This prospective study assessed the incidence and characteristics of injuries in male and female amateur football players who participated at the 18th National Sport Festival that was held in November 2012, in Lagos State, Nigeria. This study is the first to document the incidence of injuries in a completely Nigerian football tournament. The consensus protocol for data collection in studies relating to football injury surveillance was used for this study in order to allow comparison of our results with other studies . However, no prospective studies were found relating to adult female semi-professional football players in Nigeria or Africa, hence comparison in this regard was limited.
This study revealed a high overall injury incidence for both male and female football players. However, most (86 and 88% for male and female players respectively) of the injuries did not stop players from continuing in the tournament. An overall injury incidence of 113.4 and time-loss incidence of 15.6 injuries/1000 match-hours as recorded for male players is high in comparison with similar studies done outside Africa [4–18]. This result however corroborates previous studies reporting a high incidence of injury among male football players in Africa [24–26]. An overall incidence of 65.9 and time-loss incidence of 7.9 injuries/1000 h for female players is within the range recorded for female football players during top-level FIFA tournaments . However, this result is lower than the injury incidence documented for female youth football players in Kenya .
Injury surveillance studies among male and female football players in the African continent seem unequivocal on high incidence of injuries among players and our study corroborates this [24–27]. The high incidence of injuries may be hinged on a few factors as discussed in previous studies [24, 25, 27]. One major factor attributable to increased incidence of injuries is the generally low level of skills and the physical pattern of play in African football. Based on the records of International football matches, skill levels in less developed settings such as Africa and Asia have been considered to be lower than those of their European counterparts . Although the influence of the different skill levels on the incidences of injury remains a controversial issue, some researchers reported that lower skill levels were associated with more frequent occurrences of injuries . While most reported injuries are not time-loss, the trend of high football injury incidence in the African region calls for urgent attention and appropriate intervention.
In the present study, majority of the injuries affected the lower extremities (70 and 61% for males and females respectively); mostly the lower leg, ankle and knee joints, which is in concordance with other reports [4–26, 30, 31]. The most common types of injuries were contusions, sprains, and strains; this is also in agreement with previous studies [4–26, 30, 31]. It is important to note that contusion injury accounted for three out of five injuries of all injuries; most of which did not result in time-loss. Furthermore, the ankle and knee joints recorded the highest proportion of time-loss injuries by male players. This is in congruence with previous studies on professional male football tournaments [6, 8, 12]. However, time-loss injuries were not specific to any body parts for female players.
In most cases, players were able to continue playing in the male and female tournaments. Hence, the focus on injury management during subsequent tournaments should be on the field treatment of non-severe injuries such as contusions. No severe injuries (time-loss over 4 weeks) were reported for male players but surprisingly, 66% of the few time-loss injuries reported for female players were estimated as severe injuries. This finding of high rate of severe time-loss injuries among female players is in contrast with a previous study carried out on young female Kenyan players in which no severe injuries were reported  and another study carried out on male youth football players in Nigeria in which 9.8% of the injuries were reported as severe in the control sample of a randomised controlled study . More prospective studies are needed to fully understand whether this trend is a peculiar one in female football in Nigeria.
Due to the impact of time-loss injuries on football players, a separate evaluation was done to reveal specific characteristics of time-loss injuries sustained by players. Time-loss injuries were mostly reported by midfield players for both genders although tied with goalkeepers for female players. Report of which player position is more at risk for injuries varies with different studies and geographical locations. Comparable studies [24–27] in African players did not focus on this aspect of our study. Practically, midfielders’ role to succeed derive their abilities through slickly, quick and decisive skills coupled with effort to succeed in retrieval or defending of the ball. This suggests that the midfielders known for their multitasking role and high work rate at every match are exposed to injuries more than any player position. Furthermore, midfield roles require utmost concentration, close marking, agility and speed which increase the injury risk. Thus, it is important that midfielders in this population of players are given special attention for injury prevention and proper injury rehabilitation. In consistence with previous studies, players sustained more injuries in the second half of matches than in the first half [8–10].
The present study is limited in scope to semi-professional football players in Nigeria and it only presents acute injuries sustained during matches; hence the present study has its limitations. To fully understand the extent of the problem of acute and overuse injuries in Nigerian and African football players, there is a need for more prospective studies. Future studies should consider reporting both acute and overuse injuries using appropriate surveillance methodologies at the various levels of competition for both match and training injuries during tournaments and league seasons. Understanding the risk factors peculiar to injuries in Nigerian and African football is also valuable in planning prevention initiatives for players. The present study gives an insight to the pattern of match injuries among semi-professional players in an African population and generally adds to the scanty literature on the epidemiology of football injuries in Africa.