Protect Workers, Reduce Costs, Maintain Performance

Words: Telonio A, Corbeil L, Budico V, Blanchette M, Caron C-E
Photos: FRACO

Work-related low back disorders remain a significant issue in physically demanding construction trades, including masonry. In the United States, musculoskeletal disorders (MSDs) account for approximately 30% to 33% of all nonfatal occupational injuries and illnesses that result in days away from work (BLS, 2022–2023). In these cases, the back is consistently one of the most commonly affected body areas.

Masonry work involves frequent lifting of heavy materials, repeated bending, and sustained working postures, all of which place considerable strain on the lower back and surrounding muscles. Recent construction industry data show that more than 33,000 construction workers experienced days away from work due to MSDs in 2021–2022 (CPWR, 2025). Within construction, specialty trades, which include masonry, continue to report some of the highest rates of MSDs.

Furthermore, the impact of work-related musculoskeletal disorders extends beyond the job site and represents a substantial burden for employers across the construction sector:

Work-related MSDs cost U.S. employers billions of dollars each year in direct workers’ compensation expenses, with additional indirect costs related to productivity losses, staffing disruptions, and project delays (OSHA, 2023).
Even when focusing only on construction, work-related musculoskeletal disorders are estimated to result in more than 430,000 days away from work annually in the United States, based on reported MSD cases and the median duration of absence per case (CPWR, 2025; BLS, 2022).

Among emerging prevention approaches, occupational exoskeletons, wearable assistive devices used during work, are drawing increasing interest in physically demanding trades such as masonry.

These devices are designed to reduce physical strain on the musculoskeletal system, particularly during lifting, carrying, and sustained forward-bent postures commonly encountered on masonry job sites (Lowe, Billotte & Peterson, 2019).

Recent research has shown that occupational exoskeletons can contribute to:

Lower muscular effort during demanding tasks (Zelik et al., 2022)
Reduced work-related fatigue (Lamers et al., 2020)
Lower energy expenditure during manual material handling (Alemi et al., 2020)

When integrated appropriately, these technologies may complement existing ergonomic and prevention strategies already in place on construction sites. Research also highlights that worker familiarization and gradual integration play a key role in achieving consistent benefits from occupational exoskeletons. Adequate training, careful task selection, and time for adaptation are essential to ensuring both effectiveness and acceptance on active job sites (Diamond-Ouellette et al., 2024; Kuber & Rashedi, 2024).

Manual Handling And Low-Back Health: What The Data Really Shows
In masonry, construction, and industrial settings, lifting is constant. Blocks, mortar bags, stone, tools, and materials, workers bend, lift, carry, and reposition loads dozens or even hundreds of times per day.

Each movement may feel routine. But over time, the cumulative load placed on the lower back becomes one of the main contributors to musculoskeletal disorders.

To better understand how a lumbar-support exoskeleton influences that load, a laboratory study was conducted using tasks designed to reflect real-world manual handling, including movements similar to picking up masonry units from a pallet and placing them at working height. The objective was simple: measure what actually happens at the muscular level.

Recreating Real Work Conditions
A warehouse-style setup was built in the lab. Participants performed two common handling tasks:

Lift a box from the ground, carry it, place it at waist height, then return it to the floor.
Repeat the same sequence, but place the load at shoulder height.

The loads reflected realistic occupational exposure: 10 kilograms for the female participant and 20 kilograms for the two male participants.

Each participant used their own exoskeleton, adjusted according to personal preference, just as they would on the job. No lifting technique was imposed. This preserved natural movement variability, similar to what we see on masonry sites where positioning, handedness, and task flow constantly change. Each task was performed with and without the exoskeleton.

Measuring Muscle Effort
To quantify lumbar demand, surface electromyography (EMG) sensors were placed on the erector spinae, the primary muscles responsible for stabilizing and extending the spine.

EMG allows researchers to measure how hard muscles are working. The results were expressed as a percentage of each participant’s maximum voluntary contraction, making comparisons reliable across individuals.

The analysis focused on the two most demanding phases:

Lifting from the ground
Lowering the load back to the ground

These phases represent the highest spinal demand in most manual handling tasks, including masonry work involving repetitive ground-level material handling.

The Critical Phase: Ground-Level Lifting
Without the exoskeleton, lifting from the floor generated high lumbar effort. All participants exceeded 40% of their maximum muscular capacity. Two exceeded 80%, levels that indicate substantial strain,
particularly when repeated throughout a shift.

With the exoskeleton, muscle activation decreased significantly for all participants. In some cases,
reductions reached up to 70%.

In practical terms, the lower back muscles were working considerably less during lifting. The device does not eliminate effort, but it meaningfully reduces how much of that effort is carried by the lumbar muscles.

Lowering The Load: Still Demanding
Lowering the load required less effort than lifting, but it remained significant. Without assistance, muscle activation ranged between 30% and 60% of maximum capacity. With the exoskeleton, reductions of up to 50% were observed.

In masonry environments where workers repeatedly bend to retrieve materials from pallets or the ground, even moderate reductions per lift can translate into meaningful cumulative relief over the course of a day.

Adaptation Matters
Participants had been using the exoskeleton for approximately three months before testing. This is important. Like any equipment, effectiveness improves with familiarity.

Some right-left asymmetry was observed, reflecting natural, real-world movement patterns. Despite this variability, the reduction in muscle activation remained consistent across all participants.

What This Means For Physically Demanding Trades
A 50% to 70% reduction in lumbar muscle activation is not just a laboratory statistic. It represents a measurable decrease in muscular demand during the most demanding moments of manual handling.

For masonry and other repetitive trades, this may translate into:

Reduced fatigue over a shift
Lower cumulative spinal loading
Improved endurance
Potential reduction in MSD risk over time

While larger longitudinal studies are needed to measure long-term outcomes, the biomechanical data is clear: when muscular effort is objectively measured, lumbar-support exoskeletons significantly reduce the strain associated with ground-level lifting and lowering.

In high-repetition environments like masonry, that reduction matters.

Protect Workers, Reduce Costs, Maintain Performance

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