How’s it going Train Loco readers! Today we have an awesome guest blog by Dan Ogborn, one of the industry’s top experts on the effects of strength training on skeletal muscle. We’ve read Dan’s blogs before and we are big fans of his work because he uses science to back up his claims, so we asked him to spread some knowledge with the Train Loco readers so you all could get into the weight room and apply drop sets to your training protocols and further your gains. Enjoy!

-Eric and Chris

The dropset goes by many names, and opinions on their use in hypertrophy training are just as plentiful. To some, it’s a gateway to pain and overtraining, an unnecessary technique reserved only for those “advanced” enough to handle it. To others it’s the quickest ticket to slabs of muscle. Despite the widespread use and abuse of dropsets in training, and the variety of methods for their use, little is known as to whether or not dropsets are actually effective, and if they are, how they work from a physiological perspective.

The Science of Drop Sets

Unfortunately the scientific community hasn’t given much thought to the dropset, and I’m not sure this technique will see much time in the lab in the future either. Two studies from Goto et al. (1,2) have suggested that dropsets may confer a slight hypertrophic advantage. In the first (2), the inclusion of a lower load set (50%-1RM) immediately after a high-load set (90%-1RM) resulted in a greater acute growth hormone (GH) response and post-exercise muscle swelling which the authors cautiously theorized could enhance the adaptation to training. The significance of the post-exercise GH spike is unclear (3), especially in the context of recent evidence that post-exercise fluctuations in systemic hormones (like GH), do not necessarily impact or correlate with the ultimate hypertrophic response (4-8).

In the second study, Goto et al. (1) trained groups of men in what they considered to be a hypertrophy-type training program (variable %-1RM, minimal rest) for six weeks, then split the groups into a pure strength group (5 sets at 90%-1RM, 3 min rest) and a strength group that performed a final dropset for their last set (5 sets at 90%-1RM, drop to 50%-1RM on last set), over an additional four weeks. While both groups increased muscle size roughly 5% in the initial hypertrophy phase, the addition of the dropset in the subsequent training phase did not result in a statistically significant difference in growth between the groups (2% vs -1%, p=0.08). While this is a very specific experiment that may not reflect what happens in most hypertrophy training programs, it doesn’t provide the most compelling case that dropsets confer a hypertrophic advantage.

Dropsets are actually difficult to study, and in Goto et al’s (1,2) work there’s a major limitation. Scientific studies require strict controls in order to determine how individual variables contribute to the result of the experiment. In the case of the dropset it’s hard to control for the volume of exercise or work performed when you add on additional dropsets between the experimental groups. It may be that the dropset advantage in these studies (1,2) is simply because they had higher training volumes than without dropsets, that may contribute to increased muscle growth.

So it seems at this point we have many anecdotal accounts and articles singing the dropset praises, however the scientific evidence (1,2), while showing the potential for modest benefit at best, can’t give us a solid conclusion. While the data may not be there yet, there is a nice physiological rationale that can be used to justify using dropsets in your hypertrophy programming based on some recent evidence on the effects of various training intensities on muscle growth.

A Tale of Two Fibers

Without going into too much detail, skeletal muscle is mainly composed of two fiber-types, the slow-twitch type I and fast-twitch type II fibers. As their “slow-twitch” name alludes, the type I fibers are often smaller, weaker, and have lower power outputs than their type II relatives but are highly fatigue-resistant (9,10). In the hypertrophy world, it is often thought that type II fibers have superior growth potential to type I fibers (11), and that training programs should target type II fibers to maximize muscle growth by utilizing high training intensities (12). This assumption is not necessarily invalid, and work from Fry (11) has shown that when the results of multiple training studies are pooled, type II fibers respond well to high intensity (>50%-1RM) training, and to a greater extent than the type I fibers. At lower training intensities (<50%-1RM), type I fibers may grow more than type IIs, but the peak growth rates are still lower than at high training intensities. Unfortunately, the majority of training studies utilize higher training intensities (>50%-1RM) (11,13), so it’s hard to conclusively say that type II fibers always outgrow the type I fibers, or that this response is specific to higher training intensities. In fact, recent evidence has shown that low-intensity training can stimulate muscle protein synthesis (14) and produce comparable whole-muscle hypertrophy to high intensity training when sets are taken to failure (15,16). Even more interesting, in this dataset the type I fiber growth rate with low-intensity training rivaled that of the type II fibers with high-intensity (15), suggesting that we may have misjudged the ability of our type I fibers to grow. The fact that bodybuilders also have larger type I than II fibers (11), and powerlifters and olympic lifters have larger type II than I fibers, adds additional, albeit indirect support, to this recent data on type I fiber and whole muscle hypertrophy when training to failure regardless of load (15,16).

So how does this impact your training? If you’re focused on packing on more muscle mass, you need to ensure you provide a training stimulus to promote the growth of both type I and II fibers. Focusing solely on load (high intensity) may be great for type II fiber growth but may leave your type I fibers under-stimulated and craving some time under tension. On the opposite end of the spectrum, focusing on fatigue and time under tension with light loads, which can possibly still hit your type II fibers (17), may not be optimal for type II fiber growth (18). Since the scientific literature on the topic is still undecided (19) you’ll need to take an approach that maximizes type II fiber recruitment (high training intensity, high effort, and/or high fatigue/failure) and satisfies the type I fibers. Not a small order!

What Does This Have to do With Dropsets?

