Muscle Size & Strength
This page on muscle size and strength covers strategies to maximize muscle gain and strength gain. There is notable overlap in nutrition and supplementation strategies to facilitate these two goals, but there is some divergence in the best type of exercise. A larger muscle tends to be a stronger muscle.
Muscle Size & Strength falls under theMuscle Gain & Exercisecategory.
“Muscle size” refers to the goal of muscle mass gain (or hypertrophy), which occurs primarily as a result of an increase in the size and/or number of myofibrils (i.e., bundles of protein filaments within muscle fibers that produce muscle contraction). “Muscle strength” refers to the ability to produce force against an external resistance.
Muscle size is measured both at the whole-body and muscle-specific level. In the former, generally fat-free mass or lean mass is distinguished from fat mass and is commonly measured using either dual-energy x-ray absorptiometry (DEXA-DXA|DXA) or bioelectrical impedance analysis (BIA). Other assessment methods include ultrasound, computed tomography, and magnetic resonance imaging.
Muscle strength is most commonly assessed using dynamic resistance exercise in the form of a 1-repetition maximum (1RM) test. A higher-repetition maximum test (i.e., a 2–6 RM test) may also be used to assess strength and estimate 1RM. Another option is an isometric strength test, which involves producing a maximal force against an immovable resistance. Unlike dynamic resistance exercise, the muscle length does not change during an isometric muscle action.
Resistance exercise is the most effective means for increasing muscle size and strength. For muscle gain, a wide spectrum of loading ranges (approximately 40%–85% of 1-repetition maximum) are similarly effective, whereas for strength, heavy loads (≥ 80% of 1-repetition maximum) are superior to lighter loads.
For both muscle size and strength, a rest interval of at least 3 minutes between sets is best for most exercises. A shorter rest interval of about 60–90 seconds may be employed for single-joint and certain machine-based exercises during muscle gain-oriented workouts.
Do I need to get sore after resistance exercise to build muscle?
Do I need to train to muscular failure?
Why would keeping a few reps in the tank be better than training to muscular failure for strength gains?
What’s the best way to track training over time?
Tracking sets: should multi-joint and single-joint exercises be counted equally?
How often should I train to maximize gains in muscle size and strength?
If I have limited time to exercise, how should I structure my training to increase muscle size and strength?
What happens if I fall off the gainz train? How much exercise is needed to maintain what I’ve built?
Are a variety of exercises necessary to maximize muscle gain?
How often should I switch up my exercise routine?
Are machines as good as free weights?
Are light weights as good as heavy weights for muscle gain?
Are periodized training programs superior for increasing muscle size and strength?
What’s the best lifting tempo?
Which exercise should be performed first in a workout?
Supplements marketed to improve muscle size and strength are purported to do so through by enhancing resistance exercise performance (i.e., by enhancing force production or muscular endurance), by stimulating muscle protein synthesis, by increasing the availability of fuel sources (e.g., carbohydrate), and/or by supporting recovery.
Nutrition plays an important role in increasing muscle size and strength by fueling exercise, promoting recovery, and providing the materials to build up muscle. These processes are mainly influenced by protein and carbohydrate intake. Evidence suggests that a total daily protein intake of 1.6–2.2 grams per kilogram of body weight is ideal for supporting increases in muscle size and strength.
Muscle glycogen is the primary fuel source during resistance exercise, and glycogen depletion is associated with muscular fatigue and impaired muscle contraction efficiency, so consuming at least 3–5 grams of carbohydrate per kilogram of body weight per day is recommended to maximize increases in muscle size and strength.
Nonetheless, many studies have not found differences in strength gains between higher- and lower-carbohydrate diets. This is likely due to the fact that compared to muscle-gain-oriented workouts, those focused on strength adaptations tend to feature lower volumes and longer rest periods, relying less on carbohydrates for energy.
How do acute changes in nutrition and exercise affect body composition data?
Is an energy surplus required to gain muscle?
Should the magnitude of the energy surplus depend on the training status of the individual?
How does an energy deficit affect muscle size and strength?
Is a ketogenic diet good for muscle gain?
Does the source of protein matter for increasing muscle size and strength?
Does the distribution of protein intake throughout the day matter?
How much muscle and strength an individual gains in response to a resistance exercise program is influenced by a myriad of factors, including their age, genetics, lifestyle (i.e., sleep, nutrition, and stress management), and training history. For instance, the magnitude of muscle gain tends to decrease with age and training experience.
Generally speaking, the majority of a person’s strength can be attributed to their muscle mass,  which is supported by the mechanistic rationale that a larger muscle has greater force-generating capacity. Put simply, in most cases, the best way to improve one’s strength is to increase one’s muscle mass. Neural factors (e.g., the threshold at which motor units are recruited and the motor unit discharge rate) also contribute to muscle strength, and the muscle strength one can deploy in a given exercise can be increased simply by practicing that exercise.