In the most basic sense, there are two training variables that can be manipulated in a given program: quantity of exercise and quality of exercise. Given the time crunch that many of us suffer from, we should collectively strive for ways to enhance the quality of our workouts. One possible method of enhancing the quality of our strength-training workouts is through the use of descending sets.
Descending sets (also known as the multipoundage system, regression sets, burn-outs, break-down sets, or drop sets) constitute a resistance-training technique that modifies the resistance during a set of repetitions. Descending sets are generally considered a high-intensity technique for blasting through barriers to progress, such as the dreaded strength plateau (Marotti, 2000; Mejia & Velazquez, 2000).
Descending sets induce a greater level of muscular fatigue than do multiple sets performed with ample rest between sets. This is accomplished by performing a set of repetitions to the point of exhaustion, at which point you cannot complete another repetition in good form, followed by rapidly decreasing the resistance so that more repetitions may be immediately performed. This, in turn, may be followed by further reducing the resistance and performing yet another series of post-failure repetitions. Descending sets provide a unique stimulus by allowing multiple levels of muscular fatigue within the same exercise set.
Several authors have described different variants of descending sets. Brzycki (1995, p. 37) explains one version of this method, stating, "After reaching muscular failure, you (or your training partner) quickly reduce the starting weight by about 25-30 percent and the lifter does 3-5 post-fatigue repetitions with the lighter resistance." Brzycki continues, "If desired, a second series of 3-5 regressions may be performed immediately after the first series by reducing the lightened load by 25-30%."
In a similar description, Marotti (p. 197) states, at the end of an intense set, the weight is decreased by 20-30 percent and another set is performed as soon as possible. This breakdown can be done 2 or 3 times.
Fleck and Kraemer (1997, p. 124) write, "The trainee performs four or five repetitions at a 4- or 5-RM [repetition maximum] resistance. Then 20 to 40 lb (9.1 to 18.1 kg) is removed from the resistance, and the trainee performs another four or five repetitions. This procedure is continued for several sets..."
In a recommendation that resembles others on the subject, Mejia and Velazquez (2000) suggest using a heavy resistance initially (4-6 RM). They then recommend reductions of 20% or so for the following sets.
Westcott (1996, p. 41) suggests, "As a general rule, go to temporary muscle failure with your standard resistance, then quickly reduce the resistance about 10-20 percent. This should permit you to complete two to four additional repetitions, reaching a second level of muscle failure within the anaerobic energy system (under 90 seconds)."
Poliquin (1997) suggests a more elaborate, somewhat esoteric approach to the implementation of descending sets. He believes descending sets should be different according to whether or not the trainee is deemed "neurologically efficient." For the neurologically inefficient, Poliquin advocates a 12-15 RM, followed by a 12-15 RM with about 20% less weight, once again followed by a 12-15 RM with about 20% less weight. He recommends repeating this process 1-2 times. For the neurologically efficient, he recommends beginning with a 3 RM. Then, after a 10 second reprieve, a 1-2 RM is completed with 3% less weight. After another 10-second rest and another 3% or so reduction in resistance, a final 1-2 RM is advised.
For reasons that I explain in the following section, I propose my own twist on descending sets, which somewhat parallels the description by Mejia and Velazquez. I suggest that descending sets be implemented such that the first repetitions be performed with a relatively heavy resistance that allows only a 3-5 RM. At the point of muscular failure, decrease the load by an amount that allows another 3-5 repetitions to failure. Repeat the process once more such that the total set duration remains under 2 minutes. If you're a fan of either ballistic (fast) or super slow (very slow) training, then you can ignore the rep scheme and simply try to divide the set into equal portions with the heavy, moderate, and light loads. Really, the number of repetitions is immaterial. What's more important is that the repetitions be performed in a consistent, repeatable manner within a time frame that is consistent with increases in size and strength (typically under 2 minutes). Admittedly, some of these recommendations are arbitrary and are intended to serve merely as basic guidelines for implementing descending sets.
Why descend?
