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.
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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.
Anyone interested in strengthening the core and shoulder musculature should be performing some type of row variation as part of their workouts. The row is a pulling movement which involves flexing the elbow, extending the shoulder, and pulling the shoulder blade back, also known as retraction. The row challenges the muscles of the upper back (trapezius, rhomboids, and erector spinae) as well as muscles of the core and low back. Also, when performed in various standing positions, this exercise can train the entire kinetic chain from the lower body, through the trunk, to the upper body.
It is common for the row to be performed seated with the use of exercise machines. This is fine for those first learning the movement pattern. However, seated machine rows do little to challenge the core or lower body musculature. There are much better options for athletes, those with a history of injury, and those looking to take their workouts to the next level.
If absolute strength is the goal, heavy barbell or dumbbell bent over rows are the best options. However, these row variations require coaching and practice to perfect proper technique. Performing heavy rows with improper technique makes one susceptible to low back or shoulder injury. Again, there are better options, especially for those with a history of injury and looks to train in a more specific fashion. Try the following five row variations and see which ones work best for you.
Standing 1-Arm High Cable Row
Set up a cable system with the cable positioned slightly above the level of the head. Stand in a lunge position with the left foot in front of the right. The majority of body weight should be on the front leg with the knee bent approximately 45 degrees. Start with a palm down grip with the right arm extended out in front. To begin the movement, pull the cable, bending at the elbow, straight back towards the trunk while maintaining a neutral spine. Be sure to emphasize scapular retraction which refers to pulling the shoulder blade back and slightly down. Also, avoid shrugging the shoulders or arching the low back.
This exercise challenges the core by activating the trunk musculature to resist rotation as the arm and scapula produce the row movement. This makes the 1-arm high cable row a good option for those who are looking to train anti-rotational trunk muscle endurance. This high-cable position and lunge stance set-up have also been shown to result in favorable muscle activation patterns of the lower and upper trapezius. This is important for overhead athletes or those with a history of shoulder problems.
Cable Lawnmower Pull
This exercise begins with the trunk flexed and rotated to the opposite side of the exercising arm. The hand of the exercising arm starts at the level of the opposite knee. To begin the movement, the trunk is rotated toward the exercising arm while extending the hip and trunk to a vertical position. The exercise ends with the arm at waist level with the shoulder blade retracted as if placing the elbow in the back pocket. Pause for 1 or 2 seconds then slowly reverse the movement returning to the starting position.
The lawnmower pull is a multi-joint functional exercise performed in a diagonal pattern replicating many movements in sport. The exercise incorporates the transfer of force from the lower body through the trunk to the upper body. It has been shown to activate the trapezius and serratus anterior muscles at low to moderate levels. These muscles are important for maintaining shoulder health in overhead athletes (i.e., baseball players) and those with a history of shoulder pain. The exercise can be performed with a cable system, resistance band, or dumbbell.
1-Arm Band Rotational Row
Set up a resistance band anchored at approximately waist to belly button level. Position the front leg with the foot facing towards the anchored band. The rear leg will begin facing the same direction but must be free to pivot once the exercise commences. The right arm begins extended and the majority of body weight begins on the left leg. The movement occurs with the simultaneous coordination of an upper-body row, trunk rotation, and weight shift to the rear leg. Pause in the end position for 1 to 2 seconds before reversing the movement in a slow and controlled fashion.
This row variation is ideal for rotational athletes such as baseball players. It incorporates the coordinated activity of the lower body, trunk, and upper body. Controlling the eccentric, or negative, part of the exercise is important. This exercise also teaches weight transfer and weight acceptable from the rear to lead leg and vice versa. Be sure to perform the exercise from both sides to avoid reinforcing any side to side asymmetries which are common in athletes.
Suspension Trainer Row
Anchor a suspension trainer, such as a TRX, in an overhead position. Grasp both handles with the arms extended. Position the feet in front of the body spread slightly wider than shoulder-width apart. Your body should be maintained in a neutral position with your head, trunk, and legs forming a straight line. Perform the row movement and pause at the top position for 1 to 2 seconds before returning to the start position in a slow and controlled fashion. Maintain the trunk in a rigid position throughout the exercise. To increase the challenge of this exercise position your feet further away from your upper body to assume a more inverted position.
