Does HIIT cadrio encourage type muscle fibre growth?

figroll

Hello all,

Female, 28yo, 51kg, 5ft4

I've been starting to 'lift heavy' the last 2 weeks (before this i did practically all cardio) and unless i'm totally off with my measurements (i'm particularly interested in losing fat from my legs - but they are pretty toned already - upper body quite lean) my legs seem to have grown at least 3/4 of an inch around the widest part (upper thigh).. which is exactly what i don't want to happen.. i want smaller (thinner?) legs.

So, am i doing the wrong thing? Should i go back to cardio? If so, does HIIT encourage the same hypertrophy? If i do go back to cardio in the gym, i would like to make it as effective as possible ie. do as much as possible in the least amount of time, thats why HIIT would be most time effective? Or should i just do that weird walking-on-an-incline-of-everest-type-thing that most gurrls seem to be doing on the threadmill?

I would also like to say i seem to build muscle fairly easily - my brother kindly noting a few years ago that i had legs like the cyclist 'van der Eerden'.

thanks!
Figroll

celestial

HIIT is your only man. Work hard, work for a short amount of time. This will preserve your lean muscle - however much you have - while increasing your fitness and burning fat. Win win win. Walking on treadmills is a waste of time if you are at a reasonable level of fitness.

ali.c

http://www.musclewithattitude.com/readArticle.do?id=1529595&cr=

this article may be of interest to you

the point made on shrinking muscle mass was dont train it

Explanation: If a muscle group is genetically large, virtually any type of training will make it grow bigger. I'm talking everything from high volume with a light load to low volume with a heavier load will cause hypertrophy. So if your calves are big, and if you want them smaller, make a concerted effort to avoid training them. Don't even throw in a few sets of low rep calf raises in an effort to keep them strong — if you do that, they'll never shrink.

With regard to HIIT, i have heard of sprinting being used to build up the leg muscles. I certainly read an article on it but i can't for the life of me find it.

Again it could be a diet thing, if you are training and are eating over maintenance calories and are pre-disposed to building muscle quickly then you will build muscle. Bodyfat may be better to reduced through diet and excercise

Honestly i cant say more that that, though i am sure someone around here does.

Boru.

Hi Figroll,

First off congrats on starting to lift heavy - it can be a daunting task but it is hugely rewarding. As regards the growth you've experienced this is perfectly normal and don't be alarmed, they won't continually increase in size that dramatically and will in fact appear slimmer in the long run. This is primarily caused by an increase in glycogen uptake.

Glycogen is sugar as stored by the body in the muscles, liver and brain. Heavy lifting and HIIT both encourage the increased uptake and storage of glycogen which results in fuller muscles (for every 1g of sugar the body has to keep it in 3g water - so your muscles become filled and firm), hence the increase in your legs - it would be too soon for you to be experiencing dramatic increases in muscle size, it's just your muscles, and your legs in particular returning to a proper filled size.

Long endurance based cardio as you indicated you did previously depletes fat stores as opposed to glycogen and as a result the body doesn't store as much, prefering instead to increase fat uptake.

Continue with your heavy training and you will find that your muscles will knit themselves tighter together and become firmer leaving you with smaller, slimmer, more compact but far stronger and firmer legs.

After time you will of course begin to develop more muscular legs and at that point you can switch over to a maintenance program to keep the gains you've made without increasing mass.

Hope that helps.

figroll

Thanks a million folks, all comments make sense. I think i'll do a mixture, 'lifting heavy' or HIIT on alternate days (?) and some low intensity long duration in the mornings (walking/jogging to work into town, about 5.5miles). Might be a bit of overtraining on the legs though but not a whole lot i can do about that?! Will try to improve the diet too which by the sounds of it is really the key also of course.

Thanks again,

Figroll :cool: