What she has on is a pair of C3fit Impact Tights. Look at the beautiful side design. But apparently, this is not any nice design. This unique pattern is designed to reduce muscle vibration along the key muscle groups and enhance blood flow. In fact, C3fit tights are certified as General Medical devices in Japan.
The design and fit of the tights wrap the knee snugly providing a high level of support similar to that of a knee guard. This design also reduces fabric brunching and slippage.