Barbell Medicine - From Bench to Bedside

The benefits of resistance training for reducing injury risk in endurance athletes was covered in  Part 1 of this series.  In Part 2, we examined the role of resistance training with respect to endurance performance and the fundamental principles of programming. Today we will wrap things up by discussing the practical implementation of resistance training for the endurance athlete.

Programming Fundamentals


A program accounting for overload, specificity, variability, and reversibility should be dosed in a way that elicits improvement over time. According to reviews from Lesinksi et al and Borde et al, there are recommendations on how to establish that dosing in terms of sets, repetitions, intensity, frequency, and rest. Lesinski 2016, Borde 2015 Typical training programs for endurance athletes take into account sets and repetitions, but often place less emphasis on intensity of the exercise or the rest between sets.

This does a disservice to the athlete, as it does not provide guidelines on how hard to push themselves, or how long they need to recover between sets. As seen below, current recommendations for resistance training are that exercises should be performed at intensities greater than about 70% of 1 repetition maximum, and that rest should be at least two to three minutes between sets (note that these are the same guidelines used at Barbell Medicine for strength programming in general).

The evidence here is in direct contrast to programs promising a shortened workout with the same effects, including the trend towards high intensity interval training (HIIT) which ultimately amounts to cardiovascular training. This is not to say that HIIT cannot have a place in a program, but if the goal is to maximize strength to supplement endurance work, this is not the most effective approach. 

Overall, the current evidence  for resistance training in endurance athletes suggests:

  • 4-5 exercises
  • 3-5 sets
  • 4-10 repetitions
  • >70% 1RM intensity
  • 2-3 minutes rest between sets

Rest Periods


If two to three minutes rest are taken in between sets, it moves the structure of the programming away from the ratio of one exercise per muscle group, and towards increasing intensity on multiple muscle groups simultaneously. No endurance sport is a single-muscle sport, so it could be argued that the training is best approached by having multiple muscles work at one time in a coordinated fashion.

If an athlete is going to participate in one hour of resistance training with two to three minutes rest in between sets this would mean a program could only have 15-20 working sets during that time frame. The meta-analysis from Kiely et al recommends 12-25 sets per session, which is still much lower than the typical program to which most endurance athletes are exposed.Kiely 2018 

If the athlete is ready to perform another set with less than 30 seconds of rest, then the intensity of the exercise is likely to be too low. The recommendation for intensities at or above 70% 1RM implies that each set should be challenging, but this also implies that the person designing the program knows what the athlete’s current 1RM is for the exercise they are performing. Many coaches and novice athletes are not comfortable performing a 1-rep max test on athletes, and as beginners, the limiting factor for a compound exercise is more likely skill rather than absolute strength. Fortunately, there are other methods with which to determine intensity as a proxy of 1RM, such as rate of perceived exertion (RPE) and repetitions in reserve (RIR).

Rate of Perceived Exertion


Rate of perceived exertion is a zero to ten scale in which zero is absolutely easy and ten is a maximum effort. The work of Haddad et al used this scale with which to develop a proxy of 1RM as a means of athletes subjectively rating the intensity of the exercise. Haddad 2017 Here, a rating of greater than 6 out of 10 should serve as a proxy for the sufficient “lower limit” of loading, but ultimately there will be variability in determining this number for each athlete.


Figure 2. Rate of perceived exertion scale as a proxy of 1 rep max

Using a subjective scale to measure intensity has other advantages as well, as it accounts for the effects of all biopsychosocial stressors and fatigue levels on how an athlete is performing on a given day. If an athlete participated in a hard distance workout, it allows them to account for this in rating how difficult an exercise is that day and adjust their training loads accordingly. In the same regard, if an athlete is well-rested and prepared to lift, it allows for more weight to be used that day.

When concurrent strength and endurance training are taking place, RPE-based autoregulation also allows an athlete to let their overall training schedule define intensity. It should be noted that there is a learning curve here, and that application of the RPE scale may require redefining what constitutes “hard” for a particular athlete. Initially, the stimulus of training will be difficult because it is novel, and the athlete may be unsure of what actually is sufficient. While this creates greater variability of rating from session to session in the early phase of training, over time the athlete becomes more comfortable with their rating of intensity.

