Westside (Warren H Abernathy) Staff

Niel Visser, PT, DPT
Physical Therapist

Niel Visser was born and raised in South Africa. From a young age he was passionate about sports, and excelled in rugby, track and field, tennis and surfing. His love of sports, and a sustained back injury, would introduce him to physical therapy and lead him to pursue it as a career. After two years in the military and a gap year in Europe, Niel enrolled at the University of Stellenbosch, graduating in 1994 with a Bachelor of Science in Physiotherapy. Seizing an opportunity to work and travel, Niel came to the USA in 1995, and worked in various settings across the country as a PRN therapist. He gained experience working in in-patient rehab facilities, acute/sub-acute care, nursing homes, home health, outpatient orthopedics, sports medicine and work hardening. In 1999 Niel took a position in Spartanburg and became the clinical area coordinator overseeing four outpatient facilities. He co-founded Advanced Therapy Solutions, Inc. in April of 2003 and, with his business partner, Dillen Hartley, has seen their business grow from one clinic and two staff members to 5 locations and 50 employees. Niel received the Butch Buchanan Award for Clinical Excellence from SCAPTA in 2007, in recognition of his contributions and outstanding performance in the practice of physical therapy. In 2014 Niel completed his Doctorate in Physical Therapy with emphasis on Executive Practice Management through Evidence In Motion. He and his team also received the Faculty Favorite Award in the Business Plan Competition. Niel has a special interest in treating spine patients pre- and post-operatively, as well as sports injuries. He enjoys staying up to date on the latest therapy related research. When he is not at work, Niel enjoys playing racquetball, hanging out with family and friends, and following his favorite sports teams.

Jeff Leiszler, PT, SCS, ATC
Physical Therapist

Jeff Leiszler, PT, SCS, ATC, is a graduate of both Kansas State and Wichita State Universities. He is recognized as a Board Certified Sports Physical Therapist, a Certified Athletic Trainer, and a member of the Team USA Olympic Medical Network. Jeff has practiced orthopedics and sports medicine for more than 20 years and takes special interest in the wellness and care of the injured athlete. As a member of collegiate and high school athletic training staffs, he enjoys the gratification of assisting athletes of all levels in getting back to their athletic endeavors.

Erin Lowe, PTA
Physical Therapy Assistant

Erin Lowe graduated from Greenville Technical College with and Associates Degree in Health Applied Sciences with focus in Physical Therapist Assistant in November of 2006. Erin also received a Bachelor's Degree in History with Minor in Political Science from University of South Carolina. Erin has worked in physical therapy for 17 years, ranging from outpatient orthopedics to outpatient pediatrics, nursing home setting and acute care settings. Erin enjoys being a mom to her amazing son, a member of her church, enjoys playing disc golf and being active in the community.

Angela Tkachuk
Physical Therapist Assistant

Angela Tkachuk joined our team in January 2025, bringing fresh energy and enthusiasm to our organization. Originally from Sacramento, California, Angela is a recent graduate of Greenville Technical College, where she developed the skills and knowledge that make her a valuable addition to our staff.

When she's not at work, Angela leads an active lifestyle with a passion for both indoor and outdoor adventures. She enjoys playing volleyball and staying fit at the gym, while also exploring the great outdoors through backpacking and snowboarding. Her love for travel has taken her to various destinations, reflecting her adventurous spirit and curiosity about the world.

Angela's diverse interests and West Coast background bring a unique perspective to our team, and we're excited to have her as part of our growing organization.

Karla Jordan
Billing Director

Karla joined ATS Westside location as the Billing Director in January 2020. Karla has an extensive background in medical billing with over 15 years’ experience in the field with concentration in revenue cycle management. She was born & raised in Spartanburg; her hobbies include taking walks with her two spoiled dogs Jax & Gracie and spending time with her family & friends.

Kelly Cockrell
Billing Assistant

Kelly Cockrell joined ATS in October of 2016 as Billing Assistant at the Spartanburg Westside facility. She graduated September 2015, from Virginia College of Spartanburg with a Certificate in Medical Billing and Coding. Kelly was on the President's list from August 2013 to September 2015. Her hobbies are reading and shopping. She hopes to one day travel to Europe, in the meantime she and her husband love to travel here in the U.S. She loves spending all her free time with her husband, daughter and of course her beloved dog, Odie.

Lena Visser
Human Resources Manager

Lena graduated from the University of Stellenbosch, South Africa, with a Bachelor of Arts degree, and earned a post-graduate diploma from AAA School of Advertising in Cape Town in 1994. She joined her husband, Niel, in the United States in 1995, and together they traveled extensively before settling down in Spartanburg. She worked in the public relations industry for several years before officially joining the ATS team in 2008. Lena manages Accounts Payable and Human Resources for the company. She loves spending time with her husband and two sons, listening to music, reading and traveling when time affords it.