Meet Joe. Joe is a real person, Joe is not a bot. Joe is 185 pounds and 6 feet, 2 inches tall. He is standing on deck, knees locked and bends over to pick up a line on the deck. How many pounds of compressive force stress do you think are on his spine as he picks up the line?
Ten pounds? Fifty pounds? A hundred pounds?
Prof. Don Bloswick, PhD., has decades of experience with his graduate students researching stresses on the human body during work activities. He has a special interest in commercial fishing Muscular–Skeletal Disorders (MSDs). According to Bloswick, Joe is putting a whopping 585 pounds of force on his spine when he picks up that line on the deck.
Studies in Scandinavia, where they actually inserted pressure plates in the spine of researchers, have verified Bloswick’s research on the amount of this compressive force.
It’s not the weight of the line that is causing the stress, as much as the fact that Joe is actually picking up the trunk and head of his own body from the horizontal to vertical position. Also not helpful is the center of gravity of his stooped-over upper body is a foot or two away horizontally from his spine.
Joe is teaching us two lessons: one, keep your back vertical when picking up an object and two, keep the center of gravity of the object being lifted as close to the body as possible.
Fortunately, the spine can take about 2,200 pounds of force before doing damage to itself. But the cumulative effect of improperly bending over to pick up a piece of line hundreds of times a day for hundreds of days over decades of work will likely result in chronic pain, medical bills, lost fishing time, reduced work efficiency and a shortened work life span.
Worldwide, statistics on muscular-skeletal injuries in commercial fishing tell the same story. In North Carolina, 38% of fishermen in the first year of a study had a traumatic MSD (Kucera). Of these injuries, 70% were caused by lifting and moving; 50% of those involved the back.
In Sweden, 50% of fishermen reported having back problems in the past. In New Zealand 66% of fishermen have lower back pain. In Alaska, the Fisherman’s Fund, a self-insurance pool of last resort, has data that demonstrates about 40% of fishermen’s claims are due to strains, sprains, tendonitis and carpal tunnel syndrome.
This is mostly due to improper posture, lifting and moving procedures.
The spine is a well-designed part of our body’s architecture. It’s especially well-designed for use by a bipedal species such as homo sapiens.
As designed, the spine has four curves in it: the cervical, thoracic, lumber and sacral curves. On the sides of the spine and running its entire length are two long groups of muscles and tendons called the Erector Spinae. To readers who are also hunters of four-legged herbivores, these muscles are also called the “back straps.” But we won’t carry this analogy too far.
Getting back to Joe, when he bends over to pick up the line, this group of muscles does two things: it prevents him from falling on his face and it allows him to pick up his body to be vertical again.
As the muscles in his back contract, this squeezes the body’s vertebrae closer together which in turn puts pressure on the soft spinal discs, which over time get thinner and less squishy.
With enough time and abuse, this can cause the vertebrae to impinge on each other and on the rich network of nerves that run though the protective spinal column. Now you have a lot of pain, expense and downtime. Our back works most efficiently when we keep our back straight and we “Preserve the Curves,” as the saying goes.
On this page are some graphics that demonstrate better lifting postures. Use these postures when lifting until they become a habit. Reinforce these good postures with your crew. AMSEA has trained over 6,000 fish workers in ergonomics—the science of using the body more efficiently—and their employers have seen a decrease in workman’s compensation claims and their workers are happier and healthier as a result.
You can take your own free 15-20 minute ergonomic course at AMSEA’s website and also get free access to our ergonomics handbook with exercises and a training certificate. To do so, go to https://www.ergonomics.amsea.org.
Back Safety Tips When Lifting
- Keep body upright as much as possible.
- Keep load/force close to body.
- Push/pull mid torso height.
- Don’t twist the back while lifting.
- Don’t jerk when lifting loads.
- Get help when moving heavy loads.
- Tighten stomach muscles and exhale when lifting.