RESUMEN
The impact of manual material handling such as lifting, lowering, pushing, pulling and awkward postures have been studied, and models using these external demands to assess risk of injury have been developed and employed by safety and health professionals. However, ergonomic models incorporating personal characteristics into a comprehensive model are lacking. This study explores the utility of adding personal characteristics such as the estimated L5/S1 Intervertebral Disc (IVD) cross-sectional area, age, gender and Body Mass Index to the Revised NIOSH Lifting Equation (RNLE) with the goal to improve risk assessment. A dataset with known RNLE Cumulative Lifting Indices (CLIs) and related health outcomes was used to evaluate the impact of personal characteristics on RNLE performance. The dataset included 29 cases and 101 controls selected from a cohort of 1022 subjects performing 667 jobs. RNLE risk assessment was improved by incorporation of personal characteristics. Adding gender and intervertebral disc size multipliers to the RNLE raised the odds ratio for a CLI of 3.0 from 6.71 (CI: 2.2-20.9) to 24.75 (CI: 2.8-215.4). Similarly, performance was either unchanged or improved when some existing multipliers were removed. The most promising RNLE change involved incorporation of a multiplier based on the estimated IVD cross-sectional area (CSA). Results are promising, but confidence intervals are broad and additional, prospective research is warranted to validate findings.
Asunto(s)
Ergonomía/métodos , Elevación/efectos adversos , Enfermedades Musculoesqueléticas/etiología , Enfermedades Profesionales/etiología , Medición de Riesgo/métodos , Adulto , Factores de Edad , Índice de Masa Corporal , Ergonomía/legislación & jurisprudencia , Femenino , Humanos , Disco Intervertebral , Masculino , Persona de Mediana Edad , National Institute for Occupational Safety and Health, U.S. , Oportunidad Relativa , Factores de Riesgo , Factores Sexuales , Estados UnidosRESUMEN
A systematic review of the literature regarding one-handed load carrying was conducted to identify research gaps for future load carrying studies. Twenty-six articles that may be relevant to elderly and obese people were included. Only two studies evaluated the effect of age as an independent variable during one-handed carrying. Obesity was not included as an independent variable in any of the articles. In general, the results suggested that one-handed carrying is more physically demanding than other methods of load carrying. In many cases, physiological responses to carrying a load in one hand were similar to carrying twice the load equally distributed between two hands. Some studies recommended a one-handed carrying weight limit of approximately 9-10 kg for men and 6-7 kg for women. However, more research on the effects of age and obesity during one-handed carrying is needed to determine if these results hold for elderly and obese people. Practitioner Summary: A systematic review of the scientific literature since 1966 regarding one-handed carrying that may pertain to elderly and/or obese people was performed. Few studies were identified that included aging and none included obesity as independent variables. Areas for future research are identified and discussed.