The first clip gives an overall view of TI (about 7 minutes). Terry describes the body mechanics and positioning for effective streamlining and stroke propulsion. Note the position of the head (look straight down) and chest (pressing down pushes the buttock up creating less drag). Terry does a great job of showing how the core body works to create and maintain the streamline water position (breathing is turning the core as opposed to turning the head)
The next clip demonstrates different tempos (2 minutes). The thing I like about this video is the how the strength of the core is used to increase the power of the stroke. Look at how the hips rotate in a swivel manner (not side to side) to create power, especially as the tempo increases (things I don’t like are how he lifts his head to break the water surface and has his hands flapping on the extension; we won’t do this….):
The last video compares Michael Phelps to the TI format (30 seconds). Note the head position (looking down), hand entry (straight above the shoulder, not over to the side), breathing accomplished through core rotation -not turning the head, and power from hips in the core rotation. This demonstrates the value in understanding your proper streamline position: