Evaluation of musculoskeletal workload of manual operating tasks using a hydraulic jack based on ergonomic postural analysis and electromyography: A case study of non-professional young male users.
Atsushi Sugama, Takahiro Nishimura, Kouki Doi and 4 others
PMID 35527602WHAT IT FOUND
Kneeling perpendicular to a hydraulic jack lever placed the highest postural load on nine young men, while kneeling parallel and close felt least burdensome.
The study did not test whether changing posture prevents injury.
Key findings
01When the body was perpendicular to the jack lever, the study found the largest postural load index and more high-risk postural categories than in other positions.
02Participants reported less whole-body burden when kneeling parallel and close to the lever than in other positions.
03The lever required about 60 N to push and about 15 N to pull, while the upper limb force component was often 10 to 20 N and briefly 40 to 80 N.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
Only nine participants were studied, all young right-handed men, so the findings may not apply to women, older adults, or people with musculoskeletal conditions. The task was short and controlled in a lab, not a real rescue or home situation. No patients, injury outcomes, or treatment effects were measured. The study compared body positions but did not test whether changing position prevents injury. Actual jack operation may be faster and more variable, which could increase muscle activity. Whole-body burden was rated with a single 1 to 5 scale.
Declared interests
No funding or conflict-of-interest statement is provided in the supplied text.
The easy way to misread this
Do not conclude that changing body position or redesigning the jack prevents musculoskeletal injury. The study measured posture and muscle activity in nine young men during a 30-second lab task, not patients or injury outcomes.