Health and Wellness, Injuries and Illness

Ergonomics: Preventing Musculoskeletal Disorders

Musculoskeletal disorders (MSD) may be costing you in employee days away from work. MSD hazards and ergonomic practices also still command the attention of safety and health inspectors, so you need to understand your facility’s MSD hazards and appropriate ergonomic interventions.

Despite the 2001 revocation of the Occupational Safety and Health Administration’s (OSHA) ergonomics standard, the agency continues to have an interest in MSDs.

OSHA’s Region 3 recently announced a regional emphasis program (REP) of outreach, inspection, and enforcement for warehouse operations that includes a focus on ergonomics and MSD hazards, as well as forklift safety and heat hazards. The warehousing industry has rapidly expanded with the surge in e-commerce and has seen a rise in MSDs and other injuries and illnesses.

MSDs, sometimes called “ergonomic injuries,” include back strains and sprains, carpal tunnel syndrome, rotator cuff tears, and tendonitis, usually resulting from awkward or static postures, forceful exertions, or repetitive movements.

MSD risks are well known in distribution, warehousing, and the wholesale trade, as well as health care, including nursing homes; materials handling in shipyards; meatpacking and poultry processing; and public safety occupations like corrections, firefighting, and law enforcement.

The National Safety Council (NSC) has called MSDs the most common workplace injury and characterizes them as a significant challenge for employers, stating that 30 percent of unwanted days away from work are due to MSDs, resulting in annual costs of approximately $20 billion for U.S. employers. 

With no federal ergonomics standard, OSHA cites employers for violations of the General Duty Clause (§5(a)(1)) of the Occupational Safety and Health Act when the agency identifies MSD hazard exposures.

In the inspection procedures for the warehouse REP, Region 3 referred its compliance safety and health officers (CSHOs) to the agency’s Guidelines for Retail Grocery Stores: Ergonomics for Prevention of Musculoskeletal Disorders (OSHA 3192-05N 2004).

The Region 3 REP targets the warehousing, storage, and distribution operations of food and beverage manufacturers and supermarkets and grocery stores, as well as

general and refrigerated warehousing and storage and beer and ale, general line grocery, groceries and related products, and meat and meat product wholesalers.

The agency has voluntary ergonomic guidelines for a number of workplaces, including beverage distribution, foundries, meatpacking and poultry processing, nursing homes, and shipyards. OSHA’s approach to ergonomics in its industry guidelines involves providing strong management support, with clear goals and objectives; involving employees and encouraging early reporting of symptoms of MSDs, such as back pain or muscle strain, carpal tunnel syndrome, rotator cuff injuries, tendonitis, and “trigger finger” (popping or clicking sensations, stiffness, or tenderness); providing training; identifying problems and implementing solutions to control ergonomic hazards; and evaluating progress.

Ergonomic guidelines

Hazards can be unique to the task, tool, and workstation designs of an industry, so the guidelines for controlling MSD hazards can be unique to the industry, too.

Some ergonomic interventions rely on recommended motions or postures, while others involve engineering controls like assistive equipment or tools.

Storewide manual solutions in retail groceries include pinch grasps, power grips, and power lifts, as well as lifting techniques and recommended working postures to eliminate or limit exertion or pressure on joints.

In retail groceries, conveyors, hand trucks, pallet jacks, powered pallet jacks, and u-boats (carts with inverted-u handles on either end) can assist workers with manual materials-handling duties. Manual materials-handling tasks in retail groceries include unloading trucks, transporting and unloading merchandise onto storage shelves, transporting merchandise to the sales floor, and unloading merchandise from storage onto store shelves.

The National Institute for Occupational Safety and Health (NIOSH) has developed guidelines like its Ergonomic Guidelines for Manual Material Handling, covering ergonomic interventions that can lower the physical demands of manual materials-handling tasks.

Engineering controls recommended in NIOSH’s ergonomic interventions for soft drink beverage delivery include external handles and pullout steps on beverage delivery trucks, two-wheeled hand trucks with counterbalancing devices, improved carton design to ease product handling, and the substitution of plastic containers for glass containers to reduce product weight. Worker risk factors can be identified through biomechanical monitoring of manual materials handling, psychophysical discomfort assessment surveys, and videotaping.

In foundries, ergonomic interventions include:

  • Cutouts in worktables that reduce reaching distances;
  • Devices that allow parts to be easily turned in multiple directions during production to reduce awkward postures or reaching;
  • “Ergonomic” handles on tools to reduce the use of forceful pinch grips;
  • Floor mats in areas where workers stand for long periods of time to reduce discomfort and fatigue and sit-stand stools that reduce extended reaches and fatigue;
  • Hoists or balancers to transfer heavy loads that reduce lifting, pulling, and pushing forces;
  • Height-appropriate work surfaces or the modification of work heights to reduce reaching motions and permanently raised standing surfaces that reduce awkward body postures;
  • Lift tables to reduce bending, reaching, and walking and “tilters” (mechanical devices that lift and tilt to adjust materials for easier handling) and platforms or stacks of pallets to increase the height at which items are handled that reduce bending and reaching motions;
  • Mechanical grabbers and powered dollies that reduce physical exertion; and
  • Powered trolleys or roller conveyors to reduce the manual pushing of materials.

