Updated: May 5, 2022
Hip injuries are often overlooked in baseball players. Understandably, more focus is placed on the upper extremity, particularly the shoulder and elbow as that is where many injuries occur. A study by Mlynerak and Coleman showed that 5.5% of baseball injuries involved the hip or groin in Major and Minor League Baseball. “Arm care” has been a hot topic lately with significant energy and focus put on developing exercises to prevent arm injuries, but the same attention is not paid to the hips. Also, a hip injury can manifest itself into an arm injury due to a disruption in the kinematic sequence, as I addressed in a previous blog.
Before we get too far into the specifics of hip injuries and how they relate to baseball, it is important to review some anatomy. The most common hip injury in baseball is some combination of femoroacetabular impingement (FAI) and a labral tear (I wrote about FAI here if you are interested). A brief reminder about what the hip joint looks like:
The femur is the long bone in your upper leg and the head of the femur rests inside the acetabulum creating a ball-in-socket joint. The labrum is a cartilaginous tissue that extends the socket while providing stability for the femur. FAI can involve either a cam impingement, a pincer impingement, or a combination of both. A cam impingement refers to a bony overgrowth on the femur while a pincer impingement is a bony overgrowth on the acetabulum. Either deformity can result in damage to the labrum and other tissues in the area. This can result in pain along with hip tightness, locking, and clicking.
We will get into further details later on, but an important consideration is the rotational nature of baseball. Imagine you are a 100 meter sprinter. You probably do some rotational training, but your sport requires you to run in a straight line. Many other sports involve primarily straight line running as the stress on the hip. Some sports like basketball include jumping, which can result in other stresses of the hip. Baseball and softball are primarily rotational sports regarding hip stress. Running in the field or around the bases involves straight-line speed, but the most repetitive stress typically comes from hitting or pitching (catcher is an exception to this that we will discuss). Therefore, strategies to address hip impingement should focus on rotational solutions primarily.
Causes of Hip Tightness
There are several possible causes of hip tightness particularly in baseball players. The first is related to joint restrictions, part of which can be explained by FAI and labral tears as mentioned above. These require dedicated intervention from a healthcare professional to assure that the hip is able to move safely. Muscular tightness can also be a cause of limited hip mobility. Take a look at the next couple images showing the front and back of the hip and all of the muscles that are involved:
As you can see, there are many muscles that insert into the hip and can create restrictions. While mobility exercises and stretching can be helpful in some cases, tightness in a muscle can also be caused by weakness. Imagine if you tried to curl 1,000 pounds. Your biceps would feel tight after doing this, but they would not need to be stretched. They would feel tight because you contracted the muscles past their limit and they tightened to protect themselves. A similar phenomenon can occur in the hip muscles if they are not strong enough. They can tighten to protect themselves, causing the sensation of tightness. I will discuss exercises later on, but oftentimes strengthening exercises can actually increase mobility.
Hip tightness or pain can also be a result of limited mobility elsewhere in the body. If the lower back or pelvis is tight, then more rotation needs to come from the hip. If the hip only has normal rotation and is unable to rotate to compensate for the low back and pelvis, then it may feel tight. The limitation does not actually occur in the hip, but it is the culprit of tightness elsewhere.
Hip Tightness in Pitchers
Pitching requires significant hip mobility from both the front and back leg. Look at the back leg in the full stride position below courtesy of faketeams.com
You can see that he is in a position of extreme extension as well as internal rotation. If he lacked extension in his hip, then he would need to compensate elsewhere. This typically occurs in the lower back creating excessive extension. Too much extension of the lower back can decrease power transfer and cause a pitcher to overuse his arm. This is a simple example where a lack of hip extension can result in low back issues as well as arm pain.
You can also see above that the lead leg is forced into significant flexion and eventually internal rotation as the body continues to rotate. FAI is particularly aggravated in positions of flexion and internal rotation. Limited lead leg hip flexion can cause poor stabilization in the lead leg while pitching. As I mentioned before, rotation is the primary generator of force in baseball and there needs to be a point around which you can pivot. If front hip flexion is compromised, then it is not able to adequately absorb force. Imagine a pitcher such as the one below courtesy of cmllonline.org
You can see that his front leg stays relatively straight. This forces much more of his power to come through his upper body, stressing his shoulder and elbow. The decreased hip flexion can be a mobility issue or a stability issue where he is not strong enough to control the greater lunge position that was evident in the first picture.
The trail leg is also subject to significant internal rotation stress in the leg lift position as seen below courtesy of sanzeribaseball.com
Imagine if the pitcher above had hip tightness and was unable to assume this position. He would either compensate with his back or try to twist through his knee. Too much rotation through the low back can create stress reactions and eventually stress fractures such as a spondylolisthesis that I covered here. Twisting through the knee can result in damage to the meniscus, which I discussed in another blog post here. Our hips have a significant range of motion, particularly in rotation because the segments above and below do not provide much rotation. If we rely on our low back or knee to rotate, we are decreasing our power potential and increasing injury risk.