Strong Ankles Can Keep You From Slowing Down
Being able to hold your pace in the final stretch of a race or long run isn’t just about doing enough kilometres and speedwork. You also need to be able to keep running with your best form, and doing so probably includes strengthening your Achilles tendons, two new studies suggest.
In one study, published in Medicine & Science in Sports & Exercise, 25 runners did a treadmill 10K at close to race pace for the distance. Researchers measured the work being done by the runners’ ankle, knee, and hip joints approximately twice a kilometre throughout the 10K.
The researchers found that, over the course of the 10K, some of the work initially done by the runners’ ankle was increasingly picked up by the runners’ knees and hips. This switch in loads likely leads to less efficient form. According to the researchers, this finding could explain why running economy, or how much oxygen is needed to maintain a certain pace, gets worse as we fatigue.
In the second study, published in PLoS ONE, 18 runners did a 90-minute run at medium effort. Researchers measured the runners’ Achilles tendon stiffness and running economy at the prescribed moderate pace before and after the run. The researchers found that the runners’ Achilles tendons were much less stiff after the run, and that the subjects’ running economy had worsened.
Although less tendon stiffness might sound desirable, in this case it’s not – stiffer tendons should mean that the muscles they’re attached to don’t have to work as hard to generate force. As tendons become less stiff, the associated muscles pick up more of the work, and the energy cost of maintaining a given pace goes up.
Taken together, “these studies build a case for improving Achilles tendon stiffness through a resistance training program,” said Chris Napier, a physiotherapist who has published his own research on running form and who has a 2:33 marathon PB.
Strong Achilles tendons and related soft tissues are necessary for any runner hoping to maximize performance. Napier said the above two studies and the Achilles-strengthening recommendation are especially important for a few segments of the running community: women and older runners who have been found to have less stiff Achilles, and people with a history of Achilles injury.
Earlier research has pegged losses in ankle strength and function as a prime reason for slowing with age. Older runners tend to maintain the stride rate of their youth, but their stride length decreases over time; one study showed nearly a 50 percent decrease in ankle power.
A key to strengthening your Achilles and ankles may be to run faster more often. In the treadmill 10K study, the slower half of the group shifted more of their joint work to their knees and hips than did the faster runners. One explanation is that the faster runners more regularly ran at challenging paces and were more accustomed to holding good form as they tired.
But this doesn’t mean you need to bang out sets of 400-metre repeats every week. Have at least one day a week where you do quick bursts of 100 to 200 metres several times; you could do these as intervals on the track after warming up, or on a flat, level stretch of road or dirt after a short run. (Or try these sprint workouts.) Allow plenty of time between so that you can run each repeat with good form, which includes pushing off strongly from your ankles.
For real strength gains, Napier recommends some non-running work. “To increase tendon stiffness, you need to work eccentrically with heavy loads,” he said. “An example would be a heel drop program, with three sets of eight reps with heavy weight.”