Concomitant Training: What's the Best Strength to "Cardio" Ratio to Become Big, Buffed and Strong? 3:1, 1:1 or No Cardio at All? Plus: Looking Back at the Latest Meta Review

What's the best you can do after a brutal leg workout? Cardio! At least if size and not strength is your goal...
It is one of those never ending debates: "Cardio!? To do it, or not to do it!? That's the question" - especially for those of us whose main goal is to become big and buffed ... now, you know that my take on this is simple: We are not created as "either or" animals, but have the outstanding ability to make use of both our strength and endurance (just as we can eat both meat and vegetables).

If we discard these philosophical considerations and take a more scientific stance towards the topic, the question still remains: Isn't doing cardio going to interfere with your success on the bench and vice versa? I mean you can't be a marathon running, bodybuilding powerlifter, can you? Hmm... no I don't think so, at least you would be pretty bad in each of the sports - a typical Jack of All Traits, Master of None, so to say ;-)

The "big and bulky" vs. the "sinewy and weak" effect 

Not to long ago, the question of "interference" was something only meatheads would ponder. In these days, in which even women's magazines begin to incorporate the latest scientific insights into the importance of muscle mass and strength into their "shaping" and "fitness" routines, it is yet becoming increasingly interesting for "the public" and that makes it easier for scientists to get funding and get published - sometimes (yet not in today's case) even outside of the Journal of Strength and Conditioning Research.

Only a couple of weeks ago, Jacob A. Wilson and colleagues published a detailed meta-review of the interference between strength and endurance work, in which they did confirm that the often-touted interference effect between endurance and strength training exists, and that the extend of the latter latter depends on the amount, type, frequency and intensity of aerobic activity a trainee is trying to pack into his workout routine (click here for the latest on how to combine both into one routine):
Effect sizes for combined training depending on the duration of the endurance component (Wilson. 2012)
"The mean ES for power development for strength training only was 0.91; for endurance training, it was 0.11; and for concurrent training, it was 0.55. Significant differences were found between all the 3 groups. For moderator variables, resistance training concurrently with running, but not cycling, resulted in significant decrements in both hypertrophy and strength. Correlational analysis identified significant negative relationships between frequency (−0.26 to −0.35) and duration (−0.29 to −0.75) of endurance training for hypertrophy, strength, and power." (Wilson. 2012)
I would guess that the timespan between the publication of Wilson's paper in the Journal of Strength and Conditioning Research and the study by Thomas W. Jones et al. the results of which are the topic of today's SuppVersity article probably is too short to call it a "follow up" of some sort. The intention of the researchers, i.e.
"to investigate the strength, limb girth and neuromuscular responses to a variety of concurrent strength and endurance training ratios, with incremental loads in an isolated limb model." (Jones. 2013)
would yet qualify the Jones study as a follow up that could either confute of confirm the statistically derived results Wilson and his colleagues presented in their August 2012 paper.

What did the scientists do and what did they find?

Jones et al. used a balanced, randomized, between-group study design. The participants, 24 healthy recreationally resistance-trained men (25 ± 3 yrs; 82.3 ± 10.0 kg;  179 ± 7 cm; 214.2 ± 42.3 Nm; >2y of strength training experience) were randomly assigned to one of the following experimental conditions:
    True or False? "Training your legs will make
    your arms grow faster" (read more)
  • strength training, only (ST)
  • 3:1 ratio strength & endurance training (CT3) 
  • 1:1 ratio of strength & endurance training (CT1) 
  • no training (CON)
All strength and endurance training was conducted in an isolated limb model and focused on the quadriceps muscle, with the exact protocols looking like this:
  • strength training alone on all scheduled training sessions (ST)
  • strength training on every scheduled session with every third session immediately followed by an endurance training (CT3)
  • strength training immediately followed by endurance training at every scheduled session (CT1)
  • no strength or endurance training (CON)
The total duration of the intervention period was 6 weeks and all trainees, except those who had been randomized to the lazy control group, worked out three times per week with ~48h of rest in-between the sessions.

"30min of leg extensions = cardio!?"

