According to NIOSH, the three primary risk factors that cause MSDs are high force, awkward posture, and long duration or high frequency. Increasing the combination or number of these risk factors increases the chance of employees developing discomfort, pain, and/or an MSD.

• Posture – In neutral posture, the joints can absorb force more easily that in others. Awkward and extreme postures increase susceptibility to injury, as they may stress joint components and reduce or block blood flow.
• Force – Gripping, pinching, pushing, pulling, and lifting objects place additional force on the body’s joints. Increasing these forces requires additional muscle exertion, and places greater loads on joints and connective tissues which can cause fatigue and may contribute to MSD when there is inadequate time for rest and recovery.
• Frequency – Higher frequency of awkward postures and/or forces increases the potential for damage to a joint.