California-born Elisabeth “Liz” Halliday began riding when she was 8 years as an active member the United States Pony Club. Halliday moved to England in 2000 to work for famed eventer William Fox-Pitt and was based in Europe for many years before bringing her operation to the U.S. with locations in Ocala, Florida, and Lexington, Kentucky, in 2020. That same year, she earned the distinction of USEA Rider of the Year after racking up nine wins and 23 total top-ten finishes at FEI competitions over the season.

Halliday achieved her first CCI5*-L completion in 2016 at the Kentucky Three-Day Event with Deborah Halliday's HHS Cooley. She has also brought numerous horses to top-ten finishes at the level, including Ocala Horse Properties, LLC's Deniro Z, The Monster Partnership's Cooley Quicksilver, and The Nutcracker Syndicate's Cooley Nutrcracker.

In 2023, she brought Deborah Palmer's and Ocala Horse Properties, LLC's Miks Master C to his CCI5*-L debut at the Kentucky Three-Day Event where they finished in third-place overall and were reserve champions in the USEF CCI5*-L Eventing National Championship. In 2023, the pair were the Adequan USEA Advanced National Champions at the American Eventing Championships.

Halliday has represented the U.S. Eventing Team in several FEI Nations Cup competitions, including the 2022 CCIO4*-S at Bromont in Canada, where she rode Miks Master C to individual victory and led the U.S. team to secure the win. In 2023, the pair were part of the silver medal-winning team at the Pan American Games in Santiago, Chile.

Halliday continued her consistency in 2024, marking several top results with both Cooley Nutcracker and Miks Master C, with a top-ten finish coming for Cooley Nutcracker at the Kentucky Three-Day Event CCI5*-L in April. The pair were named as traveling reserves for the 2024 Paris Olympic Games. 

In addition to her equestrian pursuits, Halliday was a professional driver in sportscar and GT endurance disciplines, competing from 1997 to 2010 before focusing on her equestrian career. 

Boyd Martin, the son of Olympic speed skater Toy (Dorgan) Martin and Olympic cross-country skier Ross Martin, began riding at a young age in his native country of Australia. He made his debut at the CCI5*-L with a win at the 2003 Australian International Three-Day Event riding the Thoroughbred gelding True Blue Toozac.

He moved to the U.S. in 2007 to further his career as an eventing professional, serving as the assistant trainer to Olympian Phillip Dutton for two years before starting his own business. Martin began riding for the U.S. in 2009.

Martin is a three-time Olympian, having represented the U.S. in London 2012, Rio de Janeiro 2016, and Tokyo 2020. He is a four-time U.S. Eventing Team member for the FEI Eventing World Championship, including as a part of the silver medal-winning team in 2022 in Pratoni, Italy. With Pancho Villa, he was a member of the U.S. team that won gold at the 2015 Pan American Games, and in 2019, he won team and individual gold at the Pan American Games with Christine, Thomas, and Tommie Turner's Tsetserleg TSF.

Twice, Martin has been the USEF CCI5*-L Eventing National Champion at the Kentucky Three-Day Event. First in 2019 with Tsetserleg TSF and again in 2021 with Christine, Thomas, Tommie, and his own, On Cue. In October 2021, he won the inaugural Maryland 5 Star with On Cue, becoming the first American to win a CCI5* since 2008.

In 2023, Martin piloted his string to several significant top finishes at the CCI5*-L with five top-ten finishes at events around the world, including two top-ten finishes for Fedarman B at both Luhmuhlen and Pau. Martin brought both Fedarman B and Commando 3 forward as potential Olympic selections at the start of the 2024 season. A strong showing of both at the CCI4*-S at the 2024 Kentucky Three-Day Event did not make selection easy, but Martin ultimately chose Fedarman B as his mount of the 2024 Olympic Games, with Commando 3 as a direct reserve. Paris 2024 will be Martin's fourth consecutive Olympic appearance for the U.S. Olympic Eventing Team. 

Martin and his wife, professional dressage trainer and athlete, Silva Martin, own and operate Windurra USA in Pennsylvania.

Doug Payne joined the United States Pony Club at the age of seven and eventually earned his A certification. Though Payne has a mechanical engineering degree from Rochester Institute of Technology, he wanted to work with horses professionally. His business DPEquestrian began in 2005 and has grown into a thriving operation. Payne is a well-known international competitor, trainer, judge, coach, and author. He has produced several horses to the top level of eventing.