What the athlete rates as an 8/10 is their 8/10 at that time, and coaches should accept this. With that said, an athlete should not fail a set rated as 8/10 by definition. If a coach is looking for different means with which to frame intensity, Repetitions In Reserve (RIR) is an alternative option. Here, an athlete is instructed to perform as many repetitions as possible until they feel like they can only perform a certain number of additional reps before failure (see Figure 3). Zourdos 2016 

In other words, if an athlete is working to 2RIR they will do as many reps as they can until they estimate that they are approximately 2 repetitions shy of failure. This can prove useful in helping athletes determine what is hard and show they may be more capable of moving weight than what they previously thought.

Finally, it is important to note that with endurance athletes, the absolute amount of weight squatted or deadlifted is secondary, and that resistance training should be viewed as supplemental to their endurance goals. We could easily make the statement that the absolute weight squatted or deadlifted is secondary for any athlete, apart from sports predicated on a demonstration of 1RM strength of a squat or deadlift. Morton 2019 


Figure 3: The yellow circle indicates repetitions in reserve (RIR).

We now have different options with which to gauge the intensity of an exercise and multiple ways of framing this to an athlete to establish what constitutes hard. This allows coaches to use the principle of equifinality to add variation to a program not by changing the exercises, but by changing the dosing of the exercises. A simple example might be:

  • 5 sets of 5 at RPE 8
  • 4-5 sets working up to 2 RIR
  • 5 sets with a set weight for as many reps until RPE 8 is achieved

Progressive Overload


In a purely rational world, if the same weight were used for all sets, all things should be equal. But with beginner trainees, this is rarely the case. This is because each individual approaches the situation with their own prior training experience. Athletes rarely know what they are capable of until they are shown they are capable of more than what they originally thought. Variability can also be introduced by performing sets of the same exercise at different intensity. A basic skeleton program of squats, deadlifts, and presses can introduce variation by manipulating the rep range and RPE of different sets.

Example:
  • Back Squat
    • 3 sets of 6 at RPE 7
    • 2 sets of 6 at RPE 8
  • Deadlift
    • 3 sets of 4 at RPE 7
    • 2 sets of 4 at RPE 8
  • Press
    • 2 sets of 5 at RPE 7
    • 3 sets of 5 at RPE 8

The program above only has three exercises, but within each there are two different variables of intensity. If all sets are performed at the same weight the athlete rarely has a chance to reflect on the intensity of the exercise and when they should progress. With multiple sets at different intensities it forces the athlete to ask how much harder their RPE 8 would be than RPE 7. This can allow the endurance athlete improve on a few lifts at higher intensity than completing the same exercises at the same weights for extended periods of time. If an athlete has not changed the weight on the same exercise over the course of a year at all, they are not following the principle of overload.


Figure 4. Comparison of training protocols for endurance athletes.

Popular endurance-focused websites and magazines often advocate for resistance training, but then propose programs similar to that seen in the left hand column of Figure 4. This workout contains 300 repetitions, 24 sets, and no mention whatsoever of the intensity with which they should be performed. Instead, the workout in the right column contains only 85 repetitions, 14 sets, and three of the four exercises have intensity listed (more on Nordic hamstring curls later).

While sets of 12 deadlifts are the stuff of nightmares for powerlifters, the best way to frame intensity and rest for endurance athletes may be through one of the more common hard speed workouts, the 6 x 400 m day. If an athlete were a 50 second 400 m runner, at 80% they would be performing 62-63 second repeats with 3 minutes rest. Most athletes would accept this is a hard workout, and if the athlete was asked to only take 30 seconds rest in between sets, it would suddenly become a near-impossible workout. If the athlete were to complete it, it would be more of a 1.5 mile run than 6 x 400 m sprints.

An analogous scenario for a back squat might be 6 sets of 4 reps at RPE 8 with 3 minutes rest in between. This would have an athlete with an estimated 1RM of 100 pounds squatting 80 pounds. If that athlete is ready to get back under the bar and squat in less than a minute, there is a distinct possibility that the load is too light (or they are not technically proficient yet, resulting in an artificially low estimated 1RM).

