Originally published inFall 2017 issue of American Fitness Magazine. Decades of research have led to the creation, testing, and retesting of highly effective, evidence-based models (see “Charting a Course for Clients”) that can help athletes achieve these goals. Here we discuss training for hypertrophy versus maximal strength – a difference some experienced exercisers may not realize – and how to design a program that best suits each client's goals.
The desire to increase muscle size and strength has inspired a lot of hype and pseudoscience promising impressive profits if you do this or buy that. There's something to be said for trends that inspire innovation, but for clients who are serious about achieving maximum strength or hypertrophy (muscle growth), exercise isn't a guessing game. Following a science-based system will always be the best place to start.
Download the Fall 2017 Issue of American Fitness Magazine.
Size, strength and how they fit together
Hypertrophy (or muscle development) is the increase in size of existing skeletal muscle fibers (Goldberg et al. 1975). The National Academy of Sports Medicine (2018) defines it as “the expansion of skeletal muscle fibers in response to recruitment to develop increased tension levels, as seen with resistance training.” [It] is characterized by an increase in the cross-sectional area of individual muscle fibers due to an increase in myofibril proteins (myofilaments)."
Also see: Back to basic hypertrophyfor a good overview.
Factors such as muscle tension, muscle cell disruption and resulting metabolic waste in and around muscle fibers cause thiscellular adaptation.The effects are often felt 24-48 hours after training in the form of delayed muscle soreness. However, it usually takes several months for visible changes to occur because they only occur after thousands of individual muscle fibers have grown in size (Staron et al. 1994). Increasing hypertrophy has historically appealed to people such as bodybuilders looking for maximum (and observable) muscle growth.
poweris the ability of the nervous system to recruit as many muscle fibers as possible when needed. NASM (2018) defines strength as “the ability of the neuromuscular system to produce internal tension (in the muscles and connective tissues that pull on the bones) to overcome an external force [or external load].
Strength is considered oneneuromuscular adaptation,This means that it is highly dependent on the ability of the nervous system to communicate with the muscular system, as shown by Weier, Pearce & Kidgell (2012), who found that the brain showed structural changes in the first weeks of a strength training program.
Strength is important not only for sports performance, but also for everyday life, because it supports lifting and movement in the environment.Maximum power,specifically, “is the maximum force that an individual's muscle can produce in a single voluntary effort, regardless of the rate of force production” (NASM 2018).
Also see: Principles of strength training for new clients
So how do the two compare? A person with more muscle mass has larger muscle fibers and this can generate more tension, leading to more strength. A person who shows strength may be able to exercise for longer periods of time, which can stimulate muscle fibers to grow larger, leading to hypertrophy. Therefore, training for one will affect the other. But to significantly develop hypertrophy or maximum strength, specific (and other)training programsmust be followed.
Training variables that influence size and maximum strength
Several important variables ultimately determine whether a program will lead to muscle growth or increased strength. Five key variables discussed here are: 1) intensity, 2) reps, 3) rest period, 4) sets, and 5) exercise choice. Although these variables are discussed separately, they are all intertwined.
INTENSITY
For muscle development to occur, all muscle fibers involved must be stressed, damaged and fatigued. Different types of muscle fibers fatigue at different rates and under different conditions. The intensity should be high enough to generate stress, but low enough to allow enough repetitions for fatigue. Hedrick (1995) suggested that moderate intensity (75-85% of 1 repetition maximum) is sufficient.
Not sure what your one rep max is?Probeer de NASM one-rep-max calculator!
To improve strength, the body must be significantly overloaded. Remember that strength is a neuromuscular adaptation, so the connection between the nervous system and the muscular system must be accelerated. Neuromuscular changes can occur rapidly in the untrained individual, but the gains quickly disappear if the load is not increased. Therefore, for more than just basic strength levels, an individual is encouraged to train at intensities of 85-100% of 1-RM (NASM 2018).
The problem with intensity is that it is not generalizable to all exercises. For example, a person's bench press will be very different on a flat bench than on an incline. To get a true estimate of how much someone can lift, he or she must be tested with various exercises.
REPETITIONS
The acute variables of intensity and repetitions work closely together. As the intensity increases, the reps should decrease.
