Interviewer Mike Roberts, Ph.D.: Brad, before we start I have to brag on you a bit. You are perhaps the most prolific scientist I know. You run your own laboratory, you’re involved with numerous research collaborations, you’ve authored numerous books, and your social media presence is second to none. Alright, so let me ask:
Q1: You’ve been involved with a great deal of research examining how much weight training is potentially too much for a particular muscle group over a given weeks’ time. Where’s the science at on this topic?
A1: My answer to any applied exercise/nutrition question will always be, “It depends!” There are many factors, both genetic and lifestyle, that will ultimately dictate the amount of volume that optimally enhances results. I would say that the literature is clear there is a dose response relationship between volume and muscle growth, at least up to a certain point. Although not explicitly shown in the current research, it logically can be inferred that the relationship follows a hormetic curve (i.e. inverted-U response), whereby higher amounts of volume will have beneficial effects up to a certain point, then level off, and ultimately have a negative effect from overtraining. My general guidelines from both the literature and personal experience are that somewhere between 10 to 20 sets/muscle/week is a good starting point. Some people do better on higher volumes while others on lower volumes. I hypothesize that having short periods of higher volumes interspersed with periods of lower volumes is the best way to manipulate the variable so that an individual is pushed to a point of functional overreaching to maximize the supercompensatory response. Based on recent research, I also hypothesize that focused high volume training for a given muscle group can help those who are poor responders for that muscle.
Q2: I’ve heard that jogging on an empty stomach accelerates fat loss. Lucky for us you’ve studied how months of cardiovascular exercise training in a fasted versus fed state affects fat loss. What did you all find?
A2: Our lab carried out a study showing no body comp[osition] benefits for performing fasted cardio vs fed cardio (albeit the study was rather short in duration, lasting 4 weeks). The problem with the fasted cardio hypothesis is that fat loss shouldn’t be evaluated based on what happens during the exercise bout itself, but rather how fat is utilized over days and weeks. And the evidence in a number of ways simply doesn’t support a meaningful advantage to performing cardio on an empty stomach. I will provide the caveat that research hasn’t investigated the topic in very lean individuals, so it remains possible (although I think unlikely) that there may be a benefit for say bodybuilders in the last few weeks pre-competition. But for the vast majority of the population, it won’t make any tangible difference whether or not you eat prior to performing cardio.
Q3: You, myself, and Dr. Cody Haun who recently graduated from Auburn have had numerous conversations about weight training with light weights versus heavy weights in terms of building muscle. Cody also performed a nice study on this topic while he was at Auburn. Collectively, has the evidence favored one training form versus the other?
A3: The evidence is compelling at this point that light loads build muscle as effectively as heavy loads. Our group carried out a recent meta-analysis on the topic and there was virtually zero difference between training in a “hypertrophy range” (6-15 reps) vs high reps (20+), provided training was carried out to failure. Thus, the new paradigm for hypertrophy training is that growth can be achieved across a wide spectrum of rep ranges, at least up to around 40 reps per set (we recently showed that loads of 20% 1RM, equating to over 60 reps, was suboptimal for hypertrophy). I would point out, however, that strength gains are maximized with heavier loads, so if the goal is specific to this outcome then it is necessary to use higher intensities of load.
Q4: Several folks, myself included, like to both weight train AND treadmill train in order to build muscle while keeping the fat off. Some scientists believe that the latter will interfere with the former and negatively impact muscle mass gains due to an interference effect. You’ve written a bit on this topic of “concurrent” training. Can this be an effective strategy for optimizing body composition?
A4: It’s a very nuanced topic that is difficult to summarize in a short space. On a general level, untrained subjects typically benefit from adding aerobic exercise to a resistance training routine. For more advanced lifters, it becomes somewhat murkier, as not only do genetic and lifestyle factors enter into the picture, but the specifics of the routines are relevant, as well. Duration, intensity, and frequency of aerobic training will all interact with the specifics of the lifting program, and at some point there will be a negative interaction (chronic interference hypothesis). From a practical standpoint, the negative effects can be attenuated to some extent by performing resistance training prior to cardio; or even better, to separate the time interval between bouts so that lifting is done in the morning and cardio in the evening or (even better) on separate days.
Q5: At dinner one night at a conference you mentioned that what got you into the field of exercise science was the fact that no one really had answered several practical questions related to weight training. Undoubtedly, you’ve contributed to the field in this regard. In your mind, what are some of the next big topics for the field to tackle?
A5: There are so many areas that still require study. We have learned more through research in the last decade about resistance training exercise science than in the previous half-century. However, the research is still in its infancy. In particular, fleshing out the specific underlying mechanisms of hypertrophy will be paramount to designing programs to optimize muscle growth. We’re still a long way off on the topic. From a practical standpoint, one area I find of great interest is the potential for fiber type specific hypertrophy from training with different loading schemes. This is a topic that I’ll be collaborating on with yourself, Mike, as well as Cody Haun in the not-too-distant future. It’s an exciting time to be in the field!
For more information on Dr. Schoenfeld and his training and research, check out the links below:
Author: The M.A.X. Muscle Plan
Author: Science and Development of Muscle Hypertrophy