Concurrent training, good or bad? Here’s the truth (backed by research)…
Odds are, you’ve probably heard before that doing concurrent training or cardio is going to steal your hard-earned muscle, prevent you from making gains, or any variation of this myth.
People argue that concurrent training or cardio will make you weak, while others may shy away from doing any cardio for fear of losing every ounce of muscle mass they own.
But, are these arguments valid? Will concurrent training or cardio make you weak and skinny? Let’s see what the real research says…
Concurrent Training: Friend or Foe?
The fancy term for combining both strength training and cardiovascular activities into your fitness routine is called “concurrent training”.
The fear of concurrent training or cardio likely comes from early research that showed that concurrent training interfered with strength and muscle size (1, 2, 3).
For example, the pioneering study by Dr. Hickson investigated the training effects of a high frequency, high volume concurrent training program, and compared it to strength or endurance training alone over a ten-week period (3).
The researchers found that strength increased in the concurrent training group until approximately weeks 6-7, which was followed by a “leveling-off period” and a sharp decrease in strength the final two weeks (3).
In addition, more fear was placed in the hearts of physique-oriented individuals when a study found that the anabolic response to resistance exercise was decreased when the weight session was preceded by endurance training (4).
In one way, it makes sense because doing concurrent training violates the key training principle of training specificity. As a result, distinct differences can be seen in the signaling processes within your muscle (5,6,7) and on the molecular cell level (think cells being analyzed by a microscope) (8).
Based on all this research concurrent training or cardio may interfere with your gains. However, all hope is not lost.
Since then, multiple studies have shown no decrements when combining strength and aerobic training (2, 9, 10, 11, 12). In fact, some studies have even shown increases in muscle size and strength and anabolic studies when concurrent training is used (9, 10).
If you asked an informed and unbiased individual they would now tell you that cardio isn’t all bad and, when programmed correctly, it can actually provide health and performance benefits.
Now that you know that doing cardio or concurrent training may not necessarily steal your hard-earned gains in muscle and strength, let’s take a look at why you might WANT to include cardio into your routine.
Cardio or Concurrent Training Improves General Health
For general health, the main benefits that have consistently been found are the prevention of diseases including coronary heart disease, type 2 diabetes, hypertension, some cancers and other chronic diseases (13, 14, 15). While this may not add inches to your biceps, it’s obviously important when you look at the bigger picture.
In addition to the well-known cardiovascular benefits, some other areas of relevance are a reduction in stress, depression and anxiety (16). Physiological or psychological, the benefits of cardio are often overlooked by bodybuilders, yet are truly impressive.
Cardio or Concurrent Training Increases the Amount of Food You can Eat
Think about the Michael Phelps story back a couple years ago (where they published his diet, showing he consumed 12,000 calories per day!). Even if it was slightly inaccurate, odds are that he had to consume 8,000 – 10,000 calories per day whilst training for the Olympics.
Furthermore, it is well documented that cyclists competing in endurance events such as the Tour De France must consume massive amounts of food to maintain their weight and performance (17,18).
The calorie expenditure from aerobic training can be quite large, especially if you factor in the potential for post-exercise oxygen consumption (EPOC) by kicking up the intensity (19,20,21).
While you may not be able to consume thousands more calories, the amount of calories you can eat without gaining weight would be higher than if you did not do any cardio activities. For some, this may be important when overeating such as on vacation, or, simply to allow some more flexibility in your diet.
If you’re not looking to increase your dietary flexibility, the utilization of these extra calories can obviously play a big role in fat loss, allowing you to lose more fat without eating less.
Cardio or Concurrent Training = Less Body Fat
Aerobic training in general has been shown to increase insulin sensitivity (22, 23, 24).
As a result, the foods and nutrients you eat are more likely to be stored in muscles as usable fuel and lean mass, and not as body fat (25, 26, 27). Aside from its association with your physique, insulin function is linked to most serious diseases and long-term health.
As touched on above, high intensity cardio can be an effective way to burn calories and aid with fat loss. Used by bodybuilders for decades, cardio can help you create a larger calorie deficit without reducing food intake.
In theory, if you can add in cardio or concurrent training rather than reducing calories you can lose weight while consuming more protein and key nutrients, which is a win-win for building muscle, recovery and health.
Cardio or Concurrent Training Improves Weightlifting Performance (No WAY!)
The majority of long distance events and sports (marathon, cycling) require exceptional aerobic capacity, as do athletes in all continuous action field and team sports (i.e. soccer, basketball).
Due to heavy strength training’s short and sharp nature, the energy expenditure contributions of weight training are performed in an intervals-like fashion. For example, a 30 second period of maximal effort followed by a 2 minute rest period.
During this recovery or rest period the aerobic system comes in to replenish the depleted ATP energy stores and remove the buildup of metabolic by-products that were produced during your 30 second lift (phosphagen and glycolysis) (28).
So, the better your conditioning is in all three energy systems, aerobic, anaerobic and phosphocreatine, the better you will be able to perform and recover in the weight room.
In my experience working with 100s of clients and bodybuilders, the limiting factor when performing metabolic circuits or if using advanced techniques like dropsets and supersets, is their aerobic system. While it may not play a big role in 5 rep work, it is certainly an important factor in higher rep, shorter rest metabolic, bodybuilding-like training.
How to Perform Cardio or Concurrent Training and Still Maximize your Gains
One of the largest mistakes when it comes to concurrent training (cardio and weights in the same program) is that people try to do them too frequently (29) and/or for too long a duration (10, 29).
Concurrent (cardio + weights) can work wonders, if programmed correctly.
These days, High Intensity Interval Training (HIIT), is an extremely effective mix between moderate intensity training and high intense weight lifting. Based on the science, the cardiovascular adaptations to HIIT are similar to, and in some cases superior to, those of continuous endurance training (19, 30, 31, 32, 33).
Building on that research, HIIT may be a superior means of dropping body fat compared to steady state aerobic exercise, at least when comparing the time commitments of the two (34, 35).
So, as you can see, both normal cardio and HIIT have numerous benefits when it comes to improving health and performance. Perhaps a great compromise may be including short HIIT sessions on the days you weight train, and include longer cardio on non-training days to promote recovery, which will allow you to still optimize your main goal and weight training sessions, while improving health, burning more calories and fat.
Furthermore, research makes other suggestions when it comes to optimizing your aerobic training around strength training:
- Use a bike. Doing cardio or your concurrent training on a cycle (as opposed to a treadmill), might just eliminate any negative effects on your main weights workout or muscle growth (10).
- Separate sessions by at least 6 hours. If you are performing 2 full sessions, e.g. a lengthy cardio and a lengthy weight session, then you may want to split them up. This will allow for some recovery, reduce protein breakdown and minimize any conflicting signals to your body’s cells and muscles. For an athlete, it will also allow you to optimize performance in both sessions (36).
Cardio & Concurrent Training, Good or Bad?
Cardio and concurrent training has plenty of benefits for your physique and health. In contrast to popular belief, it will only cause negative issues if you program it incorrectly and try to do too much at the same time.
Many high level bodybuilders and athletes now combine cardio, HIIT and weight training in a synergistic manner to improve their physique, performance and health.
Be smart with it though, according to your goals, including more when you are aiming for fat loss, and less when you are bulking. But never completely eliminate it.
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