Left arm extremity angular velocity represents the angular velocity value of left arm. Near the maximum value, the larger the angular velocity value of left arm, indicating fast rotation, near the minimum value, the slower the rotation. 

To find the local maxima, we identify the ranges where the values reach a peak within the dataset. A local maximum is a point where the value is higher than its neighboring values. This indicates periods of high activity or dynamic movement. The detection is based on a threshold percentage (e.g., 80% of the maximum value) to focus on the most significant peaks. The output lists the frame ranges where these peaks occur and their respective values.