BRINGING SCIENCE TO TREATMENT

Gait deviations and running injuries: chicken or the egg?

Injuries plague roughly half of all runners(1). The most common of these injuries include patellofemoral pain (PFP), iliotibial band syndrome (ITBS), medial tibial stress syndrome (MTSS), and Achilles tendinopathy (AT). Certain musculoskeletal deficits are associated with these running injuries. However, researchers at the University of Salford wondered if there were universal running gait deviations that could result in any one of these injuries(1). They hypothesized that the deviations most likely to contribute to injury would be contralateral pelvic drop (CPD), hip adduction, and rearfoot eversion.

To measure the occurrence of these deviations, they evaluated 72 runners with a diagnosis of PFP, ITBS, MTSS, or AT. These runners had a history of injury for more than three months with associated running volume modification. None received prior treatment for their injury, and all were able to run at least 10 minutes before feeling pain. To exclude training error as a possible cause of injury, those with an increase in training volume of more than 30% prior to the injury were excluded from the study. In addition to the injured runners, the study included a control group of healthy runners who averaged at least 30 miles per week.

All subjects underwent 2D analysis while running on a treadmill at 3.2 m/s. Measurements were taken on the injured leg, while healthy runners were randomized to match the number of the injured on each side. Nine anatomical set points and a rear foot marker were used in the 30-second evaluation. The researchers took the data from the initial foot contact and midstance points of the gait cycle. At initial contact they analyzed the following angles in the sagittal plane:

  • Trunk
  • Pelvis
  • Hip
  • Knee
  • Ankle

The evaluation also included trunk and rearfoot angles in the frontal plane.

In midstance, the analysis included peak angles in the sagittal and frontal plane of the:

  • Trunk
  • Pelvis
  • Knee
  • Ankle
  • Rearfoot

The additional transverse plane analysis included the angles at the hip and knee.

Findings

The researchers divided the injured into injury-specific subgroups and then compared the parameters of the whole cohort of injured runners with the healthy ones, as well as between the subgroups. They found that as a whole, the injured runners landed with significantly more knee extension and ankle dorsiflexion. During midstance, injured runners leaned significantly more forward and demonstrated significantly more CPD and hip adduction.

When compared across the subgroups, the gait deviations – forward trunk lean and CPD during midstance, and increased ankle dorsiflexion and knee extension at foot strike – were similarly present in all the injured runners. However, those with PFP and MTSS demonstrated significantly more hip adduction than those with other diagnoses. Statistical analysis showed that CPD and knee extension at initial contact were the greatest predictors of injury.

The gluteal muscles, specifically the gluteus medius, are responsible for pelvic stability during unilateral stance.  The evidence of CPD in all the injured runners supports the long-standing thought that glute medius weakness is a contributing factor in running injuries. More knee extension may contribute to lateral tilt and displacement of the patella. The resulting joint stress may predispose runners to PFP. Greater knee extension and dorsiflexion also means that initial contact occurs further from the center of mass. This extra distance increases the knee joint loading and braking forces, known to be problematic, especially for those with ACL injuries.

The forward-leaning trunk posture assumed by the injured runners may also be a result of glute and paraspinal weakness. Runners with ITBS and PFP also demonstrated more hip adduction than the other runners. Female runners are more likely to exhibit hip adduction than males. However, this study included both genders. Hip adduction in this investigation was associated more strongly with the particular injury subgroups than with gender.

Limitations

This study was retrospective – evaluating deviations of already injured runners. As such, the gait deviations of the injured runners aren’t necessarily causational. This study has a chicken or egg problem. Knowing if the deviations are due to the injury or if they caused the damage is impossible to conclude.

The researchers undertook a 2D model of gait analysis, which is relatively easy to reproduce in the clinic setting. Therefore, the evaluation of injured athletes should include screening for these gait deviations. If found, gait retraining should commence as part of the rehabilitation course. Manipulation of cadence, stride, and gait posture may help relieve the stress on the injured area. In addition, the 2D analysis may be a useful tool for injury prescreening. Correcting these pathological deviations before an athlete presents with an injury may prevent damage from occurring at all.

Reference

  1. Am J Sports Med.
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