Sae Yong Lee1, Jay Hertel. 1. University of Miami, Coral Gables, FL 33146, USA. s.lee7@miami.edu
Abstract
CONTEXT: Clinically, lowering of the medial longitudinal arch is believed to be closely related to rearfoot eversion. However, the relationship between arch height and rearfoot eversion during gait is unclear. OBJECTIVES: (1) To examine the influence of 2 reference positions (weight-bearing neutral position [WBNP] and subtalar neutral position [STNP]) on maximum rearfoot eversion, tibial internal rotation, knee flexion, knee internal rotation, and dorsiflexion-plantar flexion of ankle joint measures during jogging and (2) to compare the relationships among static arch height, navicular drop, and the 2 maximum rearfoot eversion measures. DESIGN: Crossover study. SETTING: Gait laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty-three volunteers between 18 and 40 years of age. INTERVENTION(S): Each participant stood on the treadmill in 2 static positions: WBNP and STNP. Kinematic data were obtained using a 10-camera motion analysis system (120 Hz) when participants jogged at 2.65 m/s on the treadmill in bare feet. MAIN OUTCOME MEASURE(S): Rearfoot and shank angular kinematics, navicular drop, and static arch height. RESULTS: Maximum rearfoot eversion was greater (WBNP: 4.03° ± 2.58°, STNP: 10.91° ± 5.34°) when STNP was the static reference (P < .001). A strong correlation was seen between maximum STNP eversion and navicular drop (r = 0.842) but not between WBNP and navicular drop (r = 0.216). Differences were noted in dorsiflexion and knee kinematics during gait between the static references; however, the effect sizes were low, and the mean differences were smaller than 2°, which was less than 5% of total excursion during gait. CONCLUSIONS: Using STNP rather than WBNP as the reference position affects estimates of frontal-plane rearfoot movement but not other ankle or knee motions in jogging.
CONTEXT: Clinically, lowering of the medial longitudinal arch is believed to be closely related to rearfoot eversion. However, the relationship between arch height and rearfoot eversion during gait is unclear. OBJECTIVES: (1) To examine the influence of 2 reference positions (weight-bearing neutral position [WBNP] and subtalar neutral position [STNP]) on maximum rearfoot eversion, tibial internal rotation, knee flexion, knee internal rotation, and dorsiflexion-plantar flexion of ankle joint measures during jogging and (2) to compare the relationships among static arch height, navicular drop, and the 2 maximum rearfoot eversion measures. DESIGN: Crossover study. SETTING: Gait laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty-three volunteers between 18 and 40 years of age. INTERVENTION(S): Each participant stood on the treadmill in 2 static positions: WBNP and STNP. Kinematic data were obtained using a 10-camera motion analysis system (120 Hz) when participants jogged at 2.65 m/s on the treadmill in bare feet. MAIN OUTCOME MEASURE(S): Rearfoot and shank angular kinematics, navicular drop, and static arch height. RESULTS: Maximum rearfoot eversion was greater (WBNP: 4.03° ± 2.58°, STNP: 10.91° ± 5.34°) when STNP was the static reference (P < .001). A strong correlation was seen between maximum STNP eversion and navicular drop (r = 0.842) but not between WBNP and navicular drop (r = 0.216). Differences were noted in dorsiflexion and knee kinematics during gait between the static references; however, the effect sizes were low, and the mean differences were smaller than 2°, which was less than 5% of total excursion during gait. CONCLUSIONS: Using STNP rather than WBNP as the reference position affects estimates of frontal-plane rearfoot movement but not other ankle or knee motions in jogging.
Authors: Sandra J Shultz; Anh-Dung Nguyen; Thomas C Windley; Anthony S Kulas; Timothy L Botic; Bruce D Beynnon Journal: Clin J Sport Med Date: 2006-03 Impact factor: 3.638