Ling W, Houston VL, Tsai YS, Chui K, and Kirk J; Department of Physical Therapy, New York University, New York, NY. wkl1@nyu.edu.

PURPOSE: The purpose of this study is to examine women’s load carriage performance before and after a simulated march using Modular Lightweight Load Carrying Equipment (MOLLE). MOLLE is a new load carrying system developed by the U.S. Army Natick Soldier Center and adopted by the U.S. Army in 2001 and the Marine Corps in 1999. MOLLE consists of two main components: a weight-bearing vest and a modular backpack. The modular backpack has an external frame and a heavily padded hip belt allowing the soldier to shift the load from shoulders to hips to lessen shoulder discomfort and to facilitate more upright posture to prevent low back problems. MOLLE is designed to conform to the physical characteristics and capabilities of men. With wider pelvis, women may not be able to shift load from shoulders to hips and therefore may not demonstrate similar load carriage performance as men while carrying heavy loads using MOLLE. SUBJECTS: Seven physically active, healthy women participated in this study. Their mean age was 24.5 (+/- 3.4) years; mean height was 163.9 (+/-) 5.4 cm; mean weight was 55.7 (+/- 6.2) Kg respectively. METHODS: Each subject walks at 3 miles/hour for one hour on a treadmill with 0% inclination under five load-carrying conditions: without a load, 20 pounds, 30 pounds, 40 pounds, and 50 pounds. Before and after each treadmill walk, the subject’s over ground gait was analyzed by the GAITRite^tm electronic walkway and the Qualisys MacReflex Motion Analysis System. Spatial-temporal gait parameters (cadence, stride length, single limb support time, double limb support time, and base of support) and joint excursions of head, trunk, hip, knee, and ankle in the sagittal plane were calculated. ANALYSIS: Data was analyzed by SPSS for windows version 11.0. Repeated measures analyses of variance were conducted to examine subject’s spatial-temporal gait parameters and joint excursions at five load levels. RESULTS: With increased loads, women showed increased double-limb support time (p < 0.0001), decreased single-limb support time (p < 0.001), increased trunk forward inclination excursion (p < 0.0001), and decreased knee excursion (p < 0.005). CONCLUSIONS: Women can carry up to 50 pounds using MOLLE with similar load carriage performance as previous reported on male soldiers with MOLLE. FUNDING SOURCE: The U.S. Army provided two sets of MOLLE.

Copyright 2004 by the American Physical Therapy Association

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