Strength training or "basic strength" is training that is done in the 3-6 rep range. If your goal is purely to put on muscle size, you may sometimes wonder if there are any benefits to training for strength. Should you occasionally train with very heavy loads or would you be better suited always training for hypertrophy only? Will you leave gains on the table by avoiding strength training all together? These are very common questions that have very controversial answers. Below, I'll do my best to give you my take on the subject while explaining in detail how I've come to these conclusions.
First things first, what causes a muscle to grow?
Before we can answer the question of whether or not you need to strength train to build muscle, we first need to understand what exactly causes a muscle to grow. Luckily, there is a lot of research on this very topic and we have a relatively clear answer. Basically, muscles can grow at almost any rep range. I say almost any rep range, because anything starting at 5 repetitions and up to 30 repetitions were tested and shown to produce the same amount of hypertrophy when proximity to failure is controlled for. Anything below 5 repetitions seems to produce a little less hypertrophy and repetitions above 30 have not been conclusively looked it, but we can assume that as long as it's near failure it will also produce similar hypertrophy as the 5-30 range.
Proximity to failure is the most important factor. As long as you take a set within 4 repetitions or closer to failure in the 5-30+ rep range, you will cause optimal amounts of hypertrophy. Going lower than 5 repetitions will produce less hypertrophy.
This is the first hint that there is no correlation between strength adaptation and hypertrophy. If a stronger strength adaptation was better for hypertrophy, then we would expect that rep ranges that produce superior strength gains would necessarily produce more hypertrophy, but this isn't shown in the literature.
Growing Makes You Stronger, Not The Other Way Around
Now that we know that you can build muscle in most rep ranges and that rep ranges below 5 produce slightly less hypertrophy, we can see that there is no growth benefit to going below 5 repetitions into the strength ranges. While a set near failure may very well produce strength adaptations, these strength adaptations are not the cause of muscle growth, but the act of taking the muscle near failure. We know this because sets that produce a stronger strength adaptation (sets below 5 reps) do not produce more hypertrophy and may actually produce less, meaning there is no correlation between strength and hypertrophy.
Further, a bigger muscle is a stronger muscle. While gaining strength will not produce hypertrophy, hypertrophy will cause strength increases due to a larger muscle. This is why strength is indicative of muscle growth, so you should EXPECT to see strength gains over time. If you aren't getting stronger, you're likely not getting bigger. If you're getting stronger, then you're likely getting bigger.
Does getting stronger potentiate growth later?
So now that we know in the short term there is no hypertrophic benefit to training in the strength ranges, you may be wondering if there is any long term benefit. Perhaps if you trained for strength now, you'd be able to handle a heavier load later and thus cause a stronger hypertrophic stimulus than if you were weaker. While this is an interesting thought process, it ultimately falls flat when we look at the way hypertrophy occurs and compare individuals of different strength levels.
As we mentioned, a muscle will grow when it is taken near failure. This is regardless of the load on the bar. If it were true that lifting more load on a given exercise would produce a stronger hypertrophic stimulus, then a person who trains consistently would build more and more muscle per set as they get stronger over time, but this does not happen - on the contrary, as a person becomes more advanced, they build less and less muscle, despite being much stronger than when they first started. Additionally, we would also see that stronger individuals would produce more hypertrophy per set than weaker individuals, but again, we do not see this occur.
Being stronger simply means that you need more load to get your muscles near failure and produce the same hypertrophic response as someone weaker. A person training with 300 lbs on the bench press to failure will generate the same amount of muscle growth as a weaker person who performs a set with 200 lbs to failure. How much load a muscle will need in order to be taken near failure is simply relative to how strong it is at the time.
Doesn't heavy loading target type II fibers better?
While some fiber types may get recruited faster in different rep ranges, these differences do not affect rates of growth, which is made evident by the fact that when looking at most rep ranges, there are essentially no differences in hypertrophy when controlling for proximity to failure. This is mainly because when taking a muscle near failure, you will recruit more and more fibers as you approach failure. This can be done in any rep range and will result in recruiting nearly all fibers adequately enough to produce optimal growth across fiber types.
