Week in and week out, you go to the gym to grow your muscles. Muscle building takes time, for sure, but you don’t want the process to take any longer than it has to.

A common question at the gym is, when you want to build muscle, should you lift light weights or heavy weights? There are many opinions on this subject. In this blog, we’ll see what science says about lifting light and heavy so you can make the most of your workouts at AFAC’s gym in Thornton, Colorado.

What Does Science Say About Lifting Weights at the Gym for Muscle Growth?

When you exercise at the gym for muscle growth, it’s all about strength training. Even if you don’t want big muscles, you do need more muscle tissue to become stronger and achieve that toned look most of us strive for.

It seems logical to assume that muscle growth happens when you lift heaver weights for a small number of reps. If you do the opposite – lifting lighter weights for a high number of reps — you’re probably training your body for endurance, not muscle growth, right?

According to science, the answer is no.

Let’s take a look at the research behind lifting weights and muscle growth. Thankfully, the results are pretty clear cut.

Study No. 1

In a 2012 study, 18 men trained their legs on a leg extension machine three times per week for 10 weeks. The men were separated into three groups:

• Group #1 performed 3 sets at 30% of their one-repetition maximum for 30-40 reps
• Group #2 performed 1 set at 80% of their one-repetition maximum for 10-12 reps
• Group #3 performed 3 sets at 80% of their one-repetition maximum for 10-12 reps

What was the result? Quadriceps muscle growth was nearly identical in Group #1 and Group #3. That means the light weight (#1) and heavy weight (#3) groups gained the same muscle mass when total volume was the same.

This is a significant finding, but it received some criticism because all the men in the study were untrained beginners at the gym. Since the muscles of untrained people will respond to any strength training and grow, this may have been the cause for the results seen in the study.

Study No. 2

After the criticism on the pool of participants in the first study, another study was conducted. The difference in the second study is that it involved 49 resistance-trained men.

In the study, subjects were randomly split into a higher-repetition group and a lower-repetition group.

• Group #1 lifted loads of 30-50% of their one-repetition maximum for 20-25 reps per set
• Group #2 lifted loads of 75-90% of their one-repetition maximum for 8-12 reps per set

All sets were performed close to failure.

After 12 weeks of this whole-body resistance training, the data showed that in resistance-trained individuals, the amount of weight lifted – when exercises are performed close to failure – does not make a difference in gains of muscle mass or strength.

That’s right – both light weights and heavy weights resulted in equal amounts of muscle growth for experienced weightlifters when sets were taken close to failure.

Study No. 3

A large meta-analysis of 8 studies came to the same result that light weights and heavy weights lead to similar muscle growth when total volume lifted is equal and sets are taken close to failure.

However, the meta-analysis also showed that the use of heavy weights tends to be better for strength gains. One could presume that better strength gains would lead to better muscle growth over time.

Also keep in mind that in these studies, subjects pushed themselves to near failure regardless of the amount of weight they were lifting. In general, training to failure at a higher rep range feels a lot harder than doing lower reps with heavier weights. That’s because a large number of reps puts more metabolic stress on your muscles.

For many of us, sticking to light weights at high reps is not always a viable option since it’s not enjoyable and takes a lot more time.

Balancing Mechanical Tension and Metabolic Stress at the Gym

After considering what science says about lifting light vs. heavy weights, how can you apply the findings to your workouts at the gym?

Lifting heavy and light weights enables you to take advantage of two main contributors to your muscle growth — mechanical tension and metabolic stress:

• Mechanical tension is achieved by lifting heavier weights.
• Metabolic stress is achieved by lifting lighter weights for more reps.

This probably explains why heavier and lighter weights lead to similar muscle growth when equated for volume. Each method targets a separate mechanism but at the end of the day, lead to the same muscle growth outcomes.

To maximize your muscle growth, it could be beneficial to use both mechanical tension and metabolic stress during your workouts. For example:

• Use heavier weights and a lower number of reps for your compound movements (i.e., squats, deadlifts, bench press, overhead press)
• Use lighter weights and a higher number of reps for your accessory exercises (i.e., lunge variations, single-arm presses and pulls, cable machine work, skull crushers, curls)

This will allow you to take advantage of the multiple pathways to muscle growth. Just make sure to take each set close to failure.

The 7 Methods to Accomplish Muscle Growth at the Gym

When it comes to muscle growth, the amount of weight you’re lifting is only part of the equation.

The best way to force muscle growth is to apply a method called progressive overload. There are at least seven types of progressive overloading that you should be aware of at the gym.

1. Load — Load is simply adding more weight to your lifts. This is an easy way to measure your strength and muscle growth. However, there will obviously be a limit to how much weight your muscles can lift. You can’t keep adding weight forever.
2. Reps — When you feel like you’ve reached a plateau with how much weight you can add to your lifts, you can add more reps to force muscle growth.
3. Sets — In addition to adding more reps, adding more sets can force muscle growth. For example, one week you might do 3 sets of 8 reps on a barbell curl. The next week, keep the same amount of weight on the barbell but do 4 sets of 8 reps. Just keep in mind that there is a point where doing more sets on the same muscle group is a waste of time. A general rule is to avoid doing more than 30 sets of weight training on any one muscle group within 7 days.
4. Form — If you do the same lifts every week, but you’re able to control the weights more with each passing week, you’re improving your form. Better form means you’re relying more on the target muscles and less on momentum to move the weight. This will result in muscle growth.
5. Tempo — How fast or slow you lift weights can make a difference in how much muscle you build. By slowing down your reps, you can increase the amount of time your muscles are under tension. This can stimulate muscle growth. Try slowing down your reps to a maximum of 6 seconds for the entire movement.
6. Rest between sets — To stimulate muscle growth, the rest period should be 30-90 seconds between sets. Typical rest periods for increasing strength are between 2-5 minutes.
7. Training close to failure — The majority of research shows that training close to failure, which means stopping each set with about 3 reps left in the tank, will result in the same amount of muscle growth as training to complete failure. Training just shy of failure (instead training to of total failure) also helps you avoid the risk of overtraining and experiencing worse results over time.

Ready? Set? Grow! Your Muscles at AFAC Gym

Whether you prefer working out with dumbbells, kettlebells, barbells, landmines, weight machines, cable machines, or resistance bands, AFAC gym has all the strength training equipment you could ever need to grow your muscle mass, strength, and endurance.

We also have an experienced team of personal trainers on our staff who can assist you with designing a personalized workout program for you that maximizes your muscle growth and helps you achieve your fitness goals.

As the best gym in Thornton, Colorado, AFAC’s huge selection of strength training and cardio equipment will provide everything you need for your workouts. In addition, if you’re looking for ways to keep your workouts challenging, AFAC gym has a full schedule of group classes throughout the morning, afternoon, and evening. These are some of the many ways that AFAC gym is committed to supporting the health and wellbeing of our members and ensuring they see the results they’re working toward.

If you’re not a member of AFAC gym but would like more information, please stop by and speak to our team. For more information and assistance, you can also contact our gym owner, Susan, at 720-849-0245 or susan@adventurefitness.club.