If you train recreationally, adding running to a lifting programme is unlikely to cost you strength or muscle. The most recent umbrella review found strength, power and muscle growth comparable between people who did both and people who only lifted, while the people who also did endurance work gained more aerobic fitness [1]. Two things still deserve attention: explosive strength, which does take a small hit, and the total load on your legs across the week.

What "interference" means

Researchers call lifting and endurance work in the same programme concurrent training. The worry, known as the interference effect, is that endurance training blunts the signals that make muscle grow and get stronger, so you end up with less of both than if you had only lifted.

The question for someone who runs three times a week and lifts four is whether it shows up at that dose.

What the pooled evidence says

A 2026 umbrella review gathered 17 meta-analyses covering 144 studies and 1,492 healthy people [1]. Compared with lifting alone, lifting plus endurance work improved aerobic capacity and produced comparable strength, power and muscle size. Compared with endurance work alone, adding lifting produced larger strength gains. The authors conclude that combined training suits recreationally trained people, and note that data on highly trained and elite athletes are scarce.

A 2022 meta-analysis of 43 studies reached a similar answer with one exception [2]. Maximal strength and muscle size were no different with or without the aerobic work. Explosive strength, the kind you use to jump or sprint, was lower, with a standardised difference of about 0.28. That loss was clearer when both kinds of training happened in the same session than when they were at least three hours apart.

Running may cost more than cycling

An older meta-analysis of 21 studies found that running alongside lifting reduced gains in muscle size and strength, while cycling did not [3]. It also found that more frequent and longer endurance sessions were linked with smaller gains. The 2022 analysis did not find a difference between running and cycling [2], so treat this as a possibility.

The usual explanation is mechanical. Running involves a lot of impact and lengthening under load for the calves, quads and hamstrings, which adds soreness and fatigue to the same muscles you squat and deadlift with. Cycling asks far less of them in that way. That is a reasonable inference from the pattern, and nobody has tested it directly.

Order and spacing

The umbrella review found no clear effect of doing one before the other, with a trend towards lifting first for strength and muscle size [1]. The 2022 analysis found explosive strength suffered more when both were in one session [2].

A practical reading of both:

• If both happen on one day, lift first when strength is the priority, and run first when the run is the priority.
• Put at least a few hours between them when you can. Morning run, evening lift works well.
• Keep hard running away from the day before a heavy lower-body session. Easy running is less of a problem.

Two sample weeks

These are starting points built from the findings above. They have not been tested as programmes.

A lifter who runs, lifting four days and running two:

The hard run comes after the last leg day and before a rest day, so it never lands the day before heavy squats.

A runner who lifts, running four days and lifting two:

Neither lifting day falls the day before the long run.

Signs the total is too much

The research above describes averages. Your week is one case, and these are the usual signs it has more work than you can recover from:

• Your lifts stall or drop for two or three weeks at the same effort.
• Your easy runs need a higher heart rate for the same pace.
• Your legs are still sore when the next leg session arrives.
• Sleep gets worse, or your resting heart rate stays higher than usual.

When that happens, cut volume on whichever goal matters less this month. Close to a race, that is usually the lifting.

Who this does not cover

The studies here mostly used healthy recreational and untrained adults over weeks to a few months. They say little about elite endurance athletes, about people training for an ultramarathon while trying to set a squat record, or about anyone returning from injury.

Keeping both goals in Agyl

Agyl's plan editor lets you put each workout on a weekday, so you can arrange your lifting days around your runs as in the tables above. The Events section lists races across Mumbai, Delhi NCR, Bengaluru and Pune, plus HYROX, Yoddha and IRONMAN 70.3 Goa. Saving one puts a countdown on your Today screen. Agyl does not yet change your plan based on a race, so moving your lifting as the race gets closer is still your call.