ISSUE #100

Strength Training with Dr. Digby Sale

It is fitting that Issue #100 features an interview with a man that has greatly influenced CB Athletic Consulting. Dr. Digby Sale, Ph.D., is a neuromuscular exercise physiology professor at McMaster University whose research and writings influenced athletes, coaches, bodybuilders, and exercise physiologists throughout the entire world for 25 years.

Dr. Sale, himself an accomplished University gymnast, has explored a remarkable number of areas in the world of resistance training and has written numerous articles on the specificity of resistance training. His work has, with no exaggeration, helped strength training get to where it is today. Dr. Sale's interest in educating coaches and students about strength training is genuine, and his stories are fascinating - no wonder this interview had to be broken into two parts.

Part I will begin with a history of Dr. Sale's research, a discussion of the dreaded "muscle biopsy", and an evaluation of olympic lifting, stability training, and power training for athletes. Part II (Issue #101) will take us into the history of bodybuilding, including the years of Arnold and Mike Mentzer.


CB: Dr. Sale, it is a pleasure to have your insight. Where did you get your start in this field that has since led to 25 years of influence on strength research?

DS: My start came as an undergraduate student at the University of Toronto in the early 1960's. I competed in gymnastics as a student, with a particular interest in the rings event. The desire to be able to do an "iron cross" on the rings sparked my interest in strength training. In October of 1963, I purchased an issue of the short-lived Weider publication called All American Athlete. In it was an article giving a strength training program for the iron cross. In addition to specific exercises on the rings, the program included some weight training exercises. This was my introduction to weight training.

In 1966-67 I was a Master's student at the University of Western Ontario. During that year I was introduced to scientific literature on strength training, particularly the work of Richard Berger at the University of Illinois. He made one of the earliest attempts at determining the optimal combination of sets and repetitions for strength development (more about this later).

My career started when I came to McMaster University in 1967, as gymnastics coach and lecturer in the Physical Education Department. Two events occurred in 1970 which influenced the rest of my career. One was the arrival at McMaster of Dr. Duncan MacDougall, who had just completed his Ph.D. at the University of Wisconsin; the other was the opening of the McMaster Medical School and Medical Sciences Graduate Program. Dr. MacDougall became my partner in research for 30 years. The new medical centre gave me the opportunity to pursue my Ph.D. in neurosciences, under the supervision of Dr. Alan McComas, a neurologist with an international reputation in nerve-muscle research.

CB: What prompted you to get involved in strength training research?

DS: I have already noted how I became interested in strength training in general. At the time Dr. MacDougall and I began our research program, the focus of exercise physiology research was mainly on aerobic exercise. We decided to go in a different direction; namely, the study of resistance exercise. We wanted to apply some new and developing techniques (at that time, early 1970's), like muscle biopsies and histochemistry, to the study of adaptations to resistance training.

CB: What was known at that time in the field of neuromuscular physiology and its relation to performance? Was there other strength training research was going on at that time and how did your research then differ from the research taking place now?

DS: At the time we started, studies had shown patterns of strength increase and increases in muscle size determined from girth measurements, but little was known of adaptive changes at the cell level, or the interaction between neural and muscular adaptations. Our program set out to answer these questions. Because of our connections with the medical school, our first research project was funded by the Muscular Dystrophy Association of Canada.

CB: How did you and Dr. MacDougall come up with the idea of doing the first muscle biopsy, and what were some stories from some of your muscle biopsy studies?

DS: We knew that to study adaptations at the cell level, we would have to use the muscle biopsy technique. By good fortune, as we were planning the first study, a Sports Medicine specialist from Australia, Dr. John Sutton, arrived at McMaster. He stayed for 17 years, and he and those he trained did the biopsies for us over a period of many years.

We had a problem, however. Most biopsy studies had been mainly done on vastus lateralis, a large muscle of the thigh. We wanted to use triceps brachii for our studies, both because this muscle would respond more rapidly to training and was also more suitable for immobilization studies. However, there was initial concern that biopsies of triceps might carry greater risk of injury, such as nerve damage. So Dr. MacDougall and I offered up our triceps muscles for experimental biopsies, and the biopsies were done without problems. So we were on our way. In later studies we also used biceps biopsies, which proved easier still.

A final note on biopsies. Today it is routine the use "suction" as part of the biopsy procedure. Suction, by drawing tissue into the needle, provides large samples with minimal trauma to the subject. When we started in 1972-73, suction was not being used. Instead, we had to use what could be called the "pick and shovel" technique. The needle had to inserted and pried a bit in an attempt to force a sufficient sample into the needle. This sometimes failed and the needle had to be inserted again. Needless to say, there was more post-biopsy bruising in the early days!

CB: In your office, you have years and years and years of unpublished research on strength training. Do you have any plans for that? Are there any hidden gems of information lying around your office that could influence strength training?

