Repetitive motions are defined as:

• A. The total duration of a task
• B. The frequency of repetition of a task
• C. The number of tasks completed per shift
• D. The intensity of the task

Answer: (B)

The main idea is how often a motion repeats within a given time. Repetitive motions describe the cycle of a task in terms of frequency—how many times the same motion occurs per unit of time. That’s why the correct choice is the frequency of repetition of a task: it directly measures how often the motion is performed, which is what repetition refers to in ergonomic and BEA contexts. The total duration of a task is about how long the task takes overall, not how often the motion cycles. The number of tasks completed per shift relates to throughput, not the repetitiveness of a single motion. The intensity of the task concerns the amount of force or effort required, not how often the motion repeats. For example, doing a motion 60 times per minute indicates high repetition frequency, whereas lasting 5 minutes, finishing many different tasks, or applying a lot of force describe duration, throughput, or exertion, respectively.