Running can help swimming in specific ways, but it’s not a straightforward boost to your speed in the pool. The benefits depend on what kind of running you do, how much, and what aspect of swimming you’re trying to improve. For some swimmers, running strengthens areas that pool training alone neglects. For others, too much running can actually work against their performance.
Where Running Genuinely Helps Swimmers
The clearest benefit of running for swimmers is bone health. Swimming is a non-weight-bearing activity, which means it does little to strengthen your bones. Studies comparing athletes across sports have found that swimmers have significantly lower bone mineral density than athletes in high-impact sports like running, soccer, and gymnastics. In one study of young female athletes, the high-impact group (which included runners) had significantly higher bone density at the hip and throughout the skeleton compared to swimmers and sedentary controls. Swimmers who never do weight-bearing exercise can develop bone density profiles that look surprisingly similar to people who don’t exercise at all.
Adding some running to a swim-heavy training schedule helps offset this. Even moderate amounts of jogging or running load your skeleton in ways that water never can, stimulating the bone-building process that keeps your frame strong over years of training.
Running also builds aerobic capacity through a different movement pattern, which can give your swimming muscles a break while still training your cardiovascular system. This is why many competitive swim programs include dryland work that features running, especially during base-building phases early in the season.
The Ankle Flexibility Trade-Off
Here’s where things get complicated. An effective flutter kick depends heavily on ankle flexibility, specifically the ability to point your toes (plantarflexion). Swimmers develop significantly more ankle range of motion than runners. One study comparing collegiate swimmers to runner controls found that swimmers had greater flexibility in nearly every direction of ankle movement, with the differences being large and statistically significant.
Running does the opposite to your ankles. The repetitive impact of striking the ground tightens the muscles and tendons around the ankle joint, building the stiffness that makes running efficient but working against the loose, floppy ankle that produces a great kick. If you run frequently without dedicated ankle mobility work, you may notice your kick becoming less effective over time. This doesn’t mean you should avoid running entirely, but it does mean stretching your ankles after runs and maintaining flexibility through pointed-toe exercises matters if your kick is important to your events.
Running and Sprint Swimming Performance
If your goal is to swim faster in short events like the 50 or 100 meter, the relationship between running and swim speed is indirect at best. Explosive land-based training can improve sprint swimming. Research on concurrent resistance and swim training found that programs emphasizing explosive movements (medicine ball throws, jumps) improved 50-meter swim times by roughly 3%. But the key word there is “explosive.” Steady-state jogging doesn’t build the kind of power that transfers to fast swimming.
In fact, long-distance running before strength training can actually hurt your power output. One study found that 60 minutes of steady running at a hard aerobic pace reduced maximum force production by about 20% in the strength session that followed. For swimmers who pair running with gym work on the same day, this is a real concern. If you run first and then try to do explosive dryland exercises, you’ll get less out of the strength work. Reversing the order, doing your power work fresh and running afterward, avoids this problem.
Running as Recovery: Not Ideal for Swimmers
Some swimmers use easy jogging as active recovery between hard pool sessions. The logic makes sense on the surface: light movement helps clear metabolic waste and reduce soreness. But research specifically on swimmer recovery tells a different story. Studies have consistently shown that in-water recovery protocols remove blood lactate faster than either passive rest or land-based recovery. Swimmers recover better by swimming easy than by jogging easy.
The most effective post-competition recovery for swimmers involves varied paces in the water, including short bursts at higher intensity mixed with easy swimming, at relatively high volumes with short rest periods. A light jog isn’t harmful, but if you’re choosing between 20 minutes of easy jogging and 20 minutes of structured easy swimming for recovery, the pool wins.
How to Use Running Without Hurting Your Swimming
The practical answer is that running helps swimmers when used strategically and hurts when overdone or poorly timed. A few guidelines keep it productive:
- Keep volume moderate. Two or three short runs per week (20 to 30 minutes) provide cardiovascular and bone density benefits without creating excessive ankle stiffness or cutting into pool recovery.
- Prioritize swim sessions. Don’t run hard the day before an important pool workout. If you run and lift on the same day, do the explosive work first.
- Stretch your ankles after every run. Sit on your heels, do pointed-toe stretches, and use a resistance band to work plantarflexion range. This protects the ankle mobility your kick depends on.
- Match the type of running to your goal. Short sprints and hill runs build explosive power that transfers better to swimming than long, slow distance. Easy jogging is fine for general fitness and bone health, but it won’t make you faster in the pool.
- Recover in the water. After races or hard swim sets, choose a structured swim cooldown over a jog.
For recreational swimmers who want general fitness, running and swimming complement each other well. The combination builds a more balanced body than either sport alone, covering both weight-bearing and non-weight-bearing exercise. For competitive swimmers chasing time drops, running is a useful supplement in small doses but should never replace pool work or structured dryland training as a primary tool for getting faster.