Home Chat General Chat

Racing and %MHR

Easy enough question, really what % do you race at?

main race this yr is middle distance so any suggestions?

i know its meant to be just below aerobic threshold ( well i think so anyway..)...about 75%?!

But..i ran MK half marathon on sunday and avg %MHR was 82%....and felt great, so i'm a bit confused



  • danny_sdanny_s Posts: 235
    I'd never race with a HRM on. If I'm doing an A race and not giving it everything, then whatever my heart rate is just doesn't matter. Racing, just due to adrenaline and maybe caffeine you're taking, will give you a bump anyway.

    I'd keep track of speed and time. Gauge your effort by your perception; if you don't have a monitor telling you to slow down and you feel good with 5k to go, push it to 90-92%.
  • Jack HughesJack Hughes Posts: 1,262
    danny_s wrote:

    I'd never race with a HRM on.

    I'd sort of second that.

    I do race with the HRM on. But to record the results for the post mortem afterwards.

    I set my pace either on a specific target pace e.g. for a 10K running road race, 4 mins per k, or whatever (if doing negative splits).

    I will glance at the HRM to see if I am being lazy - i.e. when the pace drops, or it is just too hard.

    The HRM is best used to help interpret your race performance, rather than being a metronome!

    use the HRM in training, to make sure you are training at the right level - typically, to help you run SLOWER than you naturally would.

    For example, a recent 10K on a reasonably flat course: Set the objective for 4min Ks (wasn't too worried about negative splits - but hopefully, the last 2K would be the fastest).

    I always start off a bit quick, so the first K is usually a bit too fast, then settle down to the Pace.

    What I notice is that (climbs etc. excepting) the heart rate will gradually increase (once the initial "warm up" in the first K has been reached). In this race, I was at 166 bpm (average for the K) rising to 169 bpm by the 8th Kilometer. For the 8th Kilometer I started to push the pace, dropping to about 3:50 pace. In the 9th K (averaged 169), the heart peaked at 182. This corresponds to me "blowing up". Heart rate then slumped - It wouldn't go above 164 (except for the final sprint to the line). More importantly, my pace dropped off completely: 4:30 for the last two K, so I lost a minute of my target time.

    The post mortem shows that I was going too hard: My HRmax is 183 (176 if you use the age based formula) - so I was generally going between 91% - 92% for the first 8K. Then hit 99.5%!

    Now you could say this is an reason for racing with an HRM - but it would be just too inhibiting, and given the amount of variability, too misleading.

    By the time of the race you should know what you should feel like.. use the HRM to motivate etc.

Sign In or Register to comment.