What is Concurrent Training?
Concurrent training is when you go for a jog with your shake weights and do some star jumps every 2 minutes.
No it’s not. I am, of course, messing with you. No-one should do what I just described unless they’ve got the mullet, sweatband and short-shorts to go with it.
Concurrent training is where you undertake two different forms of exercise discipline – namely resistance weight training and some sort of cardio-vascular/endurance training – within the same session, day or fitness program.
Some people avoid doing any cardio for fear that it will reduce their gains in muscle strength or hypertrophy.
Others blast out a fierce cardio session immediately prior to lifting weights, seemingly unfazed (or, dare I say it, mindless) of other, more productive methods.
Choose Your Main and Secondary Goals
The fact that you’ve come to this site means you are probably more interested in growing muscle than your aerobic engine for a fast 5 km run, but it pays to outline things from the start.
If strength is your main goal, it should be your primary focus. This means the majority of your training will be geared around building strength.
Using the same 5 km run example, it won’t serve you well to aim for an 18 minute 5K if what you want more is to squat 350 lbs within the year.
One type of training would inevitably eat into the other – both in terms of time and physical progress – possibly resulting in neither being achieved.
So, pick your poison. I’m assuming it’s muscle hypertrophy (both strength and size), and always keep it in mind when you are engaging in concurrent training.
Science and Concurrent Training
Scientific studies are a controlled setting in which the theories, concepts and methodologies that are played out in the empirical world, can be put to a statistically measurable test.
There is no shortage of scientific studies that have investigated concurrent training, and more importantly drawn conclusions about the impact of cardio/endurance exercise on muscle strength and size gains.
Happily, for people like me, there has also been a couple meta-analyses of said studies.
A meta-analysis is where some or all of the individual studies are analyzed and statistically compared to determine agreement between their findings, root out the outliers, and ultimately, calculate the average of all of the results.
Meta-analyses are at the very top of the scientific study hierarchy because of the confidence level in the results.
The more individual studies there are, the higher the value of the meta-analysis. A single study can be flawed and therefore give a skewed result, but a meta-analysis of many studies cannot.
Wilson et al completed a meta-analysis of 21 individual studies that examined the detrimental effects of concurrent endurance/cardio training on resistance training outcomes.
The 21 studies involved were chosen because the matched certain criteria, namely they:
- Compared strength training alone to strength-plus-endurance (concurrent) training
- Compared combinations of concurrent training
- Measured at least one parameter from strength, power or hypertrophy
“Effect Size” – ES – is a simple way of quantifying the difference between groups of results rather than just using statistical significance.
For example, the Wilson meta-analysis found the average ES for hypertrophy amongst the concurrent training results was 0.85.
On its own that might mean very little, but it works when you also know that the average ES for hypertrophy in the strength-only groups was 1.23; and for the endurance training it was 0.27.
For clarity, the Effect Sizes for hypertrophy are summarized as:
- Strength training only = 1.23
- Concurrent training only = 0.85
- Endurance training only = 0.27
Additionally, the strength-only and concurrent training results effect sizes are significantly larger than the endurance-only training.
Here are the mean ESs for strength improvements:
- Strength training only = 1.76
- Concurrent training only = 1.44
- Endurance training only = 0.78
Again, strength and concurrent training ES is significantly greater than endurance with respect to strength gains.
Finally, the mean ESs for power development were:
- Strength training only = 0.91
- Concurrent training only = 0.55
- Endurance training only = 0.11
This time, significant differences were found between all three groups.
What Are the Takeaway Points from the Wilson Meta-Analysis?
The results show a very obvious pattern with strength-only training winning on all 3 measures: Hypertrophy, Strength and Power.
Also clear is that endurance training by itself led to significantly less gains in all 3 measured as compared to concurrent training (although endurance still led to positive effect on all 3).
Furthermore, where power was concerned, strength-only training resulted in significantly greater improvements than concurrent training, which in-turn was significantly more effective than endurance only.
Wilson notes that concurrent training, where running was the endurance type training, there were significantly smaller gains in muscle hypertrophy and strength (although they were still gains).
However where cycling was the endurance training, this decrement didn’t reach significance. Interpretation: concurrent training with cycling preserves muscle gains better than running.
No form of training resulted in decreases in muscle size, strength or power, i.e. all effect sizes highlighted positive change.
The only decrease, which is not discussed above is that VO2max – a measure of maximal aerobic output – actually reduced with strength-only training.
That’s important from a health perspective, and from the perspective of someone designing their training program.
Given strength, power and hypertrophy can be increased no matter what style of training, but cardio fitness can be reduced in strength-only training, can you really afford not to add some endurance/cardio to your routine?
Perhaps the most important point to make here is that concurrent training does not result in complete negation or “robbery” of muscle gains. Is not the reason you are not making muscle gains!
Continue reading for some information that’ll really make you question your pre-conceived notions that “cardio hurts my gains”.
Daylight Robbery or Downright Complimentary?
