Arm fold represents a quantification of the angle of the arm (wrist-elbow-shoulder angle). Near the maximum value, both arms are fully extended, and near the minimum value, both arms are folded. 

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.