Impact of habitual cranial loading on the vertebral column of adolescent African females aged 12-15 years in the Deepdale region of Kwa-Zulu Natal

Abstract

This pilot study investigated the incidence and aetiology of cranial loading musculoskeletal pain amongst adolescent females aged 12-15 years in the Deepdale region of Kwa-Zulu Natal. A descriptive survey was conducted amongst 20 adolescent females, who by voluntary consent participated in a controlled, analytical, observational, pre-test post-test, randomized cross-over retrospective study. Subjects’ biographical, epidemiological, exercise history and lifestyle information were gathered by employing the use of a validated questionnaire (van Heerden, 1996). In addition to completing the questionnaire subjects underwent a postural analysis in an
unloaded and loaded state. During the unloaded and loaded phases EMG measures were recorded of the sternocleidomastoid and trapezius muscles. The unloaded phase was when subjects stood without the 20 kg pot placed onto their cranium, whilst the loaded phase was when subjects stood with the 20 kg pot placed onto their cranium against a portable postural chart. Digital images were captured of all subjects in the unloaded and loaded phases in the sagittal and frontal views. Data were analysed using the Excel Spreadsheets for Windows, chi-square tests and dependant t-tests with the probability set at 0.05. The evidence indicated that the incidence of cranial loaded musculoskeletal pain and discomfort amongst subjects was 95% (p<0.01). The most prevalent cranial loaded musculoskeletal pain sustained by subjects were along the vertebrae (73.68%) followed by shoulder (21.06%) and arms (5.26%) (p< 0.05). Significant EMG measures (p<0.01) were recorded of the sternocleidomastoid (12.42mV vs. 44.41mV) and trapezius (7.69mV vs. 78.64mV) muscles in the unloaded versus loaded phases. The cervical
vertebrae compression was derived anthropometrically by the reduced distance from the vertex to the acromion in the unloaded phase (31.0 cm) versus loaded (23.0 cm) phase. The aetiology of the musculoskeletal pain was attributed to the downward compressive force exerted by the
cranial load, which impinged soft tissue in the cervical region. In addition, the trapezius muscles eccentrically contracted in an attempt to balance the load, which further increased the pain and discomfort. The data indicate that vertebral musculoskeletal pain is most prevalent amongst
adolescent females carrying loads in the Deepdale region of Kwa-Zulu Natal.

Key words: Musculoskeletal pain, vertebrae, adolescent children.