How Many Days a Week Should Runners Do Strength Training?

You have signed up for your next half marathon, and somewhere between the running club group chat and a coach's post on your feed, you have been told to "do strength". Fair enough. But you already run four or five days a week, work runs late, and the evenings are not getting any longer. How much strength work is actually enough?

Here is your complete guide to how often runners should strength train: how many sessions a week, how long before it works, what to do in race season, and whether it will make you heavier or slower. The numbers come from a 2018 systematic review of 24 studies on strength training in distance runners.

Strength Training for Runners at a Glance

Detail	What the research says
Sessions a week	2 to 3 in most studies; 2 is likely sufficient
Time to see changes	About 6 weeks; some changes in as little as 4
Running economy	Improved by 2 to 8% after 6 to 20 weeks
Body weight	Unchanged in 18 of the studies
Race season	1 session a week maintains your gains
Stopping completely	Gains back to baseline within 6 weeks

Source: Blagrove, Howatson and Hayes, Sports Medicine, 2018. Full link at the end.

How Many Sessions a Week

Two to Three Is the Standard

The majority of studies that improved running physiology scheduled strength training 2 to 3 times a week, in line with the guidelines for people new to strength training. One study used just one session a week and still saw moderate improvements in strength and running economy after 8 weeks.

Why Two Is Usually Enough

More is not automatically better. In a group of 311 endurance runners, researchers found only a weak relationship between how often they did strength training and how much their running economy improved. The review's conclusion: two sessions a week is likely to be sufficient.

That matters for the recreational runner. The review itself points out that strength training can eat into leisure time that could be spent running, so the lowest dose that works is the one worth knowing.

How Long Before It Works

The review calls 6 weeks a relatively short period that can still improve the qualities behind distance running performance. Improvements in running economy and 10km time trial performance have been shown in as little as 4 weeks.

Longer programmes did more. Most 6-week programmes produced small time trial improvements of 2.4 to 2.7%, while programmes of 8 to 11 weeks produced 3.1 to 5.5%.

Two sessions a week is likely enough. Keeping them going for weeks is what counts.

Will Strength Training Make You Heavier or Slower?

Body Weight: Unchanged in Almost Every Study

Body mass did not change in 18 of the studies; one study found a 2% increase. Fat mass, fat-free mass, skinfolds and limb girth measurements showed no significant changes either. The review's key points sum it up: VO2max, blood lactate and body composition appear to be unaffected when you add strength training to a distance runner's programme.

Running Economy: Usually Better

Running economy is the oxygen or energy cost of running at a given pace. Strength programmes of 6 to 20 weeks improved it by 2 to 8%, which should let you run at a lower relative intensity for the same speed. The review found benefits to running economy, time trial performance and sprint speed in runners of all abilities, though not in every single study.

The Real Risk: Tired Legs

The catch is timing, not muscle. A hard strength session can leave enough fatigue to hurt your next run, so the review recommends at least 24 hours between a strength session and an intensive running session.

Race Season and Time Off

• In race season: drop to one session a week. Runners can go from 2 to 3 sessions in the build-up to a single session during the competitive season without losing what they built, based on a 40-week study.
• If you stop completely: the improvements return to baseline within 6 weeks. A short break is fine; months off means starting again.
• After your big race: the weeks after a goal race are a natural time to build back up to two or three sessions, ahead of the next block of running.

What Goes Into a Session

• The exercises: barbell squats, deadlifts, step-ups and lunges are common in the studies. For jumping work, skipping, hopping, speed bounding and depth jumps from a 20 to 30cm box appear most suitable.
• The sets: most studies started with 1 to 2 sets and built up to 3 to 6 sets over the programme. Build up gradually if you are new to lifting.
• The load: very heavy sets of 3 to 5 reps did no better than moderate loads with 5 to 15 reps.
• Stop short of failure: grinding every set to failure can delay recovery, and it is unnecessary for building strength.

Plan Your Strength Work with ATHLO+

One detail from the review stands out. Where the strength exercises were not supervised, or were supervised only for the first 2 weeks, strength measures did not improve. The authors conclude that a suitably qualified coach is an important part of a strength programme for a runner who lacks strength experience.

If you want a plan written for runners, STR Fitness Club's Run Strong is a 12-week running-specific strength programme. STR send you your plan as a PDF within 3 working days of buying, and at the end of the 12 weeks they check in with you and re-establish your goals and baseline. Training for HYROX? HYROX Build lets you pick a Strength, Running or Station Conditioning focus.

Ready to fit those sessions into your week? Read whether to run before or after a strength workout next.