The concurrent training meta-analysis discussed in the first part of this article gives us hope that we can have our endurance training and our strength training in the same program and not significantly slow our muscle growth or strength.
Cardio will definitely not completely rob your gains, as many gym bros seem to think.
There are, of course, some signs to watch out for when you decide to go down a concurrent training path.
We don’t really know too much about the effects on people with a lot of training experience.
Most studies involve untrained individuals, and their progress tends to reflect that. Noobs, after all, make the best gains of their life in the first 6 months. I don’t believe the results can be flipped on their head if you are, say, a 5 year veteran of the gym.
In the case of experienced lifters, it might be the case that you would have to monitor your measurable factors a little closer if you decide to add some more cardio into your routine.
Another point to consider is that the longer your session of endurance/cardio training, the more it will effect your muscle strength and hypertrophy gains.
Technically, you can still improve strength and size if you do an hour of endurance a day, but combined with your gym sessions you are looking at a lot of time spent exercising, and the potential for over-training.
Overall fatigue and over-training can have detrimental effects to both your progress and your health. Downtime wasted because you are sick is not the same as downtime for recovery and growth.
Getting the right balance is key, and that is a program design issue, and one that can vary from one individual to the next.
Experts Agree – Concurrent Training Works
Data gathered from all the studies of concurrent training doesn’t support the popular belief that cardio or endurance exercise will ruin your muscle gains.
It’s great to see when experts in the field bash out opinion articles like the one Murach and Bagley did in 2016 (don’t you just love recent scientific literature? It leaves a fresh taste of nerd in your mindbrain).
These papers allow them to expand on the number crunching and offer forth what can be considered as extremely educated opinions.
Perhaps the most exciting figure from that report shows that combining aerobic training with strength training of the quadriceps leads to greater muscle hypertrophy gains than strength-only training.
This doesn’t mean concurrent training is better for muscle hypertrophy than strength training alone. That’s far too broad a statement, and we’ve already seen from the Wilson meta-study that all muscle related measurements point to strength-only training as being most effective.
For one thing, the data was from the measurement of quadriceps size. i.e. one muscle group and one measurement criterion.
Secondly the strength training volume was rather low with 2 days of lifting per week, and aerobic at 3 to 4 days per week. Most strength athletes would balk at the very suggestion.
Designing Training Programs from Scientific Studies
What’s interesting is the potential for program design that comes out from an analysis of the last few decades of studies.
Murach and Bagley highlighted previous research into the optimal timing of concurrent training, which found that a minimum 3 hour separation time between aerobic and resistance training should be observed.
Waiting 6 hours or more is even more beneficial and 24 hours is optimal. It’s logical of course, but again not always practical for a great number of people, who have time for one session a day for 4 days
However, we’re not really discussing those people. We’re discussing people for whom muscle and physique conditioning is extremely important.
For this reason, it’s not beyond the realm of sanity to recommend a 7 session week, at one session per day, alternating between aerobic/cardio and resistance training. The emphasis would be on resistance training with 4 out of the 7 days.
The logical 24 hour waiting time holds with this pattern, as does the strength training volume required for quality gains.
Provided sleep and diet are sufficient, there shouldn’t be a problem with following 7 a week.
That said, individualities do come into play, as does work/life balance. The above idea is merely an indication as to what can be done.
Bodybuilding and Body Fat Management
It occurs to me that I haven’t really focused on the benefits of concurrent training. That’s mainly because if you’re looking to pursue it, you already know why, and what you’re really looking for is information about how aerobic training affects your resistance training.
Hopefully the health aspects of aerobic training doesn’t need to be discussed in depth here anyway. I’m sure you know them.
Fat management is key to the bodybuilding physique though. And that’s definitely a goal only achievable through some formula of concurrent training.
It’s true that raising the intensity of your resistance training will increase metabolic turnover and fat burning, but to really torch fat you are going to need to add some cardio to your gym game.
Unfortunately, walking on a treadmill for 20 minutes every other day won’t really cut it. If you’re eating an anabolic diet for maximal muscle growth, you’ll need to hit the cardio accordingly.
Interval training, where you complete burst of intense cardio interspersed with steady state low-intensity cardio works well.
Alternating lower body and upper body aerobic work relative to resistance work is preferable as well.
For example: on your bench press day, you would use a power cycle or spin bike, and on your squat day you might use the rowing machine.
Final Word – For Now
I’m going to get into training programs, periodization and balance in further detail as this website matures, but I wanted to put this, albeit two-part, article up in order to leave a signpost for concurrent training.
Read the literature I’ve linked out to if you have time. It’s well worth the ten minute read, and provides detailed insights that one can only really brush over in an article of this kind.
In the meantime, the best judge of your progress is you. If you feel you are doing too much cardio and it’s bringing fatigue into your program, then step it back.
Just be aware that there are definite positives to adding aerobic fitness to your strength and size training. The research tells us cardio is not the gains killer it was once thought to be.
It may even help in some circumstances.