To appreciate the rationale behind descending sets, it's helpful to have a brief review of the mechanisms of exercise-induced muscle growth. Beware: you are entering a scientific discussion. If you despise such discussions, would prefer a frontal lobotomy performed with an ice pick, and just desire the "how to" information, skip down to the "precautions/contraindications" subheading.
Over the years, several different hypotheses regarding the nature of the stimulus for exercise-induced muscle growth have come in and out of favor. Though we do not presently fully understand all of the variables involved in the process of muscle growth, one of the currently favored adaptive triggers is that of energy deprivation. Muscle tissue, metabolically speaking, is a very busy tissue, spending a lot of time and energy on cellular remodeling and repair. Remodeling is the maintenance process by which older, often damaged proteins are degraded and new proteins are synthesized to replace them. During the process of protein synthesis in any cell, energy is consumed in the form of adenosine triphosphate (ATP), the body's energy currency.
Muscle contraction, like protein synthesis and the vast majority of other physiological processes, also consumes ATP. At this point, you may detect a conflict of interest between these two processes of protein synthesis and contraction. At some point of exercise intensity, it is conceivable that muscle contraction infringes on the ATP necessary for the synthesis of proteins. The result is that protein synthesis is temporarily put on hold. When the energy-taxing contractions cease, ATP is again available for protein synthesis. Realize that ATP depletion is not a physiological possibility as the biggest decrease in ATP that can occur with physical activity is a 25 percent reduction (Green, 1995). However, it is thought that there can be a relative deficit.
The moments of ATP shortage during protein synthesis are hypothesized to be of paramount importance. Supposedly, an unknown signal would report to the muscle cell nuclei to order them to send more protein-building instructions back out into the cell. It is proposed that when a trained muscle attempts to "catch up" on its protein synthesis during rest, it inadvertently overshoots resulting in a super compensation, or net increase, in the amount of muscle protein. Indeed, an increase in protein synthesis is how fast-twitch muscle fibers have been shown to react to resistance training, which will be addressed again later (Goldspink, 1992). The concept of this competition for energy, called the ATP Deficit Theory or ATP Deficiency Theory, is somewhat analogous to the glycogen super compensation characteristic of trained muscles (Hartmann & Tunnemann, 1995, p. 167).
We should not expect that all intensities of muscle contractions would greedily devour the available ATP. Rather, it is likely that during mild, endurance-style contractions enough ATP is available for both contraction and protein synthesis. However, with increasing loads or fatigue, less ATP becomes available for protein formation. Finally, at the point of muscular fatigue, nearly all available ATP must be used for the purpose of contraction.
So far, we've seen how ATP deprivation may provide a valuable signal for the growth mechanism response. However, there is much more to muscular growth. Energy deprivation is usually concurrent with some degree of muscular damage. This damage is commonly referred to as "micro damage" to distinguish it from gross damage such as a muscle tear. It is possible that energy deprivation is one cause of muscle damage, but a more important contributor to micro damage is mechanical stress, as in the presence of high tension and eccentric (lengthening, negative) muscle actions. Mild to moderate muscle damage from metabolic and mechanical stressors provides a second, better understood, means of growth through the enlistment of cells closely associated with muscle cells.
In addition to the genetic material found within the nuclei of a muscle cell, there also exists a virtual reservoir of genetic material residing just outside muscle cells in the form of small, relatively inactive cells. Because of their peripheral relationship to muscle cells, these reservoirs of genetic material have been aptly named "satellite cells." Much of our interest in muscle-building potential should probably revolve around satellite cells (pun intended).
Each muscle cell is associated with a few satellite cells, each with a single nucleus of its own. Satellite cells don't do much unless provoked. Otherwise, they are dormant. Insults such as resistance exercise can provoke them. On the contrary, insults such as, "You're a bunch of pathetic little cells with scanty cytoplasm!" do not provoke them. The phenomenon of satellite cell recruitment is very complex. It is currently thought that satellite cells are recruited when they somehow detect that the close association between their cell membrane and the muscle cell membrane has been disrupted (Helliwell, 1997).
