Will my muscles get bigger if I lift weights?

Resistance training using weights can have a whole host of benefits, but today we’re going to focus on just one of those: muscular hypertrophy.

What is Hypertrophy?

Hypertrophy (hi-PER-tro-fee) is a physiological term meaning “the enlargement of an organ or tissue due to the increase in the size of its cells”. This can be used to describe both healthy adaptations and the unhealthy effects of diseases/drugs. It’s important to know whether or not the hypertrophy taking place is good or bad. For instance, the disease hypertrophic cardiomyopathy is an unexplained thickening of part of the heart muscle, and while you may think it’s good to have a bigger heart, it’s actually a significant cause of sudden unexpected cardiac death! In contrast, the muscular hypertrophy you experience from exercising is a good adaptation which usually leads to stronger muscles, better overall health, and improved appearance. Lets talk about the good stuff!

Muscular Hypertrophy is the process by which your muscles get bigger. Typically this occurs due to specific types of exercise which place a weighted load on a given muscle group while they are moving. Examples are squatting with a barbell on your back or lifting heavy boxes day to day in a warehouse. Whether the stimulus is planned, like with a good workout routine, or just a part of your every day life doesn’t really matter. If you are putting the muscle under load on a regular basis and allowing for enough rest to recover from that work, the chances are your muscles will get bigger. What varies is how much bigger they get, and why. There main mechanism of building bigger muscles is myofibrillated hypertrophy.

Myofibrillated Hypertrophy

Your muscles are made up of tubular cells called myocytes, also known as muscle fibers. A muscle fiber is made up of many myofibrils, which are bundles of long protein chains. These chains move across one another to create a contraction, and the sum of all these contractions happening at once moves your body. To give you an idea of how many muscle fibers you have, keep in mind that the largest one in the body is no bigger than a strand of human hair. You need a lot of muscle fibers to make up each muscle. With weight lifting, the stimulus of the exercise causes the number of protein strands in each myofibril to increase, and the fibrils get thicker as a result. While the size increase for each individual fibril is very small, the overall effect when all the fibers are taken into account is more pronounced and visible.

In someone who is new to exercise you may see this kind of muscle growth within the first month of regular training. The muscles have only adapted to what they need, becoming “deconditioned”, or less able to handle athletic stresses like lifting heavy stuff, moving quickly, or maintaining a high cardiovascular output. Basically, you get gains more quickly when you’re already out of shape.

An interesting study completed by Lee & Farrar at the University of Texas and published in the Journal of Exercise Physiology (Vol. 6, #2, 05/2003) showed that after 8 weeks of resistance training the test rats showed an average 17.5% increase in total muscle mass and a 23% increase in peak tetanic tension. They did heavy (for a rat) climbing exercises every 3 days, once in the morning and once in the evening, for 3 sets of 5 reps each time. So over 8 weeks they did 19 days of exercise, each day completing as many of the reps as they could. They got up to 335% of their body weight in resistance during the exercise. Imagine for a moment that someone strapped three more of YOU to your back and asked you to climb a 30 ft ladder. That’s what the rats worked up to. Not bad, eh?

People with more experience in heavy resistance training will see visible myofibril gains slowly, sometimes taking months to actually “see” anything happening. Once you reach a certain level of conditioning, it becomes more difficult to improve that conditioning and maintain it over time. Gaining myofibril adaptation at high levels of muscular ability requires planning not just workouts, but also diet and rest.

Weight Lifting Schemes to Build Muscle

You can exercise at a variety of Set and Rep schemes, seeing results as low as 5-9 reps per workout (1 x 5, 2 x 4, 3 x 3) or as high as 50 reps per workout (a 7 x 7, 4 x 12, etc). The total volume for that workout can be used to determine how heavy to lift, and the general rule is the more reps you are going to do, the lighter the working weight needs to be. On a very heavy day, I don’t go below 5 reps of working set at 90% 1RM, so the table below blacks out those “extreme low rep” options.

Some lifters choose to go higher in weight to 95% 1RM and do 1-5 reps at that weight, but that is a matter of preference. In my opinion, at that point you are just doing a 1RM retest day and your body can only do that so often. For more regular lifting, the chart below is what I use to plan:

1 2 3 4 5 6 7
Reps 1 5 6 7
2 8 10 12 14
3 9 12 15 18 21
4 8 12 16 20 24 28
5 5 10 15 20 25 30 35
6 6 12 18 24 30 36 42
7 7 14 21 28 35 42 49
– – – – – – – – – – – – – – – – – – – – – – – – – – –
Weight 90% 85% 80% 75% 70% etc

There are a few parts to this table:

  • Top Axis – Sets: How many working sets you will be doing, generally with 30-90 seconds rest between
  • Side Axis – Reps: How many repetitions of the movement you will do Per Set, with minimal rest between reps
  • Intersections: Workout volume based on Sets multiplied by Reps
  • Lower Table & Color Code: Based on volume, the percentage of 1RM you should use during your workout

You can use the table in three ways:

  1. Start with Sets and Reps: find Volume based on the intersection, find Weight based on color-code.
  2. Start with Weight: find available intersections for Volume, choose Set/Rep scheme.
  3. Start with Volume: find available intersections for Sets/Reps, find Weight based on color-code.
    1. Not all exact Volumes are available; look for Volumes within 3 reps of your goal

The pattern is as the Volume climbs higher, the Weight will lower. This progression could continue for a long while, but eventually you would reach a place where the reps were so extreme and the weight so low that it would be silly. Working at 70% 1RM or higher seems to have the best effect on overall health, but you can work at lower weights for practice sets and movement training. The lower weight work is great for learning safely, and lets you start building muscle memory with little risk.

That’s it for today! Have a great week, everyone!