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Bodybuilding Science
By Robbie Durand, M.A.
Senior Web Editor
Exercise Pre-exhaustion for Muscle Growth: A Myth?
For years, exercise pre-exhaustion has been a staple of muscle growth for bodybuilders. In “Pumping Iron,” Arnold routinely used leg extensions before moving into heavy squats. A number of bodybuilders have advocated pre-exhausting muscles for greater muscular growth. The premise of pre-exhaustion is that fatiguing a muscle with a single-joint exercise such as leg extensions or flyes, before a multi-joint exercise such as squats or bench presses, will lead to greater muscle recruitment.
Motor unit recruitment states that as a muscle is fatigued, a higher threshold of muscle fibers will be activated to compensate for the pre-fatigued muscle fibers. The pre-exhaustion method involves exercising the same muscle or muscle group to the point of muscular failure, using a single-joint exercise immediately before a multi-joint exercise.
A common exercise for pre-exhaustion is leg extensions, followed by squats or flyes before bench presses. Muscular Development leads the field in bringing bodybuilders the latest cutting-edge research on exercise science, so this study may come as a shocker— because based on the research, pre-exhaustion may be just bullshit! A recent study in the Journal of Strength and Conditioning Research questions how valid exercise pre-exhaustion is for muscle growth and strength.
Previous Research About Muscle Pre-exhaustion
Before we get into the newest research, I think it’s important to take a look at what’s been done in the past. In a previous study, researchers examined the motor firing of the quadriceps and hamstrings by using a leg extension pre-exhaustion before performing leg presses. Contrary to what bodybuilders would expect, muscle pre-exhaustion with leg extensions before the leg press resulted in a decrease in muscle activity of the quadriceps muscle during the leg press, compared to no pre-exhaustion.1 Pre-exhaustion has been touted for many years to increase the number of fibers activated during an exercise— but the research showed it decreased fiber activation.
Another study reported similar findings. Researchers investigated the effect of pre-exhaustion on upper-body muscle activation during bench presses, and reported that training chest on the pec deck immediately before the bench press lead to similar muscle activation of anterior deltoid and pectoralis major muscles. However, they observed an increase in the triceps muscle activation, and the worst performance during the bench press exercise was with pre-exhaustion.2
Based on these two studies, pre-exhaustion leads to a decrease in muscle recruitment or no change in the actual muscle group performed during exercise— not an increase, as so many people once thought. Muscle growth is about keeping tension on the muscle. Any time there is a decrease in motor unit firing during exercise, tension is being taken off the muscle.
New Study: Pre-exhaustion Does Not Lead to Greater Muscle Activation
Scientists in Brazil got together to retest the validity of muscle pre-exhaustion before exercise. They took young men and they hooked electrodes all over their chests and triceps to measure muscle activation, and separated the men into two groups who performed different exercises.
1. The pre-exhaustion group performed a set of flyes and immediately performed a bench press until failure.
2. The control group only performed the bench press.
When the researchers measured muscle activation of the chest muscles after pre-exhaustion, they concluded that there was no greater activation of the chest muscle, but there was a greater activation of the triceps by 17.8 percent. So how come the triceps were activated more with a pre-exhaustion set before bench presses? Because the chest muscle was fatigued, it relied on activation of the triceps to move the weight. This research is in alignment with other studies where scientists reported a significant (33.67 percent) increase in triceps muscle activation during bench press exercises with pre-exhaustion.
The bottom line is that pre-exhaustion is not going to lead to greater muscle activation, but it will lead to greater activation of muscle groups because the muscle is pre-fatigued.3 These studies suggest that the pre-exhaustion method must be reconsidered for its effectiveness in enhancing strength and muscle size gains.
Additionally, muscular weakness induced by pre-exhaustion affected exercise form— changed the pattern movement— of the men who performed bench presses. This change in movement pattern requires caution, because limited ability to control movement is related to abnormal mechanical loads at joints. These abnormal lifting patterns may be a factor in injury during exercise.
References:
1.Augustsson J, Thomee´ R and Karlsson J. Ability of a new functional deficits after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc, 12: 350-356, 2004.
2. Gentil P, Oliveira E, Rocha Ju´nior VA, Carmo J and Bottaro, M. Effects of exercise order on upper-body muscle activation and exercise performance. J Strength Cond Res, 21: 1082-1086, 2007.
3. Brennecke A, Guimarães TM, Leone R, Cadarci M, Mochizuki L, Simão R, Amadio AC, Serrão JC. Neuromuscular activity during bench press exercise performed with and without the preexhaustion method. J Strength Cond Res, 2009 Oct;23(7):1933-40.
bron: Exercise Pre-exhaustion for Muscle Growth: A Myth?
