Hypertrophy for Hybrid Athletes:

How to Build and Keep Muscle While Training for Endurance

By James Blanchard (JB), coach at OMNIA Performance. 

Short answer: Yes, you can build muscle and endurance at the same time, but more slowly than if you specialised. Muscle grows when it is progressively loaded under mechanical tension and supported with enough protein and total energy. OMNIA coach James Blanchfield (JB) typically starts hybrid athletes at around 6 to 10 hard sets per muscle group per week, with a couple of reps left in reserve on big lifts, and the coaches agree that body weight limits endurance performance more than muscle does.

I’ve spent years in both worlds. I started as a sprinter at around 68 to 69kg, got up to 86kg for powerlifting, and now sit in the high 70s, which gives me a good mix of athleticism and muscle.

What is hypertrophy?

Hypertrophy is an increase in the cross-sectional area of muscle tissue. It happens when resistance training places enough mechanical tension on a muscle and you eat enough protein (ideally leucine-rich sources such as whey and meat) to support the muscle protein synthesis that follows. A bigger muscle is generally a stronger muscle, but the link isn’t one-to-one. The biggest person in the gym isn’t always the strongest.

Two types are commonly described. Myofibrillar hypertrophy is growth in the contractile tissue, often linked to lower rep ranges. Sarcoplasmic hypertrophy is growth in the fluid inside the muscle cell, often linked to higher reps (around 8 to 12). This split isn’t clear-cut in practice, because reps, volume and rest periods all shape the result.

How do you build muscle?

You build muscle by increasing the mechanical tension your muscles experience over time. There are several ways to do that: more sets, heavier loads, slower eccentrics (two to three seconds on the way down) or shorter rest periods of 60 to 90 seconds. Research suggests that heavy, moderate and lighter loads can all produce similar growth, provided tension is high enough.

That means the best method is partly the one you’ll stick to. Phil’s point is that if you enjoy a style of training, you’re likely to be more consistent with it, and consistency drives results.

OMNIA’s baseline for most people is lifting four or five days a week through a full range of motion, progressively overloading, and eating enough to fuel growth. Some low-level evidence suggests a calorie surplus isn’t strictly necessary, but it’s the long-established and simplest approach. For exercise selection, we also suggest thinking in movement patterns: a horizontal press, a vertical press, a horizontal pull and a vertical pull, plus some arm and shoulder work. Chasing a niche handle or angle adds little compared with progressive overload on the basics.

How many sets per week should a hybrid athlete do?

I usually start hybrid athletes at around 6 to 10 hard sets per muscle group per week, then adjust for recovery and how much endurance training is in the plan. That comes from my coaching experience rather than a research finding, so treat it as a starting point.

What worked for the OMNIA Team

Training responses are individual, and the three of us responded differently:

• Me (JB): a high-frequency upper/lower split, training everything twice a week at roughly 6 to 10 sets per body part. I kept a logbook and tried to beat it every session, adding 2.5kg or an extra rep or two. It wasn’t high volume, but I was religious about progressing. I think that range is a sweet spot for a lot of people, and Jamie agreed.
• Dr Phil Price: sets of three to five reps, lots of sets, short rest periods.
• Fergus: higher frequency of compound lifts for lower body, higher volume for upper body, because more upper-body frequency aggravated his rotator cuffs.

One more example, though it’s about strength rather than size. When I was powerlifting, a block of 10 sets of 5 back squats at around 180kg helped me squat 240kg. It doesn’t make sense on paper, but high frequency massively increased my strength.

Is it easier to build muscle or to keep it?

It’s much easier to keep muscle than to build it. In a 2011 trial by Bickel and colleagues, participants trained for 16 weeks and then cut their volume to one-third or one-ninth for 32 weeks. Both reduced doses preserved muscle gains in young adults, though older adults needed a higher dose. For hybrid athletes, that means a minimum effective dose of lifting can hold most of what you’ve built during an endurance-focused block. If an athlete has a hard run session coming, I keep their lower-body lifting that day deliberately light.

Do you need to train to failure to build muscle?

No, and it’s one of the most common questions I get. Hard doesn’t have to mean training until you physically can’t do another rep. On big, fatiguing lifts like squat, bench and deadlift, I like to keep a couple of reps in reserve. That still creates enough tension while leaving something in the tank for endurance work. On smaller muscle groups, going to failure can act as insurance for tension.

Here’s the paradox: plenty of people don’t train hard enough. There’s research where lifters did as many reps as possible with a weight they thought was their 10-rep max and managed far more than ten. If you’ve never reached true failure, you don’t have a benchmark for what an RPE 8 or 9 feels like, so you may be stopping well short.

