Musculoskeletal risk reduction - cable-pulling and shovelling

Many tasks in construction involve risk factors for musculoskeletal injury.

For example, working in awkward postures, being exposed to vibration, performing repetitive physical actions or needing to use excessive force.

Musculoskeletal injuries are often associated with poorly designed work or equipment.

Researchers from RMIT used wearable sensors on workers to understand the risk factors for work-related musculoskeletal injury in manual construction tasks.

Let’s look at cable-pulling.

Cable-pulling involves feeding and pulling cables through an underground conduit system to the required length and location.

Pulling cables can involve repetitive bending to grasp the cable at ground level and pull it upwards.

High force is involved in pulling the cable through the conduits. This force increases with the length and diameter of the cable.

Cable-pullers adopt hazardous postures in order to maximise their capacity to pull long cables.

The combination of awkward postures, high force exertion, and a repetitive bending and pulling action increases the risk of injury to the back.

Wherever possible, mechanised methods of cable pulling should be used.

A truck mounted winch can be used to reduce manual pulling. Also, the cable drum placed on a spindle or frame can be used to ease the run out. However, access, egress and work location can make using large equipment difficult and restrictive.

In these situations, smaller, mechanised cable pulling devices should be used.

However, if this is not possible, simple, cost-effective ways to modify tasks or equipment can also reduce musculoskeletal injury risk.

A simple trestle was manufactured to guide the cable at hip height.

At this height the cable was more accessible and the cable puller did not need to bend and reach down repeatedly to grasp and pull the cable.

The trestle not only improved back postures and movements, but enabled the worker to complete their task in a much safer, upright posture.

This demonstrates the potential for relatively simple modifications of tasks and equipment to reduce hazardous work postures.

However, where high forces need to be exerted to pull cables through, the preference is for this to be done mechanically, not manually.

Now let’s have a look at shovelling.

Shovelling is widely used in construction to move material manually.

Risk factors inherent in shovelling include:

• Repeated bending of the back, often for long periods of time.

• Repeated lifting and moving of heavy loads.

• Additional force exertion to work on hard ground services.

• Stretching to reach the material being shovelled, and

• Sustained gripping of the shovel handle for long periods of time.

This poses the risk of injury to the back and wrist.

A redesigned shovel handle was developed to enable the worker to maintain a straight position of the wrist.

The redesigned handle produced significantly less bending of the back and reduced shoulder movement, particularly when tossing the load to one side.

The left wrist also remained straighter in all directions.

Understanding the risk factors for musculoskeletal injury in manual construction tasks can help to identify improvements.

In many instances, inexpensive and simple modifications to work processes or equipment can significantly reduce the risk of injury.

The challenge for the construction industry is to understand musculoskeletal injury risk factors inherent in everyday construction tasks and to identify opportunities for improvements.

This study showed how creative and simple changes to work processes or equipment can significantly reduce musculoskeletal injury risk.