As we work our way through improving our return to sport testing, our first stop is at hop testing. Most rehabilitation professionals use some form of hop testing, but which hop tests should we use and what should our passing criteria be?
While it is important to use double limb hopping as part of the progression in rehabilitation, it is unnecessary for return to sport and discharge testing. In a study by, Myer et al double limb activities did not identify the unilateral deficits found after ACL reconstruction. Here are the unilateral tests supported by research:
•Single hop for distance
•6m timed hop — I don’t use this one. This is not solely based on published research (although the reliability is the lowest of the hop tests), but what I have observed clinically and through studies we have done. Basically, unless you use timing gates, your stopwatch trigger finger error is pretty close to any right/left asymmetries you would find (except in the cases of severe asymmetry — which the other hop tests would pick up)
•Triple crossover hop
•Hop & Stop — I really like the concept of this one and I am starting to use it more clinically. There are normative values and you know what a big fan I am of using population specific values to determine risk. Jeremy Boone has written about the hop and stop here
The above tests are reliable and modifiable (Munro & Herrington 2011, Reid et al 2007). I have not seen any studies demonstrating the injury prediction value of these hop tests (if you do know of such studies, please let me know) but they do have decent discriminant validity.
Criteria for Discharge and/or Return to Sport:
To me, the MOST important question is “What should the return to sport and/or discharge criteria be for hop testing?”
The most common return to sport criteria that I have come across in the literature is 85% and 90% Limb Symmetry Index (LSI). I believe neither of those is stringent enough. Remember, previous injury is the most consistently reported risk factor for future injury and we are currently discharging individuals with modifiable risk factors. So, on that basis alone, our standards should be higher.
But, let’s look at the research. Reid et al 2007 repeated hop testing on 4 separate time points after ACL reconstruction (16 weeks, a couple times more that week, and at 24 weeks post op) and found good longitudinal and concurrent validity for the four hop tests. However, consider this interesting fact from their research:
At 24 weeks post-op ACL reconstruction, the average overall Limb Symmetry Index was 88.5% and the average Lower Extremity Functional Scale score was 69.3. An athlete with a 69.3 LEFS would have moderate difficulty with the following activities
•“Your usual hobbies, recreational or sporting activities”
•“Running on even ground”
•“Running on uneven ground”
•“Making sharp turns while running fast”
If someone reported this much difficulty with these activities (I realize this is an “average” report but their LSI report is also an “average”), should she return to sport? Bottom line: In this study, 89% hop testing LSI equates with moderate difficulty with simple sport activities. Thus, 90% is not enough. Also, just because someone has returned to sport (which is what is typically considered “success”) does not mean that she is not at substantially increased risk of injury.
Finally, Munro & Herrington 2011 found that the average LSI for the four hop tests was 100% (98.38 to 101.61%.) and that 100% of healthy subjects have at least an LSI of 90%. Based on these results, the researchers advocate that the return to sport LSI criteria be increased to 90%.
Given our current re-injury rate, I suggest hop testing LSI should at least be above 95% and recommend it to be above 97%-100%. Do you think we can achieve this in rehabilitation? Do you think we should use 90% for return to sport and 97-100% for discharge?
We’ve been discussing return to sport and discharge testing. In our last post, we met Jane, a 36 year old with knee and hip pain due to lack of systematic discharge testing after her ACL reconstruction 20 years earlier. This left her with modifiable risk factors and now pain. Worse yet, she is trying to get into shape but is struggling due to this recent “injury.” Remember, we can prevent these injuries, but the key is systematic testing at return to sport and discharge. But before we get into the specific tests and criteria, let’s discuss how we should go about selecting those tests.
Obviously, the test should be reliable and measure the domain that you are trying to test. But which domains should we test? Using a Delphi study method, Haines et al created a checklist of domains that an expert panel felt were important to include in return to sport testing. The domains that the experts suggested testing included:
- neuromuscular control
- sport specific movements
- strength and range of motion ** this is my addition (we will discuss the research related to these and risk of injury)
I think we all would agree with the above list, but how do we go about selecting the specific test and criteria for return to sport or discharge? I believe most of us already test those domains, but our current standard of care is leaving people with a substantial risk of future injury.
