Evidence-Based Resistance Training Recommendations: Part 1

The recent review by James Fisher, James Steele, Stewart Bruce-Low and Dave Smith should be on the “must read” list for everyone with an interest in exercise. In fact, you should download and read it before you read the rest of this post which is the first of several commentaries I will be writing on their review.

Fisher, James & Steele, James & Bruce-Low, Stewart & Smith, Dave. (2011). Evidence-Based Resistance Training Recommendations. Medicina Sportiva. 15. 147-162. 10.2478/v10036-011-0025-x.

“Objective: There is considerable interest in attaining muscular hypertrophy in recreational gym-goers, bodybuilders, older adults, and persons suffering from immunodeficiency conditions. Multiple review articles have suggested guidelines for the most efficacious training methods to obtain muscular hypertrophy. Unfortunately these included articles that inferred hypertrophy markers such as hormonal measurements, used older techniques that might not be valid (e.g. circumference) and failed to appropriately consider the complexity of training variables.

Methods: The present commentary provides a narrative review of literature, summarising main areas of interest and providing evidence-based guidelines towards training for muscular hypertrophy.

Conclusions: Evidence supports that persons should train to the highest intensity of effort, thus recruiting as many motor units and muscle fibres as possible, self-selecting a load and repetition range, and performing single sets for each exercise. No specific resistance type appears more advantageous than another, and persons should consider the inclusion of concentric, eccentric and isometric actions within their training regime, at a repetition duration that maintains muscular tension. Between set/exercise rest intervals appear not to affect hypertrophy, and in addition the evidence suggests that training through a limited range of motion might stimulate similar results to full range of motion exercise.

The performance of concurrent endurance training appears not to negatively affect hypertrophy, and persons should be advised not to expect uniform muscle growth both along the belly of a muscle or for individual muscles within a group. Finally evidence suggests that short (~3 weeks) periods of detraining in trained persons does not incur significant muscular atrophy and might stimulate greater hypertrophy upon return to training.”

ACSM Position Papers and Responses and Anti-HIT Bias in the Field of Exercise

The authors correctly point out the guidelines in the 2002 and 2009 position papers on resistance training from the American College of Sports Medicine are not supported by the research in general and many of the statements were not supported by the references cited  for them. In addition to misinterpretation of the studies cited there were several relevant studies which were not considered, suggesting a selection bias.

Having read the position stands and the reviews and various responses to them by Otto, Carpinelli, Winett, and others, and much of the following discussion, the tradition-based, anti-HIT bias of much of the field is obvious. There are numerous reasons for this, but I suspect the two biggest are the influence of competitive weight lifting when athletes finally realized strength training was not going to make them muscle-bound and slow and were looking for guidance, and the industry backlash against Nautilus inventor Arthur Jones’ due to the perceived threat to competitors in the fitness equipment industry and to the egos of various “experts” in the field whose ignorance Arthur enjoyed pointing out.

In the earlier half of the last century athletes avoided strength training because they believed it would make them slow and inflexible, a condition referred to as being “muscle-bound”. This perception started to change in the 1950’s, and having previously avoided strength training most athletes and coaches had little or no knowledge of how to train and turned to the Olympic lifters, incorrectly assuming their expertise in competitive weight lifting would apply to the training of other athletes. This is where a lot of the misconceptions about lifting speed and explosiveness come from and the reason football players and other athletes are often told to perform power cleans and other quick lifts which are primarily skill based movements which have nothing to do with the skills of their sport and are relatively poor ways of building strength in the muscles involved.

When Arthur Jones’ articles started appearing in Iron Man magazine in 1970 he was very critical of popular training methods, particularly the very high volume approach then popular with bodybuilders and the use of explosive lifts by athletes outside of competitive weight lifting, earning him the ire of many of the “experts” at the time. The vastly superior Nautilus machines also represented a huge threat to competitors, barbell manufacturers in particular, most of whom were advertisers in the bodybuilding and fitness magazines at that time. To appease his advertisers and to spite Arthur for not advertising in his magazines Joe Weider published a long series of articles in Muscle & Fitness attributed to various bodybuilders which attacked Jones and his Nautilus machines.

Jones had a tendency to insult and belittle those he disagreed with and nobody likes being told they’re wrong, much less called an “idiot”, especially when they are claiming to be or believe they are an expert on the subject. This certainly didn’t help matters, especially when both reputations and large sums of money were at stake. People associated the Nautilus Training Principles (later named “High Intensity Training” by Ellington Darden and eventually being abbreviated to “HIT”) with Arthur, even though the principles had been around and in practice long before Arthur started writing and talking about them. Due to both their personal dislike of Arthur and the challenges his training principles presented to their contradictory and unfounded beliefs about exercise these “experts” developed a strong bias against HIT.

Despite Arthur having been right about most things and the majority of exercise research over the past several decades reinforcing his recommendations, this anti-HIT bias is still going strong. This is particularly evident in organizations like the NSCA which bases many of its resistance training guidelines on the myths and misconceptions resulting from the early influence of competitive weight lifting on athletic training, and whose former president William Kraemer contributed to and I believe was to blame for much of the unsupported recommendations the ACSM’s 2002 position stand.