In 2019, Payne and Starr Witness won The Fork CCI3*-S and the Jersey Fresh International CCI3*-L. The pair went on to represent the U.S. at the Pan American Games in Lima, Peru, earning the team gold medal and a fourth-place finish individually. That same year, Payne and Vandiver finished fourth in the Carolina International CCI4*-S and fifth in the Land Rover Kentucky Three-Day Event presented by MARS Equestrian™ CCI5*-L. For their placing as the second-highest U.S. combination in Kentucky, they claimed the Land Rover/USEF CCI5*-L Eventing Reserve National Championship presented by MARS Equestrian.

In 2020, Payne finished second and third with Vandiver and Quantum Leap, respectively, in the Stable View Oktoberfest Horse Trials CCI4*-S. He and Vandiver finished fourth in the Buckeye Nutrition USEF CCI4*-L Eventing National Championship.

Payne started 2021 with three horses in the top 10 at his first two international outings. Quantum Leap was fifth, Vandiver was seventh, and Starr Witness was 10^th in the Carolina International CCI4*-S. Next, Vandiver was first, Quantum Leap was fifth, and Starr Witness was eighth in The Fork CCI4*-S. Payne rode Starr Witness to a fifth-place finish in the CCI4*-S and Vandiver to a 12th-place finish in the CCI5*-L at the Land Rover Kentucky Three-Day Event presented by MARS Equestrian.

With Vandiver, Payne was named to the U.S. Eventing Team for the Tokyo Olympics.

Payne and his wife, Jessica, have a son named Hudson and a daughter named Abby.

Lynn Symansky began riding at the age of three and competing at the age of five. She grew up as a member of the United States Pony Clubs and earned her A certification. Symansky was competing at the Advance level by the age of 18, and has continued at the top levels of eventing. In 2018, Symansky and her seasoned off-the-track Thoroughbred Donner finished sixth in the Land Rover Kentucky Three-Day Event CCI4*. Symansky also placed second in the MARS Inc. Bromont Three- Day Event CCI3* with Under Suspection and third in the Jersey Fresh International CCI3* with RF Cool Play. Symansky is married to her husband Eric Reed.

Tamra “Tamie” Smith was a member of the U.S. Eventing Team that won gold at the 2019 Pan American Games in Lima, Peru, with Ellen and Alexandra Ahearn and Eric Markell’s German Sport Horse, Mai Baum. In 2021, Smith took Mai Baum to a top-10 finish in his CCI5*-L debut at the Land Rover Kentucky Three-Day Event. That year, they were named as the reserve for the U.S. Eventing Team for the Tokyo Olympics.

Smith has represented the U.S. in FEI Nations Cup competitions, including the CCIO4*-S at CHIO Aachen with Mai Baum and the CCIO4*-L at Boekelo, both in 2021.

Smith was the 2020 USEF CCI3*-L Eventing National Champion with Elliot-V at the Galway Downs International Event, and at the same event finished second in the CCI4*-L with Passepartout. In 2021, she and Mai Baum won the Grand Prix Eventing Showcase at Bruce’s Field. Smith went on to finish second in the CCI4*-S at the Land Rover Kentucky Three-Day Event and third at the Jersey Fresh CCI4*-L with Envogue. With Solaguayre California, Smith won the CCI3*-S at Red Hills International and the CCI3*-L at Jersey Fresh. She closed out the 2021 season with a win in the CCI3*-L at Galway Downs International with Maitanzer.

In 2022, Smith and Mai Baum competed in the Badminton Horse Trials CCI5* where they finished in ninth place. Smith was second and third in The Event at Rebecca Farm CCI4*-S with Solaguayre California and Danito, respectively. Smith and Mai Baum were second in the Great Meadows International CCI4*-S, then headed to the FEI Eventing World Championships in Pratoni, Italy, where they helped the U.S. team earn silver and finished ninth indivudally. Smith closed out the season with a win in the Morven Park CCI4*-L with Solaguayre California and a second-place finish at the Maryland 5 Star CCI5*-L with Danito. 

In 2023, Smith was first, second, and fifth in the Galway Downs Spring CCI4*-S with Mai Baum, Danito, and Solaguayre California, respectively. Smith and Mai Baum earned a historic win at the Land Rover Kentucky Three-Day Event presented by MARS Equestrian^TM CCI5*-L as the first U.S. combination to win since 2008. 

Smith has trained horses and riders at her Next Level Eventing since 2005.