Where satellite cells may make a stellar performance is in the role of supplying extra nuclei to the neighboring muscle cell (MacDougall,1992). This would result is a muscle cell with more nuclei to instruct the manufacture of muscle proteins. In support of satellite cells' supplying nuclei to muscle cells, one study reported a 46 percent increase in the number of muscle cell nuclei in hypertrophied muscle (McArdle, Katch, & Katch, 1996, p. 443). In fact, satellite cells are now considered essential for muscle hypertrophy, at least in some mammals (Brooks, Fahey, & White, 1996, p. 304; Rozenblatt, Yong, & Parry, 1994). A recent review defends the importance of satellite cells in adaptation to micro trauma following resistance exercise (Vierck, et al., in press). But, it is important to realize that greater and greater damage does not necessarily result in superior muscular growth (Komulainen, Kalliokoski, Koskinen, Drost, Kuipers, & Hesselink, 2000). Rather, there appears to be a certain threshold to damage and the growth that follows, but we simply don't know what the threshold is at this time.
From a practical perspective, it appears that because a muscle should be subjected to a challenging tension for certain duration to establish an energy deficit, and because fatigue and tension are implicated in the micro damage that elicits satellite cell proliferation; we can make some predictions regarding the best way to train. The beauty of descending sets is that they may take advantage of both of the discussed mechanisms of exercise-induced muscle growth. First, heavier weights early in the set provide greater tension on the muscle cells, which could lead to greater mechanical trauma and therefore greater satellite cell recruitment. Second, by extending the set with additional repetitions, a greater level of fatigue is induced which could serve as a stronger stimulus for super compensation of muscle protein. So, it appears that descending sets may provide the best of both worlds: micro trauma and fatigue, both of which may play complementary roles in exercise-induced muscle growth.
In addition to the possibility of enhanced muscular growth based on greater micro trauma and fatigue, the trainee stands to benefit with strength increases due to 1) increased cross-sectional area of the muscle and 2) specificity of training with heavier weights. Yet another benefit of descending sets is that they are very time efficient.
Where's the proof?
By now, you may be thinking that all this makes sense on your computer monitor, but where is the proof? Although the method of descending sets or very similar methods originated almost 50 years ago (Brzycki, 1995, p. 37) and has probably been practiced even longer, there is surprisingly little evidence that has compared the use of descending sets with other resistance training techniques. I am aware of only two training studies that have addressed this issue. Although his data do not appear in a peer-reviewed scientific journal, Dr. Wayne Westcott (1996) investigated on two occasions the efficacy of descending sets with regard to strength augmentation.
In one study, Westcott (pp. 41-42) trained 45 adults with a total-body resistance machine program consisting of 11 exercises. For 4 weeks the subjects performed one set of 8-12 repetitions to failure. From context, it appears that the frequency was 3 times per week. Then, the subjects were divided approximately in half, with half of the subjects continuing to use the prior program and the other half being assigned to also incorporate descending sets on two exercises: seated leg curl and abdominal crunch. After 4 additional weeks of training, the descending set group showed an average increase in training weight on the seated leg curl and abdominal crunch that surpassed that of the standard training group by 39%. An interesting aspect of this research is that it was performed before a strength plateau was reached. In other words, descending sets may be appropriate even if you're presently making satisfactory progress.
In a second study, Westcott (pp. 209-210) tested the use of descending sets for the commonly applied purpose of overcoming a sticking point in progress. The 22 subjects who had experienced strength plateaus performed descending sets on 3 exercises, and three other high-intensity training techniques on three exercises each. In addition, 2 exercises were performed in the traditional manner, but with supervision of a personal trainer who emphasized proper training technique. From context, it appears that the subjects performed single sets of each exercise 3 times per week. Westcott concluded, all of the training methods produced significant improvements in muscle strength, including the supervised standard training. Apparently, working with an instructor encourages better training technique and greater exercise effort. Each of the high-intensity techniques, however, produced even greater strength gains.