With the current lack of measurement of intensity in most resistance training programs for endurance athletes, and the propensity for set/rep schemes favoring very high repetition ranges, this sets endurance athletes up to fail to progress in load. While a failure to progress in load increases suspicion for an individual being a “non-responder”, it is more likely related to improper dosing in order to elicit change. If an athlete’s program is not overloading, does not include some form of variability, and does not focus on specific lower extremity strengthening, the athlete never has the chance to experience the reversibility principle because they likely never improved in the first place. Gains on the track, water, erg, mountain are only made with proper dosing. Bodyweight exercises may get an athlete so far, but at some point, the introduction of external load is necessary in order to continue to make progress.

A Caveat on Nordic Hamstring Curls


There are very few exercises that we can confidently say reduce the risk of injury with good evidential support. Nordic hamstring curls are one of those exercises and likely should be included in any endurance athlete’s program. A recent meta-analysis of implementation of Nordics included over 8,000 athletes demonstrated that the exercise could halve the number of hamstring strain injuries across multiple sports. Van Dyk 2019 Among individuals who have already suffered a hamstring strain, the Number Needed to Treat (NNT) to prevent a second hamstring strain using Nordics is three (i.e., very good).Petersen 2011 This alone should make a case for Nordics being included in resistance training program. Most protocols call for at least 6 weeks of training, but the effect of the exercise seems prone to the principle of reversibility, as adherence to the program is necessary to see ongoing benefit. Goode 2015 

High-speed running is a typical part of “speed work” programming, and this can increase an endurance athlete’s risk of hamstring strains. This is always a game of probability, but the amount of high speed running in which an athlete participates does increase the likelihood of injury. Duhig 2016 In addition, inflection points in the amount of high speed running also play a role. Among NFL players, the vast majority of hamstring injuries occur at the start of the season. Elliot 2011 For these reasons, if an athlete is just starting a training cycle (such as when coming off an injury) or is going to increase the amount of speed work they are participating, Nordics should be included in their programming.

Sample Programming Approach


At this point the evidence should be clear for the utility of resistance training in regards to the need for external load, intensity, and rest between sets. Now it needs put together into a program that can be executed by athletes so that they may not only get stronger, but reduce their risk of injury. We will advocate for two sessions per week following an A/B pattern:

  • Compound lift 1 set of 6 at RPE 6, 1 set of 6 at RPE 7, 2 sets of 6 at RPE 8
  • Single-leg lift 3 sets of 7 at RPE 7
  • Calf Raises 3 sets of 10 at RPE 8
  • Nordic Hamstring 4 sets of 6
  • Individual Specific Exercise
Day A
  • Back Squat 1 set of 6 at RPE 6, 1 set of 6 at RPE 7, 2 sets of 6 at RPE 8
  • Single leg Deadlift 3 sets of 7 at RPE 7
  • Calf Raises 3 sets of 10 at RPE 8
  • Nordic Hamstring 4 sets of 6
  • Romanian Deadlift 3 sets of 6 at RPE 7
Day B
  • Deadlift 1 set of 5 at RPE 6, 1 set of 5 at RPE 7, 2 sets of 5 at RPE 8
  • Split squat 3 sets of 7 at RPE 7
  • Calf Raises 3 sets of 10 at RPE 8
  • Nordic Hamstring 4 sets of 6
  • Lateral Lunge 3 sets of 6 at RPE 7

If an endurance athlete followed a training approach like this, they would likely be able to make strength gains for some time. The variability in RPE for the primary compound lift allows an athlete to test what hard is and adjust the weight as needed over time. This compound movement will be the primary driver of strength gains. There is a single-leg exercise on each day not because single-leg exercises have any specific advantage over double-leg, but because the sport of running is a series of single leg exercises. While increasing strength is a primary objective, training within the specific demands of a sport is also advantageous given the specificity of strength adaptations. This doesn’t require any odd balance type exercises but rather getting stronger on one leg. The downside of single leg exercises is that incremental jumps are harder to make, e.g. going from 15# to 20# on an exercise represents a 33% increase in load.

