Build Muscle With Cardio? 30 Marathons, 30 Days - Ross Edgley

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Build Muscle With Cardio? 30 Marathons, 30 Days


To prepare for 2017 I decided to attempt 30 marathons in 30 days from a treadmill in mykitchen. Odd I know! But what started out as an experiment to trial 30 different breakfasts and explore the intricacies of endurance-based nutrition, actually turned into a great experiment to demonstrate how strength and stamina, cardio and muscle mass CAN co-exist.

20 Marathons in and having lost only 1kg of body fat (now 89kg), allow me to explain… 

Traditionally bulking up consisted of mountains of food, large compound movements in the gym and a complete avoidance of anything cardio related. The latter was in fear that anything that sent your heart rate above 85 beats per minute would plunge your muscles into a catabolic state. But it’s new research published by the Department of Health Sciences at Mid Sweden University in Östersund—and advocates of German Volume Training—that seems to contradict this well-established rule of gym folklore.

Amazingly Swedish researchers not only expelled the myth that, “cardio kills gains” but they also found it could actually, “elicit greater muscle hypertrophy than resistance exercise alone.” What this means is completely contradictory to conventional thought, combining cardio with weight training could actually increase muscle size.

To test this theory T. R. Lundberg, R. Fernandez-Gonzalo, T. Gustafsson and P.A. Tesch took ten healthy men between the ages of 25 and 30 and subjected them to five weeks of unilateral knee extensor exercises. One leg was trained in a manner similar to most conventional strength training routines. Completing 4 sets of 7 repetitions at 75%-80% of their 1 rep. max. The other leg was subjected to exactly the same strength routine but was coupled with 45-minute cycle during each session.

Following five weeks researchers used an MRI scan (magnetic resonance imaging) and muscle biopsies to determine any changes in the cross sectional area and volume of the leg muscles. Specifically the vastus laterallis (muscle that’s located from the side of the leg) and the quadcricep femoris (muscle found at the front of the leg) were analyzed.


What they discovered was the leg that had been subjected to both cardio and strength training was noticeably bigger than the leg that performed strength training alone. Objectively results revealed the vastus lateralis had increased by 17% in size in the cardio-strength trained leg compared to 9% in the strength-trained leg. Furthermore, the volume of the quadriceps femoris had increased by 14% in the cardio-strength trained leg compared to 8% in the strength-trained leg.

So where did this gym-based wizardry come from? Well it’s widely known that performing any form of cardiovascular training dramatically improves your capillary density. Capillaries are the small blood vessels that network through the muscles and by increasing their density you also increase your own ability to supply the working muscles with blood, oxygen and nutrients during training.

This is one of the most overlooked aspects of strength training as power based athletes arguably place too much emphasis on shifting iron than looking after their capillaries. However using the sport of Strongman as an example (a sport that contains some of the world’s largest and strongest athletes) it could be argued that most past champions were well aware of this fact. Five-time World’s Strongest Man Mariusz Pudzianowski was famously a boxer before taking up the sport of strongman and notably incorporated intense skipping sessions into this training before most weights sessions. Also despite weighing 150kg Strongman legend Geoff Capes was rumored to have a pretty impressive 200m-sprint time clocking 23.7 seconds. Equally 3-time world’s strongest man Bill Kazmaier was a huge advocate of cardio training and heavily incorporated it into his training throughout his career.

But putting anecdotal evidence aside it seems recent research could also support this idea of caring for your capillaries. That’s because a study published in the Journal of Applied Physiology set out to monitor the adaptive changes in the muscles that occur during intensive endurance-based training. Scientists took seven athletes and had them complete a 24-week training program that was heavily cardio based. After 24 weeks muscle biopsies were taken and it was found that athletes displayed, “an increased capillary supply of all muscle fibre types.” They concluded that this in turn would improve the efficiency of the entire cardio respiratory system.