The inverted position assumed in the suspension trainer row elicits high activation of the abdominals, latissimus dorsi, upper back muscles, and hip extensor muscles (glutes and hamstrings). This exercise produces lower levels of lumbar spine muscle activity due to lower spine loads incurred from the suspended position. These factors make the suspension trainer or inverted row a good option for patients with a history of low back pain.
Dumbbell Renegade Row
Hold two dumbbells and assume a push-up position with the feet spread slightly wider than shoulder-width apart. Align the head, trunk, and lower body in a straight line and maintain this position throughout the exercise. Initiate a row with one arm while maintaining stability through the trunk and lower body. Control the descent of the load back to the floor. Be sure to alternate sides with each repetition. Light loads are recommended when first learning this exercise.
The push-up position utilized in the renegade row increases challenges to the abdominal musculature. Furthermore, 1-arm row variations have been shown to elicit great oblique abdominal muscle activity compared to rows performed with both arms simultaneously. This is a more advanced row variation so it may be best to start with cable or suspension rows before embarking on the renegade row.
There are many variations to the row exercise and I have described only five. For beginners, it is best to start with cable row variations and suspension trainer rows. The lawnmower pull and rotational row are more complex movements which require total body coordination. Thus, these exercises are more challenging to master. To really challenge the core and shoulder stability, the renegade row is a higher level option. The most important points are that you choose the most appropriate variation for your level of training and that your technique is as close to perfect as possible.
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It’s not often that I am in agreement with health insurance companies but they seem to be getting one thing right as of late. We have noticed an increase in patient’s referred to our clinics for low back pain that have not undergone advanced diagnostic imaging techniques, such as MRI. It appears that large insurance companies are denying authorization for these MRI’s until the patient has undergone a course of physical therapy (more on the topic). Physical therapists are certainly on board with these decisions but some of our patients are often confused or annoyed by their insurance company dictating their care. So, should patients with an acute onset of low back pain undergo routine MRI or undergo a course of physical therapy first? Why not be safe and undergo the MRI first? How can a physical therapist offer treatment without knowing what the problem or diagnosis is?
Physical Therapy or MRI First?
A recent study published in the journal Health Services Research investigated this question. Researchers found that those patients seeking primary care services for low back pain and were referred for an early MRI underwent higher health care utilization at increased costs compared to those receiving early physical therapy. The additional cost of receiving the MRI first was nearly $5000 more than receiving early physical therapy. Earlier research studies show that consulting a physical therapist early results in decreased odds of undergoing diagnostic imaging (here) and decreased odds of undergoing future surgery for low back pain (here). Delaying physical therapy has also been associated with increased prescription opioid (narcotic pain medication) use and most of us are aware of how big of an epidemic this is becoming (more here).
Why Not Play it Safe and Undergo the MRI First?
A 2003 study in the Journal of the American Medical Association compared the use of early MRI vs. early x-ray for patients with a new episode of low back pain. One year later, pain levels and disability were no better in those undergoing the MRI. Of note, the group receiving the early MRI was more likely to undergo back surgery. This is not surprising given the high likelihood of pathological findings in asymptomatic subjects (no low back pain) who undergo advanced diagnostic imaging. A 2015 systematic review reported the prevalence of disc degeneration in asymptomatic individuals ranged from 37% of 20-year olds to 96% of 80-year olds. Similar rates were reported for asymptomatic disc bulges. If so many people without low back pain have these findings on MRI we cannot confidently conclude that these findings are the true cause of symptoms. Making erroneous assumptions based on MRI findings often leads to over treatment. The more testing and treatment a patient undergoes the more likely factors such as fear and anxiety come into play and these are the factors that have been associated with persistent or chronic low back pain.
Physical Therapy Treatment without Imaging
MRI or further medical work up is always indicated in situations where serious pathology is suspected or when response to initial treatment is poor. However, low back pain emanating from serious pathology has been estimated to occur in less than 2 percent of cases. Doctor’s of physical therapy are trained in screening for these signs and when there are any suspicions of non-musculoskeletal problems prompt referral is indicated. In most cases these problems are ruled out based on a detailed interview and medical history. Physical therapists then base their examination and treatment on the individual patient’s signs and symptoms; not based on a diagnosis or MRI scan. Physical therapists are concerned with how movement affects symptoms and how symptoms affect movement.
In most cases of low back pain delaying the MRI is the best approach.