Bone length coherence represents how well the initial inter-articular length is maintained throughout the sequence. Near the maximum value, similar to the initial bone length, near the minimum value, different from the initial bone length. If bone length consistency is measured low, people may question the integrity of the data. 

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.