The differences between Size and Strength Training
Across the internet, training programmes often talk about strength and size interchangeably, as if training for one automatically improves the other. To be fair, that is true to some extent, as being bigger generally makes you stronger. However, strength and size are actually two very different adaptations, and there are some significant differences in training you should know if you want to maximize your results in either.
Physiology of size versus strength
First up, we need to take a quick look at some of the key physiological mechanisms that lead to increases in size and strength.
For hypertrophy, the three main mechanisms are mechanical tension (the load put the through muscles and joints) muscle damage (exactly what it sounds like) and metabolic stress (the ‘burn’) (Schoenfeld 2010)
Whereas for strength, whilst physiological factors such as mechanical tension and muscle damage certainly play a role, nervous system adaptations (including skill acquisition and the ability of your muscle fibres to maximally fire and coordinate) account for a significant portion of your results. That’s why you see 60kg female weightlifters outlifting extremely well-muscled 100kg bodybuilders.
How does this impact the way we train?
For size, because the main mechanisms we need to work are quite simple, and often overlapping, anything from 5 to 30 reps is viable for hypertrophy, with the majority of classic bodybuilding style programmes utilising 8 to 12 reps per set.
Moreover, because metabolic processes are likely beneficial for size training, we can use training techniques like drop sets, super sets and giant sets to deliberately create a metabolic burn or ‘pump.’
For strength on the other hand, we also have to consider training specific neural drive factors, for which the range of effective training is much narrower, typically only 1 to 5 reps at much heavier weights.
And since there’s no real benefit to metabolic type work, drop sets, supersets and similar training techniques are a poor choice. Instead, training is best arranged in ways that allow for repeated bouts of high intensity work.
How much should you train – Key considerations
In our in-depth article on ‘how much should you train for bodybuilding’ we cover training for size in detail. The TLDR is that the amount you should train both per workout and per week depends on:
Which muscle(s) you’re training that day
The bigger and more fast twitch the muscle, the more stressful it is to train. For example, heavy hamstring training is incredibly taxing, whereas side delt, bicep and tricep training is very easy.
How many times you’re training those muscles per week
For example, if you’re doing three leg sessions per week, you’ll need to do significantly less work per session compared to only training your legs once per week.
Your ability level and training age
Beginners need less total work in order to build muscle, whereas experienced lifters need much more. The amount often varies per person.
With strength training similar rules apply, but instead of thinking in terms of muscle groups it can often help to think in terms of movements. So instead of thinking “I’m training chest twice per week” you would think “I’m bench pressing twice per week.” The reason for this change in thinking is that strength adaptation is very movement specific, and we’ll touch on what that means for exercise selection later.
Sets and reps
Since strength training requires heavier weights, it is more taxing on your body. This means you’ll perform less sets and less reps. A typical strength set and rep scheme might be 5 sets of 5 reps.
On the other hand, since training for size can utilize a wide range of rep schemes, often bringing in much lighter weights, the overall stress on the body is much less. A typical set and rep scheme might be 5 sets of 10-15 reps.
Rest times
With strength training, you’re aiming to let your nervous system recover as much as possible between heavy lifts, this often means taking 3+ minute breaks between sets.
For size training, you’re not looking for full recovery between sets, you’re just looking to catch your breathe and feel ready to go again. Rest times of 45 to 90s are generally fine.
Exercise selection
As mentioned above, strength adaptation is very movement specific, so there’s no benefit to training seven different variations of exercise at the same time. Instead it’s a much better idea to have a smaller selection of movements that you focus on each week. To provide an example, an entire week of training might only use the squat, bench, deadlift, overhead press and barbell row.
When training for size, however, muscles respond incredibly well to variations in stimulus, and utilizing slight variations allows you to hit slightly different parts of muscles for a more well-rounded physique. Now, obviously there’s an upper limit, performing 10 different variations of bicep curl in the same week for instance is just stupid, because you won’t be able to push any of them hard enough. Instead, a good week might include 2-3 variations of exercise for each targeted body part.
How many exercises per session
As you might have guessed from the previous sections, strength training requires far fewer exercises per session than size training. Generally speaking, strength workouts will contain 1 to 3 main exercises per session, potentially followed by 1 or 2 bodybuilding style assistance exercises. For example:
| Exercise | Sets | Reps |
| Squat | 3 | 5 |
| Deadlift | 3 | 5 |
| Leg Extensions | 3 | 10 |
Size training workouts on the other hand should include a lot more exercises for maximal effectiveness. Typically anything from 6 to 10 is a good range. For example:
| Exercise | Sets | Reps |
| Squat | 4 | 10 |
| RDL | 3 | 8 |
| Leg Press | 2 | 20 |
| Superset Walking Lunges | 2 | 20 |
| Hamstring Curl | 2 | 15 |
| Smith Machine Calf Raises | 3 | 15 |
Overview
Although strength and size training do have a few rules and principles in common, maximizing the effectiveness of each requires different approaches.
For strength training, focus on a small selection of compound movements, performing 1 or 2 per session with heavy weights in the 1-5 rep range each session, with around 3 minutes rest between sets.
For size training, utilize a wider range of exercises (2-3 per bodypart), performing 6-10 exercises per session in the 5-30 rep range, with around 45 to 90 seconds rest between sets.
References Schoenfeld, Brad J. (2010) The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training, Journal of Strength and Conditioning Research: October - Volume 24 - Issue 10 - p 2857-2872