DS: I'm sure some of it will eventually be published in journals. Some of it is also likely to be included in a book that Dr. MacDougall and I are currently writing. There is one study that may be of particular interest to your readers. In the 1980's we did a three year training study. In each year the subjects trained for 7 months and had four months off. Each subject trained the elbow flexors of one arm with several sets of 1-3 repetitions with the heaviest possible weight, and the other arm with sets of 10-12 repetitions with the heaviest possible weight. Strength, whole muscle cross-section area (CAT scans), and muscle fibre area (biopsies) were measured at the start and finish of each training year.

Some of the results were as expected, such as progressively smaller gains in strength and size with each successive year of training. Perhaps a surprising result was that the low and high rep programs produced the same increases in strength and size over the three years. I say surprising because the convention is that higher reps produce more size and lower reps produce greater increases in strength.

But there are also some published studies by others that challenge this convention (e.g., Hisaeda H, Miyagawa K, Kuno S, Fukunaga T, Muraoka I. Influence of two different modes of resistance training in female subjects. Ergonomics 39(6):842 52 1996; Chestnut JL and D Docherty The effects of 4 and 10 Repetition maximum weight-training protocols on neuromuscular adaptations in untrained men. J Str Cond Res 13(4): 353-359, 1999).

CB: Can you compare the training philosophies between that period and now? Have some methods of training come "full circle"?

DS: When I began observing training practices and monitoring the magazines in the early 1960's, resistance training was just starting to become accepted in the training programs of athletes. Before then weight training was thought to make athletes slow, "muscle-bound" (i.e., decrease flexibility), and damage the heart. The first published research during this period began to dispel these concerns.

At first, application of specificity in training consisted of identifying the muscles involved in a particular sport and then selecting standard exercises that exercised those muscles. It took another 20 yrs before the importance of specificity in all its aspects - movement pattern, velocity, intensity - became widely recognized. We did our part in trying to get the message out (Sale, D. and J.D. MacDougall. Specificity in strength training: A review for the coach and athlete. Can. J. Appl. Sports Sci. 6(2):87-92, 1981.). In recent years, the approach to specificity has been further refined, and in some cases sports-specific equipment has been developed.

I believe the concept of variation in training has been around for a long time, but in the last 10 years or so it has been popularized under the name "periodization". I have not studied the history of this concept, but I believe the impetus for the current emphasis on periodization was Russian and east European literature and proponents. In the English language science journals there have been, to date, surprisingly few experimental tests of periodization.

CB: Given your research, and your years of experience, what are the training methods that you believe are most valuable to the speed-strength/power sport athlete, such as a football or ice hockey player?

DS: I haven't had hands-on experience with athletes for many years, so I can offer little in terms of specific drills etc. From a physiological perspective, I can only reiterate the importance of being as specific as possible. For example, the central nervous system (CNS) does in fact execute fast or "ballistic" movements differently than slow movements, even if the same motor units are activated. The "ballistic command" by the CNS is crucial to achieving and training the high rates of force development (RFD) needed for fast actions.

A landmark recent study has shown how ballistic training can increase maximum motor unit firing rates needed for RFD (Van Cutsem M, Duchateau J, Hainaut K Changes in single motor unit behaviour contribute to the increase in contraction speed after dynamic training in humans. J Physiol 513 :295 305 1998). This was only speculated on earlier (Behm, D.G. and D.G. Sale. Intended rather than actual movement velocity determines velocity-specific training response. J. Appl. Physiol. 74: 359-368, 1993).

CB: What are your thoughts on each of these training methods for performance enhancement of power sport athletes:

    a) Olympic weightlifting
    b) Plyometrics
    c) Machine-based strength training
    d) Stability-based training

DS: a) Olympic weightlifting.

In this activity the athlete attempts to move the weight as fast as possible. There should be a high velocity training effect from this training even if the heavy weights used prevent actual fast movements (Behm, D.G. and D.G. Sale. Intended rather than actual movement velocity determines velocity-specific training response. J. Appl. Physiol. 74: 359-368, 1993). So this activity would have application for sports where "explosive" actions are required.

Some research suggests that the leg-hip action in the clean simulates closely the leg-hip action in jumping. Furthermore, research indicates that arm swing plays an important role in jumping performance, so even the "pulling" action of olympic lifting could contribute to jump performance.

