Effect of Endurance on Hypertrophy - Negative?

Hi Charlie and the Forum,

I was discussing the effects of tempo and special endurance on hypertrophy with another coach in my area on another forum.

He was concerned that doing weight training would lead to too much hypertrophy in sprinters if they trained more than twice a week.

My stance was that if your are doing a significant amount of tempo and special endurance work, because of the conflicting demands, it would prevent you form achieving the same amount of hypertrophy that you would develop because your body would be optomised towards what you did more of (e.g. tempo/special endurance).

He was adiment that no amount of low intensity endurance work could affect hypertrophy. He is fairly well respected so I don’t know what to think. Can someone help me clear up this matter.

Thank you



So do you think it is possible to train for 1500m (50mile a week) and bodybuilding at the same time? Surely the two would be difficult to combine?


Your idea of distances or endurance work done being linked to how big a sprinters is not the case.

Your athletes are lean not primarily cos of the work on the track but cos of body type, their adaptability to CNS work and recovery. Dont forget that what ever you do both on the track and in the weight room is all about Muscle type recruiting and adaptability to managing the CNS properly.

If I get your athletes to
1, Lift to fatigue often invariable tearing micro-fibres
2, lift at specific high reps and do a high number of works

It does not matter the amount of running they do they would get big.


are you saying that it wouldn’t be be detremental for a bodybuilder to do endurance training? Do you think that it won’t make them smaller because of competeing stresses and the catabolic nature of aeorboic work? Towards competition time bodybuilders are known to walk for hours on a treadmill because they are scared that anything of higher intensity will lead to a decrease in bodymass!

Coming from the other end of the street do suggest that if all my athletes stop doing endurance work this will not lead to increased hypertrophy if the weight work stays the same?


The body builder walks cos they want to cut them self. That happens by loosing watre as you know. The body is 70% water.
My point is it does not matter how far they walk they would never loose muscles which they would have built up from doing one or 3 points as explained in my last post.

No your athletes would not hypertrophy if they stop endurance running. As you well know hypertrophy can only occur depending on the make up of your sessions as in sets, reps, volume and frequency.

Anyone trying to convince you that large volumes of running are not goign to significantly affect gains in size is crazy.

What about looking at it at a very basic level: calories in vs. calories out. If you are running 50 miles a week (not very high, but still a reasonable amount) and you are also lifting to failure, how many calories are you burning and how much time are you spending on training? Besides overtraining, at best you are maintaining a reasonable weight. Most likely though you are losing weight, possibly dropping down quite a bit depending on your previous weight, bodyfat %, and training background.

I was trying to look up some specific reasearch papers on this topic but couldn’t find dealing exclusivly with this topic. Anyone know of any?

Endurance training has to be more defined in this thread to have further discussion.

Here is an article:

Neuromuscular adaptations during concurrent strength and endurance training versus strength training

The purpose of this study was to investigate effects of concurrent strength and endurance training (SE) (2 plus 2 days a week) versus strength training only (S) (2 days a week) in men [SE: n=11; 38 (5) years, S: n=16; 37 (5) years] over a training period of 21 weeks. The resistance training program addressed both maximal and explosive strength components. EMG, maximal isometric force, 1 RM strength, and rate of force development (RFD) of the leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris (QF) throughout the lengths of 4/15-12/15 (Lf) of the femur, muscle fibre proportion and areas of types I, IIa, and IIb of the vastus lateralis (VL), and maximal oxygen uptake (V£O2max) were evaluated. No changes occurred in strength during the 1-week control period, while after the 21-week training period increases of 21% (p<0.001) and 22% (p<0.001), and of 22% (p<0.001) and 21% (p<0.001) took place in the 1RM load and maximal isometric force in S and SE, respectively. Increases of 26% (p<0.05) and 29% (p<0.001) occurred in the maximum iEMG of the VL in S and SE, respectively. The CSA of the QF increased throughout the length of the QF (from 4/15 to 12/15 Lf) both in S (p<0.05-0.001) and SE (p<0.01-0.001). The mean fibre areas of types I, IIa and IIb increased after the training both in S (p<0.05 and 0.01) and SE (p<0.05 and p<0.01). S showed an increase in RFD (p<0.01), while no change occurred in SE. The average iEMG of the VL during the first 500 ms of the rapid isometric action increased (p<0.05-0.001) only in S. V£O2max increased by 18.5% (p<0.001) in SE. The present data do not support the concept of the universal nature of the interference effect in strength development and muscle hypertrophy when strength training is performed concurrently with endurance training, and the training volume is diluted by a longer period of time with a low frequency of training. However, the present results suggest that even the low-frequency concurrent strength and endurance training leads to interference in explosive strength development mediated in part by the limitations of rapid voluntary neural activation of the trained muscles.

I agree defining endurance is a problem. That is interesting. I’m going to look for more studies today.

Have gone as high as 6 times endurance training a week (rowing with sessions were between 70-100% VO2max) and with sufficient caloric intake was still able to hypertrophy.

So IMO the most important factor is caloric intake.
Also endurance training shouldn’t, in principle, negatively have to affect hypertrophy of 2a muscle fibers, which as I understand can hypertrophy just fine (and also do so as a result from bodybuilding type training).