How Good Hip Mobility Can Help You Prevent an ACL Tear
ACL tears remain one of the most prevalent and highly studied injuries within the sporting world. While Schoffl et al (2015) reported only 14 knee injuries out of 604 rock climbing related injuries, I think we all know someone in the climbing community who has suffered an ACL tear. Most notably, Alex Puccio suffered both an ACL and MCL tear when she was competing in the 2015 Bouldering World Cup in Colorado. What was most remarkable was that Puccio was able to send Euro Roof (V10) and Euro Trash (V12) just seven weeks after surgery. While she did make a speedy recovery, it is important to remember that she was still mindful about not falling as a fall this close to surgery can easily compromise the integrity of the repair.
The majority of climbing-related ACL injuries will likely be non-contact (pivoting on a planted foot while climbing, an aggressive drop knee move, falling from a boulder, taking a whipper) mechanisms. While all of these injuries may seem different, the underlying biomechanics of the injury is fairly consistent. The mechanism of injury often begins with the foot planted firmly on the ground (or on the wall); from there, injury involves:
excessive femoral (thigh) adduction and internal rotation
and tibial external rotation (relative external rotation compared to femur)
with the knee in a slightly flexed (bent) posture.
Due to the orientation of the ACL within the knee, this position inherently directs the most force through the ligament which can lead to tearing.
Current ACL Prevention Protocol
An immense amount of research has surfaced over the past 5-10 years calling for a protocol that involves increased hip muscle strengthening and recruitment, as well as movement re-patterning to reduce the risk of ACL injury among athletes. The basic premise behind this protocol is that by training the lateral hip musculature, in particular the gluteus medius and maximus,
you gain hip external rotation (lateral rotation) and abduction (lateral movement) strength/motor control which will help prevent the knee from falling into a high stress position for the ACL.
Hip Internal Rotation Deficits and ACL Strain
Pic of Hip IR
A recent article conducted by Bedi et al (2016) investigated the occurrence of femoral acetabular (hip) impingement and peak ACL strain during pivot landings. Findings of this study demonstrated that hip internal rotation deficits were associated with significantly greater odds of ACL injury in both limbs. Another study conducted by Beaulieu et al (2015) used cadaveric knee specimens to examine whether limiting the available range of femoral (thigh) internal rotation would increase susceptibility of the ACL to fail with consecutive loading. The results of this study also concluded that hip internal rotation limitations increased the risk of ACL failure.
How Might This Affect Climbers?
In climbing, ACL injuries often occur with excessive medial knee collapse
when climbing or sustaining a fall. In the case of a fall, good strength of the lateral hip muscles to help absorb the shock and minimize this collapse is important. However, what do we do in those situations where the beta just requires us to use that aggressive drop knee? In this situation, the force at the knee will cause femoral (thigh) internal rotation on the tibia (calf). If a climber has improved hip internal rotation, they will effectively be able to limit the amount of internal rotation that occurs at the 2 bones (femur on tibia), keeping the tibiofemoral (knee) joint in a more neutral position and thus reducing the load on the ACL.
The femur (thigh) is able to maintain alignment with the tibia (calf) through a greater range providing the climber with another strategy to protect the ACL via trunk rotation. By rotating the trunk, the climber is able to facilitate even more relative hip internal rotation to further protect the ACL.
Take Home Message
With this in mind, although it is important to focus on strength and activation of the hip musculature I believe that improving hip mobility is of equal importance. Evaluation and treatment of this impairment is incredibly valuable as it is simple, time efficient, and can greatly reduce the climber’s risk of injury.
A special thanks to Dr. Kellen Matsuno, PT, DPT, CSCS for his collaboration on this article.
References:
1. Beaulieu ML, Wojtys EM, Ashton-Miller JA. Risk of anterior cruciate ligament fatigue failure is increased by limited internal femoral rotation during in vitro repeated pivot landings. Am J Sports Med. 2015; 43(9): 2233-2241
2. Bedi A, Warren RF, Wojtys EM, et al. Restriction in hip internal rotation is associated with an increased risk of ACL injury. Knee Surg Sports Tarumatol Arthrosc. 2016; 24:2024-2031.
3. Schoffl V, Popp D, Kupper T, Schoffl I. Injury trends in rock climbers: evaluation of a case series of 911 injuries between 2009 and 2012. Wilderness & Environmental Medicine. 2015; 26:62-67.
Pictures
1. https://musculoskeletalkey.com/structure-and-function-of-the-hip/
2. https://fitnesspainfree.com/asessing-and-correcting-tibial-internal-rotation-improve-your-deep-squat/
3. https://sites.google.com/site/activecarephysiotherapyclinic/acl-injury
4. https://44wj5q2j6wo23s4mp6owjohh-wpengine.netdna-ssl.com/wp-content/uploads/2014/01/gluteals-and-piriformis.jpg
5. http://www.yinyoga.com/newsletter20_planes%20of%20movement.php