It should be noted, however, that olympic lifting movement patterns are dissimilar to those of many sport movements, and so would not be the most effective method (movement pattern specific). There has been a tendency to oversell olympic lifting, to the point where it is claimed that every sport, including table tennis, would benefit from this training. So I advise coaches to assess specificity of movement pattern before getting involved in the time-consuming task of teaching their athletes the techniques of olympic lifts (not to mention the expense of the equipment).

b) Plyometrics

Plyometrics, the use of the stretch-shortening cycle (SSC) in training exercises, has been tested experimentally and found to be effective for improving jump and sprint performance (e.g., Delecluse, C Van Coppenolle H, Willems E, Van Leemputte M, Diels R, Goris M.. Influence of high-resistance and high-velocity training on sprint performance. Med Sci Sports Exerc 27(8): 1203-1209, 1995; Hunter JP, Marshall RN. Effects of power and flexibility training on vertical jump technique. Med Sci Sports Exerc 34(3):478 86 2002).

Again, the actual SSC drills used should be as specific as possible. Plyometric training causes both neural and muscular adaptations. Recently, the muscle fibre "cytoskeleton" has been identified as a site of adaptation (Lindstedt SL, Reich TE, Keim P, LaStayo PC. Do muscles function as adaptable locomotor springs? J Exp Biol 205(Pt 15):2211 6 2002).

c) Machine-based strength training
d) Stability-based training

I will comment on these two items together. There is no question that doing an overhead press with a barbell (free weight) is a greater challenge, from a motor learning perspective, than the same exercise on a machine. Doing the press with two dumbbells instead of a barbell is more challenging still. And doing the dumbbell press while standing on a large beach ball is the most demanding of all. But is the most difficult exercise necessarily the best? Specificity is key. If the sport performance consists of doing dumbbell presses while standing on a beach ball, then that is the exercise to do.

On the other hand, if the goal is to strengthen the shoulder abductors, then a "machine" exercise, which allows the trainee to concentrate on shoulder abduction, would be preferred. Selecting more difficult exercises may be intuitively more appealing, but unless the skills acquired in mastering the exercises can be specifically applied to the sport movement pattern, such exercises are counterproductive. For example, why would you have a rower struggle to learn how to do a dumbbell bent-over rowing exercise (standing on a ball?), when a seated rowing machine exercise is easier to learn and more movement pattern specific to the sport?

CB: Given that the Rate of Force Development (RFD) is a very important factor in athletic success, what training method would therefore be most suitable for an athlete? Can you explain RFD to the readers?

DS: Perhaps an example would help. Suppose athlete A is asked to pull against an immovable bar as fast and as hard as possible. The bar is instrumented with a strain gauge so that the pulling force on the bar can be recorded against time. It is found that A attained his peak force of 2000 N (newtons, a unit of force) in 0.5 s. The calculated average rate of force development (RFD) during the pull to peak force would be 2000 N/0.5 s = 4000 N/s. A second athlete B does the same test, and achieves the same peak force of 2000 N, but in less time, 0.4 s. Athlete B's RFD would be 2000/0.4 = 5000 N/s.

Why does B have a greater RFD than A? Perhaps he has a higher percentage of fast twitch fibres in the involved muscles (unlikely to be altered by training), or he was able to discharge his motor units at higher firing rates (can be achieved with specific training), or both.

A third athlete C does the test and achieves a peak force 3000 N in 0.5 s. His RFD would be 3000/0.5 = 6000 N/s. The superior RFD of C is related to his greater peak force (strength), which may be the result of greater muscle mass (can be achieved with training). RFD determines the amount of acceleration of an object (including the body) and therefore the velocity attained. Which athlete has the greatest RFD? It appears to be C.

But to this point RFD has been expressed absolutely, without reference to body mass. If B and C have body masses of 60 and 80 kg, respectively, RFD expressed relative to body mass would be 4000/60 = 83 N/s/kg for B and 6000/80 = 75 N/s/kg for C. Thus B has greater RFD relative to body mass.

Which expression of RFD is most important? If the sport task was moving an olympic barbell or an opposing lineman quickly, then C's greater absolute RFD would give him the advantage. If the task were a ski jump in which the athlete's own body must be accelerated quickly, then B would have the advantage, with his greater relative (to body mass) RFD.

This example highlights another key concept, specificity in athlete testing. The pull test described would be most specific to the task of lifting an olympic bar, mildly specific to the task of pushing a lineman aside (more specific if the lineman were pulled aside, but this could result in a penalty), but not at all specific to ski jumping (assumes the pull does not involve leg action).

CB: And finally, the last question on sport performance, what are your thoughts on the importance of speed-agility training to the development of an athlete?

DS: The key answers to this question have already been given, but can be summarized here. If the sport movement pattern is relatively simple, then the focus can be on increasing rate of force development (RFD) and hence speed, as discussed previously.

If sport movements must not only be done as fast as possible, but also require considerable skill (agility?), then attention must be given to motor learning as well. The latter can be addressed with the commonly used sport-specific drills. These are excellent and appear to be in wide-spread use. It has to be emphasized, however, that transfer from irrelevant to relevant motor skills is limited, so specificity must be borne in mind in selecting or creating the drills.

CB: Great! Issue #101 will continue with Part II of this interview.

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