Tom Awad had a great piece last week on the significant impact that playing back-to-back games has on a team's performance. I thought I'd take a look at the impact that rest has on individual player performance.
This table shows the aggregate per-game performance of NHL players over the last four seasons based on the number of days since their last game:
|Rest||% of GP||G/82||A/82||P/82||+/-||PIMS/82||TOI|
|7 or more||1.7||12.9||23.4||36.3||2.36||67.2||21.81|
I only included players with 60 or more games played in an individual season in this analysis. (Ideally I'd know which players missed part of the season because they were injured and which players played regularly in the minors but were called up for a few games here or there - that information isn't easy to get.)
At any rate, you can see that performance suffers significantly when players play back-to-back games - they're tired, but their ice time drops all of three seconds. Overall scoring drops 5% relative to two days rest, while penalty minutes go up and plus/minus goes down. On the other hand, there is no significant difference between 2 days rest and 3 days rest.
For between 4 and 6 days of rest, the situation gets muddier. Scoring drops, but ice time drops even more, so players are more productive on a per-minute basis. The group of players that gets this many days off is probably a bit different than the group that gets 1-3 days rest: while it includes teams that had long layoffs, it also includes players who needed a day off because of an injury or marginal players who were healthy scratches or shuttled back-and-forth to the minors. We can see some evidence for this theory if we look at their per-game scoring relative to the overall average at different man-advantages:
|7 or more||-11.2||-9.7||-13.0||-23.2|
So players with 1 day rest declined primarily at even-strength, losing 5.4% of their overall per-game scoring, which is a good thing to know if you're trying to figure out who to start in your hockey pool. Players who were playing on 4-6 days rest did not show a measurable decline in even-strength scoring, but put up substantially lower numbers on special teams. It seems likely that they simply had way less PP and SH ice time than the other groups of players did, which accounts for the decline on a per-game basis.
Last but not least, players who'd been off for a week or more performed worse across the board than everyone else. They got less ice time, they scored less on both a per-game and per-minute basis, and they took more penalties. Some players in this group were coming back from a serious injury and needed their ice time limited because of fitness issues. Some were 8th defensemen or 13th forwards who'd been scratched for a week and weren't good enough to play real minutes. And some - as indicated by the higher penalty totals - were goons who didn't dress regularly. There are ways to separate out these groups, and I'll come back to this topic in the future to figure it out.