T Nation

Slow and Fast Twitch Confusion

Some guys have been saying that it’s a god idea to tailor your rep ranges to the fiber make-up of the muscle you’re using.

For example, hamstrings are fast-twitch-dominant, so use low reps and heavy load for glute-ham raises and RDL’s. Calves are slow-twitch-dominant, so use high reps for calf raises. Quads are in-between, so use moderate reps for squats.

However, if I understand correctly, don’t slow twitch muscles have ZERO ability to hypertrophy? Slow twitch muscles are the ones used by marathon runners, who take high-rep work to the extreme, and they don’t tend to be jacked. It should follow that using high rep work should lead to zero hypertrophy gain since slow twitch muscle fibers cannot grow no matter how hard they are worked, but obviously that isn’t the case because high rep squats are effective for hypertrophy.

Furthermore, if you got a guy like Usain Bolt (who must be VERY fast-twitch dominant) to do 20-rep squats, would you predict he wouldn’t get much growth from it?

u are overthinking it lol…

stop it

[quote]lunk wrote:
Some guys have been saying that it’s a god idea to tailor your rep ranges to the fiber make-up of the muscle you’re using.

For example, hamstrings are fast-twitch-dominant, so use low reps and heavy load for glute-ham raises and RDL’s. Calves are slow-twitch-dominant, so use high reps for calf raises. Quads are in-between, so use moderate reps for squats.

However, if I understand correctly, don’t slow twitch muscles have ZERO ability to hypertrophy? Slow twitch muscles are the ones used by marathon runners, who take high-rep work to the extreme, and they don’t tend to be jacked. It should follow that using high rep work should lead to zero hypertrophy gain since slow twitch muscle fibers cannot grow no matter how hard they are worked, but obviously that isn’t the case because high rep squats are effective for hypertrophy.

Furthermore, if you got a guy like Usain Bolt (who must be VERY fast-twitch dominant) to do 20-rep squats, would you predict he wouldn’t get much growth from it?[/quote]

high rep work with a heavy enough weight will cause growth

20 rep squats are done with 10RM

not to mention those last 10 reps are all done very close to failure

Slow twitch muscles can hypertrophy. Where did you hear they can’t?

Train all your muscle fibers. In fact, some groups like the shoulders will respond very well to high rep/volume training because they are mostly made of slow twitch fibers. Muscles like the quads have a mix so use both rep ranges and a variety of techniques.

More than not, do your strength, power, and technical exercises first than move on to the higher reps less technically demanding movements.

Example:

Back Squats
5x5

Leg Press
5x10

Stiff legged deadlift
5x10

Back extensions
5x15

just lift weights god damn

I think slow twitch muscle can hypertrophy around 50% or something

If Grandma had BALLS… Would she be Grandpa?