Recommended engineering controls in meatpacking and poultry processing involve tool handle and workstation designs.

Recommended hand tools such as knives, pliers, and scissors are designed to minimize the bending of the wrist either side to side or up and down and minimize the finger force and contact stress to fingers and the palm. Handles should help prevent the transmission of cold or vibration to the tool user. Handles should not be so big that they prevent users with small hands from maintaining a “C”-shape of a power grip between the fingers and thumb.

A wraparound handle or strap can allow a user to maintain control of the tool while relaxing the fingers on the handle. A handle guard may be added to some tools to prevent the hand from slipping onto the tool’s blade. Powered hand tools can reduce the finger force necessary to operate tools.

Knives, saws, and scissors must be sharpened regularly.

Spray nozzles should be designed to minimize hand force and allow users to maintain proper posture and positioning. As in foundries, cutout workstations can reduce the need for worker leaning and reaching.

Tilters or dumpers can reduce bending and reaching to remove products (meat or poultry) from containers. Work stands may be necessary to fit the worker to the task assigned, reducing awkward postures or reaching, and proper workstation height minimizes excessive forward trunk-bending and lifting of the arms during production.

The backrests and seats of chairs or stools can reduce worker fatigue if workstations do not require extended forward or elevated reaching, bending, or trunk twisting.

Wheeled devices like carts, hand trucks, lift tables, and pallet jacks can assist with the manual materials handling involved in transporting containers between work areas. Belts, overhead conveyors, and roller tables can eliminate the need to carry meat and poultry products through a facility.

Researching risky occupations

While many MSD hazards and ergonomic interventions are well understood, research continues into risks and controls. E-commerce leader Amazon.com, Inc., has invested resources into ergonomics research through its contributions to the NSC’s MSD Solutions Lab. The MSD Solutions Lab conducts research and engages with workplace health and safety stakeholders to address MSD risk prevention by identifying new technology, innovating solutions, and scaling the results of research to benefit all workplaces. Its initiatives include an employer MSD Pledge and an MSD Index, which gauges an employer’s risk-reduction strategies and workplace safety culture.

The NSC recently announced a collaboration between its MSD Solutions Lab and Safetytech Accelerator, a not-for-profit established by Lloyd’s Register and the Lloyd’s Register Foundation. The partnering organizations plan to design, build, and run an innovation lab to help facilitate the development of MSD prevention technology.

NIOSH has conducted extensive research into MSDs and ergonomics across industries. For example, public safety officers—corrections officers, firefighters, and law enforcement officers—are at high risk for MSDs. According to NIOSH research, while MSDs result in 13 median days away from work overall, the days away from work for public safety officers often are higher:

  • 15 days for firefighters,
  • 24 days for correctional officers, and
  • 27 days for police and sheriff patrol officers.

The institute’s current research priorities are identifying stressors that lead to MSDs in public safety work, developing new strategies to prevent MSDs, evaluating new technologies to reduce the incidence of MSDs, and evaluating the effectiveness of various interventions.

NIOSH also has investigated MSDs among employees in health clinic pharmacies who repeatedly opened and closed child-resistant medication bottles. Repetitive-motion injuries were the most common recordable injury among pharmacy department employees. Investigators noted hand and neck symptoms and conditions that were consistent with work-related MSDs.

The institute’s recommendations include:

  • Utilizing adjustable-height workstations,
  • Alternating between computer work and repetitive-motion pharmacy tasks,
  • Increasing employee and supervisor training on MSDs and ergonomics, and
  • Reporting work-related health and safety concerns to supervisors.

While industrial exoskeletons have been touted as reducing the risk of work-related MSDs—exoskeletons may reduce spinal muscle loading and muscle fatigue during dynamic lifting tasks, and upper extremity exoskeletons, along with an appropriate ergonomics program, may help prevent shoulder injuries—NIOSH has pointed out a lack of research to confirm such benefits.

Existing studies have involved small numbers of participants—many studies had fewer than 15 participants—usually in laboratory settings. These limitations in study size and setting make it difficult to draw conclusions about the benefits of industrial exoskeletons and their role in injury prevention, according to NIOSH.

Possible risks posed by industrial exoskeleton use include compressed nerves and pressure wounds from prolonged use; an increase in the length of time a worker can hold a tool, increasing exposure to hand-transmitted vibration; and increased load to the spine while using heavy tools, as well as a shifting of loads from the shoulders to the legs and lower back. NIOSH research projects into industrial exoskeletons include:

  • Application for exoskeletons in the mining industry;
  • Effects of back-assist exoskeletons in manual materials handling in the wholesale and retail trade sector;
  • Evaluation of exoskeleton systems in reducing hand-transmitted vibration;
  • Feasibility of using exoskeletons for safe patient handling in the healthcare sector;
  • Longitudinal health effects of passive shoulder exoskeletons in the manufacturing sector; and
  • Safety hazards potentially associated with exoskeletons while working on elevated surfaces in the construction sector.

While research goes on, you should look for government, industry, and professional resources to address your facility’s current MSD hazards.