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Appetite For Construction
Mar 28 2003

By Dr. John M Berardi, Ph.D.
First published at www.t-mag.com.

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The Appetite regulars know that this question and answer column is largely devoted to nutrition talk. In other words, about once a month I'm commin' at ya with the science and art of makin' people big, lean, and healthy through proper eating and supplementation. Since this column's 2-year anniversary party will be held on March 30th, I've gone ahead and made the assumption that the column has been well received.

So where, oh where, do I ever get all the material for a monthly q and a column? I make it all up, of course. That, and I'm sure to spend a few hours a week searching through text and online journals in an attempt to glean some new information about training, nutrition, and supplementation.
Recently, during one of my early morning research review sessions, I decided to hit up the NSCA website for some applied research in their Journal of Strength and Conditioning Research. And while I was kicking my way through this jungle of applied research, I decided that this month's column would be devoted to reviewing some of the more interesting studies I found.

L-Carnitine L-Tartrate — What's That?

Safety Measures of L-Carnitine L-Tartrate Supplementation in Healthy Men (Rubin et al).

For those of you who don't know, L-Carnitine L-Tartrate is a commercially available, new-fangled carnitine supplement (L-Carnipure) that's been shown to have some interesting recovery properties. In a study published last year, this nutritional supplement, at a dose of 2g/day for 3 weeks, was shown to reduce the amount of muscle disruption, as measured by an MRI scan, after a squat workout consisting of 5 sets of 20 repetitions (Volek et al, Am J Physiol Endocrinol Metab 2002 Feb; 282(2): E474-82).

The supplement also: reduced the rise in circulating markers of muscle damage after exercise, reduced the rise in energy substrate breakdown during and after exercise, reduced muscle soreness after exercise, and reduced the rise in oxidative damage after exercise (all of these changes were seen when compared to placebo administration).

The authors speculated that since carnitine concentrations in blood cells (endothelial cells) may decrease during exercise (this decrease leading to compromised blood flow and oxygen delivery to the muscle), carnitine supplementation might improve muscle blood flow and oxygen delivery.
In this follow up study, the authors measured the safety of this carnitine supplement and found that 3 weeks of supplementation at 3g per day did not alter any of the clinical chemistry values measured. In other words, it had no effect on liver or kidney function or any other system as reflected by complete blood profiles.

Despite past research that had not been positive, l-carnitine supplements have remained popular. Since previous research examined only a narrow hypothesis (carnitine could increase fatty acid transport into the mitochondrion, leading to increased aerobic performance and increased fat burning), these new data might offer some support for it's popular use. In other words, this supplement may be worth a try if recovery is what you're after. Just remember, its effects may not be acute, therefore, a single dose will probably do nothing for you.

Muscle Activation — Abs and Back

Ever wonder how we know whether certain ab exercises work the "upper abs" or the "lower abs"; that wide grip pull downs work the lats while close grips work the rear delts? If so, here are a couple of studies that describe how we know these gym "facts." These studies also discuss whether these are gym facts or gym fiction.

Relative Activity of Abdominal Muscles During Commonly Prescribed Strengthening Exercises (Karst et al).

While everyone wants a nice looking stomach, the limiting factor for fab abs is usually diet, not exercise. However, while nice looking abs make everyone happy, strong and functional abs make everyone healthy. In this study, researchers used electromyographic data (EMG is a technique that can measure muscle activation) to evaluate the muscle activity of the upper rectus abdominis, the lower rectus abdominis, and the external obliques in response to five different abdominal exercises:

1. The Trunk Curl — a regular crunch in which you're lying on the ground and you bring your upper torso toward your legs without lifting your lower back.

2. The Reverse Curl — performed in the same position as the trunk curl but instead of raising your upper torso, you simply curl your legs and butt toward your upper body.

3. The V-sit — a combination of the trunk curl and the reverse curl in that you bring both your legs and your upper trunk together.

4. The Trunk Curl With Twist — a trunk curl in which you alternate bringing your left elbow toward your right knee and vice versa.

5. The Vacuum — what Ian King calls the "thin tummy"; where you suck your navel in toward your back.

The data showed that:

The V-sit won the most oblique activation award while the Reverse Curl came in a close second for oblique activity. (How did the old faithful, the twisting trunk curl, fare? Tied for last.)

The Reverse Curl evened the score with a win in the lower rectus category while the V-sit was relegated to second place. (No surprise here.)

The Trunk Curl, the Reverse Curl, the V-sit, and the Trunk Curl with Twist equally beat up on the upper rectus muscles. (Demonstrating that most abdominal exercises work the upper rectus.)

The Vacuum resulted in very moderate external oblique activity and very little rectus activity (keep in mind though, that the vacuum isn't supposed to produce rectus activity — it's used to activate the deep transverse muscles that lie below the rectus muscles and are responsible for trunk stabilization).

For a complete abdominal program it's important to recognize which exercises activate the specific muscles of the trunk and utilize them accordingly. As you can see, the V-sit and Reverse Curl exercise probably reign supreme over the other 5 for the "outer" ab muscles. Don't forget about those transverse muscles, though (check out Don Alessi's article The Lost Secret of Ab Training (www.t-mag.com) for more on this).

A Comparative Electromyographical Investigation of Muscle Utilization Patterns Using Various Hand Positions During the Lat Pull-down (Signorile et al).

