Which physiological process can be affected by body mechanics?

Body mechanics refers to the way we move and position our bodies during various activities, particularly in contexts like lifting, carrying, or performing patient care in medical settings. Effective body mechanics is crucial in maintaining proper posture and employing safe lifting techniques, which can significantly affect a person's physical health and movement efficiency.

When considering how body mechanics relates to posture and lifting techniques, it’s essential to note that poor body mechanics can lead to strain, injury, or musculoskeletal disorders. Conversely, applying principles of good body mechanics can enhance efficiency, reduce fatigue, and increase safety during physical tasks, which is especially critical for EMTs who often lift and move patients.

The other options relate to important physiological functions but are not directly influenced by body mechanics in the same way. For instance, muscle contraction is a biochemical process that occurs at the cellular level and is not significantly altered by how one moves their body, while gas exchange in the lungs and blood circulation involve complex physiological mechanisms that are more related to cardiovascular and respiratory function rather than the biomechanics of lifting and posture.