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Physical profile of the workforce and the effect on work capacity MMPA Congress 2012 Tia-Mari Hofmann RFA JV Physical and Functional Fitness Prerequisites… ‘--- survey of a cross-section of OHC officers working in Queensland and New South Wales mines indicated that a lack of fitness, stamina and skill rank highest ---as contributors to injury’ ‘--- broader view of this concept (‘fit for work’) should consider the interaction between a worker’s capacities and the demands of the job, and how much they do, or do not, match. It should also take a long-term view of ----- health and fitness --over a career --- and cumulative effects of work demands’ ‘---- the expectation that all members of the general workforce could perform all mining work-tasks, and that they can do so with no risk or injury, may be increasingly unrealistic.’ ‘--- physical activity and fitness levels have arguably declined, and levels of overweight and obesity clearly increased ---’ (abstracts from a paper by Parker and Worringham) … to sustained health, safety and career opportunities What does the South African workforce look like? Contents • RFA Data • Demographics of RFA Centres • RFA utilisation • Physical profile of the workforce: - Work capacity - BMI - Age - Gender - Other factors impacting on work capacity • Nature of the work • Functional analyses of occupations • Functional work capacity as part of medical surveillance RFA Data • Rehabilitation and Functional Assessment (RFA) Test Battery developed over the past 11 years • Minimum standards for fitness to perform manual work in a safe manner • Test standards originally derived from: - Internationally accepted scientific principles - Field studies - Testing healthy, in-service employees (SA mining industry) • RFA Database comprises of 324 235 work assessments • 10 mining companies using the test battery RFA Centres RFA Assessment Objective assessment of work capacity Physical Work Capacity Test Functional Work Capacity Test Aim: To determine the inherent aerobic capacity to perform manual work Aim: To assess functional abilities necessary to perform a specific task Consists of: A 10 minute step test Consists of: 21 simulated work activities and environmental obstacles © Rehabilitation and Functional Assessment Joint Venture All rights reserved © Rehabilitation and Functional Assessment Joint Venture All rights reserved Discussion Work Capacity • UK National Fitness survey: 10% of males in the age group of 35-55 years have a degree of low work capacity although they are nutritionally reasonably fed and of average health (Durnin, 1992) • People are not equal: When the distribution of genetically endowed cardiac output or haemoglobin levels were examined some individuals were clearly at a disadvantage when compared to others (Durnin 1992, Bouchard and Shephard 1994) Cardio respiratory features of volunteer subjects Parameter2 Group - SA mining industry (n = 16) Trained males (not world class) Inactive males n = >200 Age: years 36.0 ± 9.4 25.8 ±10.7 43.3 ±13,0 Height: cm 171 ± 6.8 179.6 ± 6.2 174,9 ± 6.3 Mass: kg 68.3 ± 7.0 75.1 ± 8.8 76.8 ± 9.8 MAC: ml/min 2 404 ± 43 3 663 ± 571 2 718 ± 568 MAC: ml/kg/min 34.5 ± 6.5 48.9 ± 6.8 35.8 ± 8.3 Oxygen pulse1 12.4 ± 4.3 20.6 ± 3.1 16.6 ± 2.5 Source: Hollmann et al 1Index of cardiorespiratory efficiency: VO2 Max (maximal aerobic capacity, MAC in ml/min) expressed in terms of the concurrent heart rate maximum i.e. ml/beat 2All data expressed as means ± SD Findings • MAC (Maximal aerobic power or VO2 Max) expressed in terms of body mass (ml/kg/min) suggest that the local mining population can be linked to an sedentary (inactive) group of males generally 10 years older. • Oxygen pulse, a measure of cardio respiratory efficiency is also significantly lower than the untrained/inactive reference group. Physical profiles of the overall workforce Body Mass Index (BMI) Females (n = 24 734) Males (n = 251 917) 52% 33% 26% 29% 16% 18% 10% 10% 4% < 20 20 - 25 25.01 - 30 30.01 - 35 2% > 35 © Rehabilitation and Functional Assessment Joint Venture All rights reserved BMI and the effect on work capacity BMI (> 30) indicative of obesity Ozcelik et al (2004) were able to demonstrate a significant negative correlation between maximal work rate (expressed per kg body mass) and BMI. Mainly due to - excess in body fat - increase in type 2 muscle fibres and an decrease in type 1 muscle fibres (Kissebah and Krakower 1994) - progressive decrease in heart reserve - reduced cardiac performance during progressive work rate exercise (Salvadori et al.1999) BMI and the Effect on Work Capacity BMI (< 20) indicative of individuals