Pete McCall by Pete McCall
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Do you even lift, bro?” is a popular refrain from an online video lampooning the bodybuilding subculture. Although the point of the video is to poke fun at a specific community of weightlifting enthusiasts, the underlying theme is accurate—many people who exercise with the goal of adding muscle or improving their appearance may not be doing the most effective exercises for those results. 

Each individual is going to have a slightly different response to a strength-training program. For some, simply looking at a barbell can lead to muscle growth, while for others adding a desired amount of muscle can be an elusive goal that constantly seems out of reach. The specific outcome of any strength-training program is dependent on a number of different variables including an individual’s genetics, sufficient sleep, proper nutrition, adequate hydration and, of course, the type of exercises performed. 

Regardless of an individual’s genetic background, both mechanical damage and metabolic fatigue are two essential components of promoting muscle growth in weightlifting. Moving an external resistance requires the contractile proteins to generate force to overcome the resistance, which can result in structural damage. Mechanical damage to muscle proteins stimulates a repair response that can result in the damaged fibers increasing in size. Metabolic fatigue occurs when muscle fibers involved in an exercise exhaust the available supply of ATP and are no longer able to fuel muscle contractions. It is well accepted that both mechanical damage and metabolic fatigue can result in muscle growth, but it is not exactly clear which one plays a greater role. 

The human body is an amazingly adaptable biological system and no two people respond to exercise in the exact same way. But we do know that performing the same exercises with the same intensity, reps and number of sets over an extended period of time will lead to a plateau and a concurrent lack of results. For clients who lift weights for the purpose of gaining muscle, it is a good idea to change the program on a frequent basis to ensure an appropriate amount of stimulus is used to create the mechanical damage or metabolic fatigue that promotes muscle growth. If adding muscle is important to a client’s fitness goals, the following seven suggestions for structuring his or her workout program could help you create the optimal environment for muscle growth.

1. Time Under Tension (TUT) refers to the length of time a muscle is contracting against an external resistance.

Muscles generate tension to move an external load—contracting a muscle for longer periods of time will yield higher levels of both mechanical damage and metabolic fatigue. A traditional set of 10 reps performed at a standard speed of one to two seconds lengthening and one to two seconds shortening may only take 15 to 20 seconds. Slowing the movement speed down to a four- to six-second lengthening phase followed by a two- to three-second shortening action for the same 10 reps can increase the amount of TUT up to 90 seconds and cause the necessary mechanical damage and metabolic fatigue that results in muscle growth.

2. Lifting for muscle growth requires working until momentary fatigue.

Many people only do a limited number of reps of a particular exercise and stop before experiencing fatigue. When a muscle is working, it will utilize smaller type I fibers until the larger type II fibers are needed to generate the necessary force for movement. Type II fibers can be the most important fibers for muscle growth and there are two ways to activate them, both of which involve working to fatigue: (1) using heavy weights or (2) doing a high number of repetitions. An example of working to fatigue is using drop sets, which are often best done on a machine. Select a weight and perform as many reps as possible, then drop the weight and repeat until you are no longer able to move. Working to fatigue may require the assistance of a spotter or personal trainer and could cause delayed onset muscle soreness, but it is a well-established method of promoting muscle growth.

3. Doing isolated, single-joint exercises can be an effective way to apply the necessary stimulus for muscle growth.

Multijoint exercises like the squat, deadlift or standing shoulder press engage a number of muscles that can help increase energy expenditure. The mechanical forces for moving the resistance during these exercises, however, are shared by a variety of muscles. Single-joint and isolation exercises localize the mechanical forces of an exercise into a specific unit of muscle that can lead to the necessary damage or fatigue required for growth. One strategy often used by body builders is to do compound sets, such as performing a multijoint exercise such as a squat immediately followed by an isolation exercise such as a leg extension for the quadriceps to place additional mechanical forces on the quadriceps muscles involved in knee extension.

4. Try alternating the intensity and volume of each workout to apply slightly different amounts of damage and fatigue.

Intensity refers to the amount of weight used for a particular exercise, and volume is the amount of physical work, commonly expressed as the product of repetitions and sets performed in a single exercise session. There are different models of periodization for structuring the intensity and volume of exercise; the important thing is to do it regularly. Alternating workouts between using heavy weights for a few repetitions and lighter weights for more repetitions will change the training stimulus between mechanical damage and metabolic fatigue, respectively, and can be one way to keep muscles growing.

5. Changing the exercises can use different bundles of muscle fibers.

A motor unit is a motor nerve and its attached muscle fibers; doing the same exercises repeatedly can engage only a limited number of muscle motor units. Changing the exercises used for a specific body part can activate different motor units along with their attached muscle fibers, and can be an important component of achieving muscle growth. For example, not all chest exercises use the pectoral muscles the same way, so alternating between using dumbbells and barbells for presses, changing from a flat to an incline or a decline bench, or using cables for flies instead of a pec-deck machine can change the specific muscle fibers involved, which can result in growth.

6. If the goal is building muscle, focus on strength training and limit the amount of cardiorespiratory exercise.

In a muscle cell, 1 gram of glycogen holds approximately 2 to 4 grams of water; cardio exercise can reduce the amount of stored muscle glycogen, which will limit muscle growth. Although there is some debate about how well it works for untrained individuals, understanding the science of nutrient timing can help maximize levels of muscle glycogen, leading to the desired level of muscle growth.  

7. Encourage your clients to get a good night’s sleep

The best workout plans won’t lead to optimal results if an individual is not getting enough sleep. After all, it is during the recovery period AFTER exercise that muscles experience the repair processes necessary for growth. It’s important to note that anabolic hormones such as growth hormone and testosterone are produced during the REM cycles of sleep. Although there is also some debate about the role these hormones play in muscle growth, insufficient sleep can have a negative impact on training results.

Don’t let your clients get stuck in a rut of following an exercise program that doesn’t produce results. If your clients are lifting with the specific intent of making gains and adding muscle, then it may take some trial and error to find the best method for each individual.

Become a Functional Training Specialist and help clients move more efficiently, prevent injury and build strength.

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