Analgesics are widely used in sport to treat pain and inflammation associated with injury.1,2 However, there is growing evidence that some athletes might be taking these substances in an attempt to enhance performance.3,4 Although the pharmacologic mechanisms of analgesics and their utility in treating pain, either with or without anti-inflammatory effects, are well established, their effect on sport performance is debated.1,4–7

Soccer is a popular team sport and highly demanding activity that requires high effort, especially among professional players.8–10 For that reason, the use of medication in international football has been monitored since the 2002 FIFA World Cup.11 Data at the time was alarming because up to 69% of adult male players reported use of analgesics, mostly in the form of non-steroidal anti-inflammatory drugs (NSAIDs). Besides their well-documented analgesic effects, NSAIDs also interfere with bone healing and callus formation and may cause impairing bending stiffness,12 as well as cause gastrointestinal bleeding, cardiovascular and renal effects.13 To date, all the alerts published about risks associated with their consumption seem to have not been effective, with data collected during the FIFA Women's World Cup indicating that the mean intake of medication was significantly higher among females whereas the use of NSAIDs was similar.11 Moreover, in an anonymous survey given to 211 U.S. college soccer players before the season, 96% reported current or previous use of NSAIDs. Half of these reported having first used NSAIDs in junior high school or high school, with 3-fold higher consumption after games than before games (33% vs 11%, p=0.002).14

This reported incidence is alarming, more so because it is most probably underestimated, since self-medication by the players or treatments previously prescribed by club physicians are usually not included in the published reports. Furthermore, the reports reviewed usually did not show gender-disaggregated data, and thus we cannot infer that the same evidence found in men applies to women. What´s more, a recent review that investigated 226,256 athletes showed that risk factors associated with opioid analgesic use (e.g.: Caucasian, postretirement unemployment, and undiagnosed concussion) also included participation in contact sports (hockey, football, and wrestling). Again, results were not analyzed by sex.15

The objective of this our study was to perform a systematic review of literature to determine the prevalence of analgesic use in professional soccer players. Patterns of other drug or substance use, potential side effects and the motivation for consumption (e.g.: reducing pain vs. performance enhancement), were also taken into consideration.

We conducted a systematic review on the use and the effects of analgesics in soccer using literature from January 1980 to July 2021. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed.16 The systematic review was carried out in the PubMed, Scopus, and Web of Science (WOS) databases, the Cochrane Library, and by manual searching of reference lists from studies and reviews (without language restrictions applied).

The following key words were used in combination with Boolean operators AND or OR for the literature search: “analgesics” OR “opioids” OR “paracetamol” OR “acetaminophen” OR “painkillers” OR “NSAIDs” OR “nonsteroidal anti-inflammatory drugs” OR “glucocorticoids” OR “ibuprofen” OR “tramadol” OR “codeine” AND “football” OR “soccer” OR “football players” OR “soccer players” AND “exercise” OR “performance” OR “strength” OR “agility” OR “pain” OR “injuries” OR “resistance”.

Data extraction

Fig. 1 summarizes the study selection process, in which a total of 213 articles were selected and 150 articles remained after discarding duplicates. While filtering according to the established exclusion criteria, we discarded 88 articles, resulting in 62 articles after review of abstracts. Confirmation of the initial inclusion criteria was also done once the abstracts had been reviewed. Following review of the complete articles, 48 more articles were discarded as they did not have the desired format, being reviews, only abstracts or case reports. Ultimately, the definitive number of studies included in the final review was fourteen.

Fig. 1.

PRISMA summary of the study selection process (n, number of studies).

(0.3MB).

The data collected from 14 studies included in this review were divided into two groups: 1) epidemiological studies analyzing the prevalence of analgesics and other drugs’ use (Table 1); and 2) clinical trials that studied the effects on performance after analgesic doses (Table 2).

Our review gives evidence of concerning levels of use of analgesics for successful pain relief during soccer tournaments. Data was alarming because up to 69% of adult male players reported analgesic use, mostly in the form of non-steroidal anti-inflammatory (NSAIDs) drugs. This reported incidence is most probably underestimated, since self-medication by the players and treatments previously prescribed by club physicians are usually not included in published reports.

This systematic review indicated that consumption of analgesics, remains at a high level despite limited evidence of their effectiveness on exercise recovery or tolerability. The key finding of this systematic review is that there is a lack of evidence which support the current use of analgesics in soccer. Moreover, females are underrepresented in currently available data sets, which furthermore include few clinical studies on analgesics’ effects on exercise and recovery performance. We believe this merits further investigation in these specific cohorts.

