How to Increase Muscle Size & Strength

This newsletter is sponsored by Momentous

In this newsletter, I explain the importance of skeletal muscle for longevity, health, and performance and tell how you can test, interpret and improve your muscle size and strength. 

For more on these topics, listen to the podcast episodes titled “Muscle for Performance & Longevity” and “Building Muscle & Strength.” 
​

Muscle Mass & Strength Impact Longevity

Skeletal muscle is the largest organ in the body and plays a crucial role in facilitating communication among other organ systems. It’s essential for numerous physiological functions, including blood glucose regulation, energy production, cardiovascular health, cognitive function, hormone balance, bone health, and more. Insufficient or compromised skeletal muscle leads to significant issues and negatively impacts both short- and long-term health.

Muscle mass naturally declines with age, with men losing about 40% of their muscle mass from age 25 to 80 (unless they do something about it!). Sarcopenia, the excessive loss of muscle beyond what is expected from normal aging, significantly increases mortality risk; individuals with low muscle mass and strength face a greater risk of premature death. Engaging in resistance training can prevent sarcopenia, improve health outcomes, and reduce the risk of dementia. And, unlike many factors that influence longevity, such as genetics, skeletal muscle is uniquely adaptable and hyper responsive to lifestyle changes. 

Muscle fibers are classified as slow-twitch and fast-twitch; each type serves distinct functions, and their distribution shifts with age and activity level. Fast-twitch muscle fibers are essential for generating force and explosive power, enabling activities that become challenging in older adults, such as catching oneself from a fall, climbing stairs, or lifting objects. Prolonged inactivity or insufficient exercise can lead to denervation and loss of these fibers, resulting in reduced motor coordination and weakness. 

While all muscle movements engage slow-twitch fibers, fast-twitch fibers are only activated during high-force activities. These fibers decline first with age, making high-force resistance training essential for preserving fast-twitch fibers as we grow older.

Test and Interpret Muscle Mass & Strength

Muscle Mass

The gold standard for testing muscle mass is via MRI or ultrasound, which provides high-resolution images of specific muscles or muscle groups. However, full-body scans can be cost prohibitive. Newer MRI technologies, like Springbok, offer full-body 3D imaging of individual muscle volume and allow for comparisons, such as between the right and left sides of the body, but are not practical for everyone. 

More accessible alternatives for estimating muscle mass include DEXA scans ($100-200 in the U.S.) or home scales that utilize bioelectrical impedance analysis (BIA). One common estimate is the appendicular muscle mass, which refers to the amount of muscle in the arms and legs. The Fat-Free Mass Index (FFMI) is another useful method for estimating muscle mass. Men should aim for an FFMI score above 20, while women should target a score above 16.5. While these estimates may not be as precise as some alternatives, they still provide valuable insight into whether you have adequate muscle mass.

Muscle Strength

To test your strength, try the following exercises:

  • Bench Press: Men should aim to be able to bench press their body weight (i.e., a 200-pound man should be able to lift 200 pounds), while women should target about 60% of their body weight.
  • Leg Press: Men should aim to be able to press twice their body weight, whereas women should target 1.5 times their body weight.

Grip Strength: Use hand grip dynamometers to test both hands. Men should aim for a grip strength greater than 100 pounds (45 kilograms) on each side, and women should aim for more than 60 pounds (about 27.25 kilograms) on each side. Grip strength naturally changes with age and differs between men and women. You can compare your grip strength to age- and gender-specific ​normative data​, which will show exactly how you compare to others in your age group, typically broken down into 5-year intervals.

The benefits of strength training are significant, making it a stronger predictor of longevity and quality of life than muscle mass alone. There is no upper limit to the benefits of increased strength, so don’t limit yourself to these bodyweight recommendations. Improving strength will enhance overall health and lower the risk of all-cause mortality and dementia.

If you observe asymmetries in muscle strength or mass between the front and back of the body or between the left and right sides, it’s important to take note. While some muscle asymmetry can benefit sports requiring rotation and torque, it should remain below 10% to avoid potential health issues. ​Research​ has shown that grip strength asymmetries can indicate an increased risk for sarcopenia and muscle denervation. However, it's important to note that this research is still in early stages — the 10% threshold represents our current best understanding but is not yet well-established through extensive studies. Consider this guideline as a general reference point rather than a strict cutoff while we await more definitive research.

