Statistics in football is still a very young science. There are useful stats that seem to be predictive of performance, mainly on the attacking side of the ball, and completely pointless ones that give no indication of how a player or team is doing. One metric that seems to fall in the middle -- or at least needs a certain amount of context to make any sense -- is distance covered. Adam Lallana has recently garnered praise for his tremendous ability to cover ground for ninety minutes, and Jürgen Klopp puts great emphasis on his players' physical capacity, with a team-wide total of 120km covered a stated goal. On the other hand a lot of excellent players and teams run much, much less than Klopp preaches. So, context is required.
In general, Liverpool under Klopp do better when they cover lots of ground. One can only speculate as to why, but the immediate assumption is that the gegenpress works better when the players are able to quickly close down space as the ball moves from opposition player to opposition player. If the players move less or slower, there is more time and space for the opposing team, significantly decreasing the effectiveness of the Reds' plan A. Thus, fresh players are important for Liverpool's ability to deploy their preferred strategy.
With no European football, the schedule has been kind to Klopp's charges, averaging nearly six days between fixtures, leaving the players rested and ready to run. The holiday programme has been stacked, however, and the Reds have had the second shortest time between matches of all teams in the league, playing three full games in the space of 144 hours, or six days. This bears out in the numbers, as they posted a season-high 120.2km against Stoke, which dropped to 117.4 against Manchester City, before registering a season-low 108km in their frustrating draw with Sunderland. Despite Klopps' pride in the effort shown by his players, the correlation is clear enough, and while the FA's insistence on stacking matches upon matches during the holiday is confounding — its impact on player health and performance has long been well-known — it is up to the teams to find a way to mitigate the stress on their players.
The obvious way to do just that is squad rotation, and while he almost never names a completely unchanged eleven, Jürgen Klopp is not a big proponent of squad rotation. Granted, he has been hamstrung by injuries -- although this may be a different side of the same coin — but there is cause to believe that a slightly weakened but fresh Liverpool team would be able to do better against bottom-dwellers Sunderland than fatigued first-stringers. Hindsight is 20/20, of course, but the topic was hotly debated ahead of the contest, and the decision to swap only a single player surprised many well before the opening whistle.
Luckily for the Reds, Tottenham picked league leaders Chelsea apart on Wednesday night, breaking their 13-match winning streak and ensuring that Liverpool actually gained a point on the Blues despite their frustration at the Stadium of Light on Monday, but this experience is worth keeping in mind for future fixture congestion, and especially as European competition beckons next year. Mileage matters in the Liverpool country, and maintaining it should be a priority.