The Research Meathead: Training to Failure

TAGS: workload, training to failure, Jonathan Mike, training athletes, failure, hypertrophy, power, bodybuilding

elitefts™ Sunday Edition

Introduction

This is certainly one of the many questions in training that just doesn't seem to ever end. Within the conceptual framework of strength training programs, the idea and implementation of momentary muscular fatigue is regularly discussed between coaches, trainers, clients, and athletes. Unfortunately, many coaches and trainers adhere to the mindset that if muscular ‘failure’ during a set isn't achieved, the set will be counted as an additional warm-up set or that muscular failure has to be completed on every set. The concept of training to failure is certainly not new to resistance training. However, surprisingly there is little research to confirm or deny this premise. So, due to this phenomenon, let’s get right to it.

What is failure?

Muscular failure during training represents the point when the neuromuscular system is unable to generate further increases in force to overcome a particular workload, set, or series of sets. Therefore, the individual has to stop or discontinue the set. This is followed by a brief recovery session where ATP is resynthesized. During this recovery time, some metabolic byproducts (i.e. hydrogen ions, lactate, creatine) inside and outside of the muscle fibers are removed or restored. Now, this is very important and probably a foundational basis of error. At this point, the muscle fibers involved are not completely fatigued. Simply, they just can’t generate enough force to overcome the particular load. This is why the overall load usually has to be decreased to a lighter load.

The theoretical basis of training to failure is based on, of course, motor unit recruitment and muscle fiber types. It is motor unit recruitment (and muscle fibers) that is the foundation of the force production needs of the muscle. To further illustrate this, see Table 1. In addition, if strength is the primary goal (which it almost always is), the magnitude of activation of motor units is directly linked to the magnitude of the strength training response.

Table 1: Fiber type characteristics

Training to failure literature

If you really think about it, the concept of training to failure is deeply rooted in strength training but, overall, lacks a substantial amount of supportive evidence. To give some illustration of this, a review by Willardson (7) summarizes that some research is quite misleading. As the authors state, the subjects trained to a certain percentage of a one rep max (RM), yet the investigators didn't designate if failure was attained (intentionally or accidentally).

An early study by Rooney, Herbert, and Balnave (5) investigated the effects of training to fatigue by examining strength increases produced by a training protocol in which subjects rested between contractions versus those individuals who didn't rest between repetitions. Forty-two male subjects were randomly assigned to a 'no rest' group, a rest group, or a control group (who did no training). Subjects in the two training groups trained their elbow flexor muscles (biceps) with a 6RM load for 6–10 reps three days per week for six weeks. Participants in the 'no rest' group performed repeated lifts without resting whereas subjects in the rest group rested for 30 seconds between each repetition. Intensity and volume of training were equated. The study showed that subjects who trained without rest experienced significantly greater mean increases in dynamic strength (+56.3 percent) than subjects who trained with rest (+41.2 percent).

While failure can be a valuable tool in a bodybuilder’s training routine, there is some evidence to indicate that it comes with a significant cost. Izquierdo (4) found that training to failure every set significantly increased resting levels of the catabolic hormone cortisol and suppressed anabolic growth factors such as IGF-1. This investigation demonstrated a potential beneficial stimulus of non-failure for improving strength and power whereas performing sets to failure resulted in greater gains in local muscular endurance. This study may indicate that bodybuilders who take every set to absolute failure may put themselves at risk of impeding long-term growth.

From a metabolism perspective, Gorostiaga (3) found that training to failure significantly increased levels of the nucleotide adenosine monophosphate (AMP) versus non-failure. Simply, elevated levels of AMP are an indicator that the cell is depleted of energy. As a result, protein synthesis is reduced. Athletes need to be aware that this particular training approach can be taxing and should be used intelligently.

In contrast to the previous study by Rooney (5), Drinkwater and colleagues (2) examined 26 elite junior male basketball players and soccer players, all who had been doing resistance exercise for the previous six months. The subjects completed bench press training three times per week for six weeks using equal volume programs (24 repetitions at 80–105 percent 6RM). Subjects were assigned to experimental groups designed either to elicit repetition failure with four sets of six repetitions (failure) or complete eight sets of three repetitions not to failure (non-failure). The training to failure group demonstrated significant increases in strength (+9.5 percent) and power (+10.6 percent) over the non-failure group in strength (+5.0 percent) and power (+6.8 percent).

Although the results from these two studies are mixed, they provide insight into the fact that physiological and metabolic processes are linked with fatigue and contribute to the strength training response.

Benefits and risks

There can be several benefits to training to failure, which in the right context can promote an anabolic stimulus. A recent review from Schoenfeld (6) illustrates that many contributing factors and mechanisms are associated with exercise induced metabolic stress. One such factor is greater increases in lactate within muscle from enhanced metabolic stress, which is crucial for overall hypertrophy because it stimulates greater increases in intramuscular growth factors. Further, previous science has demonstrated that training to failure also increases lactate production more than non-failure training (1).

