A method for developing organisation-wide manual handling based physical employment standards in a military context.

The benefit of job-related employment standards in physically demanding occupations are well known. A number of methodological frameworks have been established to guide the development of physical employment standards for single job functions. In the case of an organisation comprised of multiple and diverse employment specialisations, such as the Australian Army, it is impractical to develop unique employment standards for each occupation. OBJECTIVES: To present an approach to organisational level physical employment standards development that seeks to retain occupationally specific task characteristics by applying a movement cluster approach. DESIGN: Structured methodological overview. METHODS: An outline of the research process used in performing job tasks analysis are presented, including the identification, quantification and characterisation, and verification of physically demanding manual handling tasks. The methodology used to filter task information collected from this job analyses to group manual handling tasks with similar characteristics (termed clusters), across a range of employment specialisations is given. Finally, we provide examples of test development based on these key manual handling clusters to develop a limited suite of tests with high content, criterion and face validity that may be implementable across a large organisation. RESULTS: Job task analysis was performed on 57 employment specialisations, identifying 458 tasks that were grouped into 10 movement based clusters. The rationalisation of criterion tasks through clustering informed the development of a limited suite of tests with high content, criterion and face validity that may be implementable across a large organisation. CONCLUSION: This approach could be applied when developing physical employment standards across other multi-occupation organisations.

Prolonged running increases knee moments in sidestepping and cutting manoeuvres in sport.

OBJECTIVES: To investigate how knee kinematics, kinetics and loading changes during sidestepping tasks following a prolonged running protocol performed in a laboratory setting. DESIGN: All participants performed sidestepping, and crossover cutting tasks in a randomised order before and after a 60min running protocol on a non-motorised treadmill that simulated an AF game. METHODS: Eight healthy male participants who partook in semi-professional and amateur Australian Football undertook a series of straight line runs, sidestepping (SS), and crossover cutting (XO) tasks before and after a simulated game of Australian football. Kinematic data were analysed at initial foot contact of the SS and XO manoeuvres and kinetic data were analysed during the weight acceptance phase of the stance. RESULTS: The knee was significantly more flexed at foot contact following fatigue compared to pre-fatigue states. Fatigue was also a factor contributing to significant increases in internal knee extension moments. Significant differences were also observed between SS and XO trials with flexion/extension moments, with notable differences in varus/valgus and internal/external rotation moments. CONCLUSIONS: Acute angles of knee flexion at foot strike in a fatigued state may place the joint at an increased risk of injury. Increases in knee extension moments in the fatigued state suggests the knee joint must withstand significantly high stresses once fatigued.

Predicting Endurance Time in a Repetitive Lift and Carry Task Using Linear Mixed Models.

OBJECTIVES: Repetitive manual handling tasks account for a substantial portion of work-related injuries. However, few studies report endurance time in repetitive manual handling tasks. Consequently, there is little guidance to inform expected work time for repetitive manual handling tasks. We aimed to investigate endurance time and oxygen consumption of a repetitive lift and carry task using linear mixed models. METHODS: Fourteen male soldiers (age 22.4 ± 4.5 yrs, height 1.78 ± 0.04 m, body mass 76.3 ± 10.1 kg) conducted four assessment sessions that consisted of one maximal box lifting session and three lift and carry sessions. The relationships between carry mass (range 17.5-37.5 kg) and the duration of carry, and carry mass and oxygen consumption, were assessed using linear mixed models with random effects to account for between-subject variation. RESULTS: Results demonstrated that endurance time was inversely associated with carry mass (R2 = 0.24), with significant individual-level variation (R2 = 0.85). Normalising carry mass to performance in a maximal box lifting test improved the prediction of endurance time (R2 = 0.40). Oxygen consumption presented relative to total mass (body mass, external load and carried mass) was not significantly related to lift and carry mass (ß1 = 0.16, SE = 0.10, 95%CI: -0.04, 0.36, p = 0.12), indicating that there was no change in oxygen consumption relative to total mass with increasing lift and carry mass. CONCLUSION: Practically, these data can be used to guide work-rest schedules and provide insight into methods assessing the physical capacity of workers conducting repetitive manual handling tasks.

A Box Lift and Place Assessment is Related to Performance of Several Military Manual Handling Tasks.

