If you’re on a journey to build muscle, you’ve likely heard of terms like mechanical tension, progressive overload, and muscle hypertrophy. Among these, mechanical tension stands out as a cornerstone of effective training for muscle growth. But what is it exactly, and how can you harness it to maximize your results? Let’s dive into the science and practical application of this powerful concept.
What is Mechanical Tension?
Mechanical tension refers to the force that a muscle experiences when it resists a load during a contraction. It occurs in two forms:
• Active Tension: Generated when muscle fibers contract against resistance.
• Passive Tension: Created when the muscle stretches under load, such as during the eccentric phase of a lift.
When you lift weights, your muscles experience both types of tension as more cross bridges between the components of your sarcomeres occur. This combination triggers signaling pathways in your muscle fibers, leading to increased protein synthesis, tissue remodeling, and ultimately, hypertrophy (muscle growth).
Why Mechanical Tension is Key for Muscle Growth
Research over the years have shown muscle hypertrophy to rely on three primary mechanisms:
1. Mechanical Tension
2. Metabolic Stress (the “burn” during high-rep sets)
3. Muscle Damage
While all three have shown to contribute, ONLY mechanical tension consistently shows that it is the most critical factor for hypertrophy. Here’s why:
• Activates Growth Pathways: Mechanical tension stimulates pathways like mTOR, a key regulator of muscle protein synthesis.
• Recruits High-Threshold Fibers: Heavy loads activate Type II muscle fibers, which are the largest and most growth-prone. The caveat to this is that the sets in which they are done must be taken to or close to failure!
• Provides a Sustainable Stimulus: Unlike muscle damage, which hinders recovery especially if overdone, tension allows for consistent training without excessive waste of resources used to recover.
How to Maximize Mechanical Tension
To reap the benefits of mechanical tension, your training program should be designed with intentionality. Here’s how to make it happen:
1. Lift Heavy Weights
Use loads that challenge you, anywhere in the 5-30 rep range, as long as you arrive at or close to failure by the end to achieve mechanical tension. Heavier weights generate more tension and activate larger muscle fibers because you get closer to failure sooner. (ie a 5 rep max compared to a 20 rep max load)
2. Focus on Full Range of Motion
Performing exercises through their full range ensures all parts of the muscle experience tension. For example, in a squat, going below parallel stretches and activates more muscle fibers.
3. Control the Tempo
Slowing down the eccentric (lowering) phase of a lift increases the time your muscles are under tension but even more-so helps you standardize your reps. The concentric (ascent) should be done with control but forcefully, as this action contributes most significantly to mechanical tension. This can be pivotal in tracking progress through consistency.
4. Incorporate Progressive Overload
Gradually increase the weight, reps, or sets over time to continuously challenge your muscles. Without progressive overload, your gains will plateau. You unfortunately can not stay at the same weight for prolonged periods and continue to improve, however this is also good because you are improving!
5. Stick to the basics
Exercises like squats, rows, bench presses, and overhead pressing allow you to lift heavier weights and can be a huge bang-for-your-buck when it comes to efficiency. There is no need to do whacky looking isolation exercises or circus acts that an influencer is portraying online. Train the muscles through their general functions with basic movement patterns in a variety of ways that allow you to progress over time and you will do great.
Common Mistakes to Avoid
While mechanical tension is essential, misusing the concept can limit your progress. Watch out for these common mistakes:
• Focusing Too Much on Volume: Doing endless reps with light weights will limit your ability to recruit larger motor units as other factors such as cardio-respiratory demands will likely interfere from force outputs, thus it won’t generate sufficient tension for hypertrophy. (Typically 4-6 hard sets of training per muscle per week is more than adequate to elicit muscle growth.)
• Skipping the Eccentric Phase: Dropping the weight too quickly eliminates consistency and can mess with your data of how well things work for you. Drop your ego and perform the exercise how it is intended for the target muscle.
• Neglecting Recovery: Too much frequency and volume can dip into your energy stores that would otherwise be used to grow muscle. Muscle repair and muscle growth both take from the same pool of resources so the more damage you cause the less can be contributed to hypertrophy. Make sure your diet and sleep is where it should be and expect some soreness from hard training but not to the point where it affects your performance.
Final Thoughts
Mechanical tension is the backbone of any muscle-building program. By focusing on heavy, controlled lifts and progressive overload, you’ll create the conditions your muscles need to grow. Pair this with proper nutrition, recovery, and consistency, and you’ll be well on your way to achieving your fitness goals.
We know this stuff can get fairly nerdy and overly-scientific for most people, but we love it! If aesthetics, strength, or anything at all is something you care about, reach out to one of our coaches for a free consultation. We are here to help and are beyond happy to do so in any way we can!
References:
Fry, Andrew C. “The Role of Resistance Training in Muscle Hypertrophy.” Strength and Conditioning Journal, vol. 28, no. 3, 2006, pp. 115-120.
Schoenfeld, Brad J. Science and Development of Muscle Hypertrophy. Human Kinetics, 2016.
Wackerhage, Henning, et al. “Stimuli and Sensors That Initiate Skeletal Muscle Hypertrophy Following Resistance Exercise.” Journal of Applied Physiology, vol. 122, no. 1, 2017, pp. 188-198.
Phillips, Stuart M., et al. “Resistance Training and Skeletal Muscle Protein Metabolism.” Sports Medicine, vol. 40, no. 4, 2010, pp. 261-271.