Even if targeting type II fibers made a large enough difference to consider, because optimal hypertrophy still occurs in the 5-8 rep range, you wouldn't need to train heavier than this because 5-8 repetitions will target type II fibers adequately. Remember, "basic strength" in sports science requires training in the 3-6 rep range, causing small overlap between the basic strength ranges and the ranges suggested for optimal hypertrophy (5-30). If you're still concerned about the fiber types being targeted, you could simply train where this overlap occurs and perform sets of 5-6 reps.
You still must chase heavier loads over time
While training heavy isn't required to get bigger, you still need to use heavier loads over time in order to grow. This is because as your muscles grow and get bigger, their load requirements for each rep range will increase. If you do not either increase load or repetitions when you get stronger, you will no longer be taking your muscles near failure. If you were only able to lift 150 lbs on the bench press for 10 reps last year and you've been training consistently, that same load and rep range will get you no where near failure today, meaning that a heavier load is required when training in the same rep range to produce an adequate training stimulus.
If you're training properly and consistently growing, you'll naturally get stronger and need to chase heavier and heavier loads to maintain muscle growth. If you fail to increase load or reps, you'll get further and further from failure and your training stimulus will gradually decrease. To reiterate an important point: If you aren't getting stronger, you're likely not getting bigger. If you're getting stronger, then you're likely getting bigger.
Reasons to Avoid Strength Training
If your main goal is hypertrophy and you want to maximize the rate at which you get bigger, there are many drawbacks to training for strength. Here are some of the main reasons to avoid training for strength when your primary goal is hypertrophy.
- No special growth benefits for going heavy and produces more fatigue.
- Due to higher fatigue, hinders your ability to perform very high volumes, the main driver of hypertrophy.
- Due to having no hypertrophy benefits, being less hypertrophic per set and hindering your ability to perform higher volumes, strength training is just overall less hypertrophic in every sense.
- Higher risk of injury. Form breakdowns are dangerous period, but they're even more dangerous when using very heavy loads. For maximal muscle growth, we need to accumulate maximal volume. Injuries can set you back in a huge way if you're unable to train a certain muscle due to injury.
- Often times training for strength can result in changes in form in order to lift maximal weight. This can result in an increase in load lifted, but a decrease in muscle stimulation. A perfect example is creating a larger arch for the bench press. This will allow you to lift more weight, but will shorten your range of motion and potentially shift the stimulus away from the muscles you'd target with a smaller arch.
Can I train for strength without losing out on hypertrophy?
While there are drawbacks to training for strength if you want to maximize muscle growth, there are times during hypertrophy training where you may be able to get away with strength training without losing out on hypertrophy. I'll list a few below.
Rep range overlap
"Basic strength" in sports science requires training in the 3-6 rep range. Optimal hypertrophy occurs in the 5-30+ rep range. This means that there is a very small overlap where 5-6 repetitions will produce optimal levels of hypertrophy while still being adequate to produce solid strength adaptations. When training in this range, you get the benefits of both worlds and do not lose out on hypertrophy.
Resensitization or maintenance phases
When training for bodybuilding, there are periods during a macro cycle that involve low volume training that is not necessarily intended to produce optimal levels of hypertrophy, but are intended to resensitize your muscles to higher volumes again. During these periods, you can get away with performing strength workouts because the focus is less on hypertrophy and accumulating high levels of volume and more on simply maintaining your current levels of fitness while keeping overall volume low.
Improving exercise form
Using heavier loads can be a great way to practice better form. Heavier loads will require that you maintain tightness in every muscle involved in the exercise. Form breakdowns will become more evident due to the added tension on the body from the heavier loads as well. Because of this, it's much easier to practice better form with slightly heavier loads.
Working on perfecting form with heavier loads can help you maintain better form in lighter rep ranges as well, which can potentially lead to better muscle activation and therefore better hypertrophy stimulus. When performing an exercise with perfect form, you know that you you're targeting the muscles intended to be used in the movement and aren't getting help from other surrounding muscles.