However, maintains Fergus Connolly, a sports science expert and author of “Game Changer: The Art of Sports Science,” using load to assess injury risk has challenges. “The first challenge is that it’s hard to accurately define load,” Connolly says. “Is it a number defined by the previous game, or is it the chronic level for a season?” Connolly adds that it’s impossible to assess load by one simple number, formula or metric. The calculus of load is not only different for each player but also is a moving target that varies by time of season, age and even by opponent. Kawhi Leonard’s load tolerance today is surely different than it was five years ago, in ways that are difficult to understand. “It’s like painting by numbers when you don’t have all of the numbers,” says Connolly, who has served as a performance director in the NFL, “And trying to fill in those gaps with incomplete data.”