CONCURRENT TRAINING
Concurrent training: can you build muscle and train for endurance?
Yes, you can build muscle and train for endurance in the same week. The clash between them is called the interference effect, the idea that cardio can blunt the gains from lifting. A 2022 meta-analysis of 43 studies found that adding cardio did not reduce muscle size or maximal strength, and it found a small loss of explosive strength, more so when both were done in the same session. Older and smaller analyses find larger effects, tied to running and to high amounts of endurance work.
What concurrent training and the interference effect are
Concurrent training means training strength and endurance in the same period. An example is lifting three days a week and running two. The interference effect is the claim that doing both gives you smaller gains than doing one alone. The question concerns lifting: does cardio blunt your gains in muscle size, strength and power?
A 2014 review explains why people think so. Endurance exercise sets off signals in muscle that can inhibit the pathways that build protein. But the review adds that human studies have not seen that signal clash after one session of both in a way that explains lost muscle growth. It says the roles of individual training variables are still open questions.
What the research found
A meta-analysis pools the results of many studies. The table below covers five of them. An effect size is a standard way to compare change across studies, and a bigger number means a bigger gain. Hypertrophy means muscle growth. A one-rep max is the heaviest weight you can lift once.
| Study | What it covered | What it found |
|---|---|---|
| Wilson et al., 2012 | 21 studies, 422 effect sizes, strength training alone against strength plus endurance training. | Average effect sizes were lower with concurrent training: 0.85 against 1.23 for muscle growth, 1.44 against 1.76 for strength and 0.55 against 0.91 for power. Lifting with running brought significant decrements in muscle growth and strength. Lifting with cycling did not. More frequent and longer endurance work went with smaller gains. |
| Schumann et al., 2022 | 43 studies of healthy adults, at least 4 weeks of supervised concurrent training against identical strength training alone. | No loss of muscle size or maximal strength. Explosive strength was lower, more so in the same session than when sessions were at least 3 hours apart. Running against cycling, weekly frequency, training status and age made no significant difference. |
| Lundberg et al., 2022 | 15 studies that measured the size of single muscle fibers. | A small negative effect on fiber size. Early evidence that it is larger with running than with cycling, for type I (slow-twitch) fibers. |
| Petré et al., 2021 | 27 studies of lower-body one-rep max in leg press and squat. | A negative effect in trained people and none in moderately trained or untrained people. In trained people it appeared only when lifting and endurance training shared a session. |
| Murlasits et al., 2018 | Studies that compared lifting first with cardio first, in the same session. | Lower-body one-rep max was higher by about 4 kg when strength came first. Order made no difference to VO2max, the most oxygen your body can use in a minute. |
- Wilson et al., Journal of Strength and Conditioning Research, 2012: concurrent training, a meta-analysis examining interference of aerobic and resistance exercises checked 19 Oct 2026
- Schumann et al., Sports Medicine, 2022: compatibility of concurrent aerobic and strength training for skeletal muscle size and function checked 19 Oct 2026
- Lundberg et al., Sports Medicine, 2022: the effects of concurrent aerobic and strength training on muscle fiber hypertrophy checked 19 Oct 2026
- Petré et al., Sports Medicine, 2021: development of maximal dynamic strength during concurrent resistance and endurance training in untrained, moderately trained and trained individuals checked 19 Oct 2026
- Murlasits, Kneffel and Thalib, Journal of Sports Sciences, 2018: the physiological effects of concurrent strength and endurance training sequence checked 19 Oct 2026
Where the research disagrees
These results do not line up. The 2012 analysis ties interference to running. The 2022 analysis found no difference between running and cycling for muscle size or strength. The fiber analysis, from the same research group as the 2022 analysis, found a small negative effect on fiber size. The 2012 and 2022 analyses both found power reduced.
The studies differ in who they included and how much endurance work they used, and the reviews do not agree on which of those matters most. We cannot tell you which analysis will hold up. We read them as saying that most people can do both, and that the cost is small for muscle size and larger for power and for already-trained legs.
A lower-body strength day from Complete’s workout library
This is the Lower Strength (Upper/Lower Split), a session in Complete’s workout library. It is the lower day of a four-day split of upper and lower days, and it takes about 55 minutes. The library note says it is one of two lower sessions in the week.
To failure means you stop when you cannot finish another clean rep. Tempo 31X1 means 3 seconds down, a 1-second pause at the bottom, a fast lift and 1 second at the top. A single-leg RDL (Romanian deadlift) is a hip hinge on one leg. A Pallof press is a standing press that resists a twist. These are the kind of heavy leg sessions the next section keeps apart from hard cardio.