This program also allows for integration of an exercise to address any specific concerns an athlete or coach may have unique to that individual. For example, if an athlete has a history of adductor strains, the individual may want to include Copenhagen Adductor exercises. Haroy 2019  If the athlete wishes to work on power development they can do this, though they should have developed a base of strength first. Behm 2017 The primary focus of this program is to get stronger over time. Athletes do not need to push hard enough to regularly experience DOMS, detract from their endurance training, or to specialize in powerlifting. Consistency will allow them to adapt to the stimulus and make gains while continuing to strive in their sport of choice.

Equipment


It has hopefully been established that endurance athletes benefit from resistance training but that still does not give a specific prescription with which to begin working on training. Obviously, with this piece coming from Barbell Medicine the tool with which we are going to advocate for resistance training to take place is going to be a barbell. This gives the most utility for making exercises loadable, scalable, and enjoyable using durable equipment.

Dumbbells are perfectly fine for adding an external load but they often require possession of many dumbbells which require more storage space. They often only are found up to 50 pounds which will be grossly insufficient for loading a deadlift or squat for most individuals. There is utility for them for some single-leg exercises, but overall, a barbell is often preferable. Resistance bands are another common device used in designing runners training programs. While they are able to be progressed, their durability leaves much to be desired. Plus, it is difficult to truly standardize the resistance with different brands possessing different resistances and those being contingent upon the degree to which they are stretched.

“Unknown Unknowns”


The program laid forth at this point is a simple way to implement resistance training into an endurance athlete’s overall program. It is by no means the only solution, however. Each athlete has unique training history, goals, sleep patterns, nutrition, emotional stress, and equipment available to train. Every variable listed and many more can influence the overall stress load to which an athlete is exposed. This is also the beauty of using autoregulation (e.g., RPE or RIR) in programming, as it allows an athlete to become more aware of their readiness to train on a given day. If an athlete is sleep deprived and in the middle of finals a weight for a set of 5 that is rated as a 6 two weeks ago may be a 9 on that day, and that is okay. If this does become a consistent issue, however, it can also be a clue for a coach that external stressors may be adding to the athlete’s overall load.

Contraindications


While we do advocate for all endurance athletes to resistance train, if an athlete is showing signs of the Female Athlete Triad or Relative Energy Deficiency in Sport (RED-S) they should NOT have additional training stressors placed on them and need evaluation by a medical professional. The Female Athlete Triad consists of the following criteria: De Souza 2014

  1. Low energy availability
  2. Low bone mineral density
  3. Menstrual disturbances

A female athlete experiencing less than 9 menses in the prior 12 months, a history of stress fracture, a BMI < 17.5 kg/m2 or displaying a combination of those signs should be evaluated by a medical professional before exposing the athlete to additional stress. The broader syndrome that encompasses both males and females is the Relative Energy Deficiency in Sport as many endurance-trained males present with their own subset of flags for training. Mountjoy 2014, Mountjoy 2018

Conclusion


Resistance training should be an integral part of all endurance athletes training programs as it has evidence for both adding to performance and reducing the risk of injury. The program does not need to be complicated and the main variable missing from many programs for endurance athletes is sufficient exposure to heavier loads to drive strength adaptations. Strength training must be challenging in order to elicit positive changes in strength, and the utilization of RPE or RIR lets an athlete track and become accustomed to regulating the difficulty of their workout. There are no quick fixes to progressing in any training methodology. Training is a process, and athletes whose sport is predicated on how long they are able to go should not be looking for means that will get them there faster, but let them go longer.


We want to thank Christy Morgan and Sam Lyons for helping in the editing of this document to account for a more pro-biomechanical perspective. Especially to Christy for her knowledge as it relates to BMD and RED-S indications and treatments.


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About Derek Miles

Derek Miles is a residency trained physical therapist currently working at Stanford Children’s Hospital as the Advanced Clinical Specialist in the rehabilitation department. He worked at the University of Florida prior for 10 years in sports medicine treating a variety of athletic injuries from overuse to post-operative. He is involved in the peer review process for academic journals and has spoken at national level conferences within the physical therapy profession. If not treating patients or in the gym Derek is likely either cooking some form of meat or reading books related to various random topics. He occasionally brews a pretty good American Pale Ale as well.

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