Can Asymmetric Running Patterns Be Predicted By Assessment of Asymmetric Standing Posture? A Case Study in Elite College Runners

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1 REVIEW ARTICLE Can Asymmetric Running Patterns Be Predicted By Assessment of Asymmetric Standing Posture? A Case Study in Elite College Runners Paige E. Skorseth; Patrick T. Knott, PhD, PA-C Abstract Objective: This case study evaluated several elite college runners to see whether their standing posture could predict any asymmetry in their running pattern. The goal of the study was to provide sportsmedicine professionals with a basis to extrapolate running gait patterns from standing posture. Using this model, information that would otherwise only be available through sophisticated gait analysis could be easily obtained. It was hypothesized that asymmetry in standing position would be reflected in similar asymmetric patterns during walking and running. Right or Left Dominancy are often the terms used to coin these asymmetric running gaits among competitive runners and their coaches/trainers. Methods: Surface Topography measurements were collected using the Formetric 4D system (DIERS International, GmbH, Schlangenbad, Germany) to obtain postural spine measurements and foot pressure measurements in the standing position. Then each subject was measured again during walking, jogging and running to obtain motion analysis data on the spine, trunk and feet. Comparisons were made between the standing and moving measurements. Results: Standing asymmetries in the trunk did predict similar patterns of asymmetry during movement. Coronal imbalances were the most consistent, with standing postures that lean to one side translating into movement patterns during running that exaggerate that imbalance. Foot pressure imbalances during standing, however, did not translate to similar differences during running, with running forces fairly consistent between the right and left foot. Paige E. Skorseth; DePaul University, College of Science and Health, Chicago, IL USA. Patrick T. Knott, PhD, PA-C; Rosalind Franklin University of Medicine and Science, College of Health Sciences, North Chicago, IL USA. Keywords: Motion Analysis, Sports Performance, Trunk Imbalance, Surface Topography, Running, Gait. Correspondence: Patrick Knott, PhD, PA-C; Rosalind Franklin University of Medicine and Science; 3333 Green Bay Road; North Chicago, IL address: Patrick.Knott@RosalindFranklin.edu Introduction Throughout just one mile of running, according to Drozd, the foot of an average sized person absorbs over 110 tons of force. 1 As an athlete runs, this force is distributed across areas within the feet, mainly the metatarsals, which serve as excellent shock absorbers. 2 The effects of uneven force distribution in each individual foot has been thoroughly investigated, and according to stability specialists these uneven distributions lead to increased pressures in certain areas of the foot and lower extremities, which can then lead to injury. 3 Athletes that complete many repetitive motions in the same form are at higher risk, making elite distance runners prime subjects for overuse injuries. The use of orthotics and other shoe modifications have been developed to equalize these forces and to create a different foot plant. According to Eng, this may change entire lower-limb kinematics. 4 However, interestingly enough, there has been very little research on the effects of uneven force distribution between the right and left foot of a runner. Many athletes continuously injure the same leg, and this could be due to increased unilateral force generated by running on a circular track in the same direction. In this study we investigated the uneven standing weight distribution and posture of four elite female runners and then compared this to the symmetry of forces measured while walking and running. 16 Functional Neurology, Rehabilitation, and Ergonomics Vol. 7, No. 4

2 Figure 1. DIERS Formetric Motion Lab Figure 2. Spine and Foot Pressure Data Obtained in Standing and Running Most athletes, coaches, and trainers are under the impression that each athlete has a dominant side. According to Runner s World, Every runner has a dominant side that is stronger and more stable. 5 Many running specialists, including Reed Ferber PhD director of the Running Injury Clinic at the University of Calgary, believe that an athlete s weak side is genetically determined. It is widely accepted that runners have weaker muscles on one side, making them more susceptible to injury. However, there are various explanations for this injury susceptibility including: the favoring of one side leading to the rotation of the hips/ankles, the simple genetic weakness in one side of the body, or what we set out to investigate, that one side of the body may actually experience more force than the other during each stride. Methods After IRB approval, four volunteer subjects were recruited from an NCAA Division I college track team. All were female, and running more than 55 miles per week. The subjects had been consistently training at that level for greater than four years. Measurements were done using the DIERS Formetric surface topography scanning system (DIERS Medical Systems, Inc., Chicago, IL) while standing, and repeated while running at speeds of 3.0, 5.0, 6.5, 9.5 and 11.0 km/hr on the treadmill (Figure 1). Each of the four research participants stood barefoot on the pressure platform that was embedded in the treadmill with a normal habitual posture, while a measurement of left and right foot pressures were recorded. Additionally, the Formetric topographical scanner evaluated posture including standing sagittal and coronal plane imbalance, pelvic obliquity, pelvic tilt, thoracic spine kyphosis, and lumbar spine lordosis (Figure 2). Subjects then walked at 3 km/hr on the treadmill for as long as it took to reach their regular stride and form at this speed. A five second acquisition time was used to simultaneously capture trunk and foot pressure data. Then the treadmill speed was increased to the next level, and the procedure was repeated. The data was exported to an Excel spreadsheet for analysis. Comparison of standing forces on the right and left foot were evaluated in the context of standing trunk posture. Additionally, walking and running forces on the right and left foot were assessed. Results The data showed that all four athletes had an asymmetry in weight balance while standing (Table 1), giving them different forces felt on each foot. Additionally, all four athletes had some degree of postural asymmetry. Each athlete measured was leaning forward (from 12.7 mm to 43.0 mm) and to the left or right (from 4.8 mm left to 15.1 mm right). The data collected utilizing the 4D Formetric Scanner show that elite female runners do have a dominant side Functional Neurology, Rehabilitation, and Ergonomics Vol. 7, No. 4 17

