Runners have long treated strength work as medicine: something to be taken in the smallest effective dose, if at all. New research published this summer suggests that instinct may be half right — there is an optimal dose, and it is smaller than the fitness industry would like but larger than most runners currently manage. A long-running study tracking resistance training and mortality found that 90 to 120 minutes of strength work per week was associated with the greatest reduction in risk of death, with benefits plateauing — and by some measures reversing — beyond that range.
The sweet-spot finding lands on fertile ground in the running world, where the case for resistance training has strengthened considerably over the past decade. Controlled trials in trained runners have repeatedly linked combined endurance and strength programmes to improved running economy — the oxygen cost of holding a given pace — alongside better maximal aerobic speed and more stable gait mechanics late in long runs. A 20-week intervention published earlier this year reinforced the pattern: runners who lifted did not get slower or heavier, they got cheaper to run.
The 90-to-120-minute window translates conveniently into practice: two or three sessions of 40 to 45 minutes, which is close to what most evidence-based coaching programmes already prescribe. The detail that deserves more attention is what fills those minutes. The economy gains in the trial literature come overwhelmingly from heavy, low-repetition work — squats, deadlifts, step-ups, calf raises — and from plyometrics, not from the high-repetition, light-weight circuits that many runners default to on the theory that endurance athletes should train endurance in the gym as well.
The longevity framing also reshapes the cost-benefit calculation for masters runners in particular. Recent injury research — including a study of younger masters runners published this year — has pointed to declining muscle mass and tendon stiffness as central drivers of the injury patterns that arrive from the mid-forties onward. Resistance training addresses precisely the tissue qualities that running alone does not maintain, which is why the strongest practical case for the gym is not the seconds-per-mile argument but the seasons-per-career one.
None of this requires runners to become gym enthusiasts. The evidence points to a floor and a ceiling: below roughly an hour a week, the benefits are largely unrealised; beyond two hours, the return diminishes and the interference with running quality grows. Ninety minutes, lifted heavy and spent wisely, appears to buy improved economy now and durability later — about as close to a free lunch as training science currently offers. The only catch is the one runners already know: it only works if you actually do it.