Today, the NY Times Well blog featured an article For Older Runners, Good News and Bad. The bad news comes from gravity. The good news? That came from buoyancy.

Runners 60 and older are the fastest-growing group in the sport, so naturally researchers are studying them with increased interest. One recent study looked at the reasons runners slow down as they age. Researchers had assumed that a main reason is that older runners are less economical (i.e. their muscles use oxygen less efficiently) than youthful athletes. But when scientists measured oxygen use as they ran on a treadmill, runners 60 and older were just as economical as runners half their age.

The more likely reason, according to another study, is the muscles of older runners lose their spring and resilience. Statistics show that older runners suffer much more frequent problems with Achilles tendons and hamstring and calf muscles. Because the impacts of running routinely inflict microtrauma on both bone and soft tissue—and we are slower to heal from stresses of all types as we age–the researchers speculate that damage steadily accumulates in aging runners. The effect isn’t just an increase in acute injury, but that the muscles and joints lose range of motion. With shorter, choppier strides come slower times.

The good news—for those who run and swim—is that your swim practices bring several clear benefits

1)    Less impact and thus less microtrauma.

2)    The massaging effect, as well as enhanced circulation promoted by swimming between runs, accelerates healing and restores resilience to your muscles.

3)    The resistance of water to your movements builds strength.

Muscles that are both stronger and more resilient will regain their spring and snap – improving stride length . . . and running times.