Fever coach reveals secrets to Caitlin Clark's incredible physical transformation

It's no secret that Caitlin Clark spent a portion of the WNBA offseason bulking up, but what fans haven't known is how — that is, not until Indiana Fever Performance Coach Sarah Kessler spilled the details to ESPN.

Kessler told the outlet that having the opportunity to spend months on end training was unique. "I don't know the last time I've had an athlete in the W, or even on the men's side, really, where you have a consistent four- to five-month period where you get to just work together," Kessler said.

Caitlin Clark's offseason workout

Single-leg work:

The duo worked on single-leg work to build explosiveness.

"Kessler incorporated isometrics to help Clark improve her time under tension and keep a low center of gravity," ESPN noted. "She tends to play upright, [Coach Stephanie] White said, which makes it easier to get knocked off balance.

Single-arm exercises:

"Clark acknowledged her left arm previously was a bit too weak to throw certain passes -- helped ensure each limb was strong individually. To provide an additional boost of energy to her muscles, Clark added the supplement creatine to her routine."

More: Caitlin Clark and Fever teammates filmed working out after Atlanta Dream win