The effects of front infant wearing on posture, muscle activity and proprioception of rural South African caregivers

Abstract

Infant wearing is common practice during a child’s early stages of growth. The impact of front infant wearing on the posture of  caregivers is inconclusive, requiring further investigation. The aim of the study was to determine the changes in height, postural angles,  electromyographical (EMG) cervical and lumbar flexor, and extensor activities and proprioception of rural South African caregivers  associated with habitual front infant wearing. One hundred female caregivers residing in the ILembe District of KwaZulu-Natal, South  Africa willingly participated in a pretest/post-test crossover randomised investigation. The experimental group (n=50) stood in a front infant wearing loaded state, while the control group (n=50) was measured in an unloaded state (while not carrying the infant). The  experimental group crossed over into the control group, and vice versa. Caregivers’ stature, hip heights, craniovertebral angle (CVA),  craniohorizontal angle (CHA), standing pelvic angle (SPA), tibiofemoral joint angle (TFA), and cervical and lumbar flexor-extensor EMG  activities were measured. Front infant wearing diminished stature (157.2±6.0 vs 155.7±6.4cm) and hip heights (97.3±5.2 vs 95.2±5.4cm) of  caregivers when compared to their unloaded state (p=0.0000001). Craniovertebral angles (45.52±7.35 vs 55.94±9.16°), SPA (20.15±4.46 vs  23.79±5.42°) and TFJA (-9.44±4.6 vs -12.68±5.32°) were increased during front infant wearing (p<0.01). Conversely CHA (18.62±6.78 vs  15.20±6.63°) and cobb angles (24.15±4.24 vs 22.75±4.46°) decreased during front infant wearing (p<0.01). The EMG activity of the cervical  extensors (26.58±19.91 vs 41.29±23.89 mV) and lumbar flexors (23.96±18.13 vs 34.82±21.21mV) changed during front infant wearing as  compared to the unloaded state (p<0.05). Front infant wearing decreased the caregivers’ medial-lateral stability index (MLI) (3.75±3.07 vs  4.55±3.82) (p<0.01) and changed their posture by reducing their standing vertex and hips heights, increasing the CVA, SPA, and TFA, and  diminishing their MLI.