As traditionally implemented, descending sets extend the duration of a set of repetitions to failure. For example, a person may perform a lift 10 times to fatigue and then decrease the resistance to continue. However, when implemented in this fashion, after two or three breakdowns, the duration of the set becomes unusually long, and the relative resistance at the set's completion is very light. Although it is my belief that the degree of fatigue is appropriate for stimulating the desired muscular adaptations (e.g., size and strength increases), from the perspective of mechanical disruption (micro trauma), one would think that the light loads towards the end of the descending set would no longer be disruptive. Contrary to popular notion, there is no reason to believe that simply extending a normal set to fatigue would knock off any additional motor units (nerve cells and all the muscle cells each innervates) because all motor units would be expected to have already been recruited at the first episode of muscle failure. Backing off resistance would likely result in derecruitment of motor units. Therefore, any growth stimulus from conventional descending sets, which simply extend the duration of a normal set to failure, may stem from the greater degree of fatigue in working muscle fibers. Of course when heavier repetitions are included, as per my suggestion, then a greater degree of fatigue is combined with the potential for greater micro trauma, which we know is an important stimulus for muscle growth.
Are there special precautions or contraindications?
It should be noted that descending sets performed as per my suggestion will place greater orthopedic stress on the trainee due to the greater mass lifted during the initial repetitions prior to the first regression. Therefore, I would not recommend descending sets for exercises involving joints that have experienced recent trauma or overuse conditions such as tendonitis. Training with heavy loads is also contraindicated with the elderly, those predisposed to orthopedic injury, cardiac patients, and hypertensive individuals, who may be better suited to sets of 10-15 repetitions (American College of Sports Medicine, 1998; Feigenbaum & Pollock, 1999).
There are some added precautions one should take when implementing descending sets. A warm-up specific to the particular exercise should be performed (i.e., perform a light warm-up set of the exercise followed by stretches for the appropriate muscles). Obviously, competent spotters are required for many free-weight exercises when using the descending method both because of the initial heavy load and the increased level of fatigue at the end of the exercise. Fortunately for the lifter as well as spotters, the final load is relatively light. Although it may be tempting to cheat during a descending set due to the unusual degree of fatigue, technique should not be compromised during any phase of the breakdown.
How does one begin using descending sets?
As previously indicated, there is some variation in the recommendations of how exactly to implement descending sets. This reflects the lack of scientific studies that have evaluated the purported usefulness of this technique. Indeed, very little is known regarding how exactly to implement descending sets. Good judgment and trial and error will be key to maximizing program results and preventing over training. First, this strategy should be selectively employed, perhaps beginning with exercises on which the trainee has plateaued in progress. If you were not currently experiencing any sticking points, then perhaps you would like to use descending sets for those body parts, which are not your strongest assets. Westcott used the descending technique for 4 consecutive weeks on 2 exercises. So, attempting breakdown sets with no more than 2-3 exercises in a given workout may be wise. Second, this workout may generate muscular soreness over the following 24-48 hours. If you experience soreness, before training that body part again, wait until you're not sore, and then wait some more! Only stimulation followed by proper recovery will yield optimal results. I strongly recommend against using descending sets more than once on the same exercise in a workout, as I believe it could easily lead to over training.
Recall that more important than the number of reps at each stage of the descending set may be the total duration of the set. Try keeping the descending set duration under 2 minutes, which keeps you primarily within the anaerobic energy system.
Although descending sets can be performed with most weight training equipment, they are most conveniently performed with multiple pairs of dumbbells, several pre-loaded barbells, or machines having selectorized (pinned) weight stacks. These devices allow a quick transition between weight changes during a set.
Have realistic expectations of what descending sets can do for you. Descending sets are not a cure-all for every malady that ails a training program. Using this technique will not repair a hopelessly faulty exercise routine. In my experience, many individuals who weight train perform way too much exercise, which leads to over training and a stagnation in progress. If the problem is over training, descending sets will not help the matter. However, if you have previously made steady progress on an exercise only to hit a sticking point, the conservative, judicious use of descending sets may be just the novel change required to revive your progress. Train hard!
About the Author
Greg Bradley-Popovich holds a Master of Science in Exercise Physiology from the School of Medicine at West Virginia University, and a second M.S. in Human Nutrition, also from WVU. He is currently a Doctor of Physical Therapy scholar at Creighton University in Omaha, Nebraska where he is researching the use of creatine supplementation as an intervention in medical conditions.
REFERENCES
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