Affiliations: Department of Mechanical and Materials Engineering,
Queen's University, Kingston, ON, Canada | Institut National de la Jeunesse, de
l'Éducation Physique et du Sport, Université D'Abomey-Calavi,
Porto-Novo, Bénin
Note: [] Corresponding author: Geneviève A. Dumas, Department of
Mechanical and Materials Engineering, 130 Stuart Street, Queen's University,
Kingston, ON, K7L 3N6 Canada. Tel.: +1 613 533 2648; Fax: +1 613 533 6489;
E-mail: dumas@me.queensu.ca
Abstract: BACKGROUND: In Western Africa, women continue performing heavy
physical work that includes carrying loads on their heads during pregnancy.
Women may adapt to pregnancy related body changes by modifying their postures
to perform such tasks. OBJECTIVE: The objectives of this biomechanical task analysis study
were to 1) determine sagittal plane postures of the trunk and upper extremities
at specific events during the task of lifting and lowering a load to be carried
on the head, 2) compare postures of pregnant and non-pregnant participants, 3)
evaluate risk for musculo-skeletal disorders (MSD) with the rapid entire body
assessment (REBA) criteria. PARTICIPANTS: Twenty-six pregnant (26 ± 5 years, 159 ±
9 cm, 63 ± 15 kg, 25 ± 9 weeks of pregnancy) and 25 paired
non-pregnant retail merchants were recruited in Porto-Novo (Benin). METHODS: Participants were recorded on video in a laboratory setting
while they lifted a tray (20% body weight) from a stool to their head and then
put it back down. Trunk inclination and knee, shoulder and elbow flexion angles
were determined using Dartfish® software. RESULTS: The trunk was bent by more than 80° at pick-up and
set-down and knees were moderately flexed, significantly less (< 11°)
for pregnant women, possibly because it was harder to lift the trunk, or for
stability. For all postures analysed, the majority of trials were classified as
"high" risk or "very high risk" for MSD. CONCLUSIONS: Future research should investigate prevalence of MSDs
in this population to confirm the results of this study.
Keywords: Musculoskeletal disorders, pregnancy, Africa
