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Negative correlation between temperature and physical performance

The CIES Football Observatory is pleased to present a video analysing the relationship between the distance covered by players during a match and the ambient temperature. Data collected in partnership with SkillCorner from 35 leagues around the world indicates a significant decrease in the distance covered as temperatures rise.

On average, a player covers 10.1 km during 90 minutes of play if the temperature does not exceed 15°C ; this distance decreases by about one kilometre when the temperature rises to 30°C or higher.

Leagues located in the hottest regions are particularly affected by this heat stress, including the Pro League in the United Arab Emirates, the K League in South Korea, the Chinese Super League, La Liga in Spain, and the Brazilian Serie A. With the World Cup underway, MLS data also shows the negative impact of high temperatures on the distances covered.

>>> More about SkillCorner

>>> Full video

>>> New Prospect Sheet with ImpectYan Diomandé

Top-valued teams: three main favourites

Based on the estimated transfer values* of the selected players, three national teams look like the main favourites to win the 2026 World Cup. England top the ranking with a total squad value of €1.454 billion. They are followed by France (€1.436 billion) and Spain (€1.407 billion). The values of all qualified teams are listed in the 550th Weekly Post of the CIES Football Observatory.

With inflation and a larger number of participating teams, the estimated total value of all squads in the competition reaches €18.1 billion. This is €3.1 billion more than at the 2022 World Cup. As noted last week, the statistical model of the CIES Football Observatory currently values only two players at more than €200 million : Spain’s Lamine Yamal and Norway’s Erling Haaland.

At the other end of the ranking, Iran is the qualified team with the lowest total transfer value, at only €12 million. It is followed by Iraq (€13 million) and Jordan (€15 million). However, strong performances in the competition could still help some players from these teams secure a transfer to much more competitive clubs.

* According to CIES Football Observatory’s statistical model

>>> Full data

Most expensive players: Yamal in a league of his own

The 549th Weekly Post presents the 100 players in the world with the highest estimated transfer value, as calculated from the CIES Football Observatory’s statistical model. FC Barcelona’s young Spanish prodigy, Lamine Yamal, crushes the competition with a valuation of €358 million. Ahead of Manchester City’s Norwegian striker Erling Haaland (€227 million).

No other player is valued at over €200 million, with Kylian Mbappé in third place (€166 million). The following players are at the top of the list for the other positions : Gianluigi Donnarumma (goalkeepers), Pau Cubarsí (centre backs), Nico O’Reilly (wide backs), Pedri González (central midfielders) and Arda Güler (attacking midfielders).

Compared with last January, the largest increase was recorded for Yan Diomandé (+€75 million to €119 million), whilst the largest decrease was for Alexander Isak (-€54 million to €41 million). Compared with June’s 2025 ranking, the largest changes were registered again for Yan Diomandé on the positive side (+€116 million) and Jude Bellingham on the negative one (-€113 million).

>>> Top 100

Top valued player per club in 7⃣0⃣ leagues 👉 https://football-observatory.com/Tool-Value

New Prospect Sheet with Impect: Lucas Herrington

Most popular clubs on social media

The 548th Weekly Post from the CIES Football Observatory ranks clubs worldwide according to their number of followers on the main social media platforms (Facebook, Instagram, TikTok, YouTube and X). Two clubs stand out: Real Madrid (488 million followers) and Barcelona (442 million). England’s Manchester United complete the top three (239 million), ahead of Paris Saint-Germain (208 million).

Among teams ranked in the top 10 positions, German side Bayern Munich recorded the strongest growth over the past year both in absolute (+16.1 million followers) and relative terms (+11%). Clubs in the top 10 have a combined total of 2.36 billion followers, up 3.8% on last year, broken down as follows among the platforms selected: Instagram (31%), Facebook (31%), TikTok (17%), X (16%) and YouTube (5%).

Twenty-six countries from every continent except Oceania are represented in the top 100, with the highest number of clubs located in the following three nations: Spain (21 teams, often with a large following on TikTok), England (16) and Brazil (11). Outside Europe, the top three are Brazil’s Flamengo (€71.6 million), Saudi Arabia’s Al-Nassr FC (€66.0 million) and Egypt’s Al-Ahly SC (€60.1 million).

>>> Top 100

Best XIs of the season: 34 leagues

The 547th CIES Football Observatory Weekly Post presents the Team of the Season (4-2-1-3) for 34 leagues reaching their conclusion. The selection was made by taking into account players’ performances (eight game areas for outfield players and the difference between goals expected goals and conceded for goalkeepers ; Impect data), the results of matches in which players’ participated, and playing time.

At big-5 league level, the following goalkeepers are part of the Best XIs : David Raya (Arsenal), Joan García (Barcelona), Hervé Koffi (Angers), Alexander Nübel (Stuttgart), and Marco Carnesecchi (Atalanta). At the forefront of the attack are the top scorers : Erling Haaland (Manchester City), Kylian Mbappé (Real Madrid), Estéban Lepaul (Stade Rennais), Harry Kane (Bayern), and Lautaro Martínez (Inter).

The CIES Football Observatory Team of the Season in the Premier League is made up of five Arsenal players (Raya, Timber, Saliba, Gabriel Magalhães and Rice), three from Manchester City (Cherki, Haaland and Doku), two from Manchester United (Casemiro and Bruno Fernandes), as well as Adrien Truffert from Bournemouth. More information about the method used is available here.

>>> All Best XIs

>>> New Prospect Sheet with Impect: Pedro Zarza

Player exports: Brazil ahead of France

The 546th CIES Football Observatory Weekly Post presents the 50 nations worldwide with the highest number of expatriates* currently playing in 135 professional leagues across the globe. As last year, Brazil remains the leading exporter (1,455 players abroad, +37), but is being hotly pursued by France (1,275, +86), with reigning world champions Argentina in third place (1,016, +27).

Since 2021, the largest increase in absolute terms has been recorded for France (+332 expatriates), with a steady rise (+35% in five years). In relative terms, the sharpest growth among the top 10 exporting nations was observed for Portugal (+198 players abroad, +66%), Spain (+255, +60%) and Nigeria (+211, also +60%).

Only 9 of the top 50 exporting countries have seen a decline in the number of their nationals abroad since 2021, reflecting the general increase in international migration flows. The sharpest decline was recorded for Serbia (-53 expatriates, -12%). To find out the main foreign destinations for each country of origin, please consult our Migration Atlas.

* Origin is defined as the association where the player grew up and which he left following recruitment by a foreign club.

>>> Full data

>>> Video analysis of the evolution of origins in Europe’s big-5 over the past 20 years

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