Much like the last study, these authors used EMG to determine muscle activation. In this study, however, the authors investigated the muscle activation in response to four different grip/hand positions during the lat pull down exercise. The four grips were:

CG — Close (parallel) grip
SG — Supinated (palms toward you) grip
WGA — Wide pronated (palms away from you) grip, pulling down to the chest (anterior)
WGP — Wide pronated (palms away from you) grip, pulling down behind the neck (posterior)

And the following muscles were measured during both concentric (pulling down) and eccentric muscle (retuning the bar to it's original position) contraction:

PD — Posterior deltoid
LD — Latissimus dorsi
PM — Pectoralis major
LHT — Long head of triceps

The study showed the following during both eccentric and concentric contractions:

For the latissimus dorsi, the wide grip anterior positioning was king, reining supreme over the other three grips.

For the long head of the triceps, the wide grip anterior positioning beat up on the other three with the wide grip posterior position coming in second over the close grip and supinated grips.

For the posterior deltoid, the close grip, wide grip anterior, and supinated grip produced similar activation, edging out the wide grip posterior positioning.

And for the pectoralis major, the results were the same as they were for the posterior deltoid.

It's a shame that this study didn't examine pull-ups in addition to pull-downs. Regardless, it looks like the wide grip anterior pull-down is the best of these 4 variations for lat development. Given that the wide grip anterior pull-down is more effective at activating the lats and is less likely to produce injury, why anyone would perform a wide grip posterior pull-down in this day and age is beyond me.

The Single Set vs. Multiple Set Debate

Since it's becoming clear that, under most conditions, a single set is insufficient to promote maximal gains in muscle strength and size, this debate is in its final days. So how about hammering a few final nails into the coffin of the single set mentality?

Single- vs. Multiple-Set Strength Training in Women (Schlumberger et al).

In this study, 27 experienced women (experienced in weight lifting, that is) were recruited to participate in a 6-week training program that consisted of 2 days of strength exercise per week. Each training day consisted of 6 total exercises. Group 1 performed a single set per exercise for the 6 exercises, group 2 performed 3 sets per exercise for 6 exercises, and group 3 performed no exercise. Reps were kept in the 6-9 range for the exercise groups.

In these subjects, the 1 set group, as expected, gained more strength than the control (no exercise) group. However, statistical analysis revealed greater improvements in muscle strength in the 3 set group vs. the 1 set group. If this is shocking to you, you've either not spent much time in the gym or you've been brainwashed by the late Mike Mentzer.

Three Sets of Weight Training Superior to 1 Set With Equal Intensity for Eliciting Strength (Rhea et al).

In this study, 16 men were recruited to participate in a 12-week training program that consisted of 3 days of strength training per week. While training intensity was designed to be equal in both groups, one group performed 1 set per exercise while the other group performed 3 sets per exercise. Reps were kept in the 4-8 range.

In these subjects, the 3-set group out-performed the 1-set group in bench press and leg press strength, again demonstrating that multiple sets are often superior to single sets for muscle strength.

While these studies show that multiple sets performed for a given exercise are superior to single sets, the other associated exercise parameters must be recognized before the results are extrapolated to other training situations. In both studies, the subjects weren't elite lifters or athletes. In addition, the total work per muscle group was low in both conditions, as was the total amount of work for the week. Therefore, the results may be most applicable for the average personal training client. When dealing with experienced trainees and elite athletes, we've got an entirely different animal.

Bench Pressing Strength

While many sport and physique athletes often don't care much about max bench strength, strength athletes certainly do. However, the two studies below give us much more than bench-pressing results. Instead, they use the bench press to give us clues about strength performance in response to dehydration and enhanced stretch shortening activity.

Effects of Dehydration and Rehydration on the One-Repetition Maximum Bench Press of Weight-Trained Males (Schoffstall et al).

While dehydration is known to decrease endurance performance due to reductions in blood volume, the effects of dehydration on muscle strength haven't been studied extensively. In this study, subjects were tested for 1RM bench press strength and then spent 2 hours in a sauna, losing 3lbs of body mass. 1RM bench press was recorded again after dehydration. Subjects were then rehydrated within 2 hours, returning to original body mass. 1RM bench press was recorded again.

Baseline 1RM bench press averaged 260lbs. Two hours of dehydration decreased max bench press by 16lbs or 6% (1RM = 244lbs). After two hours of rehydration, max bench press returned to within 2 lbs of the original max (258lbs).

From these data it's clear that dehydration can affect strength and endurance athletes, reducing both types of athletic performance. These data are particularly relevant for athletes who compete in weight class sports and dehydrate to make weight for competitions (wrestlers, powerlifters, etc).

Fortunately, these reductions in performance are rapidly reversible upon rehydration.

Effects of Increased Eccentric Loading On Bench Press 1RM (Doan et al).

In this study, subjects performed a 1RM using a standard barbell bench press. Subjects, using this original 1RM, were then asked to perform another 1RM using an additional 5% eccentric load. For example, if the subject were to bench press 300lbs, specialized hooks would add 15lbs to the negative. At the end of the negative, the hooks would release from the bar, reducing the load to 300lbs. Subjects, using the additional 5% eccentric load, attempted to increase bench press 1RM.

Interestingly, this increased eccentric loading translated to a statistically significant 5-15lb increase in concentric strength, a phenomenon probably related to increased activation of the stretch shortening cycle.

While it's thought that eccentric loading ("negatives") is important in inducing muscle damage and the growth response, this study demonstrates that increased eccentric loading may also improve concentric strength during the same repetition.

With respect to bench press (and other forms of strength exercise), dehydration sucks while eccentric loading ain't so negative.