The Science and Importance of Taking It to the Limit
I'm a strengthaholic. I'm consumed with lifting, learning about lifting, and teaching other people how they can lift better. Because teaching other people how they can lift better is such an integral part of my passion for lifting, I'll cut to the chase and present the main message of this article:
The submaximal effort method has a limited potential to produce strength gains. You need to incorporate weights that are (or close to) maximums and/or take some of your sets to failure if you want to improve your maximum strength. If you have not made progress in a while, assess whether or not you have actually been using effective, stimulating training methods.
If you don’t believe me or if you're like me and you find that the “why” helps you more, implement the “what” and read on.
Strengthening my rationale with context
In order to convince you that taking sets to failure is important, I need to provide you with some context. You don't have to be a genius to understand the science of strength training, but you do need to know a few things if you want the important stuff to make sense. Having said that, allow me to lead you through some of the basic science behind strength.
Variation in the ability of individual athletes to generate maximal forces in similar motions is influenced by two main factors—peripheral factors and central factors. While muscle dimensions aren't the only peripheral factors affecting force production, they are thought to be the most important (who would have guessed?!). Central factors, on the other hand, boil down to intermuscular coordination and intramuscular coordination.
Intermuscular coordination, as I'm sure many of you have read about before, is “the complex coordination of numerous muscle groups” (Zatsiorsky 2006; p. 63). This brand of coordination involves movement patterns and it explains why the hypertrophy of individual muscle groups produced via single joint or machine-based exercise doesn't always immediately translate to increased strength in multijoint movements. Although the muscle is larger, it takes time and effort to coordinate multiple muscles and develop this potential into performance.
Intramuscular coordination, on the other hand, occurs within individual muscles and, put very simply, involves the activation of motor units (a motoneuron plus the muscle fibers it innervates equals a motor unit). This type of coordination is all about tapping into the muscle that you currently have, and it is a quality that is readily improved by strength training. While an untrained lifter can only call upon so much of the muscle he currently possesses, an experienced trainee may be able to activate a much larger percentage of his motor units.
A good analogy for understanding peripheral and central factors is to think of muscle as machinery, such as a crane used in construction, and the nervous system as the operator of that machinery. Machinery can be large and posses the potential to lift heavy objects or it can be small and have a limited potential to lift heavy objects. This potential, however, is useless without the operator. Furthermore, operators will be unskilled and uncoordinated if they lack proper training. With the proper training though, they can be skilled and coordinated. The takeaway here is that a trained, skilled, and coordinated nervous system is able to use muscle to its full potential, and bigger muscles have more potential.
So in the pursuit of maximal strength, you have two main avenues for improvement—get bigger machinery (increase the cross-sectional area of your muscle fibers) or improve the skill of the machinery’s operator (train your nervous system to become more coordinated). However, it is worth noting that it often takes time for an operator to learn how to use a bigger machine. If you focus on building a bigger machine for an extended period of time, be sure to give your operator time to learn how to use it!
A strength methods overview
If you're familiar with the teachings of Westside, you probably already know of the three ways to achieve maximal muscular tension—the maximal effort method, the repeated effort method, and the dynamic effort method. If you're already intimately familiar with this information, or if you're in any way opposed to this conjugate method, please stick with me. What many people fail to realize is that these three methods, in conjunction with their ugly stepsister the submaximal effort method, aren't purely Westside concepts. Rather they are the basic methods of strength conditioning and they are used in varying degrees in every strength training program.
Now that you understand the universality of these methods, let’s review a few of them. The maximal effort method usually involves one to three repetitions per set, using heavy loads that allow the lifter to complete no more than the desired number of repetitions. Technically, sets of greater than three reps can be used in the maximal effort method, but then this method begins to blend in with the repeated effort method, which is characterized by sets that are taken to failure. To be honest, there isn't any clear distinction as to where the maximal effort method ends and the repeated effort method begins. In a literal sense, the repeated effort method should involve more than one repetition, but this obvious fact does little more than exclude singles.
In practice, the maximal effort method typically implies low reps, resistances that are close to training maximums, and lifts that are, or similar to, contested movements. Conversely, the repeated effort method conventionally entails higher reps, resistances that are further from training maximums, and lifts that are aimed at general development. Despite the somewhat fuzzy scientific distinction between these two methods, it is clear that both methods involve limit (or, more realistically, very close to limit) efforts. When using these methods, the last rep of a set should be the last rep you could have completed. If this isn't the case, you're employing the submaximal effort method, which entails lifting non-maximal loads without going to failure.
The submaximal effort method, while easy to define, encompasses an incredibly broad range of protocols. Distinguishing between various submaximal effort protocols can be useful, but categorization isn't the aim of this particular article. The point of this article is to highlight the fact that the submaximal effort method isn't as effective as the other methods at improving maximum strength and to urge lifters to examine their training and see if they should be working harder.
