For farms, orchards and those who own wooded acreage, winter is the time for a variety of tasks: logging, land preparation, excavation, brush clearing and pruning. Many tasks require the use of heavy machinery, which predisposes workers to short- and long-term health issues.
Abigail Kahrs, program coordinator for AgriSafe, discussed the health risks for those working with heavy machinery. Operators who are aware of ergonomics – the process of arranging the workplace to enhance safe, easy work – can work safely and avoid injury.
“The goal of ergonomics is to improve workspaces and environments to minimize risk of injury or harm,” she said.
Constant jarring results in physical stress and strain, which leads to microscopic wear and tear injury to soft tissue. This fatigue-induced injury is fully repaired by a good night’s rest, circulation and nutrition. However, excess fatigue and insufficient natural repair from lack of rest can lead to musculoskeletal disorders (MSDs). Repeated motion, exposure to force, awkward posture when operating equipment and repeated vibration over time can also lead to problems.
Some injuries develop over weeks or years and are often ignored at first. Typically, the wrists, shoulders, neck and back are affected by slow-onset injuries. Symptoms can appear gradually as muscle fatigue or pain during work and become more severe as exposure continues. It’s easy to ignore minor numbness and tingling that disappears with rest, but gradually, symptoms become so severe that it’s hard to perform the job. Numbness, burning, pain, tingling, cramping, stiffness and muscle weakness are signs of MSD.
Several factors add to the risk of working with heavy equipment, including the combination of harsh natural environments while using dangerous tools and machines. Muscles don’t always work efficiently in cold weather, and heavy clothing can inhibit full body movement.
Those using heavy equipment often perform the same precise, repetitive, quick movements throughout the day. This work usually lacks natural breaks, so operators must remain alert and aware of their surroundings. Operating machinery that’s shaking and sometimes tilted causes the operator to tense muscles subconsciously. Machine vibration is uncomfortable and leads to fatigue that the operator may not notice immediately.
“The human body is not naturally disposed to sit still in a vibrating cab and perform repetitive arm and head movements,” said Kahrs. “These factors, combined with the pressure to sustain a high level of productivity, shift work, working in darkness and dealing with interruptions, can all lead to MSD.”
Heavy equipment operators are also prone to gastrointestinal disorders, irritability and headaches.
Maintaining a comfortable, neutral, seated position with easy accessible controls can help equipment operators avoid vibration damage. Photo by Sally Colby
Prolonged operation of chainsaws and other hand-held equipment causes a high static load on the muscles of the upper limbs. This hand-arm vibration accelerates the development of MSD in the upper limbs, especially the hands and wrists. Chainsaw operation increases pressure on muscles, ligaments, tendons and soft tissue, which reduces blood flow to these tissues and leads to numbness and tingling. Over time, operators may develop carpal tunnel pain or hand-arm vibration syndrome (HAVS).
HAVS is tingling and numbness of the fingers, inability to feel things properly and loss of hand strength. Fingers may appear white then turn red upon recovery. “For some, symptoms appear after only a few months of exposure,” said Kahrs. “Others make take a few years, and it’s likely to worsen with continued exposure to vibration and damage become permanent.”
Whole-body vibration is due to vibration over long periods of time and can lead to neck and lower back issues. The lower back is particularly prone to injury, most often the result of mechanical shocks such as sudden acceleration due to equipment jolts. This syndrome also affects vision and balance.
With exposure to constant vibration, back muscles contract, resulting in muscle fatigue. Equipment operators may also experience unpredictable non-periodic shock from driving over potholes, stumps, rocks and other hazards.
Repetitive motions lead to repetitive strain injuries. Those who operate heavy equipment often sit in the same position for extended periods of time, twisting their bodies, which contributes to awkward posture.
“When in neutral posture, the joints can absorb force more easily,” said Kahrs. “Awkward and extreme postures increase susceptibility to injury because the posture stresses joints and reduces or blocks blood flow. Working a machine that is shaking or tilted causes operators to tense muscles subconsciously while driving. These exposures, combined with full body vibration and occasional jolting, can affect the operator’s lumbar region.”
The good news is that MSDs are preventable, and prevention strategies can reduce daily fatigue, enhance the body’s recovery process and have an immediate impact on quality of life.
“With proper warmup and body mechanics, workers can reduce daily fatigue and have increased energy at the end of the day,” said Kahrs. Protecting muscles, tendons and ligaments throughout the day is key. “When an operator is sitting in equipment all day, breaks are beneficial because the angle of the joints change.”
Keeping the seat level rather than tilted at an angle can help the operator maintain a relaxed posture, which lessens stress on the back.
Equipment operators should avoid bending their heads backwards, which can increase the likely hood of injuries – especially if the machine jolts. Operators should not have to turn their head frequently or for long periods in a manner that requires the use of shoulder muscles. The seat and armrest should be easily movable and the controls within the operator’s reach to aid good visibility with minimal head or body twisting.
One strategy to decrease the risk of injury is stretching prior to work. This allows the body to better bend, reach and twist without straining muscles. Another injury prevention strategy is maintaining three-point contact – three out of four limbs are in contact with a stable surface at all times with weight evenly distributed among the three points.
Equipment operators should take their time when entering or exiting a vehicle and face the vehicle while climbing to enter. Climb on or off when equipment is still and do not jump down. Repeated jumping subjects the operator to potential fractures or severe sprains.
Harsh environments and rough terrain increase the likelihood of slipping and tripping, especially after heavy rainfall or in snowy or icy conditions. Invest in boots that minimize the likelihood of slips, trips and falls. Footwear should have the necessary traction for safe walking on damp or uneven surfaces and should cover and support the ankles.
Employers are responsible for providing a safe work environment and ensuring all workers are properly trained and working safely. Workers are responsible for keeping their body fit for work. Workers should also understand the hazards associated with the work they’re doing and be well-rested and properly clothed for safe labor.
by Sally Colby
