Symmetry represents the body is divided into left and right sides, and the similarity between the symmetrical joints is calculated. Near the maximum value, the less symmetry there is between the left and right sides of the body with moving only one side of arm or leg, and near the minimum value, the more symmetry there is between the left and right sides of the body. 

To calculate the frame length, count the total number of frames in the dataset. Each frame represents a data point collected over time. The total frame length gives the duration of the motion or activity being analyzed. In this dataset, the total frame length is determined by the number of entries in the data array.