3 Table1. Symmetry of Standing Forces and Posture Max. Foot Pressure Weight Sagittal Coronal (Newtons) Distribution (%) Balance Kyphosis Lordosis Balance Subject Right Left Right Left (mm) (deg) (deg) (mm) % 54% % 53% % 59% % 58% Table 2. Symmetry of Moving Forces Subject One Right Foot Ave. Foot Pressure Left Foot Ave. Foot Pressure 3.0 Walk 50% % Walk 50% % Jog 51% % Run 51% % Run 51% % 1200 Subject Two Right Foot Ave. Foot Pressure Left Foot Ave. Foot Pressure % 51% % % 50% % % 50% % % 50% % % 50% % 1473 Subject Three Right Foot Ave. Foot Pressure Left Foot Ave. Foot Pressure 3.0 Walk 50% % Walk 49% % Jog 49% % Run 50% % Run 49% % 1022 Subject Four Right Foot Ave. Foot Pressure Left Foot Ave. Foot Pressure 3.0 Walk 50% % Walk 51% % Jog 49% % Run 51% % Run 53% % Functional Neurology, Rehabilitation, and Ergonomics Vol. 7, No. 4

4 Table 3. Trunk balance during motion Subject One 3.0 Walk Walk Jog Run Run Subject Two 3.0 Walk Walk Jog Run Run Subject Three 3.0 Walk Walk Jog Run Run Subject Four 3.0 Walk Walk Jog Run Run and, while standing in place, this causes a pressure differential. However, when the athletes begin to walk, and as they increase speed and begin to run, this pressure differential deteriorates until it is statistically insignificant. After viewing the walking and running data, it is evident that these uneven distributions deteriorated (Table 2). Foot pressures deviated minimally from 50% on each foot while walking and running at each of the speeds tested. The posture of each runner was also studied. The forward leaning stance that each runner exhibited while standing was exaggerated while running, and generally increased by approximately 20 mm as they moved from walking to jogging to running. Their kyphosis and lordosis remained very stable throughout the different speeds, showing that the forward leaning posture originated from the hips and not from an increasing kyphosis. And, although each runner had a different pattern of coronal balance while standing, that pattern was maintained during walking, jogging and running, and increased in magnitude, showing a larger left-right movement of the trunk as speeds increased. (Table 3) Functional Neurology, Rehabilitation, and Ergonomics Vol. 7, No. 4 19

5 Conclusions This study concludes that the elite runners measured did have standing asymmetry that resulted in more weight being placed on one foot and a lean slightly forward and towards the opposite side. This is consistent with the authors observations in high level running athletes. The evaluation examined whether this asymmetry would lead to more force being distributed to one side of the body during running, and the data does not support this. Running patterns at different speeds resulted in foot pressure measurements that were remarkably symmetric, even though the sideways leaning posture became more pronounced as speed increased. References 1. Drozd S. Metatarsalgia. Runner s World. Available at: runnersworld.com/injury-prevention-recovery/metatarsalgia. Accessed: January 6th Salathe E, Arangio G. The Foot as a Shock Absorber. Journal of Biomechanics Volume 23, Issue 7, pg March 23, Merriam R. Uneven Weight Distribution While Running. Available at: Accessed: January 4th Eng J, Pierrynowski M. The Effect of Soft Foot Orthotics on Threedimensional Lower-Limb Kinematics Durning Walking and Running. Journal of the American Physical Therapy Association. March 22, Schipani, Denise. Find Your Balance. Runner s World. Runner s World, 06 June Web. 20 June Available at: health/find-your-bodys-balance/. Discussion This study suggests that in elite runners, there may be a pattern of asymmetric weight distribution while standing that does not predict a similar imbalance while running. The pattern of forces applied to each foot during running was balanced. This is important information for all trainers, coaches, and athletes because there is a common perception that the dominant side of a runner experiences higher forces, and is more prone to injury. Injury patterns are more likely due to other causes. Carrying weight on one side of the body during running to equalize the standing pressures is not likely an effective training technique, as this study has shown that the standing foot pressures do not predict the running foot pressures. Training should focus on things like balancing muscle strength, flexibility, and gait patterns to bring runners to an elite level. Continuing studies could include testing muscle imbalances between the dominant and non-dominant sides. It would also be interesting to evaluate how pure track athletes and their dominant sides are affected by always running in a counter clockwise circle, especially on smaller banked tracks, versus cross country runners who run in straight lines. All the athletes in this original study are primarily cross country runners and secondarily track athletes. They also have had extensive training, which has likely formed a pattern of a balanced, efficient gait. Perhaps the most interesting continuation of this study would be to test whether training is what is providing the elite athlete with a balanced running style. Testing this theory in untrained athletes would provide an interesting perspective. 20 Functional Neurology, Rehabilitation, and Ergonomics Vol. 7, No. 4