For decades, the concept of microtears in muscles has been a cornerstone of popular fitness wisdom. Many have been taught that lifting weights causes tiny tears in muscle fibers, and as the body repairs these tears, muscle size and strength increase. While this explanation is intuitive and widely accepted, recent research indicates that the story of muscle growth is more nuanced than previously thought. Understanding the role of microtears and the true drivers of muscle hypertrophy is crucial for anyone looking to optimize their strength training regimen at AFAC gym in Thornton, Colorado.

Do Microtears Really Happen at the Gym?

The idea that microtears occur in muscles during strength training is not entirely inaccurate but requires clarification. Microscopic muscle damage can happen during resistance training as muscles are subjected to stress, particularly during eccentric movements (when a muscle lengthens under tension). However, the term “tears” can be misleading. What actually occurs are minute disruptions in muscle fibers, which might cause mild soreness for a day or two after a workout.

These disruptions have traditionally been credited with kickstarting the muscle repair process, where blood and nutrients are directed to the area for healing, ultimately resulting in muscle growth. However, current research suggests that muscle damage is not the primary driver of hypertrophy. Instead, mechanical tension placed on the muscles during exercise appears to be a far more significant factor.

Mechanical Tension: The Real Stimulus for Growth

Mechanical tension refers to the force exerted on muscle fibers during contraction. Muscle fibers contain specialized sensors known as mechanosensors that detect this tension. When sufficient tension is applied, these sensors trigger signaling pathways that lead to increased myofibrillar protein synthesis—the process that builds and strengthens muscle fibers.

To optimize mechanical tension, it is essential to:

• Recruit as many muscle fibers as possible.
• Expose those fibers to sustained tension.

Achieving this is not complicated. Training to or near failure during a set ensures a high level of effort, which is closely related to the number of muscle fibers recruited. Additionally, as you approach failure, the activation levels of these fibers increase, maximizing the mechanical tension they experience.

Muscle Soreness: A Misleading Indicator

Many people associate post-workout muscle soreness with effective training. However, feeling sore does not necessarily indicate significant muscle damage or guarantee muscle growth. While soreness may be a byproduct of exercise, it is not a reliable measure of workout effectiveness.

The process of muscle repair and growth predominantly occurs during recovery periods, not during the workout itself. This underscores the importance of adequate rest, proper nutrition, and consistent training over time.

Microtears: A Supporting Role, Not the Main Act

While microtears contribute to the muscle repair process, their role in hypertrophy is secondary. Resistance training can lead to structural damage in muscle fibers, but repair and growth are distinct processes. After an initial workout that causes significant muscle damage, the body prioritizes repairing these disruptions over increasing muscle size. Over time, as the body adapts to regular training, the focus of protein synthesis shifts toward building new muscle tissue rather than simply repairing damage.

Evidence Against Muscle Damage as the Primary Driver

Several findings challenge the notion that muscle damage is the main catalyst for hypertrophy.

1. High-Repetition Training: Higher repetitions are more likely to cause muscle damage. However, studies show that both high-rep and low-rep training can produce similar levels of hypertrophy, provided the sets are performed to or near failure.
2. Rest Periods Between Sets: Short rest periods (under one minute) tend to cause more muscle damage than longer rests. Yet, longer rest periods (2.5 to 3 minutes) are more effective for building muscle, particularly in compound exercises.
3. Training Splits: “Bro-split” routines, where all training volume for a muscle group is performed in a single session per week, cause more muscle damage than spreading the volume across multiple sessions. Despite this, bro-splits are generally not superior for muscle growth compared to more frequent, full-body or other split routines.

The Adaptation Process

Muscle growth relies on consistent, progressive adaptation. In the early stages of training, workouts that induce muscle damage may lead to temporary increases in protein synthesis directed at repair rather than growth. As the body adapts to regular training, muscle fibers experience less damage, allowing more resources to be allocated toward hypertrophy.

This adaptation highlights the importance of progressive overload—gradually increasing the weight, repetitions, or intensity of your workouts. By consistently challenging your muscles, you create the conditions necessary for sustained growth.

Practical Tips for Building Muscle at the Gym

Given the evolving understanding of hypertrophy, here are some actionable strategies to optimize muscle growth.

1. Train to or Close to Failure: Ensure that your sets push your muscles to their limits, ideally stopping no more than three reps shy of failure.
2. Prioritize Compound Movements: Exercises like squats, deadlifts, bench presses, overhead presses, and hip thrusts recruit multiple muscle groups, maximizing mechanical tension.
3. Use a Variety of Rep Ranges: Both high-rep and low-rep training can be effective. Focus on achieving high effort within each set.
4. Allow Adequate Rest Between Sets: For compound movements, rest for 2.5 to 3 minutes to maintain performance and optimize hypertrophy.
5. Emphasize Recovery: Muscle growth happens during rest, not during workouts. Prioritize sleep, proper nutrition, and rest days.
6. Consistency is Key: Regular training, combined with progressive overload, is the foundation of long-term muscle growth.

Breaking Muscle Down to Build it Back Stronger at AFAC Gym

The role of microtears in muscle growth is not as central as once believed. While microscopic muscle damage occurs and plays a role in the repair process, mechanical tension is the primary driver of hypertrophy. By focusing on maximizing tension, training to or near failure, allowing sufficient recovery, and dialing in your nutrition, you can optimize your gym workouts for muscle growth. Understanding the science behind hypertrophy empowers you to train smarter and achieve better results in the long run.

Are you looking for a gym that will support your muscle growth goals? Visit AFAC gym today to speak to our team about our affordable memberships. AFAC gym is committed to supporting your health and wellness efforts, so you’ll see the results you’re working so hard for. That’s why we were voted the best gym in Thornton, Colorado, and have hundreds of 5-star reviews.

To learn more about our top-rated gym and our incredible array of strength training and cardio equipment — as well as our unique offerings and amenities like daily group classes, cryotherapy, InBody 770 assessments, hydro massage, and our rock climbing wall and cave — we hope you will contact us or visit for a personalized tour. Our team will be happy to help you. For more information and assistance, you can also contact our gym owner, Susan, at 720-849-0245 or susan@adventurefitness.club.