Today’s Training: 40 minute tempo run. Because of my long run this week, my schedule called for a shorter run today. I find it hard to listen to tapering suggestions sometimes- I want to run far all the time. But I can’t afford any injuries, so I oblidged. It was a muggy, damp, early morning- and dark. It’s starting to get light later again- know what that means?! It’s almost FALL!!! 🙂
So onto those Olympic runners- boy do I miss them! What did we do before the Olympics?! My sister raised the question to me, why are the marathoners so thin while the sprinters are very muscular? I was flustered to find the answer- I remembered something from college about muscle make up. I wanted to answer her with the right information. Afterall, there will be a test on this tomorrow- so pay attention! I don’t want anyone to lose sleep over it, so incase you’ve ever wondered too- here’s why:
Notice Mr. Marathon to the left and Mr. Sprinter to the right. When you run, do you ever feel like more a sprinter or more a distance runner? Well, you might be right. It’s alll about your genes, baby.
Generally, we are born with a specific muscular make up- a certain percentage of different types of muscles. Olympic athletes typically fall into the sport that coincides with their body’s muscle fibers.
Fast Twitch Muscle Fibers: Your sprinters. These fibers use anaerobic (no oxygen used) metabolism for fuel- so they’re better at shorter bursts of energy. They fire more rapidly, but they get tired faster too. So the runner sprints a short distance really fast. Fast twitch are further separated into 2 categories, type IIa (a combo of both) and type IIb. Sprinters build up their type IIb fibers, which are bigger and bulkier- hence their more muscular appearance. When they’re in motion, sprinters don’t have time to draw from body reserves or inhale deeply enough for oxygen to get to their muscles- they need to go fast and finish fast. Enter Fast twitch fibers.
Slow Twitch Muscle Fibers (Type I): Your distance peeps. These fibers use oxygen (aerobic exercise) to generate fuel, which helps with continuous contractions over time- marathon running. They take deep breaths, the oxygen goes into their muscles, and they keep going and going and going. Little Energizer Bunnies. They have enough time to draw energy from the reserves in their body- carbs, fat, etc. Of their fast twitch, distance runners utilize more of their type IIa fibers, which are leaner in appearance.
On a treadmill, you notice “anaerobic” exercise is way at the top- you’re sprinting. You’ll find the “fat burning zone” in the middle. The idea of that is you’re working aerobically- you’re running at a steady, slower pace and tapping into your fat reserves; “burning” it off.
On average, Olympic sprinters have about 80% fast twitch fibers, while marathoners have about 80% slow twitch.
I’ve definitely learned over time that I am no sprinter. I’m not really fast even when I try- and it’s very short lived when I do. I can however run for a while without fatiguing. I’d think my muscles are made of primarily slow twitch, but I have no evidence of this. I know I like running, so that’s all I really care about. Braxton can crawl all day long and he also goes really fast, so he’s got the best of both worlds. Time will tell I guess. When he’s in the Olympics we’ll know for sure.
Can you obtain more fast twitch or slow twitch muscles despite this? As far as I’ve researched, it’s really unknown still. Some studies say that yes, with training you can. Others say no- you’re born with what you’ve got.
I don’t think your muscles make it impossible to do anything– the make up just might make it easier for some people than others to get there. If you train well, your body can pull off whatever it needs to get the job done. It’s a remarkable little thing, the human body. Plus, it’s good to get all your muscles in gear. Remember overall, it’s a mental thing. Our brain isn’t fooled by twitch fibers;)
Whichever muscles you do have- get out there and use them today!