By Robbie Durand, M.A.
Senior Web Editor
Exercise Pre-exhaustion for Muscle Growth: A Myth?
For years, exercise pre-exhaustion has been a staple of muscle growth for bodybuilders. In “Pumping Iron,” Arnold routinely used leg extensions before moving into heavy squats. A number of bodybuilders have advocated pre-exhausting muscles for greater muscular growth. The premise of pre-exhaustion is that fatiguing a muscle with a single-joint exercise such as leg extensions or flyes, before a multi-joint exercise such as squats or bench presses, will lead to greater muscle recruitment.
Motor unit recruitment states that as a muscle is fatigued, a higher threshold of muscle fibers will be activated to compensate for the pre-fatigued muscle fibers. The pre-exhaustion method involves exercising the same muscle or muscle group to the point of muscular failure, using a single-joint exercise immediately before a multi-joint exercise.
A common exercise for pre-exhaustion is leg extensions, followed by squats or flyes before bench presses. Muscular Development leads the field in bringing bodybuilders the latest cutting-edge research on exercise science, so this study may come as a shocker— because based on the research, pre-exhaustion may be just bullshit! A recent study in the Journal of Strength and Conditioning Research questions how valid exercise pre-exhaustion is for muscle growth and strength.
Previous Research About Muscle Pre-exhaustion
Before we get into the newest research, I think it’s important to take a look at what’s been done in the past. In a previous study, researchers examined the motor firing of the quadriceps and hamstrings by using a leg extension pre-exhaustion before performing leg presses. Contrary to what bodybuilders would expect, muscle pre-exhaustion with leg extensions before the leg press resulted in a decrease in muscle activity of the quadriceps muscle during the leg press, compared to no pre-exhaustion.1 Pre-exhaustion has been touted for many years to increase the number of fibers activated during an exercise— but the research showed it decreased fiber activation.
Another study reported similar findings. Researchers investigated the effect of pre-exhaustion on upper-body muscle activation during bench presses, and reported that training chest on the pec deck immediately before the bench press lead to similar muscle activation of anterior deltoid and pectoralis major muscles. However, they observed an increase in the triceps muscle activation, and the worst performance during the bench press exercise was with pre-exhaustion.2
Based on these two studies, pre-exhaustion leads to a decrease in muscle recruitment or no change in the actual muscle group performed during exercise— not an increase, as so many people once thought. Muscle growth is about keeping tension on the muscle. Any time there is a decrease in motor unit firing during exercise, tension is being taken off the muscle.
New Study: Pre-exhaustion Does Not Lead to Greater Muscle Activation
Scientists in Brazil got together to retest the validity of muscle pre-exhaustion before exercise. They took young men and they hooked electrodes all over their chests and triceps to measure muscle activation, and separated the men into two groups who performed different exercises.
1. The pre-exhaustion group performed a set of flyes and immediately performed a bench press until failure.
2. The control group only performed the bench press.
When the researchers measured muscle activation of the chest muscles after pre-exhaustion, they concluded that there was no greater activation of the chest muscle, but there was a greater activation of the triceps by 17.8 percent. So how come the triceps were activated more with a pre-exhaustion set before bench presses? Because the chest muscle was fatigued, it relied on activation of the triceps to move the weight. This research is in alignment with other studies where scientists reported a significant (33.67 percent) increase in triceps muscle activation during bench press exercises with pre-exhaustion.
The bottom line is that pre-exhaustion is not going to lead to greater muscle activation, but it will lead to greater activation of muscle groups because the muscle is pre-fatigued.3 These studies suggest that the pre-exhaustion method must be reconsidered for its effectiveness in enhancing strength and muscle size gains.
Additionally, muscular weakness induced by pre-exhaustion affected exercise form— changed the pattern movement— of the men who performed bench presses. This change in movement pattern requires caution, because limited ability to control movement is related to abnormal mechanical loads at joints. These abnormal lifting patterns may be a factor in injury during exercise.
References:
1.Augustsson J, Thomee´ R and Karlsson J. Ability of a new functional deficits after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc, 12: 350-356, 2004.
2. Gentil P, Oliveira E, Rocha Ju´nior VA, Carmo J and Bottaro, M. Effects of exercise order on upper-body muscle activation and exercise performance. J Strength Cond Res, 21: 1082-1086, 2007.
3. Brennecke A, Guimarães TM, Leone R, Cadarci M, Mochizuki L, Simão R, Amadio AC, Serrão JC. Neuromuscular activity during bench press exercise performed with and without the preexhaustion method. J Strength Cond Res, 2009 Oct;23(7):1933-40.
bron: Exercise Pre-exhaustion for Muscle Growth: A Myth?
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