ISSUE 14 MAY 2021


Welcome to the 14th edition of the Learn.Physio Research Review!

Hello! And thanks once again for taking the time to read my research reviews. Like always, I hope to share with you some recent research that provides you with some practical ways to help your clinical practice – and this issue is no different!

I’ve got two papers this issue from ACLR expert Dr Nicky van Melick, who published an important set of evidence-based ACLR guidelines in the British Journal of Sports Medicine in 2016 (see article 2 for full text link to those guidelines).

The first of Dr van Melick’s great work is looking at the effect of sport-specific induced fatigue on the movement quality of ACLR patients. Some really important findings for us all to consider!

The second paper looks at the practice standards of physiotherapists and sports physiotherapists when working with ACLR patients. Once again, it highlights ways we can all simply improve our own practices to help improve our standards of care to our ACLR patients.

I hope you enjoy these 2 summaries and get something out of them to take to the clinic this week!


Athletes recovering from ACLR need to adequately evaluated during their rehab, in particular as they transition back to sport. To assist health professionals in this decision, evidence-based return to sport guidelines have been developed by Davies et al 2017, Gokeler et al 2017 and van Melick et al 2016.

Despite meeting these guidelines and recommendations, athletes returning to sport still have on average a 10% chance of a 2nd ACL injury. In athletes aged under 20yrs, this risk is much higher at around 30%.  

One of the contributing factors to 2nd ACL injury risk is the thought that the return to sport testing is not tested in a “ecologically environment” (sport specific environment) nor in a fatigued state.

Therefore, the aim of this study was to investigate the influence of neuromuscular fatigue on both movement quantity (absolute values on hop tests) and movement quality in ACLR patients and compare them with healthy soccer players in an ecologically valid environment – the local soccer field.



Males recreational ACLR patients aged between 18-30 years of age were invited to participate in this study at the end of their rehab. Up until this point, they had attended regular rehab sessions with an experienced sports physiotherapist who worked according to ACLR guidelines. They were included into the study if their usual treating physio considered them to be fully rehabilitated according to hop test battery by Gustavsson et al 2006.

Exclusion criteria for ACLR group were: other injuries of the lower back, hip, knee or ankle that would affect testing results; knee effusion at the moment of testing; or a contralateral ACL injury or previous ipsilateral ACLR.

The control group consisted of health male recreational soccer players that played soccer less than or equal to 3x per week and did not follow a professionally designed training program

Exclusion criteria for the healthy group were: ACL injury or ACLR in the past; and other injuries to the lower back, hip, knee or ankle in the past 4 weeks.

Study procedure
Both groups were not allowed to participate in strenuous physical activity on the day before testing and wore their own soccer footwear for testing (except for vertical jump testing); with all testing performed on soccer field.

Before return to play measurements in a non-fatigued state were taken, the players did a standardized 10min warm-up. After the non-fatigued measurements were taken, the players then participated in a 1hr soccer-specific field training session. After the 1hr training session, fatigue was measured using a 6–20-point Borg RPE scale, and the return to sport tests were performed again in the fatigued state.
The return to sport testing battery included;
  • Single leg vertical jump (movement quantity – vertical height)
  • Single leg hop for distance (movement quantity- horizontal distance)
  • Single leg side hop (movement quantity – number or reps in 30sec)
  • Landing Error Scoring System (LESS – movement quality test)
The 3 single leg hops were chosen as they have been identified in the literature of having a high sensitivity of 91% to detect differences between ACLR patients and healthy patients (Gustavsson et al 2006).
The number of athletes not meeting return to play cutoffs of >90% LSI were recorded.
For the movement quality assessment (LESS), a score of 6 or more (maximum score of 19) indicates a poor technique when landing from a jump and can increase the risk for an ACL injury. See images below and marking criteria for the LESS.
The number of athletes not meeting the return to sport cutoff of less 6 were recorded.


14 ACLR soccer athletes (average age 23yrs and 12 months post-op) and 19 healthy soccer players (ave age 21yrs) were included. There were no significant differences between groups at baseline.
For the single leg hop tests (movement quantity), the results are as follows:

  • Single leg vertical jump – no significant before and after effect, and no differences between groups
  • Single leg hop for distance – no significant before and after effect, but it was found that ACLR patients hopped shorter in a fatigued state (1.66m) compared to non-fatigued (1.7m) while the healthy group didn’t.
  • Side hop test – no significant before and after effect, but once again ACLR patients decreased their hop reps from 59 reps to 56 reps when fatigued whilst the healthy group did not.
For the LESS (movement quality assessment), the results are as follows:
  • LESS scores increased significantly in the fatigued state for both groups, were significantly higher in the ACLR group, and increased significantly more in the ACLR group vs the healthy group.
  • The LESS in the ACLR group increased from ave 3.6 points in a non-fatigued state to ave 6.8 points in a fatigued state, whereas the healthy group increased slightly from 3.7 points to 4.3 points in a fatigued state.
  • In a non-fatigued state, 2 out of the 14 (14%) ACLR patients scored worse than 6 on the LESS. This number climbed to 12 out of 14 in a fatigued state (86%).

Side note: Although it was a little understated in the results section, the authors also found some useful normative data (see table below) for recreational athletes (21-year-old male soccer players) that might be able to be used as an indicator of whether or not ACLR patients have returned their hopping ability back to a healthy normal standard.


