can slow twitch fibers be converted to fast twitch through specialised training? Or do you develop the fast twitch that you are born without changing the slow twicth ones.
On that note besides the actual sprinting and explosive movements like explosive jumping what would be the best to develop these fast twitch fibers? Please take into account my kid is only just in their teens. She just ran a 21 second indoor 150 M and has been training for 1 year comimg from a cross country background.
Thanks
21 sec 150m is pretty good for a girl coming from a distance background. fast twitch fibers are what they are and slow twitch are what they are. two very different fibers. it's like asking if you can turn skeletal muscle into cardiac muscle thru training...well maybe not that dramatic but you get where im going. you can make the fast twitch that is already present better, but you cant make more out of what isnt there. also try to focus on a diet that will help with anaerobic energy and ATP replenishment that way she can keep her top speed up longer
As far as i know, there is good reason to believe that a significant portion of slow twitch fibers can turn into fast twitch over a long period of time, and with the right training. This effect is hard to prove, but speculatively is probably true at least to some degree.
-doug-
the fibres are what they are as far as i know and can work differently and better depending on how you use them and how yuo want them to function but the basic makeup of the fibre is what it is. keep in mind too that sprinting is almost as much in the brain as it is in the body and the brain has to keep up with the signals it sends to the muscles. it either works fast or it doesnt...you cant change what your brain does or how it functions
Muscle fiber motor units can make physiological changes conferring to different fiber types (type II's generally being able to 'convert' easily to having characteristics like type I's, but the converse not being as efficient)... but there is nothing to indicate true fiber conversion can occur as a result of training ie complete fast myosin heavy chain conversion. It is interesting to note however that innervating type I fibers with type II nerves causes them to behave as type II's despite the difference in myosin chain composition.
Order of recruitment patterns would dictate that high tension levels be imposed to recruit the higher threshold, fast twitch motor units (or causing extreme fatigue but it's a technique that should seldom be applied when training for a strength/power sport). This means either explosive movements, or heavy loads. Focus on the posterior chain (hams, glutes) cleans, goodmornings, olympic lifts... start out with light weights if she has never lifted before and gradually increase loads.
There are actually intermediate fiber types which have a great capacity to go either way (like Doug).
But seriously. These fibers can, through training, develope the characteristics of type one or type two fibers.
Pure type ones and type twos can not convert to the other type. Training specificity will to some degree dictate how the fibers ultimately perform.
TAKU.
Taku is correct about Doug going either way.
You wish.
Dude, i owe you some stuff. Email me.
-doug-
i would also assume that if one wants to increase explosive speed one should increase muscle mass for the part they want the explosive power for. more muscle = more power
keep in mind there is a broad spectrum of fibers
slow twitch- fast twitch (varying rates of contractibility and properties). Most research indicates that type 2a (intermediate) fibers can alter proprerties while type 2b does not convert its properties.
coach hale
www.maxcondition.com
as far as i know,
a good way to train for speed is to do some kind of isometric resistance training, with an not-isometric beginning...
for example press against a cupboard which is movable for the first few cm (not isometric part) and then not movable anymore (isometric part of the movement)
also keep in mind, that alot of sprinting-capability is not at all determined by your muscle-fiber-types but also by genetics in form of where the muscles attach to your bones and joints...
(which is not changeable... well maybe through surgery :)
all the best, joey
Esoteric.
"Most research indicates that type 2a (intermediate) fibers can alter proprerties while type 2b does not convert its properties. "
-Actually there is some research indicating a high propensity for IIb's to downgrade to IIa's in response to virtually every type of training. Infact, ironically the people with generally the highest percentage of IIb's are non-athletes that lead sedentary lifestyles.
youll never have really great short term speed unless you have some beef in your legs. look at all the great short sprinters, they all had insane legs. you dont see a chicken legged kid running 10 sec 100m's
they sell those kits at Wal Mart right