It is a common sense opinion that athletes and bodybuilders should make use of deloads in their strength training programs.
However, as is often the case, the various explanations for why such deloads should be used don’t actually make sense when considered in the light of research. We may be doing the right thing for the wrong reasons.
What is a deload?
A deload is a period in which training is reduced in some way.
Typically, this reduction will involve a decrease in both (1) the total volume in each workout of the deload period, and also (2) the proximity to failure of each work set.
In many ways, a deload is very similar to a taper, which is a period of reduced training just before a competition. Yet, a deload is intended to provide only a period of recuperation prior to starting training again. A taper is intended to provide a period of recuperation prior to an optimal performance.
What is the theory behind deloading?
The theory behind deloads and tapers is the fitness-fatigue model.
This model states that performance at any point in time is a function of previous adaptations, which lead to a state of fitness, and fatigue, which impairs our ability to display that fitness. We can enhance performance at any time by either producing adaptations that enhance fitness (training), or by reducing fatigue (deloading and tapering).
The rationale for tapering is very clear. We want to perform in a competition to the best of our ability, so we need to temporarily reduce residual fatigue to its lowest possible level in order to maximize performance on the day. At the same time, we want to avoid losing the adaptations that we gained during the previous training block. This makes good sense from what we understand of the underlying biology of both adaptations and fatigue.
The rationale for deloading is less clear. Essentially, we are assuming that one or more types of fatigue have accumulated in some way, and that we need to use a period of reduced training in order to allow this fatigue to dissipate before we can continue training as before. As we will see, there are a few problems with this assumption.
Either way, to understand deloading, we need to look at both the effect of deloading on (1) the adaptations that we gained during the previous training block, and (2) residual fatigue.
Let’s look at the adaptations first.
Will deloading cause you to lose muscle size?
In most cases, neither deloading nor tapering will cause gains in muscle size to be lost, since they are usually implemented for very short periods of time. Indeed, the most popular length of time for a deload seems to be one week.
Even so, to understand how deloads might affect losses in muscle size, it is worth working through the biology of what occurs during detraining of various types, as well as during deloads and tapers of different kinds. This can also help us to understand what might happen if we implemented relatively long deloads or tapers.
During periods of detraining (not deloading), we lose muscle size relatively quickly. Complete detraining periods can involve meaningful losses in muscle size within two to four weeks, and the loss of all previous gains in muscle size typically occurs within a few months of stopping training.
Losses in muscle size occur because muscle fibers require a mechanical stimulus in order to continue carrying out muscle protein synthesis at a given rate. Limb immobilization causes immediate (and substantial) reductions in the rate of muscle protein synthesis. Yet, rates of muscle protein breakdown are not similarly affected. Consequently, the net effect is for muscle protein breakdown to exceed muscle protein synthesis during periods of detraining, and this leads to rapid losses in muscle fiber protein.
The mechanical stimulus that muscle fibers experience depends upon whether they are activated by motor unit recruitment. Therefore, the nature of our physical activities during the detraining matters.
When we stop strength training, we stop recruiting our high-threshold motor units. Yet, we continue recruiting low- and medium-threshold motor units as a result of our activities of daily life. Therefore, only the fibers controlled by high-threshold motor units experience a loss in habitual mechanical loading, and so only these fibers reduce in size. This causes a meaningful reduction in muscle size. Stopping strength training (and starting detraining) therefore differs from bed rest, which is where we stop recruiting more than just the high-threshold motor units. Consequently, we experience a loss in the diameter of the muscle fibers controlled by low-, medium-, and high-threshold motor units. This causes a dramatic reduction in muscle size.
#2. Deloading and tapering
During deloading and tapering, we will always: (1) do some strength training, and (2) use less volume than in the preceding training block. Yet, strength training deloads and tapers differ. Tapers usually involve continuing to train with a close proximity to failure, while deloads do not.
When done by performance-oriented strength athletes (powerlifters, Olympic weightlifters, and strongman competitors) tapers often involve maintaining the proximity to failure of each work set. This involves maintaining or even increasing the maximum weight on the bar. In contrast, while there is little research available into the exact deloading practices of strength athletes, it seems likely that most implement a reduction in the proximity to failure of each work set (which is usually programmed as a reduction in weight on the bar for the same number of reps).
