Team & Affiliates


Mark “Coach Rozy” Roozen started Coach Rozy Performance in 2014 when he came back to South Dakota, after working with the Cleveland Browns in the NFL.  He has been a Strength & Conditioning Coach with the NFL and College programs as well as work with all levels of athletes from grade school to Olympians. He was Certification Director for the National Strength and Conditioning Association (NSCA).

Coach is the President and Owner Coach Rozy LLC, his company that handles public appearances and speaking, consultant work, performance training and offering performance products.

He is also Co-Founder of LIVE PAIN FREE – The Right Moves, which helps folks move right and exercise right to eliminate pain and movement problems in work, life and play.

Coach Rozy is also part of of 911 Tactical Performance, an organization that does consulting, education and training with police, firefighters and military groups throughout the country.

His training methodologies have been successfully applied to the full spectrum of the population youth, geriatric, rehabilitation, and a wide range of athletes.

Kyle McKelvey has been with Coach Rozy Performance since 2016.    He holds his M.A. in Kinesiology and Sport Science from the University os South Dakota (USD) and is a Certified Strength and Conditioning Specialist (CSCS),  also XPS Certified (Certified EXOS Performance Specialist).  He did his internship at EXOS in Texas where he worked with  30+ NFL Off-Season athletes and 8 NBA Off-Season athletes.

Coach McKelvey was Graduate Teaching Assistant of Kinesiology Department at USD while working on his Masters degree.  He also was on the USD Track and Field Athlete where he was Team Captain, Pan American Shot Put Silver Medalist (Team USA), USATF Junior National Champion, 4-time NCAA National Championship Regional Qualifier, and a State, School, and Summit League Conference Record Holder.  He also served as Volunteer Assistant for USD Spring Football Strength and Conditioning in 2015.

Ronette Karstens has been with the Coach Rozy Team since 2015. She graduated from the University of South Dakota with her Bachelors Degree in Education.  She is currently a First Grade Teacher at the Gayville-Volin School District where she is Assistant Boys Basketball Coach as well as Assistant Track & Field Coach working with the jumpers.  With Coach Rozy Performance, Coach Ronette does performance training, leads Group Bootcamps and is Coach Rozy’s Personal Assistant.

Ronette truly “did it all” while at Gayville-Volin High School; participating in Oral Interpretation, Flags, Cheerleading, Band, Choir, the School Newspaper, Yearbook, Softball and Student Council.  She was named Salutatorian her senior year.  As an athlete she was awarded the Raider Award (for best athlete) and Academic All-State.

Ronette was a star basketball and track athlete starting on the varsity team as an eighth grader.  She was awarded most improved that year by her coach.  She earned team MVP every year after that as a freshman, sophomore, junior and senior.  her senior season she averages 13.4 points, 10 rebounds, five steals and 5 assists per game.   She still holds schools records in the high jump and triple jump.  With her past experience, knowledge and drive, she loves to work hard, focus and bring high energy to at all she does – helps her excel with the Coach Rozy Team.

Ronette has a husband, Justin who also coaches and is a part time assistant with the Coach Rozy Team. She has 3 boys, Caid, Spencer and Preston, whom she loves to spend time with and is involved with their athletic and school programs.


Justin Karstens, married to Coach Rozy Performance Coach Ronette Karstens, has been with the performance program since 2017.  Teaching and Coaching boys and girls his whole career, Justin brings a wealth of knowledge and sports skill to the Coach Rozy Program.

Justin has been at Gayville-Volin for the past 14 years, where he as been Heads Boys Basketball Coach for the past 8 years (he was previously Girls Head Coach at GV before that) and has been an Assistant Football Coach for the last 8 years.

As mentioned, Justin’s wife Ronette also coaches and is an assistant with the Coach Rozy Team. They have 3 boys, Caid, who plays baseball at Mt. Marty College, Spencer and Preston, who are heavily involved with their athletic and school programs at Gayville-Volin School.

Caid Rickford has been with Coach Rozy Performance since 2017 as an Assistant Performance Coach.  Prior to that, Cade was a Coach Rozy Performance Athlete all through his High School career where he as a stand out in Football, Basketball and Track & Field.  Caid finished up basic training for United States National Guards in 2018, and jumped right back into taking over coaching duties and working with teams in the area.  He is attending University of South Dakota to pursue his degree to become a Strength and Conditioning Coach.

Carlos Sanchez is  originally from Carson, California.  Carlos moved to Sioux City, Iowa at the age of 9.  He has been working at a family business running a restaurant and bar and is shifting to a career in Strength and conditioning/fitness.  He joined Coach Rozy Performance the summer of 2020, working with teams at every level.  Coach Sanchez enjoys working with all athletes and helping people get better and achieve their personal goals. His personal goal is to keep working on becoming a better coach while learning and gaining more  experience in the strength and conditioning field.
Carlos holds a Bachelors degree in Business Administration, is a Certified Strength and Conditioning Specialist (CSCS)-NSCA and a Certified Personal Trainer (CPT)- NASM.

Austin Millergraduated from South Dakota State University where he majored in Health, Physical Education, and Recreation. During that time, he worked with the men’s basketball team as a student assistant (2007-2013) and did his internship with the SDSU Strength and Conditioning staff (2010-213).   Austin has been with Coach Rozy Performance since 2019.  He also works as a player development coach, training basketball athletes from the youth to professional levels.
Miles Rademaker started as an Intern with Coach Rozy Performance and was hired as a Performance Coach when he completed his degree from University of South Dakota in Vermillion in 2019.


Billy Trosper is in the Masters program for Kinesiology Exercise Science at the University of South Dakota (USD) in Vermillion, SD.  Billy did his internship in the Spring of 2021 and joined Coach Rozy’s Performance staff in the summer of 2021.  He is originally from Rockford, Illinois. His career path is not yet set, but he is looking to pursue a career in either strength and conditioning or physical therapy. The reason he chose Coach Rozy to fulfill his internship was not only learning from very knowledgeable mentors, but also the opportunity to work with a diverse group of athletes.

Trevor Woods, MA, ATC has a bachelors degree in Athletic Training from South Dakota State University (SDSU) and a Masters Degree in Exercise Science from University of South Dakota (USD). He has been providing Athletic Training coverage to Yankton High School and Gayville-Volin High School for 18 years. He has been doing sports enhancement programs since 2002 working with numerous individual and team State Championship athletes.

He loves working with athletes to improve performance while helping reduce the risk of injuries for the athletes.


911 Tactical Performance

Live Pain Free – THE RIGHT MOVES

Jeffrey Paul Salon


Performance Sandbag Training

Performance Sandbag Training