How to Build Strength & Endurance Simultaneously

In order to feel, look, and perform at your best, you need to build a number of different aspects of your fitness. Some of these include: power, strength, high intensity endurance, and low intensity endurance. I argue this because each one has unique components that contribute to your well-being. Building strength and power is one of the best ways to ensure a health musculoskeletal system as you age [1]. In addition, having a high VO2max (a measure of endurance) is one of the best predictors of longevity [2]. Not to mention, having multiple styles of training in your program can keep it exciting, which can promote greater adherence.

The problem is that building all of these effectively is a difficult task. Hell, building one of these at a time can be hard. However, with a well-designed program, it is absolutely doable. I’d even argue results can be maximized this way. So, the aim of this article is to discuss some strategies and thought processes that can make an effective hybrid program.

The interference effect: is it real?

Have you ever heard someone say that cardio will kill your gains? Or conversely, that lifting weights will make you bulky, weigh you down, and make you a slower runner? These are the conventional thought processes that have historically plagued the fitness industry.

At first, this idea makes sense. Let’s use endurance and strength training as examples. In a lot of ways, the adaptations attained from these training styles are somewhat opposite. However, the more the concept of concurrent training gets studied, the more it seems that the interference effect does not exist. In fact, the opposite may be true.

Recent research has shown that people with better endurance recover faster in between sets of strength training and in between sessions [3]. This results in better strength and hypertrophy improvements over time than those with worse endurance [4]. Similarly, strength training has been shown to improve running economy and reduce injury risk in runners [5].

So, what actually seems to be the case is this: some form of concurrent training is the probably everyone’s best bet. The overall amounts of different types of training you do may depend on your goals, but each style of training (strength, power, endurance, etc.) should comprise some portion of your training.

At the end of the day, if your resistance training volume and endurance training volume is done right, you’ll make progress in both. The presence of one will not take away from the other.

As stated before, this article describes strategies to improve strength, power, conditioning, and endurance in relatively equal amounts.

Resistance Training Volume & Intensity

The resistance training portion of the program pertains to modalities including strength training and power training. These can be further broken down into weight training, calisthenics, plyometrics, olympic lifting, ballistics, etc. In essence, any movement in which the mechanical capability of the musculoskeletal system is the limiting factor.

For these modes of training, it is best to keep intensity high and volume lower. By high intensity, I am referring to loads equal to or greater than 80% of your 1 repetition maximum with sets being taken close to failure (1-2 reps in reserve at the end of each set).

There are a few reasons this is important. To start, intensity and volume tend to have an inverse relationship. The lower intensity you train, the higher volume you can handle. The lower volume in which you train, the higher you can push the intensity. Given that we have other fitness variables to improve, we have no choice but to opt for lower volume. Thus, intensities of each set will be high. Recent research has also shown that strength & hypertrophy are maximized on lower volume programs when higher intensities are used [6].

Still though, we need to make sure there is enough resistance training volume overall to elicit adaptations. A 2017 study [7] found that 5-9 sets per muscle group per week is enough to produce significant hypertrophy and strength improvements, however 10 or more may be optimal. In the programming that I do for myself and clients, there tends to be somewhere between 8-12 sets per week per muscle group depending on various other factors.

Conditioning/Endurance Volume & Intensity

When it comes to conditioning work, there’s really two sides to the coin: High intensity conditioning and lower intensity conditioning.

Unlike resistance training, there should be some amount of lower intensity and higher intensity training here. In fact, the vast majority of it should be done at a lower intensity, and the higher intensity work should be more limited. Earlier in this article, I noted that intensity and volume have an inverse relationship. That statement rings true here again.

Conditioning intensity is normally characterized by what percent of your heart rate max you are training in. This is where the ‘zones’ of endurance training come from. Your heart rate maximum is easily estimated by simply subtracting your age from 220. So, a 25-year old would have a heart rate max of 195 beats per minute (bpm). Based on your heart rate max, the zones of endurance training are as follows:

-       Zone 1: 50-60% HRmax

-       Zone 2: 60-70% HRmax

-       Zone 3: 70-80% HRmax

-       Zone 4: 80-90% HRmax

-       Zone 5: 90-100% HRmax

It’s worth noting that there is a good bit of variance regarding the accuracy of the aforementioned max heart rate calculation. Some studies suggest it can have a variance of +/- 10 bpm. Still, though, having this ball park estimate is still useful as long as you use the same equation throughout your training and programming.

The vast majority of your conditioning should be somewhere in a zone 2 or zone 3 range (with more zone 2 done than zone 3 for most people). At these intensities, the limiting factor is still the cardiovascular system and not the muscular system. As a result, much less muscle damage occurs, which makes them easier to recover from and easier to mix with resistance training.

Volume here can vary greatly depending on overall goals of the program, available training time per week, training status of the individual, etc. However, a good range for the zone 2/zone 3 work is 3-8 hours per week; ideally split into 3-6 sessions [8].

