Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Extremely valuable material

This video presents material that is applicable and very valuable to the practice of any style of grappling that involves a ground element. The fluidity of motion and economic transitions will increase the viability of any competitor. Even the most advanced practitioner will be able to hone their technique by assimilating the movements presented. Sonnon also does a fine job of explaining the theory behind each skill set as well as it's execution. That being said, the actual demonstrations go by very quickly, so the novice practitioner will have to review each movement many times to become proficient. Over all, it is an excellent supplement to your grappling regimen if you are willing to put in the time to master the movements.