What are we missing? I believe we are missing 3 key concepts in return to sport and discharge testing:
1) When possible, the tests we use should be predictive of injury
– Could you imagine if your primary care physician could do a few simple tests that could quickly give you a snapshot of your risk of a disease? Wouldn’t you expect her to perform them? As a matter of fact, they currently do (think heart rate and blood pressure). We owe this to our patients in rehabilitation as well. But when it comes to return to sport, I believe we put too much and too early emphasis on tests requiring high level physical function and other sport specific tests. While those are important, I think we need to consider tests predictive of injury or that identify traits that lead to susceptibility to injury.
2) The tests need to be arranged in a hierarchical fashion ( This case study in BJSM is a start).
– Currently, I think we assume (often unconsciously) that if an athlete can hop/cut/run well, then they have the foundational requirements of ROM, strength, basic movement and balance. Or, that those foundational traits are not as important. But frequently, this is not the case. There is little need to perform testing at higher levels of function if there is a fatal flaw in movement or balance at lower levels of function. If the athlete passes the higher level testing, they too ASSUME that they are good to go.
3) We need to set the minimum criteria for discharge to be near what a person at “Normal” risk would score on the test (and I would argue it should be even higher than that).
– Since we know that athletes who have been previously injured are more likely to be injured again and that motor control changes frequently remain after injury, we should demand that their test results are close to normal prior to discharge. What if you had a disease and your blood levels indicated that it was advanced and you underwent treatment and they retested your blood and found that you were better, but not normal. What would your response be? Mine would be “Is it possible to get it back to normal or is this as good as it gets?” We need to have the same attitude toward one of our largest, most expensive systems — the neuromuscular system
So, with those concepts in mind, here is what I am now giving patients at the start of their care. This list includes most of my discharge criteria. Over the next several posts, I will go through the research regarding these tests as well as any others that are suggested. Add any tests that you think are missing below.
11 Jun 2013
Not because we want to autograph our great work, but to signify that we have completed the safety checks to ensure we have removed all modifiable risk factors for injury. Why did surgeons implement signing the operative knee before surgery? As ridiculous as it sounds, the wrong knee had mistakenly been operated on. It doesn’t happen very often, but what it does, it can be catastrophic. Why should rehabilitation providers sign that they have removed all modifiable risk factors after rehabilitation?
Because we are unknowingly discharging numerous patients with modifiable risk factors for future injury. In fact, almost certainly many more patients are being discharged with modifiable risk factors than wrong knees are being operated on — and the long-term consequences can be just as catastrophic.
Let’s hear what happened to Jane:
Jane is a 36-years-old mother of two, whose youngest is 18 months. Since the birth of her children Jane’s priorities have shifted and she no longer gets to the gym as much as she’d like. She enjoys exercises, but with two kids and full-time job it’s hard to squeeze in a regular routine. As a result, Jane has put on few pounds, a fact that pushed her to recommit to getting back into shape despite her busy schedule.
In the course of her new workout routine, she developed hip and knee pain. She went to her physician and he diagnosed her with early onset knee osteoarthritis. How can that be, she’s only 36?
Looking back over Jane’s medical history, we discover that 20 years ago she had an ACL reconstruction, with several months of rehabilitation. Considering this prior injury, was Jane’s early onset of osteoarthritis just a natural course of the ACL tear, or was there something that could have been done differently to prevent her current condition? Let’s look at her post-operatively:
The rehabilitation provider that worked with Jane had her start with basic range of motion and strengthening and then progressed her through a myriad of exercises from low to high level. Finally, Jane was doing plyometrics (programs proven to reduce injury), running, and cutting and was ready to return to sport. Her strength and ROM looked good and so did her running and cutting. Jane said she was feeling great! So she went back to sport.
Here’s the problem: Previous injury is the most consistently reported risk factor for future injury in athletics. Here is one of my favorite injury epidemiologists summarizing his research findings:
“Looking at 70 teams, in 18 countries, over 8 seasons (9,000 injuries), we have found that previous injury is by far the greatest predictor of future injury in football.”
Soccer Industry Medical Symposium 2009
But what is more important is that, numerous researchers have found that modifiable risk factors remain after rehabilitation (eg. jump landing asymmetry remains 2 years after ACL reconstruction and predicts second ACL tear). If you would like to dive into that concept in more depth, check out this short video
What this means is that without standardized, systematic, and stringent return to sport and discharge testing, we are likely to discharge patients with modifiable risk factors. We MUST stop this. Since I have implemented systematic discharge and return to sport testing, I am SHOCKED to find out how frequently I am wrong — the patient appears to be normal (even by my “trained” eye) but testing reveals something completely different.
