View Full Version : Rep speed/muscle fibers
01-13-2005, 05:24 AM
I have read most of the muscle fiber articles on this site, and wanted to make sure I understood something Im not 100% sure about.
For example, if I'm training the forearms should I use a rep range of about 15+ and execute each rep at a relatively slow pace because the forearms are slow twitch type I dominant??
01-13-2005, 08:31 AM
mainly.. slow twitch dominant muscles react better to higher reps, of 20+, muscles like your abs, traps, and forearms, the speed of the reps is up to you i think, whether you want to work them harder for each rep.. the slower you go, the easier you will get to failure
01-13-2005, 05:59 PM
you got it /forum/images/graemlins/wink.gif
01-13-2005, 08:00 PM
Which article(s) talk about this stuff in particular? I'm curious. I've always wondered if some muscles specifically respond better to less or more reps... I've noticed my calves grow best when I go really heavy on them.
01-13-2005, 09:51 PM
01-13-2005, 10:01 PM
That's kind of weird. Which part grows when you go heavy? The big part is 89% slow twitch.
01-13-2005, 10:04 PM
Yep! So my understanding would be that the calves would best respond to high reps, slow contractions, with shocking techniques such as drop sets?
01-13-2005, 10:12 PM
Yes, you are correct. Shocking techniques will work well with slow and fast twitch. And if you are going to shock, shock the hell out of them /forum/images/graemlins/smile.gif
01-14-2005, 12:19 AM
Going heavy targets the fast twitchers. They are also bigger than slow twitch fibers, which could explain why you see some growth when you go heavy. Target both and you will see massive gains!
01-14-2005, 01:06 AM
Excerpt from Physiological Aspects of Bodybuilding Part I:
[ QUOTE ]
As an overview of the concepts I have covered, studies have shown that moderate repetition sets are best for improving hypertrophy in fast twitch fibers and high repetition sets are best for increasing hypertrophy in slower twitch fibers. There are several reasons why. The first is that one to 5 rep maximums based sets will most likely cause you to fail due to nervous system signaling problems before a strong enough stimulus to muscle growth can be induced (1, 2). Secondly moderate rep sets (6-12 and even 15 reps, for example) take full advantage of our body's recruiting system. The nervous system will recruit lower threshold fibers firstly and as the set intensifies it will enlist more and more high threshold fibers. By the end of a set all available muscle cells have been brought into play (3). Thirdly the release of anabolic hormones is highest after these types of sets (4, 5, 6, 7, 8) (look for detailed articles on how to manipulate natural hormone release in the near future in our anatomy section!).
This is of obvious benefit! After all, why do you think anabolic steroids are so successful? They are simply inject-able hormones! The more you have circulating in your body, the greater your muscle gains will be, and no one will argue this point! Interestingly enough, many elite trainers, doctors and professors have theorized that lactic acid production can be very conducive to the release of anabolic hormones such as testosterone and growth hormone (3, 4, 5)! Lactic acid is a by product of the G-L-A System (6). This is the energy system that is used most heavily during 30-90 seconds of work. Power lifting type movements are dependent on the creatine phosphate system which is used for extremely low rep, high percentage (of your maximum strength) sets. The PC system does not result in lactic acid production. This is just another reason to use supersets, strips, and other techniques that produce this effect.
Sets that use the Glycogen-Lactic Acid system (30-90 seconds, shocking methods or 6-15 reps) prime the pump (create extreme pumps). There are many benefits to this in regards to hypertrophy. One is to super hydrate your myofibrils (9)(see anatomy of a muscle fiber for detailed explanation of myofibrils)! A pump is caused by the collapsing of veins. As you know from the anatomy of a muscle, veins take blood out and arteries bring blood to the muscles. Even though the veins begin to fail, the arteries continue to bring blood to the muscles! This build up of fluid causes a flow of blood to go back into the muscle which in turn causes the pump! What does more fluid in the muscle cells equal? Hydration correct!? Surely you have heard of the numerous benefits of super hydration! Several studies have shown that it literally inhibits protein breakdown and stimulates protein synthesis (growth!) (10, 11, 12). Again, low repetition sets (especially 1-3 rep ranges) do not provide enough time to produce a significant pump. Blood is also responsible for the precious nutrients needed for growth or the rebuilding process of muscle tissue! Finally time under tension has been a proven factor in stimulating optimal growth (13)! The longer actin and myosin filaments interact with each other to produce contraction the greater the damage to the muscle tissue will be. It’s apparent that this time is extremely short in low rep sets. Therefore you need to recruit and expose the muscle fiber to enough time under tension to optimally grow!”
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01-14-2005, 01:21 AM
Yeah, I read that AFTER posting this topic /forum/images/graemlins/blush.gif
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