This is important, because a reduction in the proximity to failure used in a workout will lead to a decrease in the number of muscle fibers that are stimulated with mechanical tension.
When training volume and frequency are reduced to low levels, but proximity to failure is maintained at high levels, previous gains in muscle size can be maintained. Indeed, one important study found that after a lower body strength training program involving 3 workouts per week (each workout involved 3 sets to failure with 3 exercises), a subsequent reduced training block involving 1 workout per week (with only 1 set to failure on each of the 3 exercises) maintained all the gains in size from the previous block.
Therefore, low-volume, high-proximity to failure tapers (as are usually implemented by performance-oriented strength athletes) could allow the maintenance of previous gains in muscle size almost indefinitely. In contrast, low-volume, low-proximity to failure deloads will probably not. Consequently, while short deloads will not cause any meaningful losses in muscle mass (just like short detraining periods are not a problem), longer deloads could easily involve a small reduction in muscle size.
Will deloading cause you to lose strength?
In most cases, neither deloading nor tapering will cause gains in maximum strength to be lost, even when using longer time periods.
While there are several adaptations that cause increases in maximum strength (increases in muscle size, increases in voluntary activation, increases in lateral force transmission, increases in tendon stiffness, and improvements in coordination), the two most influential are increases in muscle size and increases in voluntary activation.
Unlike muscle size, voluntary activation does not reduce very quickly during detraining. Therefore, a loss in the ability to recruit motor units is unlikely to cause any reduction in strength during short-term detraining (up to a month), tapering, or deloading. Consequently, any losses in maximum strength will occur only to the extent that muscle size is reduced, as explained above.
Do deloads and tapers involve reducing fatigue?
Yes, both deloads and tapers involve the reduction of fatigue.
However, it is well worth looking more closely at the nature of the various types of fatigue that are involved during post-workout recovery. There are three categories of fatigue to consider: (1) peripheral muscular fatigue, (2) muscle damage, and (3) central nervous system (CNS) fatigue.
- Peripheral fatigue — this is not really relevant when considering post-workout recovery from one day to the next, as it is recovered fully within hours.
- Muscle damage — this can be very minor, or it can be very severe. Minor damage can take a very short time to be repaired, while severe damage can take weeks or even a month, especially if muscle fiber regeneration is needed. Importantly, we can train while we are still experiencing muscle damage from a previous workout and make gains, and the additional workouts during recovery do not damage the muscle further. This is likely because of several compensation mechanisms, some of which occur in the CNS, and some of which occur in the muscle itself.
- CNS fatigue — like muscle damage, CNS fatigue can be minimal or it can be severe. It seems to be triggered by the amount of muscle damage, although it dissipates much more quickly. Some studies assessing low volume strength training workouts have reported that CNS fatigue is recovered by the following day. Other studies that have assessed high volume or eccentric-only strength training workouts have found that CNS fatigue takes a couple of days to dissipate. When we train while still experiencing CNS fatigue from a previous workout, we cannot achieve good gains in either strength or size, because we are unable to recruit high-threshold motor units.
Ultimately, this means that we can be quite specific about our terms when talking about the reduction of fatigue during a taper or a deload. We are either recovering from (1) muscle damage, or (2) both muscle damage and CNS fatigue, since CNS fatigue always recovers faster than muscle damage. Thus, when we take a taper or a deload, we can enhance our performance by reducing fatigue in either of these ways, although it is more likely that it will only be muscle damage in most well-designed training programs that focus on achieving progressive overload from one workout to the next.
What is the point of a deload? (part I)
The fact that deloads are either conducted after a final workout that involves either (1) only muscle damage, or (2) both muscle damage and CNS fatigue requires a bit of thinking about.
- Muscle damage only — if the final workout only caused muscle damage, then the reality is that we did not *need* the deload in order to continue to experience muscular adaptations. We could have continued the training program. When post-workout fatigue only involves muscle damage, this does not inhibit adaptations from being stimulated in another workout performed in this state.