If you are new, two working squat sets to failure is plenty. Drop the tempo and swap the heavy carries for a moderate load. If you are experienced, take both squat sets to real failure, load the bar so 5 reps is the ceiling and carry at bodyweight, as the library puts it.
| Block | What you do |
|---|---|
| Warm-up | Back Squat: 2 sets of 5 reps, ramping up to working weight. Groove the pattern with no fatigue. |
| Main | Back Squat: 2 sets of 5 reps, 3 minutes of rest, tempo 31X1, loaded to failure by about 5 reps. Single-Leg RDL: 2 sets of 8 reps per side, 90 seconds of rest, to failure. |
| Accessory | Pallof Press: 3 sets of 10 reps per side, 60 seconds of rest. |
| Finisher | Farmer’s Carry: 3 sets of 40 meters, 75 seconds of rest, heavy. |
How to plan lifting and cardio together
No plan removes the trade-off. These are our rules of thumb, and what each one rests on.
| Our advice | What the research says |
|---|---|
| Keep heavy leg days and hard cardio apart. Put them on different days, or at least 3 hours apart. | In the 2021 analysis the loss in lower-body strength appeared only when lifting and endurance training shared a session, and only in trained people. The 2022 analysis found explosive strength was reduced more in the same session than when sessions were at least 3 hours apart. |
| If lifting and cardio share a session, lift first. | The 2018 analysis found lower-body one-rep max was higher when strength came first. Order made no difference to VO2max. |
| When your legs are the limit, use a bike or a rower for hard cardio. | The evidence is mixed. The 2012 analysis found decrements with running and none with cycling. The 2022 analysis found no difference between the two for muscle size or strength. |
| Keep most of your cardio easy. | The 2012 analysis found that more frequent and longer endurance sessions went with smaller gains in muscle growth, strength and power. The finding is a correlation across studies. |
- Petré et al., Sports Medicine, 2021: development of maximal dynamic strength during concurrent resistance and endurance training in untrained, moderately trained and trained individuals checked 19 Oct 2026
- Schumann et al., Sports Medicine, 2022: compatibility of concurrent aerobic and strength training for skeletal muscle size and function checked 19 Oct 2026
- Murlasits, Kneffel and Thalib, Journal of Sports Sciences, 2018: the physiological effects of concurrent strength and endurance training sequence checked 19 Oct 2026
- Wilson et al., Journal of Strength and Conditioning Research, 2012: concurrent training, a meta-analysis examining interference of aerobic and resistance exercises checked 19 Oct 2026
Hyrox is concurrent training in a race
A Hyrox race asks for both at once. You run 1 km, then do one functional workout station, and repeat that eight times. We think brick sessions are the best way to train for Hyrox. A brick is a station and a run back to back. Our guide to racing Hyrox goes through the stations.
- HYROX: The Fitness Race (official site) checked 19 Oct 2026
How Complete fits
Complete starts from your long-term goals: build muscle, lose fat, improve cardio, get stronger, general health or become an athlete. Several of those goals pull in different directions, and the daily recommendation reads your goals, your recovery and your recent load. Every workout that reaches Apple Health counts toward your score and your daily recommendation, in any sport. Over time it gets to know your body, your schedule and the sports you play.
Complete is free to download, and logging and sharing your workouts on it stay free.
Frequently asked questions
What is concurrent training?
Concurrent training means training strength and endurance in the same period, for example lifting three days a week and running two. Researchers study it to see whether doing both changes the gains from each.
What is the interference effect?
The interference effect is the idea that endurance training can blunt the gains from lifting, in muscle size, strength or power. A 2022 meta-analysis of 43 studies found no loss of muscle size or maximal strength and a small loss of explosive strength. Other analyses find larger effects, tied to running and to high amounts of endurance work.
Can you build muscle and run?
Yes. In the 2022 meta-analysis of 43 studies, adding cardio did not reduce muscle size or maximal strength. A smaller analysis of muscle fibers found a small negative effect on fiber size. Our advice is to keep most of your cardio easy and to keep hard cardio away from heavy leg days.
Should I lift or do cardio first?
If they share a session, lift first. A 2018 analysis found lower-body one-rep max was higher when strength came first, and VO2max did not depend on the order. Separate sessions by at least 3 hours if you can, since the 2022 analysis found explosive strength was reduced more in the same session.
Is cycling better than running for lifters?
The evidence is mixed. A 2012 analysis found decrements in muscle growth and strength with running and none with cycling. A 2022 analysis found no difference between the two for muscle size or maximal strength. Our advice is to use a bike or a rower for hard cardio when your legs are the limit.
Does Complete work for lifting and cardio together?
Yes. Complete starts from your long-term goals, such as build muscle, get stronger and improve cardio. Every workout that reaches Apple Health counts toward your score and your daily recommendation, in any sport.