being underweight (SIMRAC GAP 505) • Less lean body mass and muscle mass influence work output (studies done in Guatemala described by Torun et al. 1989). • In relation to work capacity the most important organ is skeletal muscle, although the heart and oxygen carrying capacity of the blood plays a significant part. It is more than just the muscle mass, but the muscle fibre and the strength of the muscle contraction (Durin 2004). • If the work task involved no external load e.g. walking, household chores (cooking, sweeping), a minimum BMI of 17 is acceptable. BMI and the effect on work capacity BMI (< 20) indicative of individuals being underweight (SIMRAC GAP 505) • A different set of criteria is required when work tasks are heavier in nature in e.g. cutting sugar cane, pushing a wheel barrow, shovelling etc. When work tasks entail handling an external load / the need to use the body mass to exert part of the force. • A low body mass makes work of this nature much more physically demanding. Age distribution of the overall workforce overall workforce of the Age distribution Males (n = 254 821) Females (n = 25 271) 93% 60% 27% 3% 4% 2% < 20 20 - 40 41 - 50 10% 0% 51 - 60 0% 0% > 60 © Rehabilitation and Functional Assessment Joint Venture All rights reserved Effect of age on work capacity • Age influences the efficiency and efficacy of muscle contraction • Proportion of muscle fibre types alters • Muscle mass diminishes and strength of the contraction is reduced (Durin, 1992, Sallis 1993, Yang et al. 1999) • Previous RFA studies showed a statistically insignificant effect of age on work capacity, with previous mining experience which may act as a counter to deteriorating of fitness levels generally found in a sedentary, aging population. Pathology Most prevalent diagnoses amongst the overall workforce Clients with pathology (n = 13 339) 24% 20% 12% 11% 6% Fractures/injuries/wounds TB HIV Respiratory diseases Low back pain 5% General symptoms and signs 4% 4% 4% Cardiovascular Contusions Hypertension 3% Malaise and fatigue © Rehabilitation and Functional Assessment Joint Venture All rights reserved (Group representation expressed as a percentage of the total number of clients with pathology, not of the gross overall number of clients) Gender Factors impacting on work capacity Females are physiologically disadvantaged • Lower haemoglobin concentration and arterial O2 content (Mitchell et al. 1992) • 15 to 30% less aerobic capacity than their male counterparts (Wasserman, 1999) • Physical strength: women are weaker than men, usually attaining between 60 and 90% of the men’s muscle strength and work output (Kroemer et al. 2001) Other factors such as… Anthropometrics Height has an impact on work capacity (Farazdaghi and Wohlfart 2001) …impact on work capacity Height and work capacity Anthropometric Data NIOSH Mining: Underground Workstation Design Principles 5% NIOSH Males RFA Data Males NIOSH Females RFA Data Females 1.64 m 1.65 m 1.51 m 1.49 m 50% 95% 1.75 m 1.72 m 1.62 m 1.62 m 1.86 m 1.86 m 1.73 m 1.73 m Women in Mining Ergonomic Design Principles NIOSH Males RFA Data Females 5% 50% 1.64 m 1.49 m 1.75 m 1.62 m 95% 1.86 m 1.73 m Anthropometrics Impact on Functional Work Capacity The nature of the work determines… The impact of low or high BMIs, age, anthropometrics and low work capacity are determined by the physical nature of the work. …the degree of risk Questionnaires Work visit Observation ABOVE shoulder Load handling Functional analyses Interview Work visit Measurements Weight: 60kg Physical demands Medical Surveillance Medical surveillance Physical Assessment Heat Tolerance screening Functional Work Capacity Assessment Ensuring a healthy, safe productive worker through all phases of employment Employment Pre-employment Preventative Baseline assessment Effective placement Preventative & reactive Periodical examinations Establish and monitor work capacity profiles Rehabilitation Disability management Lifestyle & wellness programs Exit / retirement Functional, healthy individual © AngloGold Ashanti Health All rights reserved Aerobic fitness: A health and safety requirement Removal of an aerobic fitness standard for fire fighter recruits was associated with higher levels of adverse health and occupational related outcomes during subsequent training. (Wynn P. and Hawdon P.: Cardiorespiratory fitness selection standard and occupational outcomes in trainee fire-fighters, Occupational Medicine Advance Access, 2011) ‘In order that people may be happy in their work, these three things are needed: They must be fit for it. They must not do too much of it. And they must have a sense of success in it.’ - John Ruskin -