When it comes to gaining strength one could say that it’s an entire different ball game than just gaining hypertrophy…
It is indeed possible to gain strength without having an increase in muscle size, as strength has to do with motor learning (nervous system adapting to heavier weight).
Strength training has a few more specific guidelines to it than hypertrophy.
So let’s look at the studies…
Intensity is one of the biggest factors concerning strength gains. Intensity is the amount of weight you lift for an amount of reps.
The fewer the reps and the heavier the weight, the greater the intensity. High intensity = low reps with heavy weight
Also, the guidelines for strength trained individuals are different than the guidelines for beginners.
For strength trained athletes:
A meta-analysis of 37 studies concluded that 85% of 1RM (6 reps) is the optimal intensity to continually gain strength in the long run. Also, in this study 85% or a bit less, is optimal for experienced junior powerlifters (of 3 years experience)
Another meta-analysis of 140 studies said that 80% of 1RM (8 reps) is optimal for strength trained individuals.
To compare the amounts of reps to see which is optimal, 90% (3-5 reps) is superior to 70% (10-12 reps) over a period of 8 weeks. The 90% group showed a 15% increase in strength, in bench press, after 8 weeks. And the 70% group showed a 7% increase in strength, in bench press, after 8 weeks.
The question might arise… “What if I vary the intensity to keep the stimulus fresh on the muscles?”
Constant intensity (between 80% and 85% as seen in the studies above) is best for strength gains, while only varying the exercises for that muscle group. (1) If you’re trying to increase your strength in a certain movement, put that movement first in the workout and don’t don’t switch it up.
Another thing to consider for strength gains, is doing heavy essentric work.
Take the bench press for example… When your arms are straight and you lower the bar to your chest, that’s called the essentric part of the lift. And when you push the weight back up, that’s called the concentric part of the lift.
So what is meant by doing heavy essentric work (to e.g. of the bench press) is that you take a weight you can’t push up. Meaning, it’s more than 100% of your 1RM.
As seen in this study, individuals who did 120% of their 1RM on the essentric part of their movement, resulted in significantly greater increase in strength over the group that only did 75% of their essentric 1RM. So just by doing heavy essentric work, will increase your overall bench press strength.
Now for untrained men, gaining strength is a lot easier, but there are stil a few guidelines.
As seen in this study, 60% (12-15 reps) of an individuals 1RM is the optimal intensity to gain strength. As you progress, you can increase the intensity.
If you so desire to do higher intensity, there is no difference in strength gained between 3-5 reps and 9-11 reps, however 8-12 reps is twice as effective as 25-35 reps in increasing strength.
Another factor to consider to optimize strength gains is the amount of times you train a certain muscle group a week.
And as said before, it’s different for trained and untrained individuals.
For strength trained athletes
This one study shows that when well -trained men trained a muscle group x1 or x3 a week (with equal volume), had little to no different benefit.
However, frequency might have a different result between muscle groups.
As shown in this study, training bench press x3/week is superior to x1/week (4% greater increase after 8 weeks) with equal volume (both 9 sets). But for squats, x1/week is superior to x3/week (3% greater increase after 8 weeks) with equal volume (both 9 sets).
For untrained individuals
For untrained individuals (with absolutely no gym experience), it’s recommended to train a muscle group x3 times a week. Individuals first have to master the movement, and the more frequently it’s done, the faster you will learn to do the movement. (6)
Think about it, if you throw darts once a week, you’ll get good at it eventually, but if you throw darts x3 a week, you’ll just get better at it much faster. Same goes for any sport.
Many ‘fitness gurus’ prefer tons of volume, lots and lots of sets.
This study concluded that 2-3 sets/exercise has a 46% superior benefit over 1 set/exercise. But 4-6 sets/exercise has little to no added benefits over 2-3 sets.
However, this study shows that 5 sets/exercise is superior to 3 or 1 set/exercise. Also resistance exercise sessions were performed x3/week, which resulted in 15 sets being superior to 9 sets and 3 sets/muscle group/week,
You just might be thinking right now… “But that’s so little volume!”
This study shows individuals participating in a training program consisting of 16 sets for legs, and 16 sets for back, 24 sets for chest and 8 sets for shoulders.
First off, in my opinion, the training program is terrible. The volume a very poorly distributed between muscle groups. Training back and chest with different volume, will result in muscle imbalancement, muscle weakness and could lead to injury.
Secondly, I would say the volume for some muscle groups are way too high and the volume for others are too low.
None the less, let’s look at the results…
After 8 weeks, they increased their bench press strength by 15% and squat strength by 19%. Not too bad I’d say.
But lets look at where they started and where they ended. Squat started at +-140kg and bench press at +-106kg.
Squat ended at +-166kg and bench press ended up at +-120kg.
So they had beginner/intermediate strength to begin with, and I think there are much better training programs, than having to go through that one for those kind of results.
As seen in the above studies, 15 sets/muscle group is ample volume to increase in strength and might even be too much.
And for untrained individuals it’s recommended to do 4 sets per muscle group a week.
Rest might not be one of the biggest factors to effect strength, however, resting too long (>5 min) is not good and resting too short (<1 min) is also not good.
For strength trained men:
It shows in this study that there is no evident difference between strength gains if one rests 2 min or 5 min. There’s nothing wrong with resting long, however if you rest too long, the hormonal response (testosterone and growth hormone) will be blunted, or won’t even be significant. If you are pressed for time, rest shorter. Your body will adapt and your strength gains won’t be affected.
You might think that you need more rest when training legs. But as shown here, there is no difference in strength gained if one rests 2 or 4 min between heavy leg workout sets.
However, in these two studies (12, 13) it is shown that 3 minute rest is superior to 2 min or 1 min rest between sets, for maximal strength gains, due to better volume done because of better recovery.
In this study they compared strength circuit training (3-6 sets of 6 exercises, 6 repetition maximum [RM], ∼35-second inter-set recovery) to traditional strength training (3-6 sets of 6 exercises, 6 RM, 3-minute inter-set recovery) and concluded that both were equal in strength gains.
For untrained men
Quite a few studies now shows that slower bar speed (2 sec concentric, 2 sec essentric) shows superior strength gains because the muscles now experience much more time under tension and therefore also learn to control the weight better and thus results in the greatest strength gains. (16)
So to sum it all up in just one sentence…
For trained individuals: 3-5 sets x 6-8 reps x 2/week per muscle group with 3 min rest is optimal. Or if you don’t like following a split, like me, 10-15 sets/muscle group/week is optimal.
For untrained individuals: 1-2 sets x 8-12 reps x 3/week per muscle group with 1-3 min rest is optimal (considering the benefits of the hormonal response).
Something to keep in mind, high intensity (80% of 1RM and more) strength training produces no adaptive improvement in cardiovascular function. (17)
So if you want to improve your cardiovascular health, more intense workouts might be required, such as more reps (10-12 reps), with shorter rest (30-90 sec).