Systems of work shape the physical and mental demands of manual tasks, because fatigue and strain raise muscle tension and affect muscles, nerves and blood vessels. Sources include time constraints, pace and flow of work across the shift, ability of workers to influence workload and methods and changes, level of resources and guidance, consultation processes, work roles and performance requirements or processes for conflict, staffing levels, skill mix and shifts, and inadequate training. Individual factors can increase risk: inadequate skills and experience, a mismatch between the worker's physical characteristics and the task, unaccustomed work for new workers, transferees and people returning from long leave, and cumulative effects from earlier tissue damage.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.