Key Biscayne, Florida - “Increasing Running Steps Reduces Patellofemoral Joint Forces,” is the conclusion reached by University of Wisconsin–Madison researchers, which is published in the March issue of Medicine & Science in Sports & Exercise. The patella is the kneecap bone, which in a perfect world, glides over the lower part of the thigh bone (femur), when you extend your leg.
“We have shown,” concluded the researchers, “that increasing step rate alters running form in a way that can significantly reduce the magnitude and rate of patellofemoral loading. This implies that a prescribed increase in step rate may be a simple strategy to attempt to mitigate patellofemoral pain that arises from excessive force.”
The American Academy of Orthopaedic Surgeons says, “runner’s knee is a term used to refer to a number of medical conditions that cause pain around the front of the knee (patellofemoral pain). Patellofemoral pain may be the result of irritation of the soft tissues around the front of the knee.”
In my experience, other contributing factors to patellofemoral pain may include muscle strength imbalances – such as between the quadriceps (thigh) and the hamstrings (back of upper leg), overuse syndrome, tight, inflexible hamstrings – which puts undue stress behind the knee cap, along with a knee cap that is out of alignment.
To reach their conclusion, Wisconsin-Madison researchers selected thirty pain free male runners between the ages of 19-47 and who had not undergone lower extremity surgery and been free of a leg injury over the past three months.
The participant’s normal step rate was ascertained during the final minute of a 5 minute treadmill run at each participant’s chosen speed. Then, each participant was put through “a series of randomly ordered running trials at their preferred speed at three specified step rates: preferred step rate (100 percent), 10 percent greater than preferred (110 percent), and 10 percent less than the preferred (90 percent).”
The researchers determined that by increasing the step rate (10 percent) at the participant’s chosen speed, an 11 percent reduction in peak patellofemoral joint loading occurred, “ primarily because of the 14 percent decrease in force magnitude.”
It would appear that reducing the load by controlling the step rate at one’s comfortable running speed might be a way to reduce the compression (loading) stress on the cartilage, and “hence diminish pain symptoms although maintaining the ability to run.”
“When running, there is a significant amount of stress that is placed on the front of the knee or the patellofemoral region of the knee,” noted Michael Hartman, an Orthopedic Surgeon and Sports Medicine expert at the LSU Health Sciences Center. “These stresses are higher when a runner lands with the knee in a more bent position.”
Conversely, notes Hartman, “ the stress is less when the runner lands on the knee in a more extended (or less bent) position. Increasing the number of running steps results in the runner landing in a more extended position; and therefore, results in less stress on the patellofemoral compartment or front of the knee.”
I am in agreement with the researchers, as to the effect of how changing the step rate can alter the steph length. Such an action would not only potentially compromise speed – which is dependent on appropriate stride length and stride frequency – but also the runner’s center of gravity – which will affect running efficiency and economy.
When running, your body lean acts as the “gas peddle,” while the arms are the accelerator. Sit down in front of a mirror with the legs slightly bent, with your hands cupped and bent at 90 degrees.
Perform the running action using only your body lean, arm action, and core strength to hold you in place. Take your nose, so to speak, and put it in your back pocket with each arm action. You might be surpised how you can accelerate more efficiently when you stand up and run.
Mackie Shilstone, a regular contributor to NOLA.com | The Times-Picayune, has been involved in the wellness sports performance industry for nearly 40 years. He is currently the fitness coach for Serena Williams, has trained numerous other professional athletes and consulted a litany of professional sports franchises. He is St. Charles Parish Hospital’s Fitness and Wellness expert. Contact him at mackieshilstone.com.