- Muscle damage and CNS fatigue — if the final workout caused both muscle damage and CNS fatigue, then the reality is that we were training with *incorrect* volume and frequency throughout our program. This is because the fatigue that occurs after a final workout before a deload is highly reflective of the post-workout recovery profiles of the other workouts in the program (unless the program involves large increases in volume from week-to-week, which is not a great idea because it makes it very difficult to identify whether progressive overload is happening). In this case, the chances are reasonably good that we just wasted a training block by training constantly in a state of CNS fatigue.
Even though there are these two possibilities, we actually cannot tell whether we are experiencing (1) both muscle damage and CNS fatigue, or (2) solely muscle damage, after any given workout. Consequently, if we are not fully recovered when we come to do the next workout, we are at risk of training in a state of CNS fatigue. This suggests that if we are doing a strength training program that *requires* a deload, then it probably wasn’t a particularly well-designed program.
N.B. Handgrip strength
Some coaches suggest testing handgrip strength at the start of a workout as a proxy for CNS fatigue. However, handgrip strength doesn’t test for CNS fatigue of all the muscles in your body. That would be very nice if it were true, but it isn’t. CNS fatigue is muscle-specific to a certain degree, so it primarily affects the high-threshold motor units of the muscles that have been trained. Moreover, CNS fatigue is much less in small muscles (such as those in the hand) than in larger muscles (like those in the legs).
What is the point of a deload? (part II)
Some strength coaches have suggested that deloads are useful for either (1) reducing the risk of too much accumulated fatigue damage on connective tissues (tendons and ligaments), or (2) temporarily reducing mental effort so that training can be continued with renewed determination afterwards. Both of these points are important, and are worth considering in detail.
#1. Connective tissues
Connective tissues are damaged by a process known as “fatigue damage.” This is a process by which any material structure is gradually and progressively damaged by repeated loading. Each loading bout (workout) increases the total damage, and the recovery period afterwards repairs some (or all) of it. The cumulative impact of each tiny amount of damage can eventually cause the structure to fail. This is believed to be the cause of overuse injury. Even so, in most strength training programs, it seems likely that there is enough time for connective tissues to be fully repaired after each workout.
When a strength training program involves insufficient time for connective tissues to recover from one workout to the next, then fatigue damage will accumulate and could lead to overuse injury if the program is continued without a deload. In such cases, a deload will be necessary. However, a far less risky way of training would be to reduce training volume and frequency such that there is sufficient time for the connective tissues to recover from one workout to the next. As for muscle adaptations, this suggests that if we are doing a strength training program that *requires* a deload for our connective tissues, then it probably wasn’t a particularly well-designed program.
#2. Psychological factors
Psychological factors are key to high performance in strength sports and should not be neglected. Even so, it is difficult to predict exactly when an athlete will require a period of less intensive training for such reasons.
Programming a deload within a training program after an arbitrary number of weeks for psychological reasons without taking the individual athlete into consideration seems presumptuous. Moreover, it may not have the desired effect if the athlete is mentally prepared to continue working hard at that point in the training program.
This suggests that the use of deloads on the grounds of optimizing mental effort levels is best done on a reactive, individual basis (in which the athlete gives feedback about when they are ready for one) rather than on a proactive, prescriptive basis (where the program designer gives the same one to everyone).
What is the takeaway?
Deloads probably cause little delay to long-term strength training progress. Taking a deload (or even a detraining) week is highly unlikely to cause any losses in either strength or muscle size. Therefore, if you feel like you would psychologically benefit from a deload week, then there is absolutely no reason to avoid taking one, and it may well help you return to training with renewed enthusiasm. Ideally, the decision about whether to take a deload would be made at the point when you are ready for one, rather than in advance.
However, if you are experiencing large reductions in strength (or even size) during your strength training program, or if you think that your connective tissues might be suffering fatigue damage such that they cannot recover in time for the next workout, then the ultimate solution to your problem is probably not a deload but a more permanent change to your strength training frequency or volume, such that you can recover properly from one workout to the next. In such cases, while a deload may be necessary in the short-term, it is akin to a sticking plaster that disguises a larger problem.