Existing empirical research does not provide a sufficient body of evidence to guide athletes and healthcare professionals in making analgesic medication treatment decisions. Due to the limitation evidences regarding the widespread use of NSAIDs, clinicians and policymakers should carefully assess their current recommendations for NSAIDs’ use and establish a more unified consensus based strategy for multi-disciplinary pain management in elite athletes.1,5,7

This is quite relevant in soccer because it is one of the disciplines within professional sports that has evolved the most in terms of physical demand.8–10 Nowadays, match-related fatigue leads athletes to limit muscular effort in ways that put their bodies to the test, with hardly any time for full recovery.1,34 After each game, there is significant muscle pain associated with play-induced performance demands, as well as with resulting injuries.2,4 Furthermore, the short time available for the footballer's recovery exacerbates the frequent use of analgesic drugs, thus increasing potential risk of misuse and related harms.11

Related to drugs, paracetamol has been suggested to improve endurance and performance in repeated sprint exercises by reducing activation of the higher brain structures involved in pain and cognitive/affective processing.35,36 NSAID drugs indeed affect both central and peripheral body systems, but research on their ergogenic effect on muscle strength development has provided equivocal results.4 The therapeutic use of glucocorticoids is indubitable, but no clear evidence exists for performance-enhancing effects after short-term oral administration.3 In contrast to the aforementioned analgesics, there is a paucity of research on the use of opioids such as tramadol on sporting performance. Based on the evidence presented in this review article, the ergogenic benefit of analgesics may warrant further evaluation by regulatory bodies.

Alternatively, infiltration is a therapeutic option used for the treatment of various diseases, consisting of injected administration of different substances into precise locations on the body. This procedure may have an analgesic and/or anti-inflammatory and healing effect, but it must be preceded by the appropriate diagnosis. Its use is common in the treatment of many soft tissue injuries, such as bursitis, synovitis, plantar fasciitis, sprains, muscle injuries, tendinopathies and chondral injuries. The most frequently used active substances are corticosteroids and local anesthetics that produce immediate pain relief, such as lidocaine and bupivacaine.37 However, in our review, use of these drugs was scarcely reported, meaning that the risk of non-medical usage was probably lower than for other oral analgesics.

Despite a decreasing gender gap in exercise participation, a significant under-representation of women included in sport and exercise medicine research studies still remains.38 In relation to the presence of females in the studies (prevalence and clinical trials), the results showed that only 14,3% (n=2/14 papers) included female participants. Here, any gender information was analyzed in the papers. Moreover, a recent scoping review on all aspects of competitive women's football found that the most-researched area was injuries. These were predominantly assessed in epidemiology studies that most frequently focused on the whole body, knee or head/face injuries.39 In our review we confirmed that a lack of data on the women involved in these studies exists.

Some limitations within the studies reviewed must be taken into consideration. Most studies were observational and retrospective and as such included all types of bias that accompany such a design, especially a lack of generalizability. Hence, caution is advised when applying the results to the population as a whole. Another point of concern is that the trials included in this review only one was controlled with a placebo and thus imply that all observed effects were due to the drug's consumption and not due to a placebo-effect. Future randomized controlled studies should account for this factor. Another weakness is that the use of pain medication, including NSAIDs, was only documented using questionnaires that lacked information related to tolerability. A further limitation was the lack of information about sociodemographic variables that could have increased misuse or abuse risk profiles, such as any pressure exerted by sport clinicians.

This systematic review has some of its own limitations, too. Because of the heterogeneity of the scores used in the studies, no meta-analysis could be performed. In addition, the low number of studies included (only four randomized trials) could be considered to be a limitation that might have introduced a systematic bias. Further clinical studies are needed to more precisely characterize the targeted subgroup of athletes. In the future, we hope to see more rigorous, prospective studies of various pain management strategies in elite athletes, thus enabling a shift from consensus-based recommendations to evidence-based recommendations.

At first glance, transversal or short-term observational studies showed high consumption levels of analgesics despite limited evidence of improved exercise recovery. The question of whether differences in potential analgesic abuse exist between the sexes thus remains open. We believe these merits further investigation in these specific cohorts.

Our review indicated that high consumption rates of analgesics appear to frequently be paired despite limited evidence of their effectiveness on improving exercise recovery or tolerability. The key finding of this systematic review is that there is a lack of evidence to support the current use levels of analgesics in soccer. Moreover, females are underrepresented in current data sets available, which include few clinical studies on the effects of analgesics on exercise performance and recovery. We believe further investigation in the abovementioned cohorts is needed.

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.