So, are you willing to sign your patient’s leg, arm or back? I am…..but in the mean time, I have to go apologize to some of my previous patients. Fortunately, Jane is fictional but represents a large percentage of our patients.
Over the next several posts, I hope we can all discuss what the evidenced based discharge tests should be and what is considered passing. What tests do you think should be included? Post them below so we can discuss them in this forum.
So you have decided to take the plunge — you are going to try some injury prevention with a large group or team. You have already talked with the coach and have some “buy in” (if you don’t, start here). Here are 5 things that will help make your injury prevention successful:
1. Start Small – Just like dieting, small incremental steps are key to permanent success. People hear that we test 150 athletes in 2-3 hours and give real time reports of performance, risk categories, and 3 corrective exercises for each athlete. However, this didn’t happen overnight. Just like water eroding rock over time, we gradually changed our injury prevention culture over several YEARS. If you start by simply setting a goal of making your injury prevention better than it was last year, you will gradually get there. Here are a few suggestions:
- Start with a coach you have a good relationship with and one team
- Select one or two tests to do (see below)
- Ask injury history questions
- Work with the individuals who had pain with testing
- Be sure to retest those individuals to ensure the risk factors have normalized.
2. Categorize to maximize your resources – Particularly when testing large groups, it can be a daunting task to try addressing the risk factors you find. If you categorize individuals by their degree of risk (Lehr 2013), you can make the process more manageable. Check out how a Division III college did it with their Body Armor Program.
3. It’s gonna take a village – I frequently feel like I am on an “injury prevention island”. With some discussion, I do find many like-minded individuals. Some have tried injury prevention strategies before only to stop because they didn’t have good buy in. Others (particularly coaches) want to implement injury prevention, but don’t know how. Still others have misconceptions about how long it is going to take or how difficult it is. Just like other behavioral change, Start with Why to get people on board. When talking with a coach, discuss performance and durability benefits. For medical personnel, discuss keeping our athletes healthy and on the field. Also, think outside of the box when assembling your team of testers. Elicit the help of students (of any type: exercise physiology, PT, ATC, etc can help with the simpler testing), coaches (corralling the athletes), parents (ensuring forms are completed), and front desk personnel (data entry). They can all do something to help.
4. Use reliable, evidenced-based, predictive tests that can be completed quickly – Most frequently, I use injury history, Y Balance Test and Functional Movement Screen (I clearly acknowledge my bias here — I would love to hear what you use).
5. Start with Return to Sport Testing – Remember, previous injury is the most consistently reported risk factor for future injury so be sure you are using predictive, evidence based tests in your discharge protocol. Over the next several posts, I will take research based look at discharge testing and answer some commonly asked questions like:
- What should the limb symmetry be for hop testing? (hint: it is NOT 90%)
- What percent of athletes return to sport after ACL reconstruction?
- Do strength and range of motion testing matter?
- What does research tell us about basic movement testing?
So, if you are currently doing injury prevention, write down your goals for making your injury reduction strategies better than next year. If you haven’t started, utilize a few of the strategies to get started on a small scale. For those of you who have implemented injury prevention programs, please share your strategies with the group by commenting below.
When it comes to injury prevention, we are all excited, passionate and ready to get started only to hit road blocks: No one seems to want to give it the attention that it deserves. Coaches don’t want to give up valuable practice time, parents can’t fit it into jam packed schedules, and athletes, well, they are athletes!
Over the past 15 years, I have made many failed attempts at implementing injury prevention programs, so I would like to share with you what I have learned. After a great Twitter Chat with #solvePT, I decided to focus this blog post on talking with coaches and parents.
Some of the best injury prevention researchers in the world looked back at their injury prevention efforts with a huge cohort of female handball teams over a 10 year period (Mykelbust et al 2013). One of their key findings is that for injury prevention to be successful you “must have the coach as a “partner” in the process”. But how exactly do you do that?
Frequently, because of our passion, we provide too much information and end up sounding like a pushy salesperson. When talking with coaches and parents I suggest breaking it down into several steps:
- Step #1: Ask, “Can I test your team/athlete to see how they are doing?” Don’t promise too much. Just mention that there is some good research about the ability to identify athletes at more risk of injury and improve their performance. (Remember: researchers have found that the message should focus on both performance and prevention — also remember that if you are on the bench with an injury, you can’t perform!)
