Pete McCall by Pete McCall

It is a common misperception that the larger a muscle is, the more force it is able to produce.  There is, however, a big difference (pun intended) between a muscle’s size and it’s ability to generate force. Muscles can appear large based on the volume of intracellular fluid, blood and water contained in the tissue. This is commonly referred to as the “pump” that occurs after lifting weights and explains why some incredibly strong weightlifters have a completely different physique than bodybuilders. It also explains why some bodybuilders with large muscles and amazing physiques are not necessarily capable of competing effectively in strength-based competitions like Powerlifting or Strongman. 

Bodybuilders train for the specific goal of improving size and appearance, which requires isolation training to focus on increasing a muscle’s size rather than it’s force output. Weightlifters train to maximize the net magnitude of muscle force they can produce. This is a specific skill requiring numerous muscles to work synergistically to contract at the same time. If your clients are interested in improving strength, but don’t necessarily want to experience muscle growth, here are eight things to keep in mind as you design their programs. 

1. Muscle size is due to sarcoplasmic hypertrophy.

Performing a high volume of reps to momentary fatigue produces the response of sarcoplasmic hypertrophy, which is an increase in size in the fluid-containing sarcoplasm around muscle cells, but not in the individual muscle fibers themselves. Lifting to momentary fatigue fills a muscle with blood that carries oxygen to the muscle to fuel the contractions. It also depletes the muscle of glycogen, which is used to create the ATP to fuel the contractions. Post-exercise, extra blood remains in the muscle to remove metabolic waste, deliver protein to repair damaged tissue, and replenish the glycogen used to fuel the contractions. One gram of glycogen can hold up to 3 grams of water in the muscle cell. As muscle glycogen is restored, it holds additional water in the cell, which can lead to an acute increase in muscle size. This is how a muscle can get larger without necessary becoming stronger. It is simply storing more fluid, which increases the total volume of the muscle cells.

2. Myofibrillar hypertrophy is an increase in thickness of the individual myofibrils (muscle fibers) that comprise a unit of muscle, and is the foundation of improving strength.

When myofibrils become thicker, there is more surface area connecting individual myofibrils to one another. Strength is based on a muscle’s ability to generate tension. As the surface tension between individual fibers increases, the net result is greater force output from the entire muscle. As a muscle experiences myofibrillar hypertrophy, it becomes thicker and denser, but not necessarily larger. This is why many weightlifters lack the overinflated appearance of their bodybuilding cousins—they are simply using their muscles differently. 

3. Increasing strength requires proper stimulation of the nervous system components responsible for causing muscle contractions.

In the case of improving strength, the goal is to recruit as many fast-twitch (type II) muscle motor units as possible within a specific muscle. This is known as intramuscular coordination. A muscle motor unit is the motor neuron, which initiates the signal for a muscle fiber to contract, and the specific fibers to which it is attached. Increasing the number of fast-twitch motor units that are activated during an exercise can have a significant impact on the total force a muscle can produce. Your muscles shake when you lift a heavy weight because more type II motor units are being “switched on” (as the type I, slow-twitch units fatigue) to shorten their attached fibers and generate the tension necessary to move the applied weight.

4. The Maximal Effort method of training is one way to increase strength by stimulating a significant amount of fast-twitch muscle motor units.

This method requires a near-maximal load that can be performed for just one to three repetitions. The Maximal Effort method does not need to be performed to failure; rather, the focus is on moving the weight as fast as possible to maximize the number of muscle motor units recruited. Even though a lifter is pushing as fast as possible, the exercise itself may not be that quick due to the magnitude of the weight. Using the Maximal Effort method requires long rest intervals of three to five minutes to allow both neural and metabolic recovery.

5. The Dynamic Effort method of training focuses on the speed of movement to recruit more type II muscle motor units.

Explosively moving a weight requires rapid force production. The nervous system responds by triggering the type II motor units, which can produce a high amount of force in a short period of time. The Dynamic Effort method can use elastic bands and chains to create a variable load that allows the lifter to accelerate as fast as possible all of the way through the movement.

6. The Repeated Effort method of weight lifting uses a moderate amount of weight performed until momentary muscle fatigue.

Muscle motor units are recruited based on the size principle: When a muscle receives the signal to contract, it will recruit smaller type I units first. As the need for force increases, the larger type II units will be called into action. Performing a lift to fatigue at approximately six to eight repetitions is one way to recruit all of the involved fibers within that muscle.

7. Ladder Sets, developed by Soviet sport scientists, is a training method that can produce significant strength results.

It requires a lifter to allow rest within a specific set to focus on maximal muscle motor unit recruitment without experiencing fatigue. A 1-2-3-4 ladder set requires the lifter to perform one repetition and then rest before completing two reps, followed by another rest before completing three repetitions. Finally, finally one more brief rest interval is taken before completing four repetitions in a row. This is considered one set. The amount of rest between reps in an individual set is based on the amount of weight and the speed of movement. The goal of a ladder set is to complete all reps with good form to optimize lifting technique and movement skill.

8. Rest

This is a requisite component of success for high-performing strength athletes. The muscles work during the training session, but it’s during the post-training period that the muscles rest, refuel, repair themselves and generally recover to prepare for the next training session. On days when you want to focus on developing max strength, make sure the client has had plenty of time for adequate sleep that night for optimal tissue repair and recovery. 

Training to momentary muscle fatigue is a successful method for increasing muscle size. If the goal is to improve muscle strength, however, the training program must focus on achieving successful lifts to recruit and engage as many muscle motor units as possible. This does not always require achieving momentary fatigue. As with any method of exercise, what may work for some clients may not necessarily work for all clients. Identifying what will help your clients achieve specific strength goals will require some trial and error.