Soldiers undergo regular physical testing to assess their functional capacity. However, current physical tests, such as push-ups, sit-ups, and pull-ups, do not necessarily assess job-specific physical capability. This article assesses the utility of generic predictive tests and a task-related predictive test in predicting performance against four job-critical military manual handling tasks. The box lift and place test was found to be the superior predictor in performance of four job tasks; a pack lift and place (R(2) = 0.76), artillery gunner loading simulation (R(2) = 0.36), bombing up an M1 tank simulation, (R(2) = 0.47) and a bridge building simulation (R(2) = 0.63). Pull-ups and push-ups were poor predictors of performance in the majority of job tasks. Although the box lift and place had a larger correlation with the artillery gunner loading task than the generic assessment, it only accounted for 36% of the variance, indicating that a task simulation may be more appropriate to assess soldiers' capacity to perform this job task. These results support the use of a box lift and place rather than generic fitness tests for the evaluation of military manual handling tasks.

Maximal and sub-maximal functional lifting performance at different platform heights.

Introducing valid physical employment tests requires identifying and developing a small number of practical tests that provide broad coverage of physical performance across the full range of job tasks. This study investigated discrete lifting performance across various platform heights reflective of common military lifting tasks. Sixteen Australian Army personnel performed a discrete lifting assessment to maximal lifting capacity (MLC) and maximal acceptable weight of lift (MAWL) at four platform heights between 1.30 and 1.70 m. There were strong correlations between platform height and normalised lifting performance for MLC (R(2) = 0.76 ± 0.18, p < 0.05) and MAWL (R(2) = 0.73 ± 0.21, p < 0.05). The developed relationship allowed prediction of lifting capacity at one platform height based on lifting capacity at any of the three other heights, with a standard error of < 4.5 kg and < 2.0 kg for MLC and MAWL, respectively.

On the relationship between discrete and repetitive lifting performance in military tasks.

Military manual handling requirements range from discrete lifts to continuous and repetitive lifting tasks. For the military to introduce a discrete lifting assessment, the assessment must be predictive of the various submaximum lifting tasks personnel are required to perform. This study investigated the relationship between discrete and repetitive military lifting to assess the validity of implementing a discrete lifting test. Twenty-one soldiers from the Australian Army completed a whole-body box-lifting assessment as a one repetition maximum (1RM) and a series of submaximal lifting repetitions (% 1RM). Performance was measured between the number of lifting repetitions that could be performed at different intensities between 58 and 95% 1RM. A strong curvilinear relationship existed across the entire submaximal lifting range (r = 0.72, p ≤ 0.05). The model developed demonstrated a low predictive error (standard error of the estimate = 7.2% 1RM) with no differences detected in the relationship when comparing individuals of high and low strength. Findings support the use of a discrete functional lifting assessment in providing coverage of a broad range of military lifting tasks. Parallels can be drawn between the trend reported in the current study and weight-training exercises reported in the literature.

The relationship between maximal lifting capacity and maximum acceptable lift in strength-based soldiering tasks.

Psychophysical assessments, such as the maximum acceptable lift, have been used to establish worker capability and set safe load limits for manual handling tasks in occupational settings. However, in military settings, in which task demand is set and capable workers must be selected, subjective measurements are inadequate, and maximal capacity testing must be used to assess lifting capability. The aim of this study was to establish and compare the relationship between maximal lifting capacity and a self-determined tolerable lifting limit, maximum acceptable lift, across a range of military-relevant lifting tasks. Seventy male soldiers (age 23.7 ± 6.1 years) from the Australian Army performed 7 strength-based lifting tasks to determine their maximum lifting capacity and maximum acceptable lift. Comparisons were performed to identify maximum acceptable lift relative to maximum lifting capacity for each individual task. Linear regression was used to identify the relationship across all tasks when the data were pooled. Strong correlations existed between all 7 lifting tasks (rrange = 0.87-0.96, p < 0.05). No differences were found in maximum acceptable lift relative to maximum lifting capacity across all tasks (p = 0.46). When data were pooled, maximum acceptable lift was equal to 84 ± 8% of the maximum lifting capacity. This study is the first to illustrate the strong and consistent relationship between maximum lifting capacity and maximum acceptable lift for multiple single lifting tasks. The relationship developed between these indices may be used to help assess self-selected manual handling capability through occupationally relevant maximal performance tests.