- Step #2 After testing, don’t say anything. Wait for coach/parent to say: “How did they do?” Now you have some buy in because they are asking the question — you are not pushing information
- Step #3 Tell them how they did: “I found these risk factors and research indicates that puts them at risk for injury.” Then be quiet. This is THE hardest part!
- Step #4 Parent/Coach says “Well, what are YOU going to do about it?” I say smiling, “I’m glad you asked.” — Total buy in
- Step #5 Present your evidence-based injury prevention strategy by changing the modifiable risk factors you tested
While these steps are the best way I have found to have the conversation, it is by no means 100% effective. I think the other key ingredient is persistence. Mykelbust et al said it best:
“persistent effort to promote injury prevention over several years, using every opportunity available”
It can take years to change the culture of any organization. In future posts, I will talk about specific implementation strategies. Sign up for this blog to be sure you get notified when it comes out.
I really want to hear from you. What strategies have you found to be successful to get people on board with your passion?
23 May 2013
Myklebust G, Skjølberg A, Bahr R. ACL injury incidence in female handball 10 years after the Norwegian ACL prevention study: important lessons learned. Br J Sports Med. 2013 May;47(8):476-9
After implementing ACL prevention programs in handball teams for over 10 years, the authors sought to answer the question of what made the injury prevention programs successful. They came to 3 main conclusions for successful programs:
- “must have coach as a “partner” in the process.”
- The prevention program was efficient
- The message “we delivered to coaches in seminars, through pamphlets, interviews and on our website, was no longer ‘may reduce injury risk’, but ‘will reduce injury risk by at least 50%’. This ‘specific’ information meets one of the Heath Brothers’ criteria for ‘sticky’ messages—messages that have influence.”
Finally, the authors concluded:
“Risk factor studies are necessary to identify the individual’s needs for special training and optimise the selection of preventive exercises. In the meantime, we suggest that team sports include prevention exercises in their warm-up, tailor the exercise programme to the specific sport and focus on coach education as a key factor”
Here are a few of the studies demonstrating using the Y Balance Test as a predictive tool
Plisky PJ, Rauh MJ, Kaminski TW, Underwood, FB. Star Excursion Balance Test predicts lower extremity injury in high school basketball players. J Orthop Sports Phys Ther. 2006;36(12):911-9
- “Players with an anterior right/left reach distance difference greater than 4 cm were 2.5 times more likely to sustain a lower extremity injury (P<.05). Girls with a composite reach distance less than 94.0% of their limb length were 6.5 times more likely to have a lower extremity injury (P<.05).”
- TAKE HOME MESSAGE: This was the first study demonstrating the Star Excursion Balance Test’s predictive ability. If you athletes have an asymmetry or low composite score, they may be at great risk of injury. Thus, one should consider using the SEBT for return to sport testing and in the pre-participation physical.
Gribble PA, Hertel J, Plisky PJ. Using the Star Excursion Balance Test to Assess Dynamic Postural Control Deficits and Outcomes in Lower Extremity Injury – A Literature and Systematic Review. J Athl Train. 2012;47(3):339-57.
- “The Star Excursion Balance Test is a reliable measure and a valid dynamic test to predict risk of lower extremity injury, to identify dynamic balance deficits in patients with lower extremity conditions, and to be responsive to training programs in healthy participants and those with lower extremity conditions.”
- TAKE HOME MESSAGE: The Star Excursion & Y Balance Test should be used for return to sport testing, pre-participation physicals, and annual musculoskeletal exams.
21 May 2013
Functional Movement Screen Injury Prediction Studies
O’Connor FG, Deuster PA, Davis J, Pappas CG, Knapik JJ. Functional movement screening: predicting injuries in officer candidates. Med Sci Sports Exerc. 2011 Dec;43(12):2224-30.
“Both Long Cycle and Short Cycle cohorts demonstrated higher injury risk among candidates who had scores ≤14 compared with those with scores >14 (LC: risk ratio (RR) = 1.65, 95% confidence interval = 1.05-2.59, P = 0.03; SC: RR = 1.91, 95% confidence interval = 1.21-3.01, P < 0.01). Overall, 79.8% of persons with scores ≤14 were in the group with fitness scores <280 (/300), whereas only 6.6% of candidates in the group with fitness scores ≥280 had scores ≤14.”
