Abdominal oblique injuries, also known as side strains, are common in rotational sports such as baseball, tennis, golf, and track and field. These injuries are characterized by a sudden, sharp onset of pain near or on the side of the rib cage. The injury usually occurs during some type of rotational sports movement such as swinging a bat, club or racket; or throwing a ball.
Trunk rotation plays an important role in generating and transferring power during sport. It is through the trunk or core, that forces are transferred from the lower body to the shoulder and arms. Activities such as throwing and swinging require the core muscles to both stabilize the trunk and create force in order to transfer power to the upper body.
Anatomy of the Abdominal Oblique Muscles
The core includes the thoracolumbar, abdominal, pelvic, and hip musculature. These muscle groups provide trunk stability to allow integrated limb movements, such as throwing and swinging, to occur. The abdominal core muscles include the rectus abdominis, transversus abdominis, internal oblique and external oblique. Most abdominal injuries occur in the internal and external oblique muscles. Less commonly, injuries can occur to the intercostal muscles between the ribs themselves.
The Role of the Oblique Muscles in Sport
The internal and external oblique muscles are responsible for flexion and rotation of the trunk, as well as providing trunk stabilization during complex sports movements. Poor mobility of the hips or thoracic spine can contribute to excessive stress and compensation through the trunk musculature during swinging or throwing. Rehabilitation often addresses hip mobility with manual therapy techniques performed by the physical therapist. An imbalance between right and left side oblique muscles are also common is in sports such as golf and baseball. This may place excessive forces through the lead side oblique musculature. Finally, the large forces generated by lower body muscles (quadriceps and hamstrings) may overpower the weaker core musculature leading to injury during explosive sports movements.
The incidence of Abdominal Oblique Injuries in Baseball
A 2010 study in the American Journal of Sports Medicine investigated the incidence and trends of abdominal injuries in professional baseball players. From 1991 through 2010, abdominal strains accounted for approximately 5% of all injuries in Major League Baseball. Nearly half of these injuries occurred in pitchers. These injuries occurred most often during the early part of the season.
In both pitchers and position players, the majority of injuries occurred on the side opposite to their throwing arm. Pitchers missed, on average 35 days on the disabled list, while position players missed 26 days on average. Players who receive steroid or PRP injections have been shown to miss more time from injury. More than 1 out of every 10 sustained a re-injury during their career. Most of these re-injuries occurred during the same or the following season. As a result of these injury trends, many MLB teams have increased their focus on preemptive core and trunk strengthening exercises for all players.
The incidence of abdominal oblique injuries is on the rise in rotational sports such as baseball and golf. These injuries can result in substantial loss of playing time. Proper training can prevent abdominal oblique injuries from occurring. In a few weeks, I will post an article describing exercises which can help reduce the risk of sustaining an injury. These exercises can also be part of a comprehensive rehabilitation program to safely return an injured athlete back to sport.
- Camp CL, Conte S, Cohen SB, et al. Epidemiology and impact of abdominal oblique injuries in major and minor league baseball. Orthop J Sport Med. 2015;5(3):1-8. doi:10.1177/2325967117694025.
- Conte SA, Thompson MM, Marks MA, Dines JS. Abdominal muscle strains in professional baseball. Am J Sports Med. 2010;40(3):650-656. doi:10.1177/0363546511433030.
- Nealon AR, Kountouris A, Cook JL. Side strain in sport: A narrative review of pathomechanics, diagnosis, imaging and management for the clinician. J Sci Med Sport. 2017;20:261-266.