If you are a business person, you know that the better you understand your customer, the easier it is to sell. And if you are a business person with principles, you can use that understanding to give your customer exactly what they need.
Information and understanding, gives us the power to make intelligent decisions.
You can use the same approach to improving the flexibility of your hamstrings.
The better you understand your hamstrings, and other muscles that work on the hips and knees, the easier it is to use them.
Dealing with a client, a secretary may have given you a brief on the client, some background information. While helpful, it's not the full picture. You get a better idea of the full picture by actually talking to the client.
Likewise with your hamstrings, and other related muscles. When working to improving hamstring flexibility, it helps to be able to "talk" to your hamstrings, and to the muscles that they are working with. And understand that in this instance, talk actually means both talking and listening.
Knowing some very basic anatomy is akin to having a brief on the customer. Meanwhile, biomechanics, which is the study of forces within our body, that's how we have the conversation.