Ice hockey is a fast-paced, complex, team sport, which demands a combination of quick thinking, fast reactions and superior all-around athletic skills (i.e. strength, power, speed, stability, balance, and movement quality), .
In fact, ice hockey is characterized by explosive skating patterns where players who are able to increase their speed (i.e. accelerate) at greater rates than their rivals can gain substantial performance advantages . It’s also one of the fastest team sports with players reaching peak speeds above 40 km/h [3, 4]. Given the metabolically-intense and physical nature of the sport, there’s a high occurrence of injuries sustained by the male ice hockey athlete; previous studies report injury rates between 4.9 injuries/1000 athlete exposures (AE) in NCAA Division I players  and up to 15.6 injuries/1000 AE in NHL players . In NCAA men’s ice hockey athletes, 10.3% of all injuries are classified as “severe”, resulting in time loss and restricted participation for > 3 weeks . The risk for severe injury to occur was 8.6x more likely during games compared with practices, and nearly 11% of all severe injuries occurred in the hip/groin/upper leg region . Most of all ice hockey injuries, severe or not, are caused by contact [5-13], but it’s debatably more important to focus on non-contact injury prevention because many of the factors associated with such are modifiable , as discussed above.
THE SUSCEPTIBILITY OF THE HIP COMPLEX
The hip complex is among the most common locations of the ice hockey athlete’s body to become injured when both contact and non-contact injuries are taken into consideration [5, 6, 9-11, 13, 15, 16]. Hip injuries are typically caused by non-contact events, with at least 70% of all hip injuries being strains . Most commonly, hip strains occur in the hip flexors and adductors, with at least 81% and 80% of strains, respectively, being caused by non-contact or overuse . Men’s ice hockey also has the highest proportion of hip flexor and adductor strains being recurrent, compared with all other NCAA Men’s sports . In a study investigating injury rates in NCAA Division III men’s hockey athletes over a four-year period, the hip complex was the most frequently injured site on the body, amassing 50% and 27% of non-contact, and total (non-contact and contact) injuries . This data speaks towards the significance of applying strategies to modify risk factors associated with non-contact hip injury, in order to improve athlete health and longevity. The disproportionate non-contact injury rates of the hip flexors and adductors, relative to the rest of the body, makes sense given their unique eccentric contributions to the recovery phase of the ice hockey stride. The combined modifiable injury potential and robust impact on performance from the hip flexors and adductors warrants special attention. There’s potential to apply screening/monitoring and strengthening procedures for these muscle groups to reduce injury risk and enhance on-ice performance.
GROIN STRAINS IN ICE HOCKEY
In a study involving NHL players, hip adduction strength, but not flexibility, was associated with increased risk for sustaining a subsequent groin strain . Hip adduction strength was 18% lower in the players who subsequently sustained an adductor muscle strain compared with that of uninjured players . Additionally, a player was 17x more likely to sustain an adductor muscle strain if his adductor strength was less than 80% of his abductor strength . In a follow-up study, these researchers put all players identified as “at risk” (i.e. hip adductor/abductor muscle strength ratio less than 80%) on an exercise program emphasizing adductor muscle strengthening . Strengthening the adductor muscle group effectively reduced adductor muscle strains in these “at risk” players . In high school and collegiate hockey players, all players who sustained a groin injury had a preceding bilateral adductor strength imbalance, with the injured limb possessing 75% or less of the strength as the uninjured limb .
GROIN STRAINS IN OTHER SPORTS
Research investigating hip strength and groin injury propensity in ice hockey athletes is limited, but there is a substantial amount of literature in other sports. Isometric hip adduction/abduction strength ratio was significantly lower in elite soccer players with groin pain during hip adduction testing compared with players with a pain-free test . A study in Australian Rules Football (ARF) athletes found that reduced hip adduction strength relative to baseline measures preceded groin pain onset . In a group of 508 amateur male soccer players from Norwegian first, second, and third division teams, there were also associations between hip adductor strength and new groin injuries . Players with previous groin injury or weak adductor muscles were 2.6x and 4.3x more likely to sustain a new groin injury, respectively . In elite tennis players with a history of groin injury, isometric adductor strength and adductor/abductor strength ratios were lower in the injured limb (16.4% and 20.1%, respectively) compared with the uninjured side . Performance during a pre-season adductor squeeze test was able to predict subsequent groin injury in Gaelic football players; increased injury risk was associated with lower adduction strength . A rehabilitation program was applied to a group of 68 football players with longstanding groin pain (40 weeks, on average), . Athletes were assigned to either 1) an active training program aimed at improving strength and coordination of the muscles acting on the pelvis, in particular the adductor muscles, or 2) a physiotherapy treatment without active training for 8-12 weeks. Athletes who did the active training program were 12.7x more likely to make a full return to sports at the same level without groin pain 4 months later .
REVIEWS AND META-ANALYSES: GROIN STRAINS IN MULTIPLE SPORTS
A recent meta-analysis found that there is consistent evidence that previous groin injury, higher level of play, reduced hip abductor and adductor strength, and lower levels of sport-specific training are associated with increased risk of groin injury in sport . A separate systematic review was performed in field-based sports (FBS) only and found that previous groin/hip injury was the most prominent risk factor for subsequent hip/groin injury (odds ratio 2.6-7.3), followed by weak hip adductor muscles (odds ratio 4.3), by older age (odds ratio 1.1) and weak adductor muscles (odds ratio 4.3), . Another review of sports-related groin pain (SRGP) found evidence for decreased hip adduction strength, but not internal/external ROM, to be associated with SGRP . A large study of 303 male soccer athletes also found that athletes with past-season groin pain lasting longer than 6 weeks are likely to begin the next season with a high-risk groin injury profile. This high-risk groin injury profile includes hip adductor weakness . Relating to hip range of motion (ROM), a recent systematic review determined that total hip rotation below 85 degrees could differentiate athletes with groin pain from those without . Given the aforementioned research, developing an approach to identify, monitor, and improve hip adductor function in athletes at high-risk for groin injury is warranted.
Coming Up! — Part III: Groin Strain Imposters
Written by Adam Virgile / @ShakeBotApp
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