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Women carry for less: body size, pelvis width, loading position and energetics
1Department of Biology, Seattle Pacific University, Seattle, WA, USA and Department of Anthropology, University of Washington, Seattle, WA, USA.
Evolutionary Human Sciences
|August 17, 2023
Summary
Women carry babies more efficiently than men, with back-carrying being the most economical method. This study explores the energetic costs and speed changes associated with carrying babies in different positions.
Area of Science:
- Human locomotion
- Biomechanics
- Human energetics
Background:
- The metabolic cost of carrying loads is complex, varying with mass, speed, and load position.
- Cultural observations suggest women may be more effective carriers, prompting investigation into sex-based differences in carrying efficiency.
Purpose of the Study:
- To investigate the energetic cost and speed changes in men and women carrying their own babies.
- To compare the metabolic and kinematic effects of carrying babies in front, side, and back positions.
Main Methods:
- Nine women and six men walked carrying their babies (mean mass 10.6 kg) in an Ergo fabric baby sling.
- Carrying positions included front, side, and back.
- Metabolic cost and walking speed were measured.
Main Results:
- Carrying babies on the back allowed participants to maintain unloaded walking speed with the lowest increase in metabolic cost per distance (17.4%).
- Women exhibited lower energetic costs than men across all carrying conditions (p < 0.01).
- Wider bi-trochanteric breadth was associated with reduced carrying costs.
Conclusions:
- Back-carrying is the most energetically efficient method for carrying babies, aligning with cross-cultural practices.
- Women are more efficient carriers than men, potentially due to physiological or anatomical differences.
- Bi-trochanteric breadth is an important factor influencing the energetic cost of carrying loads.
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