Muscle development that occurs at a moderate intensity and pace should be performed with a moderate number of repetitions. Hedrick (1995) and Schoenfeld (2010) suggest that the repetition interval should be 6-12. If a person performs a lift at 85% of 1-RM, they should aim to complete 6 reps. Conversely, performing a lift at 75% of 1-RM guarantees approximately 12 reps.
(Note: A person beginning muscle development training should perform more repetitions at a lower intensity, slowly increasing the intensity and decreasing the number of repetitions over time.) The repetition rate is 2/0/2, which is 2 seconds of eccentric action, 0 seconds of isometric hold. and 2 seconds of concentric contraction (NASM 2018).
Training for maximum strength takes place at higher intensity levels. So the number of repetitions must be drastically lower. Campos et al. (2002) found that neuromuscular changes during strength training occur with 1-5 repetitions. The repetition rate for maximum force is as fast as can be safely controlled, shown as X/X/X iexample of a programming diagrambelow.
REST PERIOD
The moderate repetitions and intensity of training for hypertrophy/muscle development require a moderate rest period of 60-90 seconds (Hedrick 1995). A longer rest period can reduce the hypertrophic effect of exercise; while a shorter recovery may not allow for the completion of the sets necessary to induce hypertrophy.
Training at maximum strength is very different: training at almost maximum intensity requires almost maximum recovery. Research shows that it takes 3 to 5 minutes for a muscle group to fully recover (Willardson & Burkett 2006). If the rest period is too short, the lifter will not be able to complete multiple sets at high intensity, usually resulting in minimal or no increase in strength.
SET
Muscles naturally do not want to grow; they must be forced to grow through consistent periods of stress. Therefore, higher amounts of training have been shown to produce better results in hypertrophy (Hedrick 1995). Normally 3-5 sets are recommended for optimal hypertrophy.
Conversely, strength development can occur at moderate volume. For this reason, Peterson et al. (2004) suggested that 2-6 sets were ideal for improving strength, with the NASM guideline being 4-6 sets (2018).
SELECTION OF EXERCISES
For both strength and muscle development, multi-joint exercises are highly recommended. These are basic movements such as squats, bench press,deadlift, shoulder presses and rows.
Schoenfeld (2010) suggested that multi-joint exercises are ideal for hypertrophy because they promote uniform growth of muscle tissue, which is essential for maximizing total muscle size. It's worth noting that hypertrophy training also requires variety. Muscles have many different attachment sites, with fibers running in many different directions. Therefore, performing similar exercises at different angles and in different positions will enhance the muscle growth effect.
Strength also benefits from foundation lifting, which integrates more muscles (prime mover, stabilizer, synergist, etc.) than single-joint exercises. Therefore, multi-joint movements lead to more overall improvements in strength. In a segment produced by T-Nation, notable strength coaches Bret Contreras, Brad Schoenfeld and Charles Staley add that specificity is important (to get strong in the squat, you need to squat) and that secondary lifts can be used to target weaknesses suits (Contreras 2013).
Go to an example of hypertrophy trainingin another blog.
Training for strength and size at the same time?
Many people think (and train) as if hypertrophy and strength occur at the same time. In fact, many training variables overlap. For example, higher intensity hypertrophy training meets lower intensity strength needs, leading to some strength gains.
However, it is a very small overlapping window. To achieve these two more effectively, training hypertrophy and strength as separate entities will yield the best results.
Designing a course for clients
The science of exercise probably began in 1569, when the Italian physician Gerolamo Mercuriale published a book describing how the Greeks and Romans approached diet, exercise, and the treatment of disease (Ford 1955).
Since then, thousands of studies have been conducted on these topics, leading to the creation of evidence-basedNASM Optimal Performance Training™model that allows clients to safely progress through three levels of exercise (right), including the strength level, including Phase 3: Muscle Development (Hypertrophy) and Phase 4: Maximum Strength (NASM 2018).
The acute variables used in the NASM OPT™ model integrate the same scientific principles mentioned in this article, along with much of the same research. The OPT model is designed to take the guesswork out of training and provide personal trainers with a proven reference guide.
Below are examples showing the differences in training protocols for muscle development versus strength.
The acute variables of intensity and repetitions work closely together. As the intensity increases, the reps should decrease.
For both strength and hypertrophy, multi-joint exercises are highly recommended. These are basic movements such as squats, bench presses, deadlifts, shoulder presses and rows.
Check out this blog for more information on achieving muscle growth
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