For strength athletes this would also mean faster recovery rates between sets and therefore an ability to increase work rate. Especially important for anyone involved in high volume training or anyone who performs super-sets, drop-sets and even forms of ‘pyramid’ training like DTP (Dramatic Transformation Principle), which typically involves a rep scheme of 50-40-30-20-10-20-30-40-50.

But most notably a well-designed cardiovascular routine has been shown to work very well in conjunction with German Volume Training (GVT) to increase muscle mass. Often referred to as the “tens sets method” this is one of the oldest and most effective forms of training that involves completing 10 sets of 10 repetitions. Believed to have originated in Germany in the 1970’s it was made popular by Germany’s weight lifting coach Rolf Feser who advocated it’s use to weight lifters who wanted to move up a weight class during off-season. Canadian weightlifter Jacques Demers—silver medallist in the Los Angeles Olympics—also famously used this training protocol and credited it for the renowned size of his thighs.

Now the entire program works on the premise that you subject the muscles to an extensive volume of repeated efforts on a single exercise. The muscles are then forced to adapt and grow as the body is loaded above its habitual level (what it’s accustomed to). Typically it involves choosing a large compound movement such as the squat, bench or deadlift and using a weight that’s roughly 60% of your 1 rep. max (or a weight you could perform 20 repetitions with). You then perform 10 sets of 10 repetitions, with 60 to 90 seconds rest in between.


As a hypertrophy-inducing training protocol very few programs are supported by as many experts as German Volume Training. Gains of 10 pounds are not uncommon in 6 weeks, even in the most advance lifters. But it’s clear to see how cardio and an improved capillary density can help you in those final sets. Since even the strongest of athlete’s would struggle without any endurance capability and as a result would be unable to complete the workload recommended by GVT training to increase muscle mass.

Another important thing to consider is how cardio has been shown to improve our body’s insulin sensitivity. This is basically how efficiently your body can absorb and process carbohydrates. Basically someone with bad insulin sensitivity will be more prone to storing carbohydrates as fat. Typically these are people who after a large bowl of porridge oats, pasta or a cheat meal will feel tired, lethargic and ready for bed. Someone with good insulin sensitivity on the other hand will eat that same quantity of carbohydrates but instead will feel their muscles are full, pumped and primed for a workout.

In fact cardio was found to be so effective at improving insulin sensitivity that research published in the journal of Sports Science entitled, “Role of Exercise Training in the Prevention and Treatment of Insulin Resistance and Non-Insulin-Dependent Diabetes Mellitus” actually states “epidemiological studies indicate that individuals who maintain a physically active lifestyle are much less likely to develop impaired glucose tolerance.” This means cardiovascular training not only has benefits for those who go to the gym but also those needing to improve their insulin sensitivity for medical reasons too.

So you’re probably thinking this all seems pretty promising so where does this fear of cardio and muscle loss actually come from? Well firstly there is the view that to bulk up you need to consume more calories than you use and any form of cardio will burn those precious calories and therefore your muscles. But you must understand this is a very, very simple view of the human body.

This is because the human body isn’t just a calorie-controlled machine. It’s not as simple as counting calories in and out and then watching the muscle grow or shrink in relation to this. As we’ve discovered there a thousands more processes within the human body that have an influence on this (capillary density and insulin sensitivity only being two). Whilst this is a whole other article in itself, put simply know that if you’re meeting your macronutrient needs (protein, carbs and fats) with a nutrient-dense diet with sufficient calories (it’s important to note ‘sufficient’ and not excessive like so many people believe), you won’t simply waste away by going for a jog a few times a week.

Next it’s often been quoted in Strength and Conditioning Journals that cardio will cause the body to develop slow twitch muscle fibres. These are better for endurance training and less prone to fatigue but they’re also smaller in size than fast twitch muscle fibers that are needed for strength, speed and power. This identified difference is often accompanied by a misleading picture of a lean and light Olympic Kenyan long-distance runner standing next to a sprinter to illustrate this point. But you have to understand this type of muscle adaptation only occurs after months—if not years—of endurance training. As proven by scientists from Ohio University in Athens who discovered after a lifetime of training long distance runners had a higher proportion of slow twitch muscle fibres compared to strength athletes. Therefore it’s safe to say performing forming 20 minutes of cardio five times a week with your strength training will not suddenly transform your physique into that of a Kenyan long distance runner.