Improve Muscle Mass & Strength

Although there are many methods of increasing muscle size and strength, it's crucial to remember that functional performance matters more than muscle size alone. With this performance-first mindset in mind, here are a few fundamental training principles to guide your journey:

  1. Nutrition: Aim for a daily dietary protein intake of 1 gram of protein per pound of body weight (2.2 grams of protein per kg of body weight); consuming less than 0.7 grams of protein per pound of body weight (about 1.6 g/kg) can hinder muscle growth. You may also need to slightly increase your overall caloric intake to support your training.
    • Many find it difficult to hit the 1 gram of protein per pound of body weight. Personally, I like to incorporate 1-2 scoops of a high-quality, grass-fed whey protein into my daily routine to help me hit this target. The bars from David also help me with this, given their 28 grams of protein per bar, with just 150 calories. These bars are delicious. (Please note that both Momentous and David are sponsors of Perform.) 
  2. Exercise Selection: It's important to train all major muscle groups weekly. 
    • You can choose from a wide range of exercise options, including dumbbells, kettlebells, weight machines, bodyweight exercises and resistance bands. 
    • Many types of exercise — including eccentrics (negatives), isometric training styles (high intensity and low volume, moderate or low intensity and high volume), and various workout splits (full body, body part, push/pull) — are effective.
  3. Range of Motion: Train all joints through their full range of motion while maintaining proper posture and joint integrity, generally avoiding excessive wobbling or shaking. 
    • Ensuring adequate muscle support around each joint is essential to protect both the exercising joint and the surrounding joints.
  4. Be Intentional: During each exercise, focus on technique, movement and tempo (fast or slow). 
    • Master form before increasing intensity. 
  5. Balance Movement Planes & Posture: Engage all muscle groups, not just those with aesthetic appeal. Strive for balanced strength both front to back and side to side to prevent weaknesses in muscles and joints that could impact future movement. 
    • Vary exercise equipment occasionally (but not too frequently) and incorporate unilateral, bilateral and rotational exercises to correct asymmetries and improve balance in all movement planes. 
  6. Progressive Overload: Intentionally and gradually challenge the body. Note that it’s typically best to increase by just 2-5% (either the weight, or the reps, but not both) each week to effectively, and safely, execute on progressive overload. This increase should only take place if you’re able to maintain proper form.
    • For strength training, this typically means increasing intensity (weight) each week. 
    • For hypertrophy training, this typically means increasing volume (the number of sets, or the number of reps) each week. 
  7. Know Your Goal: Are you aiming to build muscle size (hypertrophy) or increase muscle strength (force production)? Training for hypertrophy generally involves higher rep ranges, while strength training focuses on heavier weights with lower rep ranges.

Hypertrophy Training to Increase Muscle Size

Use the following guidelines as part of your training program to increase muscle size:

Repetitions: Typically 8-12 reps per set, though effective muscle growth can occur with rep ranges from 5 to 30 reps (or possibly more).

Intensity: The amount of weight lifted scales with the number of reps; for 8-12 reps, aim for 70-80% of your one-rep max (1RM), while 20-30 reps might be closer to around 30% of your 1RM.

Rest Intervals: Rest for 30 seconds to 5 minutes. Shorter rests lead to fatigue and require fewer reps or lifting less weight.

Frequency: Aim for 15-20 working sets weekly per major muscle group, spread across 2-3 days. For example, when targeting the hamstrings, pick 2 exercises and perform 3 sets of each. By training 3 days a week, you'll accumulate a total of 18 working sets throughout the week.

  • 72-hour rule: Train all muscle groups every 72 hours to effectively stimulate growth while minimizing overtraining or excessive muscle soreness.

A well-structured program will integrate these training guidelines and is particularly beneficial for beginners. Consider trying the Hypertrophy Training Program by Menno Henselmans for 8 weeks, which focuses on full-body hypertrophy in 4 training sessions per week. Listen to learn more and access the program here.

Strength Training

Incorporate the following guidelines to increase muscle strength: 

Repetitions: Aim for 3-5 reps per set. Excessive reps will lead to fatigue and reduce the amount of weight you can lift. 

Intensity: Lift heavy! Use weights close to your 1RM (> about 80%). But be smart and conservative with the load (weight). We can always add weight next time. Don’t get hurt!

Rest Intervals: Rest for 2-5 minutes between sets for adequate recovery and to maintain movement quality.

Frequency: Aim for 3 to 5 training sessions per week.

  • The 3-to-5 Rule: To maximize strength improvements, select 3-5 exercises, perform each exercise with 3-5 reps for 3-5 sets, rest for 3-5 minutes between sets, and train 3-5 days per week.

An excellent training program to improve full-body strength and power was developed by Travis Mash. This is a 12-week program with training sessions 4 days per week. Listen to learn more and learn about the program here.

Remember: In the words of Bill Bowerman, “If you have a body, you are an athlete.” 

Best,
Andy