Is it Better to Lift Light Weights or Heavy Ones?

Now do you still believe lifting light weights leads to more tone?

Guys in particular are always asking me questions about how much weight they should be using for this or how much weight they should be using for that. They ask me if they should lift heavy weights or light weights.

Most people are still convinced that lifting light weights for high repetitions means that you will get more toned, particularly women but this ignores entirely three of the four different types of muscle fibers.

Plus it won’t help you look like the woman above, who looks good doesn’t she? That’s a lot of weight she snatched overhead too…

Essentially you have various muscle fibers, and light weight, high reps targets your type I, mainly aerobic — fibers that resist fatigue best — only.

Kind of incomplete isn’t it?

You still have Type II a, x and b fibers that all have various degrees of fatigue resistance, quickness, speed and power generation. These are the fibers targeted more during weight lifting that lasts less than twelve reps, and even more specifically two of them are less than eight reps.

Which provides some physiological evidence towards training various rep ranges at various times in order to achieve the optimal body composition.

If you’re worried about bulking up, hopefully this helps you understand muscle development a little bit further and why you should probably train with heavy weights (6 or less reps) and really light weights (more than 12) for health and aesthetics at a bare minimum.

In order to understand this all, you have to understand that there are generally acknowledged two different types of “muscle hypertrophy.**”

  1. Sarcoplasmic Hypertrophy (where by the sarcoplasm surrounding the muscle increases in volume, so the cross-sectional area of a muscle increases but the muscle fibers themselves elicit no actual gain in size – mostly the result of lifting in an 8-12 rep range)
  2. Sarcomere or Myofibril Hypertrophy (actual muscle fiber hypertrophy)

**Hypertrophy is just a fancy word implying growth/expansion or ‘an increase in volume,’ and is essentially the opposite of ‘atrophy.’

The former is what you typically see in Bodybuilders or Sumo Wrestlers, and the latter is what you typically see in powerlifters or Olympic lifters and other high intensity, low rep sports —  power sport athletes, like most people from all walks of life, would be better served by going after this type of hypertrophy.

The former also is generally acknowledged not to last as long, because it is the plasma surrounding the muscle that increases in size (organelles and other structures) and thus those structures can more easily deteriorate than actual muscle growth can deteriorate.

Often people will distinguish these two different types of muscle hypertrophy as ‘Non-Functional Hypertrophy’ (Sarcoplasmic Hypertrophy) or ‘Functional Hypertrophy’ (Sarcomere Hypertrophy).

There is a third and fourth type of hypertrophy that is generally dismissed as rarely occurring, but has been shown to occur (particularly in cats and other animals) and is believed to occur in human beings too (we’re just not going to cut up human beings, to really take a look, ya know?).

Hyperplasia – is the highly debated phenomenon whereby muscle fibers actually split apart into new fibers. It’s again observed that there are two types:

  1. Sarcoplasmic Hyperplasia (whereby organelles in the sarcoplasm increase in number)
  2. Myofibrillar-Mitochondrial Hyperplasia (which notes an increase the mitochondria of the muscle cels and the number of myofibrils within a muscle)

Were this type of hypertrophy to take place — and it’s possible — you would in theory have a very difficult time losing any muscle mass once this type of muscle has been built, and again Sarcoplasmic Hyperplasia would probably be lost long before myofibril hypertrophy.

Generally speaking:

  1. 1-6 reps of work is generally accepted/acknowledged towards building Myofibril Hypertrophy (actual muscle fiber hypertrophy) and more importantly  — particularly for women — is the rep range responsible for the greatest increases in bone density, a key determining factor in osteoporosis prevention and other health markers.
  2. 6-12 reps is work is generally accepted/acknowledged towards building Sarcoplasmic Hypertrophy (tissues surrounding the muscle fibers) — which I’m not saying you should avoid if you don’t want to ‘bulk up’ or that conversely you should focus on exclusively if you do want to bulk up, this isn’t entirely how it all works.
  3. 12+ reps develops mitochondria and fatigue resistance of a muscle, particularly Type I, predominantly aerobic fibers.

As you can see it can get quite complicated as people can start talking about fiber typing, then they’ll debate time under tension (lifting tempo), or debate exercise selection, etc…

In a nutshell though and based on the information above, my recommendation is to lift a wide variety of rep ranges from high intensity (which means low reps, high weight) to medium intensity (traditional 8-12 body building approach) to light intensity (endurance fiber training/fatigue resistance up in reps of 15-50 in some cases) at various times in your program for maximum results in pretty much any pursuit.

More Specifically:

  1. Women who are worried about bulking up should follow a program where lifting is 12+ reps on Day 1 of the program and 6 or less reps on Day 2 of the program as a general guideline.
  2. Men who want to bulk up and add additional weight should lift in all three rep ranges but more specifically less than 12 reps more often than above 12 reps.

As a final note, Nutrition plays a vital role in whether or not you put on weight. You will need lots of high quality calorie intake — especially pre and post workout — in order to gain weight, this is easier said than done actually.

To avoid bulking up, be more modest in your calorie intake and don’t worry about liquid supplement consumption pre or postworkout, stick to whole foods all the time.