Relationship between Pelvic Motion, Torque, and Metabolic Energy in Running (P189)

Abstract

PURPOSE: To investigate the relationship between frontal plane pelvic angle, gluteus medius muscle (GM) torque, and changes in metabolic energy demands while running. METHODS: Five healthy, female Subjects (mean age 22.8 +/- 2.2) were obtained from a sample of convenience. Subjects were recreational runners who ran >= 5 miles per week (mean 28.0 miles +/- 15.2). Subjects were asked to run oil a treadmill for 30 minutes at a self-selected speed (6.52 mph +/- 0.2). Torque - GM isometric strength was determined prior to the run with the subject side lying using a hand-held dynamometer (Lafayette Instruments), and converted to torque. Kinematics - Three-dimensional data oil pelvic position was sampled at a rate of 60 Hz using an electromagnetic kinematic tracking system (Motion Monitor(TM), Innovative Sports Training) with sensors (Polhemus Fastrak) secured over the posterior Superior iliac spines. Metabolic Energy - Oxygen Consumption (VO2) was obtained through ventilatory expired gas analysis (SensorMedics, Inc., Yorba Linda, CA) during rest, exercise and five minutes into recovery. The change in VO2 between 25-30 minutes (average value) was determined (Delta VO2) as was the time constant of VO2 recovery kinetics. MatLab v 7.1 was used for kinematics analyses. A Pearson's Correlation was calculated using SPSS v 14.0; statistical significance was defined as p<0.05. RESULTS: The rate of change in maximum pelvic drop was significantly correlated with GM torque (R-2=0.942) and VO2 recovery kinetics (R-2=0.939). A positive trend between torque and recovery kinetics existed (R-2=0.785). However, Delta VO2 was not correlated with pelvic motion, torque, or kinetics. CONCLUSION: It appears that subjects with an increased GM torque Could tolerate a larger degree of pelvic drop. VO2 recovery kinetics were not influenced by Delta VO2, rather by biomechanical factors. These findings suggest that increased pelvic motion during running results in metabolic inefficiency, and could therefore adversely affect running performance.