Ultimately our understanding of muscle growth and fiber-type specific hypertrophy is not at the level where we should be making black-and-white statements to training exclusively at high or lower intensities to maximize mass. There’s a multitude of ways to address the needs of your type I and II fibers across a strength training program, but the dropset allows us to get the best of both worlds in a single, but painful, set.

While there are many ways to structure a dropset, the traditional dropset allows us to maximize both load and time under tension. In the first portion of the set, load can be emphasized, even as high as a 3-5RM, to demand high levels of muscle activation so you’ll have to recruit your full complement of motor units and tap into your fast-twitch fibers. As you work through each subsequent drop in weight, you’ll be providing greater time under tension than if you stopped after one set, giving the type I fibers the stimulus they need to get growing. If things couldn’t get any better, the increased fatigue will act as a safe-guard to ensure you really hit those type II fibers, as fatigue can actually make it easier to recruit your type II fibers at a weight where their use wouldn’t be normally be required (17).

Conclusion

Maximizing muscle growth is a balancing act of training variables, but simple techniques used judiciously in a well thought out training program, consistently executed is the path to pounds of extra muscle. While the research hasn’t given us conclusive insight into the use of dropsets for hypertrophy training, based on our understanding of muscle physiology it’s likely that dropsets are still a viable and valuable component of your training toolbox.

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References

Goto K, Nagasawa M, Yanagisawa O, Kizuka T, Ishii N, Takamatsu K. Muscular adaptations to combinations of high- and low-intensity resistance exercises. J Strength Cond Res. 2004 Nov;18(4):730–7. Goto K, Sato K, Takamatsu K. A single set of low intensity resistance exercise immediately following high intensity resistance exercise stimulates growth hormone secretion in men. J Sports Med Phys Fitness. 2003 Jun;43(2):243–9. West DWD, Phillips SM. Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training. Eur J Appl Physiol. 2012 Jul;112(7):2693–702. Schroeder ET, Villanueva M, West DDW, Phillips SM. Are Acute Post–Resistance Exercise Increases in Testosterone, Growth Hormone, and IGF-1 Necessary to Stimulate Skeletal Muscle Anabolism and Hypertrophy? Med Sci Sports Exerc. 2013 Nov;45(11):2044–51. West DWD, Burd NA, Tang JE, Moore DR, Staples AW, Holwerda AM, et al. Elevations in ostensibly anabolic hormones with resistance exercise enhance neither training-induced muscle hypertrophy nor strength of the elbow flexors. J Appl Physiol. 2010 Jan;108(1):60–7. Mitchell CJ, Churchward-Venne TA, Bellamy L, Parise G, Baker SK, Phillips SM. Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy. PLoS ONE. 2013;8(10):e78636. West DWD, Kujbida GW, Moore DR, Atherton P, Burd NA, Padzik JP, et al. Resistance exercise-induced increases in putative anabolic hormones do not enhance muscle protein synthesis or intracellular signalling in young men. J Physiol (Lond). 2009 Nov 1;587(Pt 21):5239–47. Wilkinson SB, Tarnopolsky MA, Grant EJ, Correia CE, Phillips SM. Hypertrophy with unilateral resistance exercise occurs without increases in endogenous anabolic hormone concentration. Eur J Appl Physiol. 2006 Dec;98(6):546–55. Burke RE, Levine DN, Zajac FE. Mammalian motor units: physiological-histochemical correlation in three types in cat gastrocnemius. Science. 1971 Nov 12;174(4010):709–12. Burke RE, Levine DN, Tsairis P, Zajac FE. Physiological types and histochemical profiles in motor units of the cat gastrocnemius. J Physiol (Lond). 1973 Nov;234(3):723–48. Fry AC. The role of resistance exercise intensity on muscle fibre adaptations. Sports Med. 2004;34(10):663–79. Thibaudeau C. High Threshold Muscle Building. F. Lepine Publishing; 2007. Wernbom M, Augustsson J, Thomeé R. The influence of frequency, intensity, volume and mode of strength training on whole muscle cross-sectional area in humans. Sports Med. 2007;37(3):225–64. Burd NA, West DWD, Staples AW, Atherton PJ, Baker JM, Moore DR, et al. Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men. PLoS ONE. 2010;5(8):e12033. Mitchell CJ, Churchward-Venne TA, West DWD, Burd NA, Breen L, Baker SK, et al. Resistance exercise load does not determine training-mediated hypertrophic gains in young men. J Appl Physiol. 2012 Jul;113(1):71–7. Ogasawara R, Loenneke JP, Thiebaud RS, Abe T. Low-load bench press training to fatigue results in muscle hypertrophy similar to high-load bench press training. International Journal of Clinical Medicine. 2013 Feb;4:114–21. De Luca CJ, LeFever RS, McCue MP, Xenakis AP. Behaviour of human motor units in different muscles during linearly varying contractions. J Physiol (Lond). 1982 Aug;329:113–28. Campos GER, Luecke TJ, Wendeln HK, Toma K, Hagerman FC, Murray TF, et al. Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. Eur J Appl Physiol. 2002 Nov;88(1-2):50–60. Schoenfeld BJ. Is There a Minimum Intensity Threshold for Resistance Training-Induced Hypertrophic Adaptations? Sports Med. 2013 Aug 19.

About Dan Ogborn:

Dan Ogborn PhD, CSCS. Dan recently completed his PhD in medical sciences specializing in the molecular adaptation of skeletal muscle to strength training. He has previously completed a MSc (kinesiology) and has been involved in the fitness industry in various capacities for the past 14 years. He is currently a post-dorctoral fellow at McMaster University and is completing a degree in physiotherapy.

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