After taking a break from running to recover from injuries (My Recovery Story), I have recently been pounding the pavement (and trails) again and really enjoying how I feel now that running is a part of my life again. Beyond feeling generally healthier when I am running consistently (I don’t run a ton, but try to get out for 4-6 mile runs about 3 times per week), I have been curious about the physiological and health benefits this reintroduction to running is having on my body. I have also been interested in the impact that running more could have on my other training goals, such as improving strength. Here is what I found out…

As it turns out (probably no surprise to any of us), regular physical activity, such as running can have a plethora of health benefits, including: improved sleep and cognition, and many positive physical and physiological effects including lowering blood pressure, improving insulin sensitivity and slowing progression of and/or preventing many chronic diseases such as diabetes and cancer, as well as improving fitness and quality of life^.7 Though, improvements in some of these areas can be realized with just one bout of physical activity, to promote overall health and best outcomes from physical activity…

The 2018 Physical Activity Guidelines Advisory Committee Recommends:

150-300 minutes of moderate intensity physical activity per week

(or roughly 30-60 minutes of physical activity 5 days/week)

Running for 30-60 minutes at a moderate intensity should confer these health benefits, but what else is it doing for you? For example, can you expect to get stronger or will this type of activity only improve your endurance capacity?

Moving beyond the goal of generally improving health/well-being, when thinking about athletic training effects on the body from physical activity, there is a common dichotomy of goals that emerges:

1- Increase Endurance

OR

2- Increase Strength and/or Power

There has been lots of research in exercise physiology that tells us that endurance training is the best way to improve endurance and that resistance training (short bouts of close to maximal muscle contractions) is the best way to improve strength and power.^{2, 4} This translates to:

Your Body Gets Better at The Activities You Practice!

In exercise science language, this is often referred to as: “The specificity principle” or “SAID”: Specific Adaptation to Imposed Demands.

But, what if you are like me and you want both?!? I want to get stronger AND improve my endurance. Am I out of luck?

The type of training that I am talking about (and what I currently practice), is integrating endurance training (e.g., distance running) with resistance training (e.g., weight lifting- assuming heavy loads). This type of training has been termed “concurrent training”, and simply put, it looks like this:

Concurrent Training = Endurance Training + Strength Training

A recent article in The Journal of Physiology², tells a compelling story of the research that supports what was initially termed the “interference effect” by Hickson in 1980.⁵ The “interference effect” refers to the decrease in strength gains found in concurrent training compared with the resistance only training (authors concluded that endurance training “interfered” with strength gains from resistance training). This effect appears to hold out in well trained individuals, however there is some evidence that any type of training can initially improve strength and endurance in untrained individuals (see figures below for a nice visual, from: Coffey & Hawley, 2017):

ET = Endurance Training; RT = Resistance Training; CT = Concurrent Training (ET + RT)

This suggests that once you become trained (and even more so if highly trained) the best gains in strength are with resistance training alone.

Interestingly, though, it seems that there is no sacrifice to the gains in endurance with concurrent training! In fact, some studies show that resistance training added to endurance training (so: “concurrent training”) can actually increase endurance performance.^2,6 There is also some research to support that shorter bouts of high intensity running (i.e., interval type training, HIIT)) can improve power (vertical jump) and running at the same time.³ But, at least from my research on this subject, I have not seen any evidence to support strength gains from endurance training alone in trained individuals, even if performed in interval style training.^1,3

In conclusion, it seems that running could make you stronger (if you are untrained) and as you approach a highly trained state, it may interfere with optimum strength gains. However, that does not mean that strength gains are not possible with concurrent training, just that they may be lessened compared with strength training alone.

Whew, a lot to think about, I think I’m going to need to go for a run to process it all…

Resources:

1. Buckley S, Knapp K, Lackie A, et al. Multimodal high-intensity interval training increases muscle function and metabolic performance in females. Applied Physiology, Nutrition, and Metabolism. 2015;40(11):1157-1162.

2. Coffey VG, Hawley JA. Concurrent exercise training: do opposites distract?: Concurrent exercise training. The Journal of Physiology. 2017;595(9):2883-2896.

3. García-Pinillos F, Cámara-Pérez JC, Soto-Hermoso VM, Latorre-Román PÁ. A High Intensity Interval Training (HIIT)-based running plan improves athletic performance by improving muscle power. The Journal of Strength & Conditioning Research. 2017;31(1):146–153.
4. Glowacki SP, Martin S, Maurer A, Baek W, Green JS, Crouse SF. Effects of Resistance, Endurance, and Concurrent Exercise on Training Outcomes in Men. Medicine and Science in Sports and Exercise. 2004; 36(12):2119-27.

5. Hickson RC. Interference of strength development by simultaneously training for strength and endurance. European journal of applied physiology and occupational physiology. 1980;45(2-3):255–263.

7. Vikmoen O, Rønnestad BR, Ellefsen S, Raastad T. Heavy strength training improves running and cycling performance following prolonged submaximal work in well-trained female athletes. Physiological Reports. 2017;5(5):e13149.
8. 2018 Physical Activity Guidelines Advisory Committee. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services, 2018. https://health.gov/paguidelines/second-edition/report.aspx Last updated: 7/20/2018, accessed 7/20/2018.