs. If you can do that and recover to train as normal afterwards great, but I’d seriously consider their value. The training load achieved is comparable with racing which would be a far more enjoyable way for the same result. I want long bricks to be challenging, but I don’t want them to break me down to the detriment of the following week. This sort of session needs recovery, you’d be better dividing the work over a couple of days and keeping consistency.

I won’t deny there’s prejudice involved, but consider whether bricks are going to give you the improvements you want. Don’t remove them from your plans, but when you want to run better in triathlon don’t turn to them as the answer either. Run performance in triathlon is highly dependent on how you’ve paced your bike relative to fitness. To make improvements look to develop bike fitness further as well as working on run fitness. In the overall scheme brick sessions are fine tuning.

Ironman Training Library

From nutrition to pacing - a collection of CoachCox blog posts focused specifically on Ironman training and racing.


  • James D

    Russ, while I agree with your comments regarding making sure your recovery isn’t impacted by long bricks, I still see real value in them each week during the big training weeks leading up to an ironman.

    I use long bricks (up to 3 hour ironman paced ride followed by a run up to 2 hours at ironman pace) as a way getting my body used to the fuelling and pacing requirements. The three hour ride should feel easy, and the run only should only become tougher towards the end if your paces are right. The pace does need to be realistic and can be a reality check.

    As you said, there are many ideas about long bricks, but I find that I can schedule one of these a week (building up to the times above) and still recover for the weekend sessions. I do this by having Thursday off work which allows me to put super recover techniques into practice for the rest of the day.

    Don’t get me wrong, I agree with your post, but don’t write-off the long brick as a real value long training session that could be repeated week after week as one of your Key Ironman training session!

  • James,

    Some people probably can cope with the session, but not everyone. Part of the problem is that a 3 hour Ironman pace bike and two hour Ironman pace run, if fully glycogen loaded can be completed without much need for fuel (you could get away with under-fuelling). Well rested I could complete that session at my Ironman pace without eating, it’d be tough and require a lot of recovery.

    I think the long bricks highlight major mistakes and can be a quality session, but I don’t think they’re essential to determining pacing or fuelling strategies. I’d rather have a more challenging ride in their place and not need so much recovery the next day. In terms of race pace/fuel practice I’d rather a longer bike and shorter run too, if our concern is ensuring we’re sparing glycogen through feeding the bike is critical. Lengthening the bike portion gives a better test.

    Clearly it works for you though and that’s the main thing. It’s also given me another idea for a post on training for fuel efficiency. I never specifically thought about it in the past, but I seem to be quite fuel efficient, how much is genetic and how much training is another question.


  • James D

    I am starting to see a pattern with our questions/responses. It seems that I will always fully ‘fund’ my glycogen stores for all training sessions >2 hours (i.e. I take 200-300 Kcal/hour while training) and you seem to take the opposite view, preferring to rely on your fat stores and ‘sip’ your glycogen stores. I do this for the sole reason of recovery. If I don’t take in sufficient kcal while training, my recovery is impaired and my ability to back up my quality sessions is in danger.

    It seems that you have become extremely fuel efficient over the last few years of consistent big training weeks (and based on your metabolic testing etc), which I would therefore say is 90% trainable.

    As I am time limited with the total training I can do, I have never had the time to train my fuel efficiency to the same extent (very low fuelling rides), without negatively impacting the rest of my training.

    I am looking forward to your post on this topic.

  • Certainly true I’ve spent a lot of time training on very little and the result seems to be combined with high volume I’m pretty fuel efficient. Trouble now is teaching myself to eat a bit more in training! Certainly learning the advantage of taking in more before harder sessions (and during), but still comparatively a low eater.

    Interesting post here – seems that the top performers in Ironman are consuming a lot more than I do on the bike in the race. Think there’s room for me to mix some practice of that into my sessions. It’s all about the glycogen reserves come the run.

    I think there are some sessions time limited athletes can do (good article by Torbjorn Sinballe in Inside Triathlon recently) to help. Not starvation training or bonk training or similar, just tightly managed calorie consumption. Xtri carried this piece by Jesse Kropelnicki on fuelling training – recommends practicing race fuelling there.

    I’d say on the fuel side of things there’s a balance to be had, I need to swing more to the fuelling side a little. That said, you’d still not get me doing a 3hr bike/2hr run brick! 😉