There are two types of muscles sprinters and endurance defined by your genes. You may not have the right muscles for it.
He can still sprint. It just won’t look like it. 
running coach 99+% slow twitch.
But earlier you were saying you wanted increased muscle tone also, so I was saying cardio is best for the fat loss, and bodybuilding for the muscle gain.
Again, if you don’t enjoy working out, I sympathize, and you’re fine to choose alternative methods. But you’re kidding yourself if you think the kind of dense body that elite weightlifters have is caused by working out.
Look at any model or actor whose body you would love to emulate, and then research how they got there. Just as you were surprised that most sprinters work out, so I think you’ll find “cut” looking models and actors also workout.
BTW
“If you’re a sprinter you run 100’s, you run 200’s - stuff like that. You don’t run 400’s or 800’s because I think you’re wearing out those fast twitch fibers and you’re working on a whole different system… the neuromuscular system is now firing at a slower rate as you’re teaching it endurance. You’re not teaching it explosive dynamics mechanics.” “…If you want to be a sprinter don’t spend too much time in the distance field”
“Whenever I train somebody… I get them to do sprint intervals because I think that would be the fastest way to lose weight…”
I like short distance sprinting… it is enjoyable but on the other hand going much longer makes me feel very exhausted.
You sure? I thought it was all from eating kale.
I think it is misleading to call bodybuilding a type of exercise (not saying you did) since it would include diet I think.
“It’s [sprinting] one of the few fat burning activities that can actually build muscle tissue instead of catabolizing it”
I think that means that cardio can cause muscle loss or at least I think marathon running leads to muscle loss - fast twitch muscle that is - slow twitch muscle is very hard to see.
I’m saying that weight-lifting alone isn’t good for fat loss. Sprinters always seem to have a low body fat percentage. Weight training would just add fast twitch muscle - I think their sprinting keeps their fat low (see the earlier quote).
Yeah I know celebrities work out - especially if they need six pack abs for their movie. My goal is a flat stomach - not big muscles. (for now)
Well I’m absolutely horrible at endurance. I’m below average at sprinting short distances but I’m still ok. BTW people can gain muscles - though apparently slow twitch muscles are hard to see. So I’m not going to bother with endurance (except for walking).
More pics:
115 lb / 52 kg marathon runners:
Obese weight-lifters
Sprinters (and 110m hurdles)
So my aim is no focus on endurance - just short explosive bursts
Having a lot of muscle mass makes it easier to maintain a low body fat. All that muscle is living tissue and requires calories even at rest.
Endurance training does not selectively destroy fast twitch. Someone who is naturally disposed to marathon running already is almost all slow twitch.
Even slow twitch muscles can gain mass. A considerable amount if you work at it.
Something to consider is that for less than national/ world class sprinters(after college), there’s little competition to be had so almost all the sprinters you see are highly motivated to stay in shape.
What you don’t see are those who didn’t have the speed or didn’t have the genetics for a very lean build and thus dropped out of high level competition.
At the time of my accident, I weighed 156@10-11% bodyfat.
Three years later, I rode a 100 miler on my handcycle while weighing 185@12% BF and bench-pressing 315 max.
It is possible to build muscle while doing cardio.
Sprinters do spend time in the gym, you’re not going to build the torso and arms on just sprinting.
Dean Karnazes-ultramarathoner.
Frank Bozanich-ultramarathoner
Then why are those weight-lifters in my previous pic so obese? Surely they’d do better if they didn’t have to lift their fat with their lifting. I think having a low fat percentage makes it easier for muscle to be catabolized (a guess).
I’m saying that maybe endurance exercise doesn’t improve fast twitch muscles much - not that it actively destroys it.
What about weight-lifters though. Why aren’t those obese ones “staying in shape”? I know lighter ones are less obese though due to trying to stay under the weight limit.
Interesting though Dean Karnazes has done swimming and swimmers seem quite muscular. For some reason ultramarathoners seem to have more visible muscles than normal marathon runners - I looked through quite a lot of Google image search results. Maybe it has to do with them storing a lot of energy for their big runs so that they don’t need to eat so regularly.
Part of it is overeating. Also, for the really big guys, they may not be as overweight as they look.
If you weigh 300 lbs @ 15% bodyfat ( a perfectly healthy level), that means you’re carrying 45 lbs of fat and since men tend to store their fat around the belly, guess how that looks.
Lighter lifters, trying to stay in a weight class are more likely to have lower bodyfat levels.
Unlike bodybuilders, weightlifters aren’t as concerned on low bodyfat as they don’t have to worry about having a defined physique.
If you have a little amount of fast twitch, you’ll be spending a lot of time for very little gain.
Maybe the muscle was actually being built by other exercise. I think the muscle from cardio would be minimal. Otherwise marathon runners would have more muscle I think. But anyway I don’t like doing cardio if I’m exhausted (even after a sprint of several seconds lately).
That’s a pity. Though if I did explosive sprints a lot I think my arms would get built slightly while I’m trying to build speed.
Ultras do have more big runners though there are plenty of the skinny types.
It does not help store more energy, the highest glycogen storage recorded was 750 g, about enough for at most 30-maybe 40 miles depending on a number of factors. Even highly trained runners don’t usually approach those levels, that’s just the highest recorded.
Then how do body-builders achieve low body fat? My guess is their diet.
But can’t their muscle be “catabolized” to get energy?
Don’t forget the marathon selects for skinny runners.
Cardio is not intended to build muscle, that’s what weights are for.
running coach:
I wonder for muscle development is it better to sprint every day or have some rest? If rest is recommended, how much?