Question

The Indian tractor drivers have suffered more than 70% of spine deformation. This type of deformation occurs due to:
A. Vibration
B. Shock
C. Bad sitting posture
Choose the correct answer from the options given below:

• A. A and B only
• B. A only
• C. C only
• D. B and C only

Hint:

Whole-body vibration (WBV) and repeated mechanical shocks are the two most critical physical factors that cause spinal disorders in heavy machinery and tractor operators.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Ergonomic studies of agricultural workers indicate that tractor drivers are exposed to significant physical hazards.
These hazards can cause occupational health disorders, particularly spine deformation and lower back pain.
The primary physical agents responsible for these disorders are mechanical in nature.

Step 2: Detailed Explanation:
Tractors are heavy off-road vehicles that generally lack sophisticated suspension systems between the chassis and the cabin.
During fieldwork, drivers are exposed to the following mechanical hazards:
- A. Whole-Body Vibration (WBV): The engine, transmission, and movement of the tractor generate low-frequency vertical and lateral vibrations.
These vibrations are transmitted directly through the seat to the driver's spinal column.
Exposure to low-frequency vibrations (particularly in the resonance range of the human spine, which is \( 4 \text{ to } 8 \text{ Hz} \)) causes fatigue and wear in the intervertebral discs.
This matches statement A.
- B. Repeated Shocks: When driving over uneven fields, ridges, and ditches, the driver is subjected to sudden vertical accelerations (mechanical shocks).
These repeated micro-impacts place high compressive loads on the vertebrae, leading to micro-fractures, disc degeneration, and spinal deformation over time.
This matches statement B.
- C. Bad sitting posture: While a poor sitting posture can contribute to fatigue, ergonomic research identifies vibration and mechanical shocks as the primary physical hazards responsible for structural spine deformation in tractor drivers.
Therefore, vibration (A) and shock (B) are the primary causes of this occupational health issue.

Step 3: Final Answer:
Spine deformation primarily occurs due to A and B only.