Stop pounding the pavement with cadence manipulation

More people are taking to Minnesota roads to join the 5K craze or check one off the ol' bucket list by finishing a marathon. This year it is estimated that up to three out of four runners will endure set-backs from a running-related injury. My task as a RunSMART (Skilled Movement And Rehabilitation Team) physical therapist is to keep runners running and not sacrificing any time side-lined by an injury.

Cadence manipulation is one method that is increasing in popularity. It is an intervention I can initiate immediately and it easily helps more than 50 percent of my runners. Cadence manipulation involves intentionally increasing the number of times that the runner's feet hit the pavement, thereby decreasing the stride length. Research shows that shorter stride length limits the ground reaction forces that the joints and muscles have to absorb, especially at the hip and knee. And with less time for each stride, there is also less time for the hip to drop,  the  pelvis to tilt or any of the other glitches in gait that occur with running. 

Over-striding, or landing with the foot too far ahead, is often associated with a higher rate of injury. Reaching a foot out in front of the body is not efficient, essentially it wastes energy. It's as if the runner is stopping his or her motion only to have to restart it again that same stride. Plus, runners with slower cadences often lose energy bounding up and down as they run. 

A cadence of 170-190 is common in elite runners and has been shown to be more efficient. If a runner has a slower cadence such as 140-160 steps per minute and is running injured, increasing his or her cadence by five to 10 percent is often an effective solution. When I'm working with runners with a slower-cadence I can often hear just how hard their foot strikes the ground. If I can hear it, just think of how it feels on the joints! 

When assessing a runner I like to take video of his or her current running cadence and compare it to a new cadence. Many of the issues noticed with the runner's form melt away at the new frequency. Ideally if you change the cadence the runner immediately notices improvements. 

Putting it in motion

Recently, I worked with a 35-year-old female runner who was experiencing patellofemoral (knee cap) pain for the last three months. Our work together began with her running intervals on the treadmill. She took a few minutes to warm up and find her stride. Then I counted her foot strikes per minute; she had a cadence of 150. After just four minutes of running she reported mild knee pain. 

I then set a metronome to 165 beats per minute, or 10 percent higher than her normal cadence, and asked her to run matching the audio feedback. After a minute interval running, she returned to walking. The next running interval I again offered her the help of the metronome, and when she was on beat, I eliminated the metronome for 10 seconds to see if she maintained 165 steps per minute. I continued to fade in and out the sound over the next few intervals of jogging. She caught on quickly and also reported she had less knee pain than running at 150 steps per minute.

It was easy for me to see that she was an ideal runner to try cadence manipulation. Over the next few weeks I had her try running small increments with a metronome (or music set to 165), gradually increasing the time spent at the new cadence. I warned her, a gradual increase is key or she would begin to feel increased stress and strain on her ankles and Achilles tendon. After three weeks she was running one and a half miles without pain and she no longer required the metronome—165 steps per minute had become mentally ingrained. 

Cadence manipulation won't be the solution for all injured runners and other interventions may be needed. What I like about intentionally increasing the step frequency of runners is that it is a simple solution. With cadence manipulation I'm not making big changes to how a runner runs, which means it's safer too. Add in strength training, fewer training errors (too much too soon), good sleep and nutrition and we have a winning combination for getting runners back on the road again.