A deep dive into the physiology, injury history, and strategic logic behind Solbakken's most controversial call at the 2026 World Cup so far.
When Norway's head coach Ståle Solbakken left Erling Haaland on the bench for the group-stage finale against France, the reaction was predictable. Fans around the world were not happy and questioned the logic of surrendering a Haaland-versus-Mbappé duel and potentially first place in Group I, in the name of squad rotation. Norway lost 4–1, with Ousmane Dembélé completing a first-half hat-trick.
But here is the thing: Solbakken had a point. And the science backs him up.
A Season That Never Stopped
Before we discuss the bench decision, we need to understand what Haaland's body had been through. The 2025–26 Premier League season was Haaland's most prolific yet, 27 goals, 8 assists, and nearly 3,000 minutes in the league alone. He reclaimed his Golden Boot, surpassed 100 Premier League goals in just 126 appearances, and crossed the 150-goal mark for Manchester City across all competitions.
That is an extraordinary output. But output at that level comes at a cost measured not just in goals, but in the microscopic wear and tear accumulating inside the very muscles that make him special.
Then came the World Cup. Haaland entered the tournament in searing form, scoring four goals in Norway's first two group matches, putting him level with Mbappé for second place in the Golden Boot race. He played full minutes in both. His body had not stopped since August.
By the time Norway faced France, Haaland had logged not just two intense World Cup matches, but an entire European season's worth of high-intensity sprinting. Solbakken confirmed that medical tests had detected accumulated fatigue in multiple squad members, describing the rest decision as a "no-brainer." The coach was explicit: "We are not here just for fun. We want to proceed as long as possible."
The Injury File Nobody Wants to Read
Critics of the decision often point to Haaland's current form and overlook his history. That history is instructive.
Over the course of his career, Haaland has sustained 17 documented injuries, including recurring knee problems (the most frequent), muscle strains in the thighs and hip flexors, ankle injuries in 2022, 2023, and 2025, and a serious bone stress reaction in his foot during the 2023–24 season that sidelined him for 54 days across 11 missed matches. During his time at Borussia Dortmund, he missed 20 games in a single season due to hip and muscular issues. Even at Manchester City, where proactive load management is one of the most sophisticated in European football, he missed approximately 18% of matches in 2024–25.
The pattern matters. The injuries are not random bad luck. They are the predictable consequence of what Haaland's body does during a match.
The Science of the Sprint Machine
Haaland is not a typical striker in any physiological sense. He covers fewer total kilometres per 90 minutes than almost any elite forward in the game. That might sound like a criticism; it is actually the key to understanding why protecting him is so important.
What Haaland does instead of pressing or tracking back all the time is explode in the right moment. He averages approximately 20 high-intensity sprints per match, consistently reaching speeds above 34 km/h, with peak measurements recorded at 35.04 km/h. He conserves energy with ruthless efficiency between these efforts and then releases it in the penalty box, where games are won.
This movement profile makes him essentially an anaerobic athlete operating within a 90-minute aerobic contest. His energy system during those sprints is primarily phosphocreatine (PCr) and anaerobic glycolysis, not the sustained aerobic metabolism that a box-to-box midfielder relies upon. That distinction is everything.
What Happens Inside the Muscle
To understand why fatigue in a player like Haaland is so consequential, it helps to understand what repeated sprinting does at the cellular level.
Each sprint draws first on the PCr system a fast, powerful, but finite energy source stored directly in the muscle fibre. When recovery between sprints is short, PCr stores cannot fully replenish. The body then shifts increasingly toward anaerobic glycolysis, producing lactate and inorganic phosphate as by-products. These accumulate, progressively impairing the muscle's ability to generate force. Sprint times slow. Stride frequency drops.
Research in professional football players has shown that those with better repeated-sprint performance display faster muscle deoxygenation during efforts and critically faster reoxygenation during recovery periods (Morin et al., 2014, European Journal of Applied Physiology). That reoxygenation rate is not just about aerobic fitness in the traditional sense; it reflects the muscle's capacity to resaturate with oxygen-rich blood quickly enough to restore PCr and clear metabolic waste before the next sprint is demanded.
This is where muscle oxygen saturation (SmO₂) becomes a uniquely powerful tool.
