What problem might someone with upper crossed syndrome experience?

Individuals with upper crossed syndrome often exhibit a pattern of muscular imbalances characterized by tightness in the upper pectorals and the upper trapezius, combined with weakness in the deep neck flexors and the lower trapezius. These imbalances can lead to a forward head position and rounded shoulders, which directly impact the biomechanics of the golfer's swing.

A fluid swing relies on proper posture, alignment, and movement patterns. However, when a golfer has upper crossed syndrome, their altered posture can create disruptions in the swing path, result in compensatory movements, and create inconsistencies. These issues can lead to a less coordinated and less fluid motion during the swing, ultimately affecting performance and accuracy.

Thus, the presence of upper crossed syndrome would likely hinder the fluidity of a golfer's swing, making it the most accurate choice among the options provided.