Manual handling covers a wide range of activities including lifting, pushing, pulling, holding, restraining, throwing, and carrying. It includes repetitive tasks such as packing, typing, assembling, cleaning, and sorting, using hand-tools, operating machinery and equipment, and handling and restraining animals. Good posture and lifting techniques can help reduce the risks, but research indicates that making changes to workplace design is the most effective way to prevent manual handling injury.
It’s likely accurate to state that any worker engaged in tasks involving lifting or manual handling faces some degree of risk for musculoskeletal injury, with low back injuries being the most common. While completely eliminating this hazard may not be feasible, organizations can diminish both the frequency and severity of injuries related to manual handling by implementing safe work practices.
In order to prevent back injuries in the workplace, it is crucial to pinpoint the factors that increase workers’ vulnerability to injury or directly contribute to it. A successful strategy integrates understanding of ergonomics, the work environment, and human capabilities and constraints. The following facets should be considered for material handling:
Eliminate the need for heavy manual materials handling: If complete task elimination is not possible, the consideration of utilizing powered or mechanical handling systems is recommended. The risk of back injury is decreased by these mechanical aids, as they diminish the physical effort demanded of the worker to handle heavy objects.
The process of manual handling, including lifting and carrying, can be facilitated, and made safer through mechanization, which involves the use of lift tables, conveyors, or trucks. However, it is important that the worker receives proper education and training in the safe utilization of the available equipment.
Decrease the demands: The subsequent step involves a reduction in the demands of manual material handling. This can be achieved through several methods:
Careful workflow planning is essential. Often, inadequate planning leads to the repeated handling of the same object (e.g., when articles are temporarily stored in one place, moved to another, stored again, and then moved once more).
Objects should be replaced with weights within acceptable limits.
Weight can be reduced by assigning two individuals to lift the load or by dividing it into two or more containers. Additionally, the use of lighter containers may result in a lighter overall load compared to other types of containers.
Altering the required type of movement can be effective. Lowering objects generally imposes less strain than lifting them. Pulling objects is generally less strenuous than carrying them. Pushing is typically less demanding than pulling.
Modifying the layout of the work area can also be beneficial. Significant reductions in handling demands can be achieved by minimizing horizontal and vertical lifting distance. Likewise, decreasing travel distances for carrying, pushing, or pulling can lead to lower work demands.
Allotting more time for repetitive handling tasks is crucial. This reduces the frequency of handling and allows for additional work/rest periods.
Alternating heavy tasks with lighter ones can help prevent the accumulation of fatigue.
Reduce stressful body movements: It is important to design tasks in a way that allows the worker to perform them without excessive reaching, bending and twisting. These body movements pose a particular risk and can lead to back injuries, even when not coupled with handling heavy loads.
Some points to consider:
- Ensure that all materials are provided at a work level adjusted to the worker’s body size.
- Deep shelves should be eliminated to prevent the need for excessive bending.
- Adequate space should be provided to allow the entire body to turn.
- Objects should be located within easy reach.
- Ensure that there is clear and unobstructed access to load.
- Whenever possible, utilize handles or ensure a secure grip.
- Use slings and hooks for the movement of loads that lack handles.
- Balance the contents of containers.
- Employ rigid containers.
- Modify the shape of the load so that it can be handled in close proximity to the body.
Pace of work and rest breaks: The worker’s discomfort, and consequently the onset of musculoskeletal injuries, may be significantly influenced by the pace of work, especially when it is externally imposed. Generally, being pressured to work at a specific pace generates a mental need to work quickly. This perception, in turn, induces tension not only in the mind but also in the body. Muscles that are tense are much more susceptible to injury.
For instance, the frequency of a lift is correlated with the pace of work. Lifting equations, such as the Revised NIOSH lifting equation, incorporate this factor as one of the means to assess the impact of a lift. The assessments encompass not only the quantity of lifts performed but also the duration of rest intervals between lifts.
It would be desirable if workers could operate at their own pace and have the flexibility to take a break when they begin to feel fatigued. However, this option might not be feasible. Incorporating two additional 15-minute breaks, one in the mid- morning and another in the mid-afternoon, in addition to the 30-minute lunch break, appears reasonable. If adhering to this schedule is still impractical, shorter but more frequent breaks can serve a similar purpose.
It is also important to afford individuals new to a specific job or task adequate time for adjustment by allowing them more breaks.
Education and training: When combined with work design, education and training assume an important role in the prevention of injuries. Part of this education and training process also involves demonstrating to the worker how to actively contribute to injury prevention. A program should:
- Ensure that the worker is made aware of the hazards associated with manual material handling.
- Provide demonstrations of methods to reduce unnecessary stress.
- Train workers in appropriate material handling techniques.
- Instructions on how to lift “properly” can be a topic of contention. While there are numerous guidelines, there is no single correct way to execute a lift. Due to this fact, on-site, task-specific training is deemed essential. Some general lifting techniques includes:
- The lift should be planned- obstacles along the path to be traveled should be removed.
- Muscles should be warmed up in preparation for the lift.
- The worker should stand close to the load, facing the direction they intend to move.
- A wide stance should be used to establish balance.
- A secure grip on the load should be ensured.
- The natural curve in the back should be maintained (as it help distribute mechanical forces more evenly over the spine)
- Abdominal muscles should be tightened.
- The knees should be bent (to remove forces from the spine)
- The lift should be initiated with body weight.
- The load should be lifted close to the body.
- The lift should be executed smoothly without jerking.
- The load should be kept close to the body, whenever possible.
- Breathing should be maintained throughout the lift.
- Muscles should not be tensed.
- There should be no twisting or side bending while lifting.
- The lift should not be attempted if there is uncertainty about safely handling the load.
Additionally, workers should:
- Utilize rest periods to relax tired muscles, as this prevents the accumulation of fatigue.
- Report any discomfort experienced during work, as reporting helps identify hazards and rectify working conditions.
- Know how to recognize a manual material handling hazard and report concerns.
Finally, an aspect of training that cannot be overlooked for it to be part of an effective prevention program is that workers should be informed that muscles, tendons, and ligaments are not prepared to handle the physical stress of handing tasks when they are not “warmed up”. Pulls, tears or cramps are more likely to occur when stretched or contracted suddenly under such conditions. These injuries can lead to more serious and permanent damage if physically demanding work is continued. Therefore, warming up and being mentally prepared for physically demanding tasks are crucial for any type of material handling, especially for occasional tasks where the worker is not accustomed to handling loads.
