Which trio of factors are ergonomic risk factors that contribute to musculoskeletal disorders?

• A. Repetitive motions, awkward postures, and heavy or forceful exertions.
• B. Prolonged sitting, loud noise exposure, and poor lighting.
• C. Handling heavy equipment only.
• D. Temperature extremes, humidity, and glare.

Answer: (A)

Ergonomic risk factors that contribute to musculoskeletal disorders are about how the body is loaded during work tasks. Repeated motions wear on muscles and tendons over time, leading to overuse injuries as tiny tissues fail to recover between cycles. Awkward postures place joints and tissues in nonneutral positions, increasing muscle activity and pressure on joints, which reduces circulation and accelerates fatigue and strain. Heavy or forceful exertions impose high forces on the musculoskeletal system, elevating the risk of strains and damage, especially when combined with limited recovery.

These factors directly involve mechanical stress on the body's support structures, which is why they are the best indicators of risk for musculoskeletal disorders. Other listed conditions, like prolonged sitting, loud noise, or poor lighting, mainly affect comfort, concentration, or sensory factors rather than the direct mechanical load that drives MSD development.