Extremity speed represents the speed of movement of the end joints of the limbs (both wrists, ankles). Near the maximum value, the faster the speed of the extremities, near the minimum value, the less movement of the extremities. 

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.