Strengthening These Overlooked Muscles Might Be Key to Avoiding Injuries

New research finds that these exercises can increase running performance, too.

  • A new study found that six weeks of foot exercises helped runners with pronated feet improve their foot posture and boost their running performance.
  • Runners with neutral feet did not show significant changes in biomechanics or performance after doing short foot exercises
  • This study suggests that strengthening the soles of your feet may be the key to running faster and reducing risk of injury.

Staving off injuries
When runners strength train, we tend to target the big guns in our legs—such as our glutes, hamstrings, quads, and calves—and often neglect smaller muscle groups (think: those tiny muscles that wrap around the arches of our feet that are equally as important for powering our strides). But according to a new study published in BioMed Research International Journal, strengthening “plantar short” foot muscles (the 10 little muscles that stretch from your heel to your toes) may help improve running performance and stave off injuries.

In the study, researchers from Poland divided 47 long-distance runners into one of two groups: those with neutral feet (normal arches) and those with pronated feet (low or flat arches). The groups were decided after each participant’s feet were assessed using the Foot Posture Index, which evaluates the position of the forefoot and rearfoot using a neutral foot, which classifies as “zero” as a baseline comparison. Runners with neutral feet ranked between zero and five on the Index, while those with pronated feet ranked between six and 12. There were no excessive supinators included in the study.

After joining their respective groups, the participants completed a 35-meter sprint test that measured the torque, work, and power of their knee flexors and extensors. Both groups were then assigned a six-week strength training program that targeted the plantar short foot muscles. The program’s aim was to improve the participants’ foot posture to a more neutral position, with the hope that this would boost running performance and decrease injury risk.

“The plantar short foot muscles play a crucial role in supporting the medial longitudinal arch, providing the foot stability and flexibility for shock absorption,” study author and marathoner Iwona Sulowska, Ph.D., tells Runner’s World. “When these muscles are fatigued, such as after long distance running, there is a change in foot posture towards a pronated position.”

Sulowska explains that overly-pronated feet have a lowered medial longitudinal arch, which is less stiff and generates less torque, or explosive power, than a neutral arch. As we’ve written about before, overpronators’ feet roll inwards by more than 15 percent when they land, which forces the big toe and second toe to push off the ground without help from the rest of the midfoot. This motion causes extra stress on the foot and lower leg muscles, which can potentially lead to injuries like plantar fasciitis, Achilles tendinitis, and runner’s knee.

Benefits of Foot Exercises
Luckily, according to the study, pronation can be corrected through short foot exercises. For six weeks, the participants regularly completed these movements below. Before doing the exercises, the participants were advised to roll out the bottoms of their feet with a tennis ball.

  • Scrunching the foot to bring the toes to the heel (without curling the toes)
  • Walking backward in a straight line with one foot directly behind the other, putting weight evenly on the ball of the foot
  • Standing with one or two legs on a stability disc
  • Flexing and rotating the ankle using a band loop.

After six weeks, the participants ran a second 35-meter sprint test. In both groups, higher power was recorded. But the overpronators showed the most improvement in performance, shaving off more time from their sprint test than the neutral group. Interestingly, the strength exercises didn’t only help fix the pronators’ foot posture—it also boosted the peak torque of their knee flexors.

“The results suggested that the exercises of plantar short foot muscles may improve energy transfer through body segments,” says Sulowska. “After six weeks of foot exercises, we observed a significant change of foot posture towards neutral position among runners with pronation. Thus, more beneficial biomechanical conditions were restored, which allowed for better [performance] results.”

Unfortunately for runners with neutral feet, the exercises didn’t make much of a difference in strength or performance.

If pronation is causing hang-ups in your training, however, the study suggests that strengthening the soles of your feet may be the key to running faster and reducing risk of injury.

“I have observed that exercises of foot are usually ignored by runners,” Sulowska says. “Based on our results, we can suggest that [these exercises] are effective and should be included as a part of a daily training program.”

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