March 20

Concurrent training and interference effect: Part 2.

Fat loss

What can we do to optimise concurrent training and minimise interference effect?

After reading part 1, you should now be familiar with the idea of current training and interference effect, and have a basic grasp of the main reasoning for some of the key reasons why we can see reduced gains in strength and muscle when trained concurrently alongside endurance training.

If not, check that out here.

So, now we know some of the things which may increase the risk of a substantial “interference effect”, what can we do about it?

Here’s some key things you can do to make sure that you can get the most bang for your back when adding cardio based training sessions to your strength programme.


Endurance training type

Firstly, the impact of endurance training on strength, muscle and power development seems highest when training is relatively intense and continuous in nature, and/ or involves a high amount of muscle damage and total stress on the system.

This suggests that a 60 minute continuous run may lead to a higher interference effect than a cycling based interval session. This is probably due to the increased recovery demands and less similarity between type of muscle contraction in the running based sessions.  As with properly designed training, endurance response may be similar between the two modalities, you want want to consider alternatives to that typical 10k run if muscle building is also a priority.

Side note: if running performance is the priority, then run. Obviously.


Better programming

We’ve mentioned that the overall quality of the training stimulus, recovery between sessions and potential for adaptation are key considerations to optimise training response. This is the case whether training concurrently or not, but I suppose it can get lost in the noise sometimes.

When training concurrently, recovery demand is likely to be higher, and more consideration needs to go into the day-to-day structure. There’s a couple of reasons for this.

First off, we want to be starting resistance training sessions with reasonable energy levels (carbohydrate stores) to allow for sufficient intensity and quality of training. If training endurance first for a relatively intense session, we will need to refuel and rehydrate.

Ideally, we want a minimum of 6, or up to 24+ hours between endurance sessions and resistance training to optimise muscle development. This allows us to refuel and recover appropriately for the resistance training session- making it a better quality stimulus, and may have a more favourable impact on net protein balance and anabolic response.

This particular order of training (endurance followed by resistance training) may be the more appropriate exercise order if building strength and muscle mass is a focus of the concurrent plan, from the cell signalling point of view (remember the AMPK/ MTORC1 interaction discussed in part 1?).

Finally, we also know frequency of endurance type training sessions (cardio) plays a big role, with over 3 sessions a week seeming to show again an increase in interference effect. We may also see some rationale in training parts of the body that are unaffected by the endurance session where possible (eg. cycling based endurance followed by upper body work).

So, the right balance?

Optimise signalling response, and train with sufficient intensity and volume and frequency.

Pro’s and Con’s to both orders, but where possible, endurance training first, with an interval style approach of relatively short duration and appropriate fuelling within or between sessions is the optimum. Try to keep frequency of endurance to around 2x per week or less to optimise strength and muscle gains.

If you must get both modes of training into one session- as most people will- you won’t melt, and you’ll still progress. Just be aware that the longer and more damaging the endurance session, the more time may be needed to recover, so keep it short and sweet.

Optimise what you can, but be practical.


Periodisation of training

If we zoom out and consider the bigger picture, periodisation and planning will be key.

To optimise results we’re going to want to split training into focused training blocks to achieve a long term goal. By doing this, we can maxmise the results from each block. This leads to a greater cumulative effect over long periods of time.

This process of breaking down training into focused training blocks to achieve long term goals is known as “periodisation”.

If you want to be strong, muscular, lean, aerobically fit and healthy, you probably want to spend time where you’re more focused on specific areas at the right time. For example, times with strength and muscle with LESS (not zero) endurance training. Then other times where strength and muscle development may take a back seat (but absolutely stay along for the ride!).

This way, we can put sufficient energy into the key focus for that training block, and match training type, intensity, volume, frequency, intensity, nutritional strategy and recovery all targeted towards a specific measurable outcome.

Remember, we can only adapt to so much at once. Make it effective.

Although concurrent training targets add another dimension to this, the considerations of total work, total recovery capacity and specific adaptations are a priority in all well-structured training plans.

For most people starting out at the gym, your focus is to train on a regular basis and recover well. NEVER let optimisation get in the way of doing enough to progress.



