Muscle injuries represent the most frequent type of injury in professional football.
This is not an isolated finding linked to a single tournament. FIFA‘s official injury surveillance across international tournaments from 1998 to 2012 documented a stable average of 2.6 injuries per match, with muscle and tendon injuries consistently ranking as the most common diagnoses. At the 2014 FIFA World Cup, the thigh was the most frequently affected body region, accounting for 25% of all injuries. At the 2022 FIFA World Cup in Qatar, updated data confirmed the same pattern: 48 muscle–tendon injuries out of 82 total injuries, corresponding to a match incidence of 20.6 injuries per 1,000 player-hours of exposure. Hamstring injuries were once again the single most common diagnosis.
The most concerning finding is the continued rise in hamstring injuries in men’s professional football. Their incidence has increased by approximately 4% per year since 2001, and they now account for nearly one in every four injuries sustained by professional players.
The same pattern is also emerging at the 2026 FIFA World Cup.
Even before the start of the tournament, muscle injuries had already affected several national teams. Estêvão (Brazil) was ruled out with a hamstring injury sustained against Manchester United; Serge Gnabry (Germany) underwent surgery for an adductor injury suffered during the quarter-finals of the UEFA Champions League; Wesley França (Brazil, Roma) was forced to leave the field in tears after just 17 minutes of a friendly match because of an adductor strain; and Éder Militão (Brazil) was sidelined by a hamstring injury that ultimately required surgery. Meanwhile, Lennart Karl, the 18-year-old Germany call-up, sustained a thigh injury in training only days before the tournament opener.
The pattern documented by the scientific literature continues to be confirmed, tournament after tournament.
Sprinting, shooting, changing direction, and pressing: during these actions, the hamstring muscles operate under eccentric contraction, lengthening while generating force. Under these conditions, mechanical loads can reach extremely high levels within fractions of a second, placing substantial stress on the muscle–tendon unit.
Dr. Marco Gastaldo
These injuries are primarily caused by the forces generated during high-intensity actions. Sprinting, shooting, changing direction, and pressing all place substantial demands on the hamstring muscles. During these movements, the hamstrings work under eccentric contraction, lengthening while generating force, and are exposed to extremely high mechanical loads within very short time intervals.
A video-analysis study conducted by the Isokinetic Group (Della Villa et al., British Journal of Sports Medicine, 2023), involving 103 severe muscle injuries sustained by players in the Italian Serie A, identified four main injury mechanisms that accounted for 88% of all cases:
- high-speed running and acceleration (34%),
- closed kinetic chain stretching movements (20%),
- open kinetic chain stretching movements (18%),
- kicking actions (16%).
Notably, 83% of the injuries occurred without any direct contact, highlighting the predominant role of intrinsic biomechanical and neuromuscular factors rather than external trauma.
The same study produced a finding that challenges a long-standing belief.
For many years, muscle injuries were thought to be primarily a second-half phenomenon, largely attributable to fatigue accumulated during the match. However, the analysis showed that 71% of severe muscle injuries occurred during the first half, with more than half taking place within the first 30 minutes of effective playing time.
For calf muscle injuries, this proportion rose to 94%. The authors concluded that match-induced fatigue is unlikely to be a primary risk factor for severe muscle injuries. Instead, the high mechanical loads generated during high-intensity actions appear to play a more decisive role in injury occurrence.
Fatigue appears to play a role on a different timescale: between matches rather than during an individual game.
The largest study ever conducted on this topic, involving more than 130,000 observations from professional matches over a 14-year period (Bengtsson et al., British Journal of Sports Medicine, 2017), demonstrated that the risk of muscle injury increases significantly when the recovery period between matches is less than five days.
At the 2014 FIFA World Cup, team physicians from all 32 participating national teams identified reduced recovery time and a congested match schedule as among the leading risk factors for injury occurrence.
The impact of the World Cup on the subsequent club season was also documented in 2022. In the French, English, and German leagues, both the overall number of injuries and the incidence of muscle injuries increased during the season affected by the winter 2022 FIFA World Cup in Qatar, compared with comparable seasons played under the traditional calendar.
For the 2026 FIFA World Cup, every risk factor identified in the scientific literature is amplified: 48 teams instead of 32, 104 matches instead of 64, and a 39-day tournament spread across the United States, Canada, and Mexico.
Return to play after a muscle injury cannot be determined by the competition schedule. It must be guided by functional criteria, including muscle strength, limb symmetry, movement quality, and the athlete’s ability to tolerate the physical demands of match play.
Dr. Marco Gastaldo
Return to play after a muscle injury should not be dictated by the competition schedule. Instead, it must be based on functional criteria, including muscle strength, inter-limb symmetry, movement quality, and the athlete’s capacity to tolerate match-specific workloads. A muscle that is no longer painful is not necessarily ready to withstand the high mechanical demands of sprinting, kicking, and other explosive football actions.
This will likely become evident in the coming weeks of the 2026 FIFA World Cup, as return-to-play decisions involving injured players attract increasing media attention. Behind every high-profile comeback lies a complex medical and performance-based assessment, balancing the urgency of competition against the need to ensure that the player is truly prepared to tolerate the demands of elite-level football.
Dr. Marco Gastaldo
MD, Specialist in Physical and Rehabilitation Medicine
Isokinetic Medical Group Turin
FIFA Medical Centre of Excellence
