Boss Thai Boxing is a martial arts school. We teach and train the combat sport of Muay Thai, which is rooted in the principles of honour, perseverance and respect. We offer a uniquely supportive and motivating environment for people of all walks of life to engage and evolve alongside like-minded members of our growing community. 

Boss is run by the dynamic husband & wife team: Yuki Yamanaka and Milena Hrebacka of Kemptville. Since 2019, it has been their mission and honour to mentor, coach and provide a safe space for children, teens and adults to discover their full potential. 

(Center) Kru Yuki Yamanaka and Coach Milena Hrebacka taking a group shot with MuayThai Ontario officials before Bushido II on July 8, 2023 at the Municipal Centre in Kemptville.
MuayThai Ontario COVID-19 safety and compliance certification

MuayThai Ontario COVID-19 Compliance

Certification showing that Boss Thai Boxing & Fitness Inc. and its instructors have met or exceeded the prescribed guidelines for COVID-19 safety and prevention as dictated by our governing sport authority, MuayThai Ontario.

COVID-19 Safety Certification

Our Head Muay Thai Instructor, Kru Yuki Yamanaka, has completed a Martial Arts Instructor course certifying him as safe COVID-19 Instructors in our facility.

WAKO member

WAKO Member 2023

Boss Thai Boxing is proud to be a member under WAKO Canada.

Muaythai Ontario Member 2023

Boss Thai Boxing is proud to be a member under MuayThai Ontario.


Yuki began his Martial Arts journey at the age of 7 when he joined a Karate school, and 11 years later he earned his 2ND degree Black Belt. He started his Muay Thai journey at the age of 22 while specializing in Structural Engineering at Carleton University.

Since 2013, Yuki has entered the ring over 30 times and has competed all over the world, representing Team Canada in the 2014 and 2016 World Championships. His competitive career has taken him across Ontario, Western Canada, the United States, Mexico, Italy and Thailand.

He earned his Kru certification (meaning ‘teacher’ in Thai) under Kru Jeff Harrison, presented by Ajahn Burklerk Pinsinchai (record of 172-6), a living legend in Thailand during the Golden Era of Muay Thai.

Kru Yuki has cornered fighters in a variety of events— from exhibition matches to sanctioned competitions, including one of the largest professional organizations in the world: Glory World Kickboxing Series. He can also be seen Officiating at provincial events where he judges and referees sanctioned amateur bouts under MTO.

As Head Muay Thai Instructor, Kru Yuki is excited to share his passion and knowledge of Muay Thai— the Science of 8 Limbs— to the people of Kemptville, of all ages, inside and outside of the gym.

Throwdown in O-Town Championship bout, Ottawa, 2015
Kru Yuki Yamanaka, Head Muay Thai Instructor
Journey Fight League, Alberta, 2016
WKF World Championships, Italy, 2016
Toronto, 2017
Ottawa, 2018



Milena Hrebacka Co-Owner Boss Thai Boxing


Co-Owner of Boss Thai Boxing; Muay Thai Instructor

Coach Milena teaching a Boss Women Only Class
Zach Marquez Boss Thai Boxing


Instructor in our Adult Muay Thai, Women Only and Little Nak Muays (Kids) programs
Coach Zach taking the win! (2023)