The key finding here for clinicians dealing with ACLR patients is the worsening LESS scores from a non-fatigued state to a fatigued state, that took the LESS scores to a high risk of ACL Injury (6 or greater). The same degree of change was not observed in the healthy athletes with only 32% scoring higher than 6 compared to 86% in the ACLR group, which suggests that even at 12 months post-op ACLR, ACLR patients’ rehab is still incomplete (in this ACLR group anyway).

The other important thing to note was that the degree of change from a non-fatigued state to a fatigued state was not as significant for the single leg hop tests that measure quantity rather than quality. These findings justify the inclusion for an assessment of movement quality in the return to play discharge tests; especially in a fatigued state and ideally in a sport specific environment such as a soccer field of basketball court.

In regards to the ecological testing, the authors did note something of interest in that, prior to the commencement of the study all of the 14 ACLR patients could pass all of the return to play criteria (>90% LSI on all 3 hop tests and <6 on LESS), yet 4 ACLR players could not pass all of the 4 tests in the new environment. Once again, this is a valid reason to try and identify and conduct return to play testing in sport specific testing environments.

The big question now remains is - do any of these athletes who worsened their hop test distances and LESS scores in a fatigued state go on to actually sustain a second ACL injury? Only time and more research in this space will tell.
This was a really clever study that aimed to answer some really practical questions that gives us clinicians a more thoughtful return to sport testing battery for our ACLR patients.

Importantly, this study highlighted the need to be being more thorough with our testing batteries and looking at movement QUALITY (via LESS) as well as QUANTITY (hop test distances, hop heights, side hop reps and LSI cutoffs). Furthermore, movement quality assessment should be conducted in a fatigued state.

The authors also recommended that based on this study, that return to sport testing be carried out in an environment specific to the environment that the athlete is returning to, and that limb symmetry index cutoffs for return to sport be set at 95% LSI minimum.
If you’re interesting in learning more about high quality rehab, consider taking our ACLR Masterclass by clicking
Take your learning to the next level with our ACL Rehab Masterclass
ACL Rehab Masterclass


Returning to pre-injury level of sport following ACLR is the desired endpoint for most ACLR patients. Before doing so though, it is now considered best practice to pass a series of strength, function and psychological readiness tests before playing the first competitive game, rather than just wait for time to elapse (usually 9-12 months post-op).

There are some slight differences between studies and guidelines on what tests should be performed, but the Royal Dutch Society for Physical Therapy published guidelines in 2014 that incorporates both measures of movement quantity (quads and hamstring strength scores and single leg hop scores) and movement quality (single leg hop + hold and LESS) to decrease second ACL injury risk.

Even though these measures have been published, and many ACLR experts recommend their utility, many athletes are still not being adequately tested before returning to pivoting sports. In Sweden, only 20% of adults who already had returned to sport met the pass requirements of discharge testing, while in the USA only 14% of adolescent athletes met the pass requirements of discharge testing.

Therefore, the primary aim of this study was to analyse if Dutch physical therapists adhere to these practice guidelines. The second aim of this study was to explore if there was a difference in adherence of practising these guidelines between physios specialised in sports physical therapy (additional 3-4 years of Masters level university training on top of a Bachelors degree) vs those who have not.


This was a prospective observational cohort study on pivoting ACLR athletes (pre-injury Tegner activity level 6 or above) with an age range from 16-50yrs of age. Athletes were excluded if they had undergone a revision ACLR, contralateral ACL injury or contralateral ACLR in the past.

ACLR athletes were allowed to choose their own physical therapist during the 12 months of rehab and the physical therapist was contacted by the research team to be advised on the 9 return to sport tests as outlined above. ACLR patients who were not returning to pivoting sports were still strongly encouraged to meet all the 9 return to play criteria.

At the end of rehab, the usual treating physical therapist assessed the ACLR patient and determined that they were ready to play. They then contacted the research team. Within 4 weeks after notification, the research team performed their own independent return to sport test and thus re-evaluated the original physical therapists’ judgement on whether the ACLR patient was actually ready to return to sport.

Additionally, the ACLR athlete was asked if they were familiar with the testing process as conducted by the research team. If the ACLR patient was not familiar with any of the testing, it was considered that the original physical therapist was not adhering to the ACLR guidelines.

Outcome measures:
To answer the first question of the study, which focused on adherence to the Dutch ACLR guidelines, an ACLR athlete was labelled as tested by their primary physical therapist as “yes” or “no” and having met return to play criteria as “yes” or “no”. Note, even if 1 testing criteria was not passed, and the other 8 were passed, the ACLR patient still received a “no”.

For the second aim of the paper in exploring adherence rates between sports physical therapists and those who are not, the athlete was labelled as having rehab with a sports physical therapist “yes” or “no”.
158 pivoting athletes (54 females, 104 males, ave age 24yrs) were included in this study. All of these ACLR patients conducted their return to play testing under the research team on average 12 months post-op.

There were 108 different physical therapists involved in these 158 ACLR rehabilitations, with 49 registered as sports physical therapists.

Of the 158 ACLR athletes, only 25 (16%) met all 9 return to sport criteria when the primary researcher performed all the tests.

30 athletes (19%) met return to sport criteria for all 7 quantitative tests (strength and hop tests) and 81