Weight training experiment – Week 10

Last fall I happened across Body by science in the bookstore. I tend to see the weight loss and fitness industries as genetically above average humans telling genetically average humans that they aren’t doing it right. But these enthusiastic trainers don’t usually have much in the way of systematic research to back up their claims.

The first things I read when leafing through BBS was the research on the genes one needs to build a body like Arnold Schwarzenegger used to have. It turns out that we can currently identify 4.  This means that there of some variations in genetic disposition to build large muscles with people having all four in the “on” position having a clear, measurable advantage when it comes to building muscle. This knowledge undermines much of the current body building industry–if you don’t have the genes, there is not workout regime, personal trainer, magical powdered drink or incantation that will make you grow big muscles. (Steroids appear to be the exception.) Given the constraints, however, most people can become stronger than they are now.  Body by Science tries to answer how that is most effectively done.

After reading the sections on metabolism and muscle growth, it seemed clear that BBS was serious about recommendations based on evidence so I committed to try the workouts. I hate lifting weights.  I learned the high-school “state of the art” 20 years ago, but never really caught the bug.  The routine then was 3 sets with tapering reps 25, 20, 10 or something like that.  Recommendations were to work out 3-5 times per week for 30-45 min and do lots of different exercises.  You need to work out hard and stick with it.

Body by Science starts by recognizing that there are only two phases to muscle growth: first work a muscle very intensely, then rest long enough for the muscle to recover and grow.

“Work” in this case means one set of 9-11 repetitions done very slowly (10+s per rep) with muscle failure coming after about 90 seconds.  Work large muscle groups and use machines (since working to complete failure.) The recommendation is to work only 5 muscle groups during the first 15 weeks.

This means the schedule is to workout for about 23 minutes per week.

Rest means 7-10 days between workouts–that’s 1 or fewer work outs per week. One obstacle to this program is that you don’t feel like you paid your dues. The big advantage is that the investment of time and effort is sustainable.  If progress slows, add a day of rest.

Is the science sound? One anecdote is not evidence that it works for everyone, but it seems to be working for me. I just completed week 10.  Results charted below.

The unanticipated challenge of this system is finding the weight that results in muscle failure at 90-100 seconds.  This is because one’s strength changes quite a lot from week to week.

Percent change in strength

From the percent change chart, it is clear that there are 2 (maybe 3, see below) different growth rates for muscle groups.  The chest and leg muscles gain strength most rapidly, with arms and shoulders growing more slowly.

To give some reference, here are the actual weights moved in the workouts.  As you can see by the very steep rise at the beginning, I started with too light of weights and had to increase a lot the first week to reach failure in less than 12 reps.

Weights (machine) week by week.

One mistake I persisted in was with Pull Downs.  I increased the weight too quickly in week three and didn’t realize how important thorough muscle fatigue is to strength building.  The weight was too heavy and I was only able to do 4-5 reps.  I thought I would improve enough during the week (based on my other exercises) to use the same weight the next week and reach failure in 9 or 10 reps.  But strength didn’t improve nearly enough.  In my last workout, I decided to reduce the weight down to 175 lbs in order to completely fatigue the muscle.  The next few weeks should tell if this diagnosis is correct. If so, the red line should start taking off like the other smaller muscle groups.

On hearing about this experiment, a friend pointed me to an older book with essentially the same message.  Check out The power of ten if you want a second opinion.