Another benefit from training to failure is smaller motor unit fatigue. Toward the completion of a set or series of sets, smaller motor units become fatigued. Therefore, fast twitch fibers and motor units are called upon from the nervous system in order to complete the necessary task.

A main potential risk with training to failure is overtaxing your nervous system. Almost all of us have experienced this from training heavy and competing. With training to failure, once your nervous system has been taxed, the ability to perform all the subsequent sets will be reduced. For example, if you can perform twelve reps at complete failure on the first set, you may only obtain eight reps on the second set. However, if you stopped at ten reps on the first set, you’ll most likely be able to perform eight or nine reps on the second set. This is mainly contributed to less overall fatigue. Therefore, from a training perspective, it’s recommended to train to failure only on the last set of a given exercise. This has been previously supported by Drinkwater (2), who showed that failure on the last set of each exercise resulted in greater strength and power. However, from a practical perspective, this may not always be the case, as it depends on several factors such as total workload, intensity, volume, specific exercises (i.e. squat, bench, deadlift), amount of reps per set, and so on.

Practical application

It’s always imperative to discuss the overall practical application to various training concepts. Most of the evidence does suggest that training to failure is a necessary part of promoting optimal muscle hypertrophy. Over the last several decades, the majority of bodybuilders have instinctively recognized this and continue to employ training to failure as an essential part of their training programs. The fundamental question then becomes how frequent should one go to failure? Unfortunately, there isn't any clear answer. However, there is ample evidence that continuous training to failure for long periods of time can be attributed to overtraining and may lead to performance decrements. The overall recommendation is to employ some type of periodization or reduce the number of sets that are taken to failure. In addition, there are a few ways to go above and beyond failure such as forced reps and drop sets. However, these techniques can be even more taxing than using a traditional training to failure approach and may even require additional recovery time, depending on the individual's response.

If you're training the main lifts, it’s recommended that you don’t go to failure on low rep (i.e. 1–5), max strength work. Due to the added stress on the central nervous system, this will surely impede your ability to recover. It is also important to note that training to failure shouldn't be used on Olympic lifts, with any dynamic effort training, or with speed and power exercises. In contrast, when training at higher rep ranges (8–12 or even up to twenty) that are overall less stressful, training/stopping closer to failure may be used more. For example, to illustrate this, pull-ups or dumbbell rows to failure is completely different than deadlift reps to failure. This is where true training experience and understanding your own response to various training concepts and protocols are key.

With body weight exercises (although generally less stressful than heavy, compound lifts), it is important to use some intelligence when attempting a new movement pattern that requires high levels of skill and coordination. It is suggested that the athlete or client stop the set when performance technique is being compromised (i.e. poor posture, body shifting, accessory movements) to lift the weight. Some exercises (body weight and dumbbells) are often better when multiple sets for lower reps are used (far from failure) in order to establish specific motor patterns before engaging in failure. This approach can also be employed for beginners. They should never go to failure because it not only develops bad habits, but this is the crucial time for them to learn proper technique and repeated effort through excellent technique. As previously discussed, competitive athletes and those individuals trying to maximize strength and hypertrophy may have greater needs to train more frequently to failure in order to achieve their performance goals. The bottom line is if you’re going to train to failure, do so strategically and appropriately in a training program.

References

  1. Ahtiainen JP, Pakarinen A, Kraemer WJ, Hakkinen K (2003) Acute hormonal and neuromuscular responses and recovery to forced vs maximum repetitions multiple resistance exercises. Int J Sports Med 24:410–18.
  2. Drinkwater EJ, Lawton TW, Lindsell RP, Pyne DB, Hunt PH, McKenna MJ (2005) Training leading to repetition failure enhances bench press strength gains in elite junior athletes. J Strength Cond Res 19:382–88.
  3. Gorostiaga EM, Navarro-Amezqueta I, Calbet JA, Hellsten Y, Cusso R, Guerrero M, Granados C, Gonzalez-Izal M, Ibanez J, Izquierdo M (2012) Energy metabolism during repeated sets of leg press exercise leading to failure or not. PLoS One 7:e40621.
  4. Izquierdo M, Ibanez J, Gonzalez-Badillo JJ, Hakkinen K, Ratamess NA, Kraemer WJ, French DN, Eslava J, Altadill A, Asiain X, Gorostiaga EM (2006) Differential effects of strength training leading to failure versus not to failure on hormonal responses, strength, and muscle power gains. J Appl Physiol (1985) 100:1647–56.
  5. Rooney KJ, Herbert RD, Balnave RJ (1994) Fatigue contributes to the strength training stimulus. Med Sci Sports Exerc 26:1160–64.
  6. Schoenfeld BJ (2013) Potential mechanisms for a role of metabolic stress in hypertrophic adaptations to resistance training. Sports Med 43:179–94.
  7. Willardson JM (2007) The application of training to failure in periodized multiple-set resistance exercise programs. J Strength Cond Res 21:628–31.
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