Submaximal effort, suboptimal progress
One of the main reasons why the submaximal effort method is largely ineffective at producing maximum strength gains has to do with acceleration and intermuscular coordination. Remember that equation you learned in middle school—net force equals mass times acceleration? Well, that equation is useful because in the most basic sense lifting boils down to the force that is applied to the weight being lifted. When it comes to lifting free weights, the mass portion of the Fnet = ma equation is fixed, as this value represents the weight of the implement. The variable that manipulates the force is acceleration. The larger the acceleration, the larger the force (or more accurately, the greater the force, the greater the acceleration). In case you've forgotten all this basic physics jargon that you learned in middle school, allow me to remind you that acceleration refers to changes in velocity and it can be both positive and negative. Velocity, on the other hand, is the speed of something in a given direction. Got it? Good. Let’s continue.
When a maximal weight is lifted, the weight reaches a certain velocity and then remains at that nearly constant value. Because velocity reaches a fairly fixed value, acceleration therefore varies around the zero level, and the force applied to the weight must be approximately equal to the weight of the object being lifted. Conversely, when a submaximal weight is being lifted, acceleration values vary in a fairly standard manner. Assuming the lifter is trying to apply the maximum amount of force to the submaximal weight he is lifting, acceleration will increase in the first phase of the lift and then fall to zero and even become negative in the second phase of the motion. Understanding the Fnet = ma equation, it's easy to deduct that the force applied to the weight is greater than the weight itself in the beginning, equal to the weight when acceleration is zero, and less than the weight in the second phase of the lift. Furthermore, in the second phase of the lift, “the motion is partially fulfilled via the barbell’s kinetic energy” (Zatsiorsky 2006; p. 75). This pattern of varied accelerations, combined with the fact that kinetic energy contributes to the movement when using submaximal weights, creates some notable complications for the development of maximal strength. Movement patterns in which the correct muscles aren't being activated at the correct time in the second phase of the lifts are created, and these faulty patterns are not conducive to one-repetition maximum (1RM) performances.
According to Zatsiorsky, “[t]he heaviest weight that is lifted through a full range of joint motion cannot be greater than the strength at the weakest point” (Zatsiorsky 2006; p. 41). This obvious truth refers to sticking points and it is based on the fact that strength is joint angle specific. Strength values will change as joint orientations change, and the weakest orientation is the limiting one. Therefore, improving the ability to exert force at the weakest joint angle can lead to an improvement in maximal strength performance. Additionally, improving the ability to exert force at every joint angle will have a similar positive effect. When the submaximal effort method is used, the second phases of lifts are neglected, and these portions of the ranges of motion don't receive sufficient training stimulus. If this neglect occurs over a period of several months, muscular strength will not only fail to improve but will begin to drop. In the pursuit of maximum strength, this training outcome, combined with the faulty intermuscular coordination patterns that are created, isn't favorable.
The third and final reason why the submaximal effort method isn't as effective at improving maximum strength has to do with intramuscular coordination and the size principle. The size principle indicates that “[d]uring voluntary contractions, the orderly pattern of recruitment is controlled by the size of motoneurons” (Zatsiorsky 2006; p. 61). The smallest motoneurons are called into action first, and the larger motoneurons meet the demands for larger forces as needed. The largest motoneurons make up the fast motor units, which “are specialized for relatively brief periods of activity characterized by large power outputs, high velocities, and high rates of force development” (Zatsiorsky 2006; p. 60). These fast motor units are the ones that need to be recruited and trained in order to substantially improve 1RM performance, and the submaximal effort method doesn't do this effectively. With the submaximal effort method, a smaller number of motor units are recruited and a smaller number of them are fatigued. Without experiencing fatigue, these motor units aren't subjected to a training stimulus in this single set. Unless a set of this nature is meant to be a warm up, it doesn't provide much value in the quest for heavier lifts. Sure, rest periods can be adjusted and the total number of sets can be increased to induce fatigue. However, the corridor of trained motor units would likely be inferior to what other methods could affect.
While I was fairly dismissive of the submaximal effort method in the preceding paragraphs, I don't mean to imply that it will never have any value for any lifter. However, if this method is going to be used, it needs to be backed up with a sound rationale and then put to use with a well-designed training program. All too often, I see lifters get stuck in the rut of feel good workouts, where they don't lift heavy enough and they don't push to failure. If you want to lift heavier weights but you choose to use unmistakably inferior methods, you'd better have a damn good reason for doing so!
- Zatsiorsky Vladimir M, Kraemer William J (2006) Science and Practice of Strength Training. 2nd ed. Champaign, IL: Human Kinetics.