Even with a new push by the league to reduce back-to-backs and four-in-fives to all-time lows, there are still 533 back-to-backs in the NBA schedule.

Incumbent All-Stars from 2013-14 missed 19 games on average last season, or about a quarter of the season. Compare that with 2009-10, when incumbent All-Stars missed just 10.8 percent of their games -- or one of every 10 games.

In the 2000s, incumbent All-Stars missed 15.9 percent of games, 13.6 percent in the 1990s and just 11.4 percent in the 1980s.

The number of players averaging 35 or more minutes per game stands at 21 this season, down from 58 a decade ago. 

Teams play three points per 100 possessions worse on the second day of back-to-backs. 

"It's almost ludicrous how often they play," says Steve Magness, who has a master's in exercise science and wrote the book The Science of Running.

An NBA team will log 44,214 miles per season on average, more than NFL teams, MLB and NHL.