The WTA's top-ranked player, Caroline Wozniacki, failed to win a major in 2010. Serena Williams won two but played in only six tournaments. Justine Henin's comeback faltered, and Maria Sharapova battled injuries. One highlight, though, was the return of Kimiko Date Krumm, who rose to No. 4 in 1995 but quit at the end of the next season. Twelve years later she unretired (don't they all?), and in 2010, the year she turned 40, she beat Sharapova, No. 8 Sam Stosur and former No. 1 Dinara Safina to finish in the top 50.... After reaching the Wimbledon final, Tomas Berdych won only nine of his next 23 matches.... Think tennis requires physical maturity? The average age of players in the ATP's top 100 is 26, a record high.