“I want to build lean muscle to improve my self-esteem.”

This is easily the top reason I’m hearing from clients when asked about their health and fitness goals.

The body image-driven impulse to join a gym, hire a personal trainer, and start lifting weights may not always originate from the healthiest place, but there are many physical and mental health benefits of engaging in resistance training.

Here are some I often cite to my clients to try to help them evolve their attitude towards resistance training and exercise more generally.

• Mental health. In addition to self-esteem and self-confidence, [exercise also supports stress management, improves sleep quality, and reduces anxiety and depression].
• Muscular strength. Resistance training makes us physically stronger, which enhances our ability to perform activities of daily living (ADL). It also strengthens the bones as well as connective tissue (such as our tendons, ligaments, and fascia), which in turn helps with injury prevention.
• Weight management. More lean muscle translates into a higher basal metabolic rate, allowing you to burn more calories even at rest. This helps to prevent overweight and obesity, which has been linked to virtually every chronic disease out there.
• Improved regulation of blood glucose levels and increased insulin sensitivity. [Resistance training helps with the prevention and management of Type 2 diabetes].
• Cognitive function. [Resistance training improves brain health, especially in terms of the structural functioning of the brain and the prevention of structural atrophy]. Older adults in particular should not neglect strength training.

So, What Are The 3M’s?

If gaining lean muscle is such a desirable goal, how might we go about it as effectively and efficiently as possible?

The most effective way to build muscle is through resistance training.

Programming resistance training, however, can be complex, as we have to combine science-based approaches with individual responses to exercise.

Here, I will briefly review the three mechanisms of muscular hypertrophy ([as outlined by Brad Schoenfeld] and others) and share how I implement them for my clients.

The three mechanisms of muscular hypertrophy are:

• Mechanical tension
• Muscle damage
• Metabolic stress.

Although I will discuss each in turn, they are in reality interrelated, which enables us to achieve multiple training objectives in a single workout.

Mechanism #1: Mechanical Tension

By far the most important factor in muscle growth is mechanical tension, which refers to the force produced when a muscle contracts against a load.

The mechanical tension created by resistance training triggers mechanotransduction, the process by which mechanical signals are converted into chemical activity, specifically anabolic pathways that build lean muscle tissue.

Below are three important ways to optimize mechanical tension during resistance training.

Form & Range of Motion

Every exercise should be performed with proper technique and form to subject the working muscle to the maximum amount of mechanical tension possible at any given resistance.

Proper form means that there should not be too much unnecessary movement of the body, especially in areas of the body that are contracting the muscle. For instance, when performing a bicep curl, only the arm (specifically the elbow joint) should be moving. Using one’s back, shoulders, or wrists to lift some of the weight takes away from the work that the biceps are supposed to do on their own.

One of the most important aspects of form is the range of motion (ROM), which refers to the extent to which a part of the body can be moved during an exercise. For example, when performing a flat bench press, the bar should be lowered until it touches (or almost touches) the chest. It should then be raised until the arms are straight but not locked out. To optimize mechanical tension, perform every exercise to its full and intended ROM.

In short, never sacrifice form and/or ROM to lift a heavier weight.

Time Under Tension

Time under tension (TUT) refers to the total amount of time that a muscle is under activation (i.e., performing a concentric, isometric, or eccentric contraction) during an exercise. In the most simplistic terms, more TUT means more mechanical tension, which means more muscle growth.

How can we optimize TUT? My favorite strategy is to leverage tempo.

An appropriate tempo for many exercises would be 1-0-2-0 (or even 1-0-3-0), where we spend 1 second on the concentric contraction (the lifting of the arm during a bicep curl), a momentary pause during the isometric contraction at the top of the movement, 2 or 3 seconds on the eccentric contraction (the lowering of the arm to the starting position), and another momentary pause during the isometric contraction at the bottom (when the arm is straightened but not locked out).

Progressive Overload

This is perhaps the ultimate expression of the concept of mechanical tension. The basic idea is to gradually increase the intensity of one’s workouts, typically quantified in terms of weight lifted and/or number of repetitions performed.

In terms of implementing progressive overload, I encourage my clients to perform 12 repetitions of any exercise for 3 sets (with good form, of course) before increasing the weight by 5% to 10%.

However, this does not mean that you should try to implement progressive overload to every exercise at every workout. Instead, focus on one or two exercises, especially compound movements that target the big muscles. Bench presses, back rows, squats, and deadlifts are great options, especially for exercisers just beginning their hypertrophy training program.