Training in the zone 4-5 range should be much more limited. At this intensity, it is likely that a good degree of muscle damage will also occur. So, a good rule of thumb is 30-90 minutes 1-2x/week.

Conditioning/Endurance Exercise Selection

With your conditioning work, you want to make sure that the limiting factor is your energy systems and cardiovascular system, and not your musculoskeletal system. This was the reasoning behind a majority of the work here done at a low intensity. However, another way to ensure this happens is with smart exercise selection.

One of the easiest ways to achieve this is choosing modalities that have little or no eccentric action. The eccentric is the lengthening of a muscle under load, or the lowering of a weight. For instance, the descent of a squat is the eccentric portion. For this reason, super high rep sets of squats probably wouldn’t make a good choice.

Running is the most common and easily accessible form of endurance training. It has only a small eccentric component, but there are actions you can take to make it even smaller. One way is to shorten your stride length. At any given speed, shorter steps will result in less work being done by the leg with each step, specifically less eccentric work. This is part of the reason why elite long-distance runners use short stride lengths.

Something else you can do in regard to running is run on sand or on a treadmill. These have both been shown to have less impact, result in less muscle damage, and produce less next-day soreness [9,10]. So, if these are available, they can be helpful additions to a program.

Of course, though, running isn’t the only option. Cycling is another common modality that has no eccentric component at all. Also, it is much less likely that a spike in heart rate occurs while cycling, making it easier to stay within your target zone. This arguably could make it better than running for a concurrent athlete.

More options that I’d highly recommend include an air bike, ski erg, or rower. Similar to cycling, these have no eccentric components. To take it one step further, though, these also provide a valuable option for giving some aerobic conditioning to the upper body as well. That factor could arguable make these three modalities better than running or cycling for a concurrent athlete.

Separation of Intense Training

A crucial factor to a successful concurrent program is enough recovery time allotted between higher intensity sessions. Specifically, high intensity training of the same muscle group. This will apply whether it is resistance training or it is high intensity conditioning.

Whenever a significant amount of muscle damage occurs, you will need more time to recover than low intensity training. For most people, the recovery time needed will be 48-72 hours depending on various factors including training age, volume done per session, etc. With the lower intensity work (zone 2-3 endurance), the effort is small enough where your cardiovascular system is the limiting factor and not the muscular system.

So, if you weight trained legs on Monday, you shouldn’t weight train legs again until Wednesday or Thursday. For many, this might be obvious. However, the same is true if you did high intensity running (sprint repeats, 0.25 mile reps for time, etc.) on Monday. Similarly, if you did sprints on the ski erg or arms only on the air bike with high intensity on Monday, then you might not want to weight train upper body until Wednesday or Thursday.

This is one of the reasons that the high intensity conditioning should be kept to 1-2x/week max. The low intensity training will bring most of the aerobic adaptations that you are after, however it is still important to spend some time using the higher intensity energy systems.

Weights & cardio on the same or separate days?

An investable question you run into when designing a concurrent program is whether you should separate the resistance training and conditioning to separate days or keep them on the same day.

In my opinion, the first factor to consider here is how many days you have available to train per week. I personally follow the template below in regard to this:

-       2-3 training days per week: same session

-       4 training days per week: can go either way

-       5-7 training days per week: separate sessions

It’s generally considered best practice to have the conditioning and resistance training on separate days. However, what really matters most is making sure you have enough overall volume of each throughout the week (volume prescriptions discussed in previous sections). That tends to be easier to do when they are done in separate sessions. However, doing your conditioning and resistance training in separate sessions might not be feasible for some busier folks.

References

1. Age-related muscle anabolic resistance: inevitable or preventable?

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2. Survival of the fittest: VO2max, a key predictor of longevity?

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3. Relationship between oxygen uptake kinetics and performance in repeated running sprints

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4. Short-term aerobic conditioning prior to resistance training augments muscle hypertrophy and satellite cell content in healthy young men and women

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5. Resistance Exercise for Improving Running Economy and Running Biomechanics and Decreasing Running-Related Injury Risk: A Narrative Review

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6. Influence of Resistance Training Proximity-to-Failure on Skeletal Muscle Hypertrophy: A Systematic Review with Meta-analysis

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7. Dose-Response Relationship of Weekly Resistance-Training Volume and Frequency on Muscular Adaptations in Trained Men

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8. Haff, Gregory G., Triplett, Travis N., 2016, Essentials of Strength Training & Conditioning, 4th edition.

9. Physiological responses during intermittent running exercise differ between outdoor and treadmill running

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10. Sand training: a review of current research and practical applications

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11. Sousa, António C. PhD1,2; Neiva, Henrique P. PhD1,2; Izquierdo, Mikel PhD3; Alves, Ana R. PhD1,2; Duarte-Mendes, Pedro PhD4,5; Ramalho, André G. MSc4,5; Marques, Mário C. PhD1,2; Marinho, Daniel A. PhD1,2. Concurrent Training Intensities: A Practical Approach for Program Design. Strength and Conditioning Journal 42(2):p 38-44, April 2020. | DOI: 10.1519/SSC.0000000000000520