How much protein do you need to build muscle?

For most lifters I work with, protein isn’t the limiting factor. In my view, training intensity and its surrounding variables are more likely to hold people back than eating 1.4g per kg instead of 1.8g per kg. If you’re in a slight calorie surplus, extra carbohydrate is also somewhat protein-sparing, so your protein needs may be a bit lower.

For hybrid athletes, the bigger change is mindset. Eating only for body composition often means minimising carbs, while eating for endurance training as well means giving carbs a bigger share of your energy. For more on fueling, see our guide to electrolytes for hybrid training.

Can you build muscle and endurance at the same time?

Yes, but more slowly than if you specialised in either one. We argue that hypertrophy is a harder balance with endurance than strength is, because you’re chasing a specific adaptation in the muscle itself and it competes for the same energy and recovery. The more endurance volume you add, the harder it gets.

How we approach balancing both:

1. Pick a slight bias. We say you can improve two qualities at once, but it helps to prioritise one for a block and make sure the other doesn’t get neglected.
2. Use a minimum effective dose. Keep lower-body volume low on days alongside key run intervals.
3. Keep reps in reserve on big compound lifts so you can still perform in endurance sessions.
4. Expect heavy legs. Hybrid athletes rarely run on fresh legs, and part of the adaptation is becoming efficient under fatigue.
5. Fuel for both. Energy availability is often the hidden constraint.

What is the interference effect, and should you worry about it?

For most hybrid athletes, the interference effect is small. Previous studies have found that adding aerobic training did not compromise muscle growth or maximal strength, but explosive strength gains may be attenuated, especially when both are done in the same session. The attenuation wasn’t significant when sessions were separated by at least three hours.

Phil’s advice is to manage fatigue rather than fear molecular signalling. The real issue is whether fatigue from a hard lifting session compromises a maximal-effort run or ride. Submaximal endurance work can usually be done on tired legs. Stacking your hard sessions on the same days and keeping the rest of the week easy helps.

Does more muscle mass slow you down in running and cycling?

Usually it’s body weight, not muscle itself, that slows you down. Endurance performance tracks body weight more closely than it tracks muscle mass, because more muscle often means more body weight and more force per stride or pedal stroke. Our post on advice for heavier runners covers this in more depth.

How the muscle was built matters too. Muscle trained only with lifting tends to have lower capillary density and fewer mitochondria than muscle trained for endurance, which affects blood flow and oxygen delivery. You can build a large muscle with those qualities as well, but you have to train for them.

How much muscle is too much for a hybrid athlete?

It depends on your body weight and goals. A lean 175lb (about 79kg) athlete can look like a bodybuilder and still run or race triathlons well. Pushing to around 200lb lean takes far more emphasis on hypertrophy, with greater trade-offs for endurance. At the extreme end of muscle mass (for example, 6ft and 95kg at under 10% body fat), chasing a fast 5K at the same time becomes very difficult, because specialisation demands more input the closer you get to your limits.

My advice is not to get bogged down in the extremes. People say marathon runners are skinny, so you must be skinny to run a marathon. But for most of us there’s a much bigger range of acceptable physiques for running a marathon or doing a powerlifting meet you’re not trying to win.

Can too much endurance training make you lose muscle?

It can, but there’s no universal threshold. For Fergus Crawley, it was around 15 hours or more of mostly easy endurance work a week, combined with just one lifting session. After he dropped from two full-body sessions to one, his visible muscle fullness declined and body fat rose, even though he was eating a lot. Returning to four lifting sessions a week brought it back without a change in body weight.

My takeaway: find your minimum effective dose for each discipline, then build up gradually through trial and error. That’s the fun part of the journey.

Do you need a muscle base before starting hybrid training?

It helps. Our OMNIA Coaches started endurance training with a decent strength and hypertrophy base, which let us develop endurance faster than someone starting from scratch. That’s a fair criticism of the hybrid approach, but it doesn’t undermine it. It means your starting point may be higher or lower, and you should be realistic about the timeline.

Bottom line

Hypertrophy is simple but slow: load the muscle, progress over time, eat enough, and be patient. For hybrid athletes, the aim is to find the lowest effective dose of each discipline, protect the muscle you’ve built, and keep an honest eye on body weight. Most people sit in a wide middle ground where you can look strong, lift well and still run or race.

Curious about Hybrid Training? Download our Hybrid Training Guide here 

Want a plan built around your goals? Apply for OMNIA 1:1 coaching and our coaches will balance your lifting and endurance training for you.