Low HR Training

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Weight vs. Pace vs. HR (Read 37 times)

SD_BlackHills


    Has anyone tracked how weight really affects your performance?

     

    A friend of mine is obsessing about his weight.  Thinks he is too heavy to BQ right now and says he needs to lose 10 lbs before his race in April.  His outward appearance is lean.

     

    Personally, I'm a pretty lean guy and my weight will naturally vary from 147-152 lbs.  Occasionally I'll pig out and get up to 155 or really watch what I eat and get all the way down to 140.  However, I've never noticed a change in pace.  Some of my fastest running has been at about 150 lbs.

     

    I understand that the less you weigh, that you'll be faster at the same power output.  However, if you're already lean I don't think it's worth obsessing over even 10 lbs.  When I'm at my absolute lightest, it's because I'm operating at a calorie deficit.  I can't be sure but I'm guessing that at my lightest that my energy levels are probably not optimum and therefore have less power output???  In other words, is my friend (and by extension the rest of us) better off not worrying about it and race at the same weight that we carry naturally?

     

    Having said all this I'm sure that someone that loses a lot of excess weight will certainly be WAY faster at the same HR by simply shedding the pounds.  I'm referring to someone who is trying to go from lean to super lean.

     

    I certainly don't want to go through the exercise of logging weight vs. pace vs. hr (similar to a MAF Test) but if someone has already done this I'd be interested in seeing the data and sharing it with others.

    Bert-o


    I lost my rama

      I meant to reply a while ago, but forgot...  Our weight is similar (I'm about 147 right now) and I try to get down for big races (shorter races, I really don't care so much).  Best I could do was down to about 142.  But here's the irony... because like you say, there's a calorie deficit during training, when taper week came I shot up to 148 on race day!  Partly due to packing carbs, and from what I understand when you store more glycogen in your muscles, it requires more water retention.  I'm sure I was fully hydrated too.  Come race, I felt great!

       

      I do have all the data points - HR, pace, weight - for every run for the past two years.  It would be very difficult to see any relationship among the three though, because both pace and HR are far more affected by weather than by weight.  Also, when I start running from a hiatus or start to train hard, I think I'm also building more muscle mass, which also adds weight, but in a good way.  About a couple months into solid training will I start to see weight loss.

       

      In any case, I do think your friend is over-thinking it.  His goal should be optimal % body fat.  I wouldn't want to give up muscle, IMO.

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      SD_BlackHills


        I meant to reply a while ago, but forgot...  Our weight is similar (I'm about 147 right now) and I try to get down for big races (shorter races, I really don't care so much).  Best I could do was down to about 142.  But here's the irony... because like you say, there's a calorie deficit during training, when taper week came I shot up to 148 on race day!  Partly due to packing carbs, and from what I understand when you store more glycogen in your muscles, it requires more water retention.  I'm sure I was fully hydrated too.  Come race, I felt great!

         

        I do have all the data points - HR, pace, weight - for every run for the past two years.  It would be very difficult to see any relationship among the three though, because both pace and HR are far more affected by weather than by weight.  Also, when I start running from a hiatus or start to train hard, I think I'm also building more muscle mass, which also adds weight, but in a good way.  About a couple months into solid training will I start to see weight loss.

         

        In any case, I do think your friend is over-thinking it.  His goal should be optimal % body fat.  I wouldn't want to give up muscle, IMO.

         

        Good point on the body fat %.  I think that is correct.  I don't know how many of us have an accurate way of measuring that but totally makes sense.  I just don't think that a few pounds (+/- 5) will be the difference between a PR or not.   I think conditioning and weather play far bigger factors.   I think it would be different if we were Olympic athletes.  I suppose if your conditioning is at an absolute peak then yes, 2-5 lbs would be worth it (maybe).

        BeeRunB


          I've kept  track of my weight over the years and there is an effect. Plain old physics says that under the same conditions and fitness more weight will make one slower 1-2 seconds per pound per mile. Also, one has to take into account that more fat means your body dissipates heat slower. Like running in a blubber suit. So that 1-2 seconds per pound might be a little more time  the fatter one gets. Currently I'm 30% body fat, and my times always start out this slow when I'm that fat and not fit.

           

          Has anyone tracked how weight really affects your performance?

           

           

          SD_BlackHills


            I've kept  track of my weight over the years and there is an effect. Plain old physics says that under the same conditions and fitness more weight will make one slower 1-2 seconds per pound per mile. Also, one has to take into account that more fat means your body dissipates heat slower. Like running in a blubber suit. So that 1-2 seconds per pound might be a little more time  the fatter one gets. Currently I'm 30% body fat, and my times always start out this slow when I'm that fat and not fit.

             

             

            Can you share the physics on the 1-2 sec per mile per pound statement?  I'd be curious to see the math there.  I too have heard this but suspect it is more of an old wives tale and a flat out guess.

             

            My concern is the fact that when you are already at a lean body weight that your body is genetically comfortable being at, that it is bad to go under it.  In other words, I think it is difficult to maintain your body's power output if you are underweight or lacking nourishment.  So if your speed is a ratio of power to weight then if your weight goes down and you maintain or even increase power than that's great!  But, if you become weakened by the weight loss, so does your power which is not desirable.  There is a local cross country runner that was recently hospitalized for malnutrition probably because he looked at every single pound as being critical to racing.  I think the correct physics will tell us (if anyone has the math) that there is a point of diminishing returns that eventually turns dangerous.

             

            I totally agree with having more fat and dissipating heat more slowly.  My last 2 races were pretty warm at the finish (high 70's and low 80's) and was surprised at how well I had handled it running at a lean (but safe) body weight.

            BeeRunB


              I don't remember the formula, though I have seen it a long time ago that showed how they figured the 1-2 seconds (or maybe it was a study). Though, common sense (layman's physics) says that if one gets to a starting line and suddenly carries twenty pounds extra weight from fat (not muscle) that one will be slower. It will take extra oxygen and work to be able to go the same speed. Here's a good page:

               

              http://blog.airiarunning.com/weight-affect-running-speed/

               

              Also common sense that if one is losing muscle weight, then one is losing some strength, and ability to accelerate and apply the necessary forces to push off the ground to be fast. If I put on ten pounds of muscle from running, I'll be faster. If I put on ten pounds of fat from eating, then that will slow me down. Heavier runners can beat lighter runners. Depends on the muscle/fat ratio.

              SD_BlackHills


                I don't remember the formula, though I have seen it a long time ago that showed how they figured the 1-2 seconds (or maybe it was a study). Though, common sense (layman's physics) says that if one gets to a starting line and suddenly carries twenty pounds extra weight from fat (not muscle) that one will be slower. It will take extra oxygen and work to be able to go the same speed. Here's a good page:

                 

                http://blog.airiarunning.com/weight-affect-running-speed/

                 

                Also common sense that if one is losing muscle weight, then one is losing some strength, and ability to accelerate and apply the necessary forces to push off the ground to be fast. If I put on ten pounds of muscle from running, I'll be faster. If I put on ten pounds of fat from eating, then that will slow me down. Heavier runners can beat lighter runners. Depends on the muscle/fat ratio.

                 

                Right.  If you have 20 pounds to lose then there is no debate.  If you are already lean and strong, then I guess that's where my argument with my friend was.  If he chooses to starve himself in order to potentially run a faster marathon then that's his choice!