Mechanism #2: Muscle Damage

Resistance training should ideally result in localized damage to muscle tissue. The body detects the muscle damage and produces cytokines in response, triggering the release of muscle growth factors. The body is thus able to rebuild bigger and stronger muscle fibers during the recovery phase to better withstand future muscle damage. This is subject to other conditions being met, such as sufficient intake of the right macronutrients and micronutrients, as well as an appropriate recovery protocol.

Muscle damage is often conflated with muscle soreness. However, research has demonstrated that Delayed Onset Muscle Soreness (DOMS) is not a prerequisite for muscle development. Too much muscle soreness (for example, that turns into pain or lasts beyond a day or two) can negatively impact muscle growth, as it indicates that the body is not able to fully repair the damaged muscle tissue.

Here are two areas to focus on to facilitate appropriate muscle damage for muscle hypertrophy.

Eccentric Contractions

Most of us, especially when we are just starting to lift weights, focus on the concentric contraction. This is understandable. After all, most exercises are named after the concentric movement, such as the chest press, the bicep curl, or the squat.

However, it is during the eccentric contraction (when we return the weight to its starting position) when most of the microtrauma to the protein tissues occurs. During recovery, the body rebuilds the damaged muscle fibers, making them bigger and stronger to better withstand future stresses. This in turn makes progressive overload critical if we want to continue building muscle as we get stronger.

Therefore, pay as much attention to the eccentric phase of an exercise as you probably already do with the concentric contraction. It is imperative to control the weight as you return the weight to the starting position; your work is not done until the movement is completed. Do you see how this also ties back to the recommendations regarding ROM, form, and TUT discussed earlier?

One of my favorite tactics to emphasize the eccentric contraction is to begin an exercise at the top rather than the bottom. For example, during a bicep curl, start with the weight at the top (near the shoulder) and begin the exercise by lowering it toward the floor. This will force you to really concentrate on the eccentric movement before you complete the exercise by lifting the weight back to the top.

Cross-Training

While performing the same exercises is useful for progressive overload, it is also important to vary our training stimulus. The novelty of performing an exercise for the first time can cause beneficial muscle damage. Different exercise equipment can work the same muscle in very different ways. Dumbbells and kettlebells generally offer a larger ROM than barbells and selectorized machines. Cables subject a muscle to constant tension (which translates to more TUT), as opposed to the variable tension provided by free weights.

In a nutshell, using a variety of equipment in a single workout can create more opportunities for muscle damage and consequently muscle hypertrophy.

Mechanism #3: Metabolic Stress

Metabolic stress is [defined] as the physiological process that occurs during exercise in response to low energy that leads to the accumulation of metabolites (such as lactate, phosphate inorganic, and hydrogen ions) in muscle cells.

The idea is to activate muscle growth by subjecting the target muscle to constant tension for a relatively long period of time. In layman’s terms, it is the “burn” or “pump” we feel when we perform an exercise to fatigue or failure.

Higher Repetitions

We may associate the combination of lighter weights and higher repetitions with training for muscular endurance rather than muscular hypertrophy. However, this is not the case, as performing higher repetitions with light weights creates metabolic stress that can trigger muscle growth.

Slow Tempo

Exercises aimed at eliciting metabolic stress should be performed at a slow tempo to draw more blood to the working muscle, which helps accentuate the “pump” we feel at the end of a good workout.

I prefer to program exercises geared toward metabolic stress at the end of the workout, often as the penultimate exercise or even a “finisher” exercise. Exercises using cables or resistance bands are a great option as they naturally subject the moving muscles to constant tension.

Key Points

To summarize, these are five takeaways from this article:

• Incorporate all 3 mechanisms of muscular hypertrophy into every strength training workout.
• Mechanical tension is the most important mechanism. Every exercise should always be performed with good form and to the full range of motion while leveraging time under tension. Use tempo to devote appropriate attention to the concentric, isometric, and eccentric contractions in an exercise. Program exercises that you intend to implement progressive overload near the start of the workout, when the muscles are capable of greater force production.
• Muscle damage helps us build bigger and stronger muscles over time. Use a variety of training stimuli to maximize opportunities for muscle damage (and recovery). However, soreness let alone pain is not a requisite for building muscle.
• Metabolic stress can be imposed on muscles by performing higher repetitions of exercises to fatigue with lower weights and at a slower tempo than other exercises in the same workout. Maintain constant tension. Feel the “burn” or “pump”, which are signals of metabolic stress.
• The 3 mechanisms of muscular hypertrophy have to be supported with the right conditions, including proper nutrition and recovery protocol. I will address this in future articles.