Man becomes machine

In the quest to reduce musculoskeletal disorders (MSDs), exoskeletons have become a technology that’s catching many an eye – and not only because they look rather space-aged… GAVIN MYERS finds out more.

“Work smarter, not harder”, goes the old adage. When it comes to manually intensive work – such as bending, lifting or carrying heavy objects – working hard is sometimes unavoidable.

Sure, many hands make light work (unless you’re Eskom – sorry, couldn’t resist) and we have developed equipment such as lifts, trollies and dollies to make moving heavy objects less strenuous… But, with one slip or a bad grip, injury can still occur.

Exoskeletons (usually powered) have been used for some time in military and medical applications. These include increasing stamina and the capacity to carry heavy objects, as well as to aid in rehabilitation of injury, or to improve quality of life for individuals who have lost limbs. In recent years, applications in the workplace have been found for them.

Some systems seem to have found particular favour: the Chairless Chair, the Laevo exoskeleton and the Exo-Jacket are just some of the many examples. It’s important to note upfront that there are two differing types of exoskeletal devices – active, which uses powered motors to actively assist the wearer’s movements; and passive, which simply supports the body.   

Passive support

Having gained popularity with over 100 countries around the world (Swiss company Noonee developed the concept in close cooperation with Audi over two years), the Chairless Chair can be attached around the individual’s ankles, thighs and waist, and allows the wearer to “actively sit”.

Interestingly, Noonee claims that the Chairless Chair is not an actively supporting exoskeleton, but an “ergoskeleton”. As soon as the wearer bends to a certain angle in a sitting position, the mechanism engages to support him or her. Noonee claims this is less tiring than standing up and removes 65 percent of the pressure from the knees and feet.

“The chair offers great relief wherever there are standing workstations that involve a regular change from standing to sitting,” comments Lars Schilling, CEO of Noonee, which describes itself as the world’s first supplier of “wearable ergonomic mechatronic devices”.

Weighing just 3,3 kg, the device is adaptable to an average range of adult body size and heights (it can support up to 130 kg and fit adults measuring between 1,6 and1,95 m), is compatible with safety shoes, and takes less than a minute to put on.

The height of the seating position can also be adjusted which means that posture is maintained. The Chairless Chair has been designed to not limit mobility.

Of course, a solution such as the Chairless Chair has limitations in its application – it cannot be used in scenarios such as kneeling or climbing stairs. This is where a device such as the Laevo exoskeleton comes in.

Developed in the Netherlands, this wearable chest and back support is designed to transfer force from the wearer’s back to their thighs when leaning forward. In doing so, it supports the wearer’s body weight, whether standing, kneeling or squatting, thus reducing the stress on their back by up to 40 percent.

The device is made to measure and the wearer simply dons it like a jacket. It underwent testing with
German company Hermes Einrichtungs Service. The devices were fitted with motion sensors for monitoring and analysis.

“The Laevo exoskeleton is a passive system that uses a spring mechanism to relieve strain on the back muscles. We noticed significant relief (among the wearers) with lifting,” explains Nadia Uliana, director of project “Exoskeleton” at Hermes Einrichtungs Service.

Active support   

A device like the Exo-Jacket comes into its own when heavy lifting or overhead work is required. The device’s electric motors support the wearer’s limbs and aid movement.

At Audi, again, the potential for these devices to aid ergonomic work has been explored.

Ralph Hensel, ergonomics expert in industrial engineering at Audi, says: “It is, for instance, no longer possible to rotate the car once it reaches the end of the assembly process, because it has already been filled with liquids. That is where an exoskeleton can, for example, assist in easing the burden on the person’s back while the work is being carried out.”

While the advantages are obvious, simply adding four motors (and their batteries) to the shoulders and elbows means the wearer has to carry about 10 kg of weight, according to Urs Schneider, who designed the Exo-Jacket.

This type of system seems more suited to lower-body application. Peter Heiligensetzer designed the German Bionic Cray X, which uses two motors at hip level to assist in lifting up to 15 kg tirelessly and without damaging the lower back.

“The wearer’s forward tilt is detected by sensors, which also measure muscle tension on the arm. When the person picks something up, the support system is activated and he is pulled up via backpack straps,” explains Heiligensetzer. This, he says, reduces muscle tension in the lower back by 40 percent.

Direct health benefits

A 40-percent reduction in tension is not to be scoffed at, especially when lost days due to complaints associated with MSDs amount to millions each year, worldwide.

In her dissertation: Repetitive strain injury among South African employees: Prevalence and the relationship with exhaustion and work engagement, Gillian Schultz notes that MSDs are “the most common occupational-related form of ill-health”.

Her study of more than 15 000 employees found that, of those who indicated that they experienced MSD symptoms sometimes and frequently, 47 percent indicated experiencing neck, shoulder and back pain and 24 percent experienced muscle stiffness.

Similarly, in his research titled: Assessment of musculoskeletal disorders and absenteeism at a foundry, SA Society of Occupational Health Nursing Practitioners (SASOHN) member Petro de Beer found that there was a correlation between musculoskeletal complaints and absenteeism, with 55,3 percent of participants reported to be absent from work due to MSD complaints.

Of the foundry workers surveyed, the most common body part affected by pain was the back (71,1 percent), followed by the shoulders (68,4 percent). The most common body part affected by stiffness was the fingers (13,2 percent), followed by the wrists and shoulders (10,5 percent).

“Participants standing for the entire shift were found to have the majority of complaints related to the back and shoulders,” he states. “All the participants took rest breaks; however, 78,9 percent suffered from muscle stress and 60,5 percent from muscle fatigue.”

While the picture in worksites around the world is similar, there can be no denying that support devices such as exoskeletons can go a long way to reducing the impact on workers’ bodies, and their productivity. After all, why work harder when you can work smarter?