Answer by Jane Savoie: People often ask me to explain the difference between “running” and “lengthenings”. In fact, in this article I’m also going to describe the difference between running, lengthenings, medium gaits, and extended gaits.
1. Running– When you ask your horse to lengthen his strides and frame, and you hear his tempo (the rate of the repetition of the rhythm) get QUICKER, he’s not lengthening. He’s just running.
2. Lengthenings– In a good lengthening, your horse lengthens his stride and frame to the utmost he can at this relatively early stage of training (around 1st Level) WHILE staying in the same rhythm and tempo. He ends up covering more ground with each stride.