Effects of Foot Strike on Low Back Posture, Shock Attenuation, and Comfort in Running

DELGADO, TRACI L.; KUBERA-SHELTON, EMILIA; ROBB, ROBERT R.; HICKMAN, ROBBIN; WALLMANN, HARVEY W.; DUFEK, JANET S.

Medicine & Science in Sports & Exercise: March 2013 - Volume 45 - Issue 3 - p 490–496
doi: 10.1249/MSS.0b013e3182781b2c
Applied Sciences

Purpose: Barefoot running (BF) is gaining popularity in the running community. Biomechanical changes occur with BF, especially when initial contact changes from rearfoot strike (RFS) to forefoot strike (FFS). Changes in lumbar spine range of motion (ROM), particularly involving lumbar lordosis, have been associated with increased low back pain. However, it is not known if changing from RFS to FFS affects lumbar lordosis or low back pain. The purpose of this study was to determine whether a change from RFS to FFS would change lumbar lordosis, influence shock attenuation, or change comfort levels in healthy recreational/experienced runners.

Methods: Forty-three subjects performed a warm-up on the treadmill where a self-selected foot strike pattern was determined. Instructions on running RFS/FFS were taught, and two conditions were examined. Each condition consisted of 90 s of BF with RFS or FFS, order randomly assigned. A comfort questionnaire was completed after both conditions. Fifteen consecutive strides from each condition were extracted for analyses.

Results: Statistically significant differences between FFS and RFS shock attenuation (P < 0.001), peak leg acceleration (P < 0.001), and overall lumbar ROM (P = 0.045) were found. There were no statistically significant differences between FFS and RFS in lumbar extension or lumbar flexion. There was a statistically significant difference between FFS and RFS for comfort/discomfort of the comfort questionnaire (P = .007). There were no statistically significant differences between other questions or the average of all questions.

Conclusion: Change in foot strike from RFS to FFS decreased overall ROM in the lumbar spine but did not make a difference in flexion or extension in which the lumbar spine is positioned. Shock attenuation was greater in RFS. RFS was perceived a more comfortable running pattern.

1School of Allied Health Sciences, University of Nevada, Las Vegas, NV; and 2Doctor of Physical Therapy Program, Western Kentucky University, Bowling Green, KY

Address for correspondence: Janet S. Dufek, Ph.D., FACSM, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Box 453034, Las Vegas, NV; E-mail: janet.dufek@unlv.edu.

Submitted for publication September 2012.

Accepted for publication October 2012.

© 2013 American College of Sports Medicine