Intensity, Load and Repetition Range

Most in the field of exercise use the term “intensity” to refer to the percentage of one’s one repetition maximum load used during an exercise. Because of this, there is often a disconnect when discussing training intensity with people outside of the high intensity training community where the term is used to refer to the percentage of one’s maximum effort used during an exercise.  For the reasons stated in the review, the definition based on effort is the correct one, since percentages of one rep maximum loads can result in varying levels of difficulty for individuals with a different fatigue response.

This is one of the reasons I rarely perform one repetition maximum testing with clients to determine starting loads and discourage others from doing so without expert supervision. Different trainees will be able to perform widely different numbers of repetitions with a given percentage of their one rep max and the test itself is unreliable. A typical one repetition maximum test involves one or more light warm up sets, followed by a series of maximum attempts, starting with an individuals estimated one rep max, either based on previous test performance or on calculations or tables which give an average and are not appropriate for all individuals. Any one rep max test will involve at least two attempts. If the first attempt fails, the weight is reduced for the second. If it succeeds, the weight is increased. Even after several minutes rest there will still be a momentary reduction in strength due to microtrauma, resulting in a decrease in the strength available for subsequent tests.

The best case scenerior would be if you succeed on the first attempt and fail on the second with a slightly heavier weight, which gives you a rough idea of your max, but you still won’t know if you might have been capable of succeeding with the heavier weight if not for the first attempt.

There are additional problems with this when working with new trainees. Due to a lack of skill and familiarity with both the exercise and the ability to put forth a true, maximum effort, the one rep maximums of new trainees will understate their actual strength. If the test is being done to determine starting loads or in conjunction with a fatigue response test to determine rep range, the result may be a load that is too low or a rep range that is too high based on the individual’s actual strength and fatigue response. Loads should be lower and reps higher starting out for learning purposes, but not because the trainer or trainee is putting too much confidence in the results of one rep max testing.

In addition to the above problems with using one repetition maximum testing to measure strength (there are many more) there are problems with performing a muscular endurance test by performing a set to failure with some percentage of the estimated one rep max afterwards to determine an individual’s relative endurance or fatigue response. Like the one rep max test, both the trainee’s skill and their ability to push to a point of true muscular failure will limit the number of repetitions they perform. Additionally, the time between the one rep max test and the endurance test has an effect on performance. If the endurance test is done too soon after performance will suffer due to fatigue or a reduction in muscle force caused by microtrauma. If the endurance test is done too long after performance may be improved slightly as a result of adaptations stimulated during the one rep max efforts.

Another problem with using one rep max testing with beginners is when the above problems aren’t considered subsequent tests appear to show much greater strength gains than actually occurred. Most improvements in exercise performance during the first six to eight weeks of training are due to neural adaptations, improvements in skill and confidence, and acclimation to the discomfort associated with intense muscular work. Comparing one rep max tests performed at the start and after six to eight weeks of training will give you some impressive numbers, but it is misleading to claim these accurately represent increases in strength.

This is also a huge problem with exercise studies which rely on one rep max testing and are of too short a duration to rule out factors other than strength as major contributors to improved test performance. A bigger problem with this is neural adaptation and skill benefit from more frequent practice, so a higher number of sets or greater training frequency may result in improved test performance in shorter studies, resulting in misleading conclusions about the effects of different numbers of sets or frequency of training on strength. Due to these factors, during shorter studies with previously untrained subjects using skill based tests like one repetition maximums, the deck is stacked in favor of multiple sets and higher frequency. To accurately determine which is more effective for improving strength studies must be of long enough duration to rule out skill and neural adaptations as a significant factor in test performance. Ideally, pre-testing shouldn’t even be performed until after the first six to eight weeks and should be static to minimize the influence of skill and other factors associated with dynamic testing.

An Alternative to One Rep Max Testing

The goal for a new trainee or when starting a new exercise should be to learn and practice correct performance during the first few weeks while gradually working up to a high level of intensity, and the starting load and repetition range should be appropriate to that goal. One repetition maximum testing is not required to determine either. Start with a light load, test and increase until it feels only moderately challenging during the first few reps, and aim for 10 to 15 repetitions (approximately sixty to ninety seconds at a controlled pace).

After a reasonable level of proficiency has been gained, the repetition range can be reduced or increased based on the individual and their goals. While a wide range of loads and rep ranges will work, some people will have a preference for or respond better to higher or lower repetitions and goals must also be considered. If a person has a difficult time performing more than some lower number of repetitions but is able to handle increases in loads without their reps dropping too much, use that as their upper guide number. If a person has a hard time handling increases in resistance without first performing some higher number of reps, use that as their upper guide number.

Another problem with one rep max testing is it encourages the exact opposite mentality you want during exercise. The focus during exercise should not be on lifting as much weight as possible, which requires moving in a way that makes the exercise easier, but on using the weight to challenge the muscles as effectively as possible, which requires moving in a way that makes the exercise harder. The only people who should perform one repetition maximums are competitive lifters. There is no good reason for anyone else to do so.

A more accurate way to evaluate strength increases would be to compare the loads used for the prescribed repetition range over time, starting after the first two months of training. If, for example, during a workout three months ago you performed 10 repetitions of an exercise with 200 pounds and you recently performed 10 repetitions with 220 your strength increased by 10% during that time (assuming the same style of performance, equipment settings, etc.). If you are keeping accurate records of your workouts, or your clients’ workouts if you’re a trainer, you have all the data you need without having to perform inaccurate and unnecessarily risky one repetition maximum testing.

Part 2: Momentary Muscular Failure