Restoring Muscle Function in the Painful Hockey Hip

Hip issues in hockey players has become a well-known problem. In a recent study by Worner et al. (2019) of over 300 professional hockey players during a single hockey season, they found that over 50% of players suffered some form of hip or groin issue. In a separate study, Worner et al. (2019) also found that almost 70% of goalies suffered a hip or groin issue during the same time frame. We have yet to find a way to prevent these issues, so we have to manage them. Understanding the underlying pathology will help direct our focus in better managing hip pain in hockey players.

Origins of Hip Pain

Mechanical hip pain can be complex. According to Haversath et al. (2013), the labrum, ligamentum teres and hip capsule all contain high amounts of nociceptive free nerve ending, making all 3 structures plausible sources of hip pain. Previous research by Epstein et al. (2013), Silvis et al. (2011) and Philippon et al. (2010) have shown that hockey players often have tears of the hip labrum and ligamentum teres. Additionally, FAI is often associated with inflammation of the joint which can cause thickening and irritation of the hip capsule (Cannon et al., 2020). Increased sensitivity of these structures could explain the sources of hip pain in hockey players due to the high concentration of nociceptive nerve fibers in the tissue.

Effect of Hip Pain on Muscle Function

Pain will often lead to changes in how we move. For example, when someone sprains their ankle, they start limping. Although not all pain will lead to such a dramatic change in movement, more succinct changes can still occur. For example, in a study by Freeman et al. (2012), researchers injected participants’ hip joints with a solution to mimic hip joint effusion which often occurs with conditions such as FAI. They found significant decreases in glute max muscle activity during a glute bridge and prone hip extension, suggesting that joint effusion could lead to glute max inhibition. Along those same lines, Kierkegaard et al. (2017) tested hip muscle strength in participants scheduled for hip surgery with diagnosed FAI. They found that hip flexion strength was 15%-21% lower and hip extension strength was 10%-25% lower in affected hips compared to controls. They also found that those with FAI demonstrated decreased rate of force development (RFD) bilaterally in both hip flexion and extension when compared to controls. A bilateral decrease in RFD could suggest that there may be a central protective mechanism which could reduce strength and power output of muscles surrounding the hip.

Hip pain has also been shown to have an effect on muscle coordination. Diamond et al. (2016) used intra-muscular fine wire EMG to collect activation patterns of the deep hip rotators (grouped as part of the hip rotator cuff outlined here) during walking in participants with FAI. They found that the activation patterns of the deep hip rotators had less variability during early stance, which could be a protective mechanism as they move towards the provocative position of weightbearing in flexion and adduction. This type of activation pattern is what we would expect to see in a someone learning a new skill, where the movement is stiff and choppy rather than smooth and adaptable. It could be that the pain affects the feed-forward mechanism of the hip cuff muscles which activate in preparation for movement (Retchford et al.,  2015). Instead of the hip cuff muscles varying activation patterns to create stability during different phases movement and perturbations, they are active to create stability without context.

 Effect of Labrum Tears on Muscle Function

The labrum provides static stability to the hip, acting as a suction cup on the femur (as I wrote about here). Most often in hockey players the labrum is torn anteriorly, losing the suction effect along with some of the stability it provides and allows the femoral head to “wiggle”. In addition to the stabilizing hip rotator cuff, the psoas muscle is thought provide stability to the anterior hip. Anatomically, the psoas tendon passes directly anterior the hip joint. It has been postulated that a shortened psoas muscle may cause labrum pathology due to their close proximity (Domb et al., 2011). However, the inverse could also apply. With increased “wiggle” and translation of the femoral head from a torn labrum,  the psoas takes on an increased role in stabilizing the anterior hip. Over time, protecting the anterior hip would lead to a shortened or chronically tight muscle as it attempts to reduce the amount of “wiggle” and limit anterior translation of the femoral head. Additionally, Nepple et al. (2015) found that hip flexion weakness was correlated to the larger hip labrum tears in those with FAI and labrum tears. This correlation of weakness and size of labrum tear could be explained by the psoas having to do more work with a larger tear, becoming overworked in its duty of stabilizing the anterior hip due to a lack of support from the labrum.

Improving Hip Muscle Function

 The goal of restoring hip muscle function is to improve coordination and co-contraction in order to increase dynamic stability of the hip and limit the amount of “wiggle”. Reducing the amount of “wiggle” would decrease the demand on the psoas thus allowing it to relax, as well as potentially reducing the irritation of other static structures such as the labrum. Some would suggest that isolated strengthening may be beneficial in improving muscle coordination and restore the feed forward response (Retchford et al., 2015).

Isolated strength work around the hip often gets overlooked in rehab and performance programs, but a weak muscle can’t stabilize. Some of my go to isolated hip exercises based on EMG studies (here, here, here) include, clam, reverse clam, sidelying abduction and the glute bridge. These can be progressed by adding manual resistance, bands or weights.

These can also be progressed to increase the demand on hip stability. Decreasing the number of contact points with the ground increases the challenge for the athlete to stabilize against the perturbations of the movement.

As athletes progress into more functional hip training, I like to keep these in as activation before training and for maintenance throughout the season.

Conclusion

In summary, the origin of mechanical hip pain can be complex. Pain and pathology of the hip can lead to strength and coordination changes of the hip muscles. Performing isolated strengthening of the hip cuff and challenging hip stability in different planes can improve hip muscle function before progressing to more functional training. Additionally, isolated hip cuff strengthening can be used as an activation circuit before training and as a maintenance throughout the year .