England’s reward for reaching the last 16 is a meeting with co-hosts Mexico at their Azteca Stadium stronghold in the early hours of Monday morning.
It’s a massive game and one that presents a challenge that Thomas Tuchel and his players have yet to face at this World Cup: playing at altitude.
Their opponents will be in their element at 2,240 metres above sea level in Mexico City, but what does it mean for England and how much greater is the risk of their hopes of glory vanishing into thin air?
Daily Mail Sport got the answers from James Barber, lead performance specialist at The Altitude Centre who prepared the Three Lions squad for the 2010 World Cup in South Africa and have been working with England’s rugby team ahead of the Nations Championship clash in Johannesburg on Saturday.
How does playing at altitude affect the game?
It can have a really big impact on footballing performance. The main reason is that the air at altitude is very thin, so the molecules are more spaced out. Every time you take a breath of air, you are taking in less oxygen. Football is basically 90 minutes of repeated sprints, and it makes it much harder to recover between those.
Over the first 10 or 15 minutes, you might not feel too much difference. But as time goes on, it’s harder to get those little micro recoveries and that really accumulates over the course of 90 minutes, let alone if it goes beyond that.
Data shows that the greater the height of a match, the less distance players cover. So it affects the style they can play.
A lot of the South Africa venues were at 1,600 metres, but Mexico City is quite iconic in terms of altitude. At the 1968 Olympics, there was about a six per cent impairment in the 5,000m and 10,000m times, so it’s a very real impact.
The iconic Azteca, where England will face Mexico 2,240metres above sea level
What about the flight of the ball itself?
The ball can fly further and it might fly a little bit more quickly because there’s less resistance against it. We see it in rugby, for example, where the ball is kicked a good 10-15 metres further at altitude than it is at sea level.
It might change what’s going on with the flight of the ball as well, and there will be differences in how it’s curling.
So it’s impacting the players physically, but also the ball will be doing things differently to what they would expect it to do at sea level, which makes it really interesting from a skill performance point of view.
How much of an advantage will it be for Mexico?
It will be an advantage for two reasons: the fact they’re born at altitude helps them, which is partly why the East Africans are so good at distance running, for example.
But it’s also trainable and something that people can pre-acclimatise to. If you’re able to spend a lot of time at altitude – a good couple of weeks – then your body will start getting used to it, which is what we did with the FA at the 2010 World Cup.
You are probably looking at least a week to overcome an initial acclimatisation phase. If England can get up there for a little bit of time beforehand, that’s not going be bad for them but it’s very unlikely to be meaningful.
Mexico beat Ecuador 2-0 in Mexico City in the last 16 – they have lost just two competitive games there since the Azteca opened in 1966
Have England made a mistake by not preparing better to play at altitude?
The amount of travel potentially involved in this World Cup is pretty unprecedented. England have had to pick their battles: do they prepare for the heat or do they prepare for the altitude? With the preparation in Portugal and where they’ve been based in Kansas City up to this point, is seems as though they’ve chosen to look at the heat.
There will be come benefit to that, some crossover adaptation between the heat and altitude, but that seems to be the route they’ve gone down.
Could it influence Tuchel’s team selection and tactics?
Part of the challenge for sports scientists working with the team is that you’ve got a squad of people who respond differently. It can vary massively from individual to individual.
If they find when they get up there, some players are particularly impacted by the altitude then, yes, maybe that’s something that would need to be taken into consideration.
The best thing to do is to identify those people who deal well with the altitude, and those people who are a bit more susceptible to it. Things like fitness don’t really factor in. These guys are all incredibly fit, but that’s not necessarily protective against the effects of altitude.
So really, if the altitude is going to impact the tactics they decide to play with, then it might directly impact on things like team selection.
Is there anything else England squad can do to prepare?
There are a couple of things they’ll be paying attention to: overall your energy intake needs to be higher because you burn more calories, and it’s quite dehydrating being at altitude so you need to be focused on your hydration.
It’s nothing that’s particularly different to what they’ll be doing anyway, but they just need to be paying a little bit more attention to it than you would at sea level.