Take Home: Functional Movement Screen score is associated with injury risk in Marine officer candidates regardless of the length of the basic training session.
Kiesel K, Plisky PJ, Voight ML. Can Serious Injury in Professional Football be Predicted by a Preseason Functional Movement Screen? N Am J Sports Phys Ther. 2007 Aug;2(3):147-58.
“The results of this study suggest fundamental movement (as measured by the FMS™) is an identifiable risk factor for injury in professional football players. The findings of this study suggest professional football players with dysfunctional fundamental movement patterns as measured by the FMS(™) are more likely to suffer an injury than those scoring higher on the FMS™.”
Take Home: Performance on a basic test of fundamental movement patterns is helpful in predicting injuries in professional football players.
Chorba RS, Chorba DJ, Bouillon LE, Overmyer CA, Landis JA. Use of functional movement screening tool to determine injury risk in female collegiate athletes. N Am J Sports Phys Ther. 2010;5:47-54.
“A score of 14 or less on the FMS™ tool resulted in a 4-fold increase in risk of lower extremity injury in female collegiate athletes participating in fall and winter sports. The screening tool was able to predict injury in female athletes without a history of major musculoskeletal injury such as ACLR.”
Take Home: It is interesting to note that athletes with history ACL reconstruction were included in the study. This may indicate that the Functional Movement Screen may be able to pick up some of the motor control changes that occur after injury that place athletes at increased risk.
Asymmetries are common in the human body and can lead to a wild goose chase in musculoskeletal assessment. But how do we know which asymmetries are important and will lead to injury? Well, let’s look at some common misconceptions as well as the research.
Common Misconceptions About Asymmetries
1. If someone performs well at their sport with an asymmetry, the asymmetry doesn’t matter.
Who ever said that asymmetry IS related to performance? Asymmetry is related to injury risk, not necessarily performance. While I am concerned about performance, I am more concerned about keeping them in the sport and participating without being encumbered by injury.
2. Asymmetries are only important if they cause pain.
I am mostly concerned with asymmetries that cause movement inefficiency or are related to injury risk. To me, asymmetrical fundamental movement patterns will lead to injury or inefficiency (i.e. energy expenditure that is unnecessary for performance of the activity).
3. There is no research that indicates asymmetry increases risk of injury
Those who have an anterior reach distance asymmetry on the Y Balance Test (Star Excursion Balance Test) are at increased risk of injury in high school basketball and multiple collegiate sports (Plisky 2006, Lehr 2013)
Those who have an asymmetry on the Functional Movement Screen (Kiesel 2013 in press) are at increased risk of injury in professional football
Strength and flexibility asymmetries:
- Athletes experienced more lower extremity injuries if they had knee flexor and hip extensor strength asymmetries (Knapick 1991, Nadler 2001)
- Eccentric hamstring strength asymmetries were at greater risk of sustaining a hamstring muscle strain. (Fousekis 2011)
- Hamstring/quad ratio asymmetry (Soderman 2001)
- Ankle strength asymmetry (Baumhauer 1995)
Asymmetrical landing patterns predict second ACL tear in previously reconstructed athletes (Paterno 2010)
Bottom Line: I really don’t put much stock into isolated bony asymmetries (e.g. torsions, misalignments, etc.), but I do feel that modifiable movement asymmetries that are related to risk of future injury are extremely important. Further, the literature is replete with studies that indicate asymmetries exist after pathology (Gribble 2013, Hewett 2013). Since previous injury is the most robust risk factor for future injury, we owe it to our athletes to normalize these modifiable risk factors.
What do you think?
In athletes with chronic ankle instability, 2 studies report that fatigue decreases the reach distance on both sides(Gribble 2004, Gribble 2007). However, the unstable side is affected to a greater degree. So, performing a fatigue protocol prior to testing for return to sport might be a good idea. It will amplify those remaining neuromuscular control deficits. But remember, it will also decrease the composite score as well, so the results might not be as comparable to the age, gender, and sport specific injury risk cut points. But, I wouldn’t want anyone’s composite score so close to the risk cut point that fatigue tips them over the edge. Another
You should also consider fatigue with pre-participation physicals. Many places use the Y Balance Test not only for risk identification, but also as a baseline measure for return to sport after musculoskeletal injury or concussion. So if the athletes have a heavy workout prior to testing, their scores may be a little lower. I think that may be important to note, but would not cause me to postpone testing.
What do you think?