Ab training - fast twitch or slow twitch fibers ?

[Terra Nova]

Need some info from our " resident experts ".

Never having had a course in anatomy or kinesiologyl, I'm trying to reconcile the " optimal " volume of reps someone would do during ab / core training as it relates the proportion of slow or high twitch muscles that make up the various muscles of the midsection. The goal of ab training would be to simply strengthen abs muscles for the most part - but in the most efficient manner possible.

Here's my problem.

Some articles I've read have said that the " abs " consist mostly slow twitch fibers. As a result, the suggestion is to expect them (under normal training ) to require many more reps to reach a fatigue level as a result. More reps than what might be expected if one was training arms or legs for example. To that extent, the claims suggest these muscles are somewhat different than other muscles and that the training principles should be different - i.e you don't train them the same way as any other muscle. Reps of 20-25 are not considered atypical in this context - unlike doing 6-8 reps for arms example.

Conversely, I've read that " abs " consist mostly of fast twitch fibers and so they'll actually will respond to hypertrophy training much like any other muscles - that ab muscles are no different from a training principle perpective than any other muscles. With the right adjustments for intensity, ab routines that focus on strength and ( a bit of mass ) should be with sets of 6 - 10 reps instead of reps of 20-25 for example. The argument is, you wouldn't do 20-25 reps in most biceps sets - why do it for abs ?

I'm confused !!!!

- can somehow confirm the extent to which fast and slow twitch fibers are represented among the ab / core muscles and how these fibers should influence the sets and reps of a given ab routine / exercise ?

Appreciate any help you guys can provide - I'm lost !

[Jason B]

The way I see it, your abs (as well as several other core muscles) are holding you erect all day, so a few sets of 20-25 reps ain't gonna do shit for them, that's nothing. I believe the best way to train abs is with higher intensity, leave the crunches for fat people looking to 'tone' up. I also believe as much (if not more) ab/core training should be static in nature, not dynamic. As in prone planks, hanging L's, glute bridge holds, etc. because that's the primary mission of the abs, to stabilize and prevent movement, not necessarily create it. Heavy squats, deadlifts, and overhead presses (standing) accomplish this as well.

[Lisa~]

It’s the wrong question. It’s like somebody who asks whether they should do the twisty ab machine or the ab crunch machine if they want to lose the fat off their midsection. You just don’t know how to answer because they’re simply asked the wrong question.

The whole fiber type question comes from a bodybuilding point of view. What muscles are we even talking about? Were you interested in the fiber make-up of the rectus abdominus only? Or maybe you wanted to know the fiber make-up of the QL, or maybe the multifidus? What are you going to do if the fiber make-up of differing core muscles is different! YIKES!

If you’re more interested in movement based fitness, then it doesn’t matter what the fiber make-up of the core is. You want to train the core to do whatever it is you’re training to do. For most of us we need to learn to stabilize our core more effectively and over longer periods of time, so we train that way. We choose stabilization movements preferentially over crunching or twisting movements and we do them mostly unloaded and for increased time (planks, side planks, elbow touches). Athletes specifically need to learn to stabilize the core while moving during their specific sport, so their exercise choices will begin with stabilization and move on to stabilizing while moving (like cable chops, MB twisting movements, etc.).

How you choose to train your abs depends on your goals, not the fiber make-up of the rectus abdominus. If you are exceptionally lean, entering a bodybuilding competition, and your goals happen to be to increase the size of the rectus abdominus or obliques to improve their visibility, then maybe you’d want to know about muscle fiber type. Except even then it’s going to depend on the individual and how they respond to a training stimulus. So you’d still really have to just give it a try and see what works best for growth for you (probably a hypertrophy rep range of 8-10 with an adequate load).

High rep ranges train endurance. Low bodyfat reveals abs. Hypertrophy rep ranges increase muscle size. Low rep ranges increase strength. So determine what it is that you want to accomplish and train that way.

[Lou Schuler]

Lisa, great answer.

The aspect of "ab" training I've found most interesting in recent years is how those muscles can be worked in conjunction with other muscles.

It started with an observation I made while looking at anatomical charts. (I think it was when I was working with Ian King on Book of Muscle.) I noticed that the connective tissue (fascia) from the lower pectorals flowed directly into the upper part of the rectus abdominis.

I thought that was really interesting -- nobody who approached strength training from a bodybuilding perspective would look at the "pecs" and "abs" as having any kind of connection. But if the fascia connected them, then there had to be some kind of functional link.

Plus, I knew (as all fitness professionals know) that the rectus abdominis and external obliques work together on trunk flexion -- crunch-type movements. You can't separate them and work one without the other.

On top of that, we also know the deltoids are linked functionally to the pectorals, and that the front part of the deltoids work together with the deltoids on most pressing-type movements, whether you call it lateral flexion or adduction of the upper arm.

Finally, we know that the pectorals and latissimus work together on internal rotation of the upper arm in the shoulder joint.

So there you have functional and anatomical links between:

* lats and pectorals

* delts and pecs

* pecs and abs

This is all came together for me when Bill Hartman lectured at JP's Summit last spring. Bill talked about anatomy trains, which are structural links between muscles from head to toe.

I bought the Anatomy Trains book after hearing Bill talk about it, and that's where it all comes together. The book is expensive ($52 on Amazon), but it's really the master class in anatomy for muscleheads.

You can feel all these muscles working together on two movements:

1. Straight-arm lat pulldown

Stand facing the machine, take a wide grip on a straight bar, get into an athletic stance, and pull the bar straight down toward your thighs. (Your ROM is dictated by your height and the machine's mechanics. Don't be one of those tools who clanks the weight plates at the top of the machine.) You'll feel it in your lats, shoulders, lower chest, and abdominals, as well as your triceps.

Go slow on this, and you can feel the muscles firing in sequence.

2. Kneeling cable crossover

Bill told me this is a classic PNF movement, and I'm going to quiz him some more about this in Little Rock next week. (Fair warning, Bill.)

With this movement, you can feel everything from your biceps through your pectorals, serratus, obliques, rectus, and even inner thighs (adductors), which is called the front functional line in Anatomy Trains.

The reverse of that movement, a crossover lateral raise, lets you feel the connections between deltoids and traps, as well as triceps and external rotators.

We never think of these muscles as having physical or functional links, but the closer you look, the more connections you find.

[finboy]

Great stuff Lisa, Lou and Jason too...thanks!