Zuzana "Zuzka" Light (born April 29, 1982; née Majorová), is an internationally known fitness instructor, model, businesswoman, and author. She was born in Czechoslovakia and presently resides in Los Angeles, California.

Light runs one of the most popular online fitness instruction channel s on YouTube, and her videos have been viewed over half a billion times. Prior to starting her current YouTube channel, Light co-founded the fitness website and YouTube channel "BodyRock.tv" with then-husband Frederick Light. The couple split in 2011, and divorced in 2013.

Before moving to North America, Light worked as a model and a softcore pornographic model under the name "Susana Spears".

She described the experience as "an incredibly humiliating situation", and said she felt lucky to have survived the experience, and that "working on fitness helped me heal emotionally and rebuild my sense of self worth."

Light has appeared in national TV advertising spots for companies such as Airbus, Stroda, Gambrinus, and Raiffeisen Bank.

She has contributed to various fitness publications, such as Shape Magazine, BodyBuilding.com, and various other news outlets.

She released a book in December 2015 entitled 15 Minutes to Fit: The Simple 30-Day Guide to Total Fitness, 15 Minutes At A Time.