While the resistance training consisted of 5 sets of 6 repetitions (reps) at 80±5% of unilateral leg extensions (weight was increased progressively to keep the intensity), the endurance training protocol consisted of 30 min of repeated isokinetic unilateral leg extensions at 30±5% individual maximally voluntary contraction. The frequency was set at 1s per muscle action and the tempo was standardized via electronic metronome throughout the trial. This is obviously not a realistic "cardio" program, but it has the advantage of really isolating the targeted muscle group, which would not be the case if the scientists had had their participants cycle on a classic ergometer. 
Figure 1: Effects of strength only (ST), strength + "cardio" at 3:1 (CT3) and 1:1 ratio (CT1) and not training at all (CON) on maximal voluntary contraction (strength), limb girth (size) and time to exhaustion (conditioning) - focus on the colors(!) not the figures with their hilariously large standard deviations (Jones. 2013)
As a brief peak at the data in figure 1 is going to tell you (due to the huge standard deviations, you better rely on the colors instead of the figures ;-) the researchers from the Northumbria University in Newcastle upon Tyne (UK) and the North West University in Potchefstroom (SA), the scientists did, just as they had expected, a whole host of statistically significant differences:
"Following training, ST and CT3 conditions elicited greater MVC increases than CT1 and CON conditions (P ≤ 0.05). ST resulted in significantly greater increases in limb girth than both CT1 and CON conditions (P = 0.05 and 0.004 respectively). CT3 induced significantly greater limb girth adaptations than CON condition (P = 0.04). No effect of time or intervention was observed for EMG (P > 0.05)" (Jones. 2013)
What remains to be seen, though is in how far a "saner" endurance training protocol would have produced a similarly pronounced negative effect on the training induced increases in limb girth (size) and strength (MVC), while still yielding at least some of the beneficial effects on time to exhaustion (TTE).

There may be something to higher volume for legs (learn more)
If this is not your first visit to the SuppVersity you may yet remember a couple of previous posts on leg training, all of which clearly suggested that the legs need to be hammered to grow. At first the results of the study at hand seem to contradict this assumption, but if we are honest, "a little more hammering" is not exactly doing 30 min of continuous leg extensions.

The latter takes us back to the previously mentioned methodological shortcomings of this study. In as much as the 30-min of 30% MVC leg extensions may be suitable to really isolate the muscle, they have little to nothing to do with the classic endurance protocols most people are thinking about, when the hear the term "concomitant training".

We do, on the other hand, know from previous studies, such as the Psilander study, I covered in some detail in a previous blogpost that additional cycling before a leg workout can potentially boost the growth response to a subsequent workout (learn more). Whether this means of training is sustainable over time, would obviously be a different question.

Bottom line: Due to the specific design of the "cardio" part of the study, and the exclusive focus on the quadriceps muscles, it is difficult to say something definitive about the practically more important question whether 30min of classic low to medium intensity cardio training (e.g. on a cycle ergometer) would actually hamper your gains in such a profound fashion - regardless of whether you perform it before or after your workout.

Effect of strength vs. endurance only vs. combined training on body fat loss and changes in VO2Max, power, strength and size; data expressed rel. to avg. effect sizes for each parameter (Wilson. 2012)
If I am yet looking back at the results Wilson et al. presented in their meta-review, it would seem that low-intensity, low frequency cardio training is not the no-go the study from the study at hand would suggest it was. HIIT training, obviously a whole different animal and not necessarily something you would want to perform after a strenuous leg workout, for example does provide an anabolic stimulus of its own (learn more). HIIT vs. steady state is yet only one of the any parameters that will ultimately determine, whether or not an additional aerobic component is going to hamper your strength performance.  Another interesting observation Wilson et al. made was that the equipment the subjects used (and thus probably the effective metabolic demand) had an affect on the effectiveness of the strength training, as well.

Specifically, Wilson and his colleagues were able to show that the lack of weight support during treadmill running / jogging vs. cycling increased the detrimental effects on strength, power and size gains in the 21 studies the meta-analysis was based on. More than three cardio sessions per week, and high(er) intensity aerobic activity in general were likewise associated with practically relevant reductions in effect size.

Listen to Dr. Wilson in person! My friend Carl Lanore had him on Super Human Radio a couple of weeks ago.
On the other hand, some of these effects can be mitigated by doing cardio on separate days, so that you can still benefit from the concomittant (or endurance only) exclusive improvements in conditioning and avoid the VO2Max loss the scientists observed in the strength only groups. Skipping endurance work altogether is thus probably not the ideal method for the average physical culturist.

In the end, you will yet have to answer this question for yourself. Personally, I feel a baseline of 3x30min of various forms of "cardio" training (in the broadest sense) has always served me well.

  • Jones TW, Howatson G, Russell M, French DN. Performance And Neuromuscular Adaptations Following Differing Ratios Of Concurrent Strength And Endurance Training. J Strength Cond Res. 2013 Mar 21.
  • Wilson JM, Marin PJ, Rhea MR, Wilson SM, Loenneke JP, Anderson JC. Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises. J Strength Cond Res. 2012 Aug;26(8):2293-307.
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