Is muscle size a good predictor of strength? Is bulking up those muscles the best way to get stronger? When we see bigger muscles, many of us associate them with more muscle power. After all, researchers have shown that staying committed to the gym generates results over time and grows muscle size and strength simultaneously.
Personally, I’ve seen my muscles grow bigger while feeling stronger at the same time after dedicating months to my training, so I can attest to this. Recently, researchers studied whether muscle size is indeed a good predictor of strength and how changes in muscle size relate to strength gains following resistance training. Let’s explore.
The study

In a study published in the journal Medicine & Science in Sports & Exercise, researchers explored how adaptations in muscle size and neuromuscular activation impact strength gains. For this study, 39 healthy men who hadn’t previously been training finished 15 weeks of lower-body workouts. Three times a week, the participants completed leg extensions, leg presses, and leg curls.
The researchers used advanced tools like high-res MRI to measure the muscle mass of the quadriceps and surface EMG (electromyography) to determine the neuromuscular activation. The surface EMG analyzes electrical activity from the muscles through electrodes placed on the skin’s surface. Participants also completed one-rep max testing before and after training, as well as using as much force as possible on the leg extension machine to test their strength.
The results

The results showed the following:
- The size of the quadriceps muscles increased by around 13%, and strength in the isometric test was enhanced by 22% and 29% for the one-rep max test. In just 15 weeks, both strength and muscle size were enhanced simultaneously.
- After analyzing the progress of each participant, the researchers concluded there is indeed a close connection between muscle growth and strength improvements.
- The ability of the nervous system to activate those muscles was associated with moderate strength gains.
Concluding thoughts

This interesting study highlights the close link between muscle growth and strength gains. After resistance training, the healthy young men in this study boosted muscle mass and power by working out three times a week for 15 weeks. Neural adaptations happen when your nervous system gets better at recruiting muscle fibers to perform the exercises against the resistance of the weights or machine.
While neuromuscular activation is also a good predictor of strength gains, at least in this study, muscle growth was found to be five times more important, leading us to conclude that the size of those muscles is a superior indicator of muscle power. Focusing on building muscle with effective techniques and strategies, such as progressive overload and proper recovery, is the best way to get stronger over time.