Monitoring the Muscle: The Role of SmO₂
SmO₂ measured in real time using Train.Red near-infrared spectroscopy (NIRS) sensors worn against the skin, captures the balance between oxygen delivery and oxygen consumption in the working muscle. During high-intensity efforts, SmO₂ drops as the muscle desaturates; during recovery, it rises as oxygenated blood returns.
For a sprint-dominant athlete like Haaland, the two critical metrics are:
- Desaturation rate: how rapidly oxygen is depleted during each sprint effort (a proxy for the intensity of the anaerobic demand)
- Resaturation rate: how quickly the muscle reloads oxygen between sprints (a proxy for recovery efficiency and PCr replenishment capacity)
Studies on repeated sprint ability in soccer players have found that both desaturation and resaturation dynamics are strongly associated with performance specifically, that greater oxygen extraction capacity (larger drops in muscle saturation) combined with faster recovery are the hallmarks of elite repeated-sprint athletes (Vasquez-Bonilla et al., 2021, IJERPH). Research on sprint cyclists has confirmed that SmO₂ kinetics can distinguish between sprint and endurance athlete profiles and reflect the capacity of the alactic anaerobic system, the PCr-dependent system Haaland relies on most (Comparative Bilateral Measurements study, PMC 2024).
Other research has demonstrated that a player's desaturation and resaturation rates correlate directly with their repeated-sprint performance, with faster oxygenation dynamics predicting better maintenance of sprint speed late in protocols (Morin et al., 2014).
In practical terms, this means that if fatigue has compromised a muscle's resaturation rate, as cumulative loading over a long season and tournament schedule can do, the muscle is physiologically less capable of sustaining peak sprint output. It is slower to recover between efforts. The mechanism that makes Haaland dangerous in the 88th minute is then degraded.
How SmO₂ Could Transform Haaland's Training
Applied proactively, SmO₂ monitoring offers a remarkably precise tool for optimising a sprint-dominant athlete's preparation and load management.
In training, Haaland's team could use NIRS sensors during repeated sprint sessions to identify his individual SmO₂ thresholds, the exact point at which the muscle transitions from aerobic to anaerobic metabolism, and calibrate recovery intervals accordingly. Research using portable NIRS devices has shown that SmO₂ is a reliable complementary parameter for identifying the shift from aerobic to anaerobic workloads and tracking ventilatory threshold transitions in real time (Quintero-Arévalos et al., 2023, PMC). Unlike heart rate, SmO₂ is localised to the specific muscle group being monitored, and it responds in real time, offering feedback on the state of the muscles from the leg (vastus lateralis or gastrocnemius for example) during the sprint itself, not 30 seconds later.
In-match, SmO₂ data could give staff a live readout of muscular fatigue, not a subjective impression, but a measurable signal of whether Haaland's muscles are recovering between sprints at their baseline rate or whether that rate is degrading. A drop in resaturation efficiency across successive sprints is an early warning sign, one that appears before visible performance decline.
The Bigger Picture: Protecting the Tournament
Here is the strategic reality Solbakken understood that the crowd in Foxborough perhaps did not.
Norway had already qualified for the round of 32. The group stage was decided. Facing France, onw of the world's most dangerous attacking side, with their full-strength lineup, without a rested Haaland offered the possibility of winning the group at the cost of exposing their most important player to aexhausting high-intensity 90 minutes. Given his injury profile, his anaerobic demand profile, and a season that had already pushed close to 3,000 minutes, the risk of muscular strain in that game was not negligible.
Resting Haaland did not just mean he got a day off. It meant his PCr stores would be fully replenished. His resaturation kinetics, potentially dulled by back-to-back matches, would return toward baseline. He would arrive at the round of 32 against Ivory Coast as the athlete he can be at his best: explosive, sharp, and healthy.
A Haaland at 100% is one of the most lethal weapons in world football. Norway lost 4–1 without him. But the question was never whether Haaland would have changed the score against France. The question was always whether Norway wants to see Haaland step onto the field in the knockout rounds and be the player who changes scores there.
Solbakken understood that. Science agrees with him. The result on the next game will tell if he was actually right.
Morin et al. (2014), European Journal of Applied Physiology
Vasquez-Bonilla et al. (2021), IJERPH
Quintero-Arévalos et al. (2023), PMC
PMC Bilateral SmO₂ Sprint Study (2024)
ESPN; Fox Sports; beIN Sports.