Lastly, there is the argument that cardiovascular training will reduce your testosterone levels. Obviously a hormone of particular importance for strength athlete but scientists from the University of Carolina were quick to point out that this dip in testosterone only occurred after, “chronic exposure to prolonged endurance training.” So again performing 30 to 45 minutes of cardio is certainly not considered “chronic exposure” so don’t feel you’ll wake up feeling weak as kitten with low testosterone following a brief stint on the cross-trainer.

So, to come back to the original question that haunts anyone in search of gains, will cardio kill your muscle? Not according to our Swedish scientists and not if you adopt the right training protocol. Which is why we’ve put together the following cardio routine that will work synergistically with any resistance program to increase functional and lean muscle mass.

Low Intensity Cardio Vs H.I.I.T.

Some strength and conditioning coaches will adamantly argue that low intensity cardio (working at 60-70% of your max. heart rate) is the best whilst others are big advocates of High Intensity Interval Training. But the truth is both have their merits and understanding how your body responds to both is the best way to determine which one to use in your training. So below we’ve listed when it would be best to perform each form of cardio:

Cardio & Fat Loss:

One of the most quoted studies in the low intensity Vs high intensity cardio fat loss debate is one conducted at Laval University in Quebec Canada. Scientists separated a group of young, healthy adults into two groups. Group number one followed a 20-week-long endurance-based training protocol while group number 2 followed a 15-week sprint-based training routine (essentially a High Intensity Interval Training routine).

Amazingly after analysing muscle biopsies and fat measurements the results revealed athletes following the sprint-based (H.I.I.T) routine lost more fat compared to the low intensity group. They concluded that high-intensity, sprint-based training brings about metabolic adaptations within the body that favours fat loss compared to low intensity training.

Cardio & The Immune System:

One thing that must be considered when coupling your cardiovascular training with your strength training is not to over train. This is because it’s widely accepted in Strength and Conditioning circles that light, easy, moderate cardiovascular training has a positive almost stimulating effect on the immune system. This is because it can stimulate the lymph system, which in turn helps the entire body. High intensity training on the other hand can have a negative impact on the immune system and that’s because the body cannot cope with the oxygen demands of the exercise. As a result oxygen debt skyrockets, lactic acid goes through the roof and ultimately the body goes into biochemical overload, which can negatively affect our body’s lymphocyte production. These are the body’s natural killer cells which fight of disease and when these are affected you can become run-down, ill and unable to train.



  • Tommy R. Lundberg, Rodrigo Fernandez-Gonzalo, Thomas Gustafsson and Per A. Tesch (2012) ‘Aerobic exercise does not compromise muscle hypertrophy response to short-term resistance training’ Journal of Applied PhysiologyJanuary 1, 2013  114 no. 1 81-89
  • Frederick P. Prince, Robert S. Hikida, Fredrick C. Hagerman (1976) “Human muscle fiber types in power lifters, distance runners and untrained subjects” Pflügers Archive, 1976, Volume 363, Issue 1, pp 19-26
  • Dr Anthony C. Hackney (1989) “Endurance Training and Testosterone Levels.” Sports Medicine, August 1989,Volume 8, Issue 2, pp 117-127
  • F Ingjer (1979) “Effects of endurance training on muscle fibre ATP-ase activity, capillary supply and mitochondrial content in man.” September 1, 1979 The Journal of Physiology, 294, 419-432.
  • Dr John L. Ivy (1997) “Role of Exercise Training in the Prevention and Treatment of Insulin Resistance and Non-Insulin-Dependent Diabetes Mellitus.” Sports Medicine, November 1997,Volume 24, Issue 5, pp 321-336


Post Author
Ross Edgley