James A. Hodgdon, Ph.D., Naval Health Research Center, San Diego, CA 92152

The presentation provides an overview of relationships between body composition elements and performance of physical tasks, and explores gender differences in these relationships. A review of body composition analysis was provided. A two-compartment model in which the body is divided into fat and fat-free masses was used as the basis for discussion in this paper. Relationships between body compartment masses and lifting and carrying tasks were explored. Lifting and carrying are the most common physically demanding tasks in the military. They differ from one another in that the body mass is moved in carrying tasks, whereas the body mass is not part of a lifting task. Women have a lower muscle mass, on average, than men, and the distribution of this mass differs between genders. It was hypothesized that (1) the magnitude of the fat mass would be negatively associated with work capacity for tasks that involve movement of the body; (2) women, having less fat-free mass than men, have a smaller work capacity, on average; and (3) differences in the distribution of muscle mass between genders will lead to a difference in the physical performance-fat free mass relationship between genders. Analysis of data collected from 62 male and 38 female Navy personnel revealed fat-free mass, but not fat mass, was related to maximal box lifting capacity (r² = 0.71) and strength measures (typical r² = 0.66); and fat-free mass was positively associated and fat mass negatively associated with box carrying capacity (R² = 0.40) and running performance (R² = 0.55). Men performed better, on average (p < 0.05), than women on all tasks. When body composition variables were used to predict performance, gender did not account for any additional variance. Furthermore, there was no gender interaction with body composition in the prediction of physical performance. There appear to be no gender differences in the relationships between body composition variables and physical task performance. Differences in physical performance between genders are related to differences in body composition.

LTC Karl E. Friedl, USA, Ph.D., Army Operational Medicine Research Program, U.S. Army Medical Research and Materiel Command, Ft. Detrick, Frederick, MD 21702-5012

Weight standards have been used in the U.S. military for over a century and have been applied to selection of female servicemembers since they were first applied as upper weight limits in World War II. Today, all of the services have body fat limits for men and women, and retention in the military depends on meeting these standards. The stated goals of the regulations vary across services, but all include some mix of physical fitness/job performance, long-term health, and military appearance.

A DoD directive specifies that all services will use circumference-based equations to assess body fat in overweight servicemembers to enforce weight control regulations. The intent of this directive is to distinguish between those individuals who are overweight because of excess

Front Matter (R1-R16)

Executive Summary (1-24)

1 Introduction (25-32)

2 Body Composition (33-60)

3 Physical Fitness Policies and Programs (61-86)

4 Weight Management (87-108)

5 Nutritional Concerns of Military Women (109-126)

6 Pregnancy and Lactation and Postpartum Return-To-Duty Fitness (127-156)

7 Conclusions and Recommendations (157-170)

Appendixes (171-172)

A Workshop Summary, Agenda, Participants, and Abstracts (173-252)

B Practices and Policies Tables (253-262)

C Military Occupational Specialty Classification Tables (263-280)

D Search Strategy for Literature Review (281-284)

E Civilian Inquiry Letter and Table of Responses (285-290)

F Abbreviations (291-294)

G Bibliography (295-334)

H Biographical Sketches (335-338)

Index (339-352)