Poor Hip Joint Mechanics Increase Risk of Injury in Baseball Players

In researching injuries sustained during baseball, the focus of most studies has been primarily on the shoulder and elbow, and for good reason. Baseball players are known to sustain many injuries from head to toe but due to the specific components of their sport, including overhead motions, the majority of injuries occur in the upper extremities. According to the 2007 study by Hootman et al in the Journal of Athletic Training looking at injury rates for men's college baseball from 1988-2004, 45% of all injuries were to the upper extremity and about 30% to the lower extremity.¹ Another study in 2011, by Posner et al in the American Journal of Sports Medicine, looked at Major League Baseball injuries from 2002-2008. They found that among all player injuries, upper extremity injuries accounted for 51.4%, while lower extremity injuries were 30.6%²

A more recent study in March of 2016 by Colman et al in The American Journal of Orthopedics reported 1823 hip and groin injuries in Major and Minor League baseball players from 2011-2014, which accounted for 5% of all injuries. Of these, 96% were extra-articular which included adductor strains, hip flexor strains, hip contusions, bursitis and various areas of tendinitis. The intra-articular injuries, which accounted for 4%, included FAI (femoral acetabular impingement), labral tears, capsulitis, osteoarthritis, chondromalacia and loose bodies. On average, the majority of extra-articular injuries were treated successfully non-operatively, but still resulted in 12 days missed. The intra-articular injuries, which usually required surgery, resulted in 123 days missed.³

Newer studies have linked injuries to the torso, shoulder and elbow to poor mechanics at the hip joint. Hip mechanics play an important and vital component to the kinetic chain during overhead activities such as pitching and throwing. Studies of pitching mechanics demonstrate forces at the shoulder and elbow are strongly influenced by hip/pelvic rotation4, while leg drive is connected to wrist5 and throwing velocity6. Decreased hip strength and range of motion (ROM) may limit stride distance and lead-leg positioning. This will impede the overhead athlete from being able to generate the necessary torque from the pelvis/hip and in turn transferring the torque requirements to the upper extremity. This will greatly alter normal upper extremity mechanics thus leading to increased risk for injuries to the upper quarter.

In addition to decreased hip ROM and strength contributing to upper extremity injuries, it also can lead to increased intra-articular stress at the hip. Femoral Acetabular Impingement is a hot topic amongst all sports right now and is being greatly researched. It can limit the amount of rotation needed at the hip to demonstrate normal mechanics. Baseball players need to rotate greatly through the hip to be effective. If the hip joint keeps getting slammed against a brick wall due to FAI or OA, it can lead to or worsen a variety of serious intra-articular injuries. These injuries can and should be treated conservatively as early as possible.

An important part of rehabilitation of these injuries can be joint mobilization to restore capsular mobility at the joint. Due to the constant loading, compression and rotation during competition, the individual can obtain a great deal of relief with traction at the hip. Long axis traction (LAT) is commonly used by team physical therapists and athletic trainers as part of normal daily recovery for their athletes as well as rehabilitation for injuries when they occur. A portable independent hip traction device, the HipTrac™, may be used to supplement this therapy by enabling the player to apply the same level of traction whenever it is needed to manage their pain and mobility. This is especially helpful during the season, as players have little time to rest and recover, due to baseball's intensive training and competition schedule.

Although the majority of injuries sustained during baseball are in the upper quarter, the hip joint plays a major role in the prevention of these injuries. It is also directly related to specific injuries in the lower extremity. Improving hip joint mobility, decreasing pain and increasing training/activity tolerance can decrease missed days due to injury and help to prevent a flare up of a pre-existing, congenital condition in the first place. Not only do better mechanics and ROM at the hip joint lead to decreased risk for injury to the upper and lower extremities in baseball players, but it also leads to improved performance overall.

1. Hootman JM, Dick R, Agel J. Epidemiology of Collegiate Injuries for 15 Sports: Summary and Recommendations for Injury Prevention Initiatives. J Athl Train. 2007 Apr-Jun; 42(2): 311–319. 2. Posner M, Cameron KL, Belmont PJ, Owens BD. Epidemiology of Major League Baseball injuries. Am J Sports Med: 2011 Aug;39(8):1676-80. 3. Colman SH, Mayer SW, Tyson JJ, Pollack KM, Curriero FC. The Epidemiology of Hip and Groin Injuries in Professional Baseball Players. Am J Orthop. 2016 Mar-Apr;45(3):168-75. 4. Klingenstein MD, RobRoy M, Kivlan B, Kelly BT. Hip Injuries in the Overhead Athlete. Clin Orthop Relat Res. 2012 Jun; 470(6): 1579-1585. 5. MacWilliams BA, Choi T, Perezous MK, Chao EY, McFarland EG. Characteristic ground-reaction forces in baseball pitching. Am J Sports Med. 1998;26:66–71. 6. Stodden DF, Langendorfer SJ, Fleisig GS, Andrews JR. Kinematic constraints associated with the acquisition of overarm throwing. Part I. Step and trunk actions. Res Q Exerc Sport. 2006;77:417–427.