Is it necessary to be thin to be a strong runner?

Depends on your defintion of a strong runner. I knew one guy in basic training that looked like a small arnold and could run 2 miles like the wind, I was suprised. He will probably never be top notch marathon runner, however. Typically, the heavier you are, the harder long distance and endurance sports are for you. If if is heaviness due to fat, slef explanatory. If you are very muscular, those muscles need oxygen to function and you will tire easier than a person who is basically thin endurance machine.

I think to be fast for longer distances (Marathon or longer?), you do have to have a lower bodyfat % and Lean muscle.

I am 5'10" 175lbs(as of today). I run anywhere from 5-10 miles on a given day and can average from 9-11 minute miles depending on my reslove.
I have no doubt that as I get lighter(25 lbs left to lose) I will get faster and stay stronger, however, I think I am a pretty descent runner as is. So, No, I don't think you "HAVE" to be thin to be a stong runner but, it definatly helps. Especially if your looking into distance running.

I completed my first race this weekend, a 4-mile one. I was proud of my time ( sub 9 minute miles), but I was mostly in awe of the runners who were there doing the 10 mile race. I noticed that almost every single one of those runners doing the 10 mile race was thin. The four mile runners were very varied--many different body types--but the 10 milers were all very lean.

So I'm asking this: to be a strong long-distance runner who is able to run and not walk the distance, is it necessary to have a fairly low BMI? I have always been around the top of a healthy BMI--would it be necessary for me to lower it in order to be successful at the longer distances? or does it just happen that most people who train that hard are thin?

Recently ran a half-marathon at a 10-minute-mile pace (didn't walk a step). My BMI isn't high, but it isn't low either (23.19--I'm 5'8", 152.2 pounds). Trust me, you can be just as successful at long distances as anybody else--I trained incredibly hard for this half and didn't lose a pound (though I did lose inches) and I'd consider my time a fairly successful one.

I think you might be confusing cause and effect... Are they strong runners because they are lean? I doubt it. They are lean because they regularly run long distances in preparation for the 10 mile race. Chances are if you made that 10 mile race your goal and trained for it you'd be leaner by the time you actually ran it. Just guessing!

Depends on what you mean by strong. If you mean fast, like olympic marathoners running 7 minute miles, then yeah you probably have to be pretty thin. But that's not a be thin to run thing.. that's a be thin FROM running. Those guys are eating well and running 100s of miles a week, that's *****in cardio.

I completed a half marathon at somewhere around 285 pounds, but I wasn't quick about. I averaged like 14:30 miles.

from running consistently the body will adapt accordingly to enable you to become a more efficient runner by dropping bodyweight (fat and muscle) and lowering ur BMI

That's a good question. I ran some college track and the body types fell into three categories. Sprinters (less than half a mile) were "stockier" in build. They had incredible capacity to build muscle and spent more time doing it for explosive bursts of speed. My best friend was a sprinter and often complained about her thighs not being able to fit in her jeans any more because they were so muscular, but in contrast she could probably toss me 200 yards. The middle distance runners (half a mile to a mile distances - which is what I am: 5'9.5" 135 lbs now, 124 lbs then) were lean but we had middle capacity to build bulk. We didn't really want a ton of bulk, we want a medium amount. We also ran cross country but we usually weren't the best at it. The best long distance runners had the least to carry with them. Tiny little girls with tiny bone structures (if you watch the elite marathoners on TV they are like 5 feet tall and could fit in your suit case). They lifted rarely, and gained most strength from training. That being said our nutrition was DEFINITELY sub-optimal. It seemed like we could never get enough food in. In the long and middle distance crews menses were lost or greatly diminished, and stress fractures were the norm (aka I was basically the only girl on the team that got away without one likely due to the fact that I started with higher body fat than the other girls - read: normal . This is NOT GOOD or healthy for the body. By training 60+ miles a week it's hard to maintain anything but a lean body habitus (and remember we weren't appropriately nourished).

All that aside, it is very important to remember what healthy means for you. Many of the leaner intense long distance runners in college are not healthy. I put myself at risk for osteoporosis dropping down to 124 considering my bone structure lends itself to a medium build (and made my poor mother cry!), you are likely much healthier than I was right here and now. Your under 9 minute miles is AWESOME, and truly an accomplishment. Your body may become leaner if you wish to train for those longer races by default but don't forget to increase your calories accordingly, and listen carefully to your body if uncharacteristic aches or pains come up that may foreshadow serious injury. You may indeed be the sort of woman whose body's ultimate athletic potential l is built more for middle distance or sprinting or some other field event in the end (which is powerful and beautiful as well , but we don't have a lot of local sprints or hammer throws out there, and longer distance races are fun and challenging to run and train for. I have found it better to focus on overall health (which means not ignoring weight training despite my hatred of it, as well as increasing my food intake to appropriate levels leaving me a fat pad that protects my bone health). Your body type sounds similar to some of the most outstanding rowers I have had the pleasure of meeting!

it really depends on your fast versus slow twitch muscle fibers. A lot of it is genetic, you're born with more of one type than the other. Slow twitch muscle fibers use oxygen to generate energy and are typically for endurance, while fast-twitch ones are typically for short bursts and tired quickly (look at a marathoner compared to a sprinter).

I can't remember exactly, but in my Anatomy and Physiology textbook I think I remember it saying that your muscle can convert to another type and back, but only to an extent that is independent for every person. So its probably not necessary to be thin to be a strong runner (in the distance sense) but you will need more of those slow twitch muscle fibers if you want to go further without getting fatigued easily.

MelKut -> not a bad summation! :-). being in med school, I tried to refrain from that type of stuff, but yes that's a HUGE part of the equation. Well done

very interesting

chiquita1984 - sounds about right . Do you start coughing in short-quick spurts here and there? You use an albuterol-based short-acting inhaler I assume? I rarely need mine anymore. On bad days I sneak a methylprednisolone tab (perks of being in medicine) which decreases inflammation in the respiratory system

Well, depends on what your goal is. I have a more compact build, athletic and stout, certainly not the typical runner build with long, lean muscles and super-low body fat, and I don't go very fast (my default speed for long runs is around 10:45-11:30 minute miles). But I can keep going, and going, and going. I'm built for distances at slower speeds, which makes me happy, because I love trails, and long runs in the middle of nowhere. I want to run an ultramarathon someday, and most of the ultramarathoners I've seen are not build like elite marathon runners. A majority are built like me, with thicker muscles, not the super-lean of the elite runners. Of course, they're not going for crazy-fast times, because that's not what you need on 100 mile trail runs through the mountains.

If you want speed, though, more often than not, the leaner you are, the faster you'll tend to go, with training, because you'll be carrying around less mass, which naturally translates to speed. But not all strong runners are fast, and not all fast runners are strong. There are different goals with different runners, and you can focus on different goals, and be strong with yours.

Right, I understand that there are tons of thin people out there who can't run. People can run because they train for it, of course. I am just wondering if a BMI on the high side of normal would hold me back, or if I trained hard enough, having a high-normal BMI wouldn't set me back or affect my time/distance.
But as one commenter said, maybe I'd lose weight/inches anyway, from training so hard.

It is likely that a heavier person can train themselves to run longer distances and to run them "strong" (by "strong", I mean to finish with a good, steady pace).

It is also true that lowering weight will improve almost anyone's performance. So, while a heavier person can successfully and enjoyably "run strong", they will probably not be at their peak performance level. (And I am not saying that should be the only goal).