Nutrition can have a huge impact in our ability to respond, recover and adapt to training.

We could look at concepts such as nutritional periodisation alongside the training block, but today’s point on nutrition is really simple.

Eat enough carbs to fuel your training. Eat enough protein to recover and adapt from training. Consider timing of carbohydrate and protein. Avoid nutrient deficiencies, and avoid low energy intakes when training concurrently with a focus on strength/ muscle development.

If fat loss is a key focus, you’ll need to manipulate energy intake to keep it low. Keep the nutrition you do consume to a high quality. Managing training and recovery in this situation is more important than ever.

If you want to maximally adapt to training, optimise performance or muscle mass, this isn’t the ideal time to diet. But if you must, here’s a reminder of the key considerations.

Start resistance training sessions with a reasonable amount of muscle glycogen, well hydrated, and follow them with adequate protein intake. Maintain an overall reasonable energy balance in line with body composition goals.


Final thoughts

Clearly, we can benefit from both endurance and resistance training at the same time. This means the same training block, same week, same day, even the same session. The complexities seem to arise as we get more advanced in training status, requiring higher specific training demands to continue making progress.

As you get more advanced and training needs to increase in specificity, the best way to continue to progress will be to dedicate training blocks to specific adaptations, supported with appropriate nutrition strategies.

I suppose the key question is, “what will help me to achieve my goals?”. For athletes, knowing how to implement concurrent training effectively is key. For most other people, it’s probably much further down the list than other factors, such as appropriate nutrition, sleep, recovery, and actually getting the work done.

That said, knowing how to optimise helps, but NEVER use optimisation as an excuse not to do the work.


Here’s a summary of key points when it comes to concurrent training and interference effect:

  • Interference effect DOES exist, although the cell signalling aspect is just one of several key factors that play a part.
  • Adding strength training to endurance programmes can lead to improved endurance performance.
  • Interference effect appears to act mainly to reduce strength, power and muscle gains with the addition of endurance training. NOTE: This is still an improvement in strength and muscle mass, just at a potentially slower rate than strength training alone.
  • Properly designed training and nutrition plans can help to reduce any interference effect.
  • Never lose sight of the key focus for YOU. For athletes, this may be crucial. For most other people, it’s unlikely to be the top priority, but worth considering.


Some key practical applications. Things you can do to minimise interference effect in training:

  • Continuous training appears to have a larger interference effect than high intensity intervals, although endurance gains can be similar in both modalities. Use an interval based approach where possible.
  • Running-based exercise appears to have a larger interference effect than cycle-based or rowing based exercise on strength, power and muscle gains. Use these modailities where possible.
  • Ideally, leave 6-24 hours between training sessions to allow refuelling and recovery. Where this isn’t possible, adjust training volume and nutrition appropriately.
  • Avoid high volumes and frequency of endurance training.
  • Keep endurance focused sessions to less than 3x per week
  • If practical, avoid both endurance and strength training on the same body part within the same day.
  • Nutrition should consider key factors such as adequate energy, protein and carbohydrate intake. Commence resistance training sessions with adequate fuelling and hydration.
  • As training status improves, interference effect may be more pronounced. This could be due to the increased requirement for specific volume and intensity to continue making progress.
  • Training should be periodised to focus on the right areas throughout the block to maximise recovery and adaptation.


We have a limited capacity to train, recover and adapt. Concurrent training approaches should absolutely consider the interference effect to optimise the process.

Should you train strength and endurance together? For most people, yes.

But have clear targets for each phase. This allows you to really focus on what’s important. It also helps to avoid the downsides of poor programming and inadequate recovery.


Josh Kennedy MSc, ASCC, CSCS

P.S. We have loads of easy to understand content on youtube, check that out here.


Key papers:

Skeletal Muscle Hypertrophy with Concurrent Exercise Training: Contrary Evidence for an Interference Effect, Murach and Bagley, Sports Medicine, 2016

Integrative Biology of Exercise, Hawley et al, Cell, 2014

Minimising interference effect during programmes of concurrent strength and endurance training. Part 2. Programming recommendations, Blagrove. Professional strength and conditioning, 2014


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