Which of the following is NOT one of CrossFit's ten fitness domains?

• A. Coordination
• B. Reaction time
• C. Agility
• D. Balance

Answer: (B)

CrossFit’s framework centers on ten general physical skills that together describe well-rounded fitness. These include cardiovascular/respiratory endurance, stamina, strength, flexibility, power, speed, coordination, balance, agility, and accuracy. Reaction time isn’t listed among them.

So the reason this choice is the best is that reaction time is not one of the official ten domains, even though it can influence performance. The other options—coordination, agility, and balance—are explicitly named domains, reflecting the neuromuscular control, quick directional changes, and stability that CrossFit charts as separate skills. Understanding that distinction helps when matching training focus to the framework: you’d strengthen coordination, balance, and agility directly within the ten domains, while reaction time would be addressed more indirectly through drills that challenge quickness and stimulus-response, but it isn’t a separate domain itself.