Kenneth Ray Sprague (born July 14, 1945) is an American bodybuilder, entrepreneur, author, and educator best known for purchasing and operating the original Gold's Gym in Venice, California, from 1970 to 1979, during which time it emerged as the epicenter of the golden era of bodybuilding and hosted events featured in the documentary Pumping Iron. Under his ownership, the gym attracted elite athletes including Arnold Schwarzenegger, grew its annual revenue significantly from modest beginnings, and gained national media attention through coverage in outlets like 60 Minutes and the Wall Street Journal. Sprague, who began weight training in childhood and competed in bodybuilding, powerlifting, and track and field events, later authored several instructional books on strength training, such as The Gold’s Gym Strength Training Book (1994) and The Gold’s Gym Bodybuilding Book (1983), drawing from his experiences coaching adolescent athletes and world champions across multiple sports. His tenure at Gold's Gym played a key role in popularizing weight training, though Sprague has noted in interviews being underrepresented in mainstream narratives of the era.

1969–1973: Modeling Career with COLT Studio

In 1969, while attending the University of Cincinnati, Ken Sprague was encouraged by a friend to pursue modeling; a photograph of him was submitted to Colt Studio in New York City, resulting in an invitation to pose for the studio's founder, Jim French. Colt Studio, established in 1967, specialized in homoerotic physique photography of muscular men, primarily appealing to a gay male audience through mail-order prints, calendars, and magazines. Adopting the pseudonym Dakota, Sprague's initial work involved a four-day posing session in New York, showcasing his athletic build from prior strength sports and bodybuilding endeavors.

Sprague relocated to Los Angeles in 1970, signing formally with Colt and expanding his output to include appearances in gay erotica publications such as Blueboy stroke books and calendars, as well as occasional pornographic films. His modeling emphasized raw muscularity and minimal attire, aligning with Colt's signature style of celebrating male physicality without narrative constraints. This phase lasted until 1973, during which his earnings from the studio provided financial means for subsequent business ventures, including the acquisition of Gold's Gym. Sprague's tenure as Dakota positioned him among Colt's early iconic models, contributing to the studio's reputation in the emerging market for explicit male imagery.