Science of Hybrid Training: How to Balance Lifting & Running

Bench 100kg in the morning, run 10km in the afternoon. Sounds good, right? The trainee that can lift and run well earns my respect, as they have exhibited physical prowess in two disciplines, which is no easy feat. This is referred to as ‘hybrid training’, which has become increasingly popular in the past decade or so, particularly with the rise of CrossFit, Hyrox, and mixed-discipline trainees. At the end of this article, you will know exactly how to pursue these two goals, lifting & running, simultaneously.

 

Physiology: Conflict Between Running & Lifting Adaptations

The primary concern for lifters taking up running, or vice versa, is that the pursuit of adaptations in one domain may negate or cancel out those of the other. This is most classically reflected in the old adage of ‘cardio killing your gains’. Such concerns are not without merit, but I’d like to share with you why they may be overblown, particularly when we look at some of the early evidence that influenced this view.

A seminal study by Dr Robert Hickson (1980) examined the impact of concurrent training (strength + endurance training) on fitness outcomes in each domain. Three groups were compared, strength only, endurance only, and concurrent. However, not only did the concurrent group do both strength and endurance training, they did both training protocols without any adjustment. What this meant was that the 6 days of endurance training were simply stacked on top of 6 days of strength training. As we would expect, the concurrent group gained less strength (but, notably, the same improvements in endurance). My conclusion here would not be that performing concurrent training inherently harms strength outcomes, but rather that a gross excess of training volume may do so. This is especially the case in the absence of any nutritional adjustments to support this training volume.

In reality, the conflict between strength and endurance training exists on a spectrum, which has been reinforced by the research carried out over the last 50 years. It is influenced heavily by nutrition, training load in each domain, training scheduling, and other non-training factors such as stress and sleep. If performing a couple of hours of cardio per week, you needn’t worry about gaining less muscle or strength, but as you move toward marathon training volumes, trade-offs will occur. This is why optimising what you can is important, and that starts with scheduling your workouts.

 

Scheduling: How to Optimally Schedule Running & Lifting Workouts

There will inevitably be some crossover between running and lifting workouts, with fatigue from one potentially being of detriment to the other. This can be minimised through smart scheduling throughout the week, but before we get to that, I want to make one thing very clear:

Building fitness is not the same as testing fitness.

You don’t need to be at your best during every workout. If your legs are a little tired from your lifting session and you have to slow your running pace by 10-20s per km, that is okay. It would not be okay if you were testing (i.e. racing), but this is just training. When we train, we seek adaptations that will allow us to perform better in future, and thus we needn’t worry about small deviations in performance.

With that said, that doesn’t mean scheduling and crossover fatigue doesn’t matter. Doing your hard interval runs right after a hard leg day isn’t very smart if you’re trying to maximise output during those runs, and vice versa if you have a heavy leg day to tend to. What we can do instead is lay out the sessions for each modality and assess which have the greatest crossover.

Lower body resistance training + hard interval run = high crossover.

Lower body resistance training + light run = moderate crossover.

Upper body resistance training + any running = low crossover.

Sessions with the highest crossover should be spread out most within the week, whereas those with low crossover can easily be performed back-to-back, even on the same day. Let’s see how that might look when applied to a training week. We will use the example of an Upper / Lower / Full Body training split to illustrate this.

This is just one example of applying these principles in practice. There is no one ‘best’ way, but if you follow the basic principle of spreading sessions out in accordance with their crossover, you will be well on track. When performing back-to-back sessions, there are some considerations related to the molecular signals of each mode of activity. As alluded to previously, endurance training increases AMPK activation, which may compromise the response to resistance training. AMPK remains elevated for approximately 3 hours after high-intensity endurance training, and thus resistance training should be performed at least 3 hours after, but preferably longer (e.g. morning and evening) (Baar 2014). However, for low intensity aerobic sessions, this is not as much of a concern (e.g. light shake-out run, bike work, or swim), and the performance of resistance training after this may even enhance the aerobic training stimulus, without compromising strength (Wang et al. 2011; Coffey et al. 2009). The AMPK & MTOR relationship is complex, and this is something we cover in a lot more detail in our Nutrition Certification.

One final note on this is that you should consider your current strengths when deciding on scheduling. For example, if a seasoned runner was adding in lifting, then I might encourage them to schedule in such a way as to optimise gym performance, or vice versa for a lifter getting into running. Therefore, in such a situation, I would suggest training your weaker activity first (e.g. if doing both on the same day).

 

Periodisation: How to Periodise Running & Lifting Around Competition

Your training schedule does not have to remain the same throughout the year. In fact, I would suggest varying it regardless, even if you don’t compete. I will often suggest periods of focus during the year for my clients, regardless of whether or not they have a ‘real’ competition or race. Let’s take the example of a seasoned lifter who wants to pack on as much muscle as possible during winter, but also has the goal to compete in a half-marathon in the summer.

Spring: 40% Running, 60% Lifting

Summer: 60% Running, 40% Lifting

Autumn: 50% Running, 50% Lifting

Winter: 30% Running, 70% Lifting

By varying training load in this way, you can focus on maximising adaptations during a given period of time in one modality, rather than always trying to balance the two. The irony in ‘balancing’ two activities is that it’s best applied in an imbalanced way, but the balance emerges over time through adaptations from your well-periodised training plan.

For those who have spent most of their training career lifting, this is often difficult to accept. To overcome this psychological barrier, remember that it takes a lot less to maintain what you have built than to build it in the first place. This also applies to running. If you are dropping from 5 days of lifting to 3 days (60% baseline), you’re likely to still maintain muscle and strength, even if it doesn’t feel like much compared to what you’ve been used to.

This approach can be very psychologically liberating, and makes for far more enjoyable training. Rather than just being 50/50 all the time, you can now dedicate your focus to one modality while allowing the other to drop back a bit, nonetheless reassured that you are going to maintain most of your gains. In my experience as a coach, this promotes far better longevity for hybrid athletes who wish to maintain 2 or more sports or activities over the long term.

 

Summary

You can get fitter and stronger at the same time. You can run further and build more muscle. Don’t listen to the nay-sayers. This is exactly what I help my clients achieve with our coaching service. With that said, I don’t want you to get carried away with what I am saying either. If you want to be the best runner you possibly could be, or the best bodybuilder you could be, you do have to accept trade-offs. Phil Heath (arguably the greatest bodybuilder of the 21st century) could not transform into Eliud Kipchoge (arguably the greatest runner, albeit challenged now by Kiptum!), nor could Kipchoge get up on the Olympia stage. But, for those of you who’d like to run a 10k and maybe even a marathon every now and then, while still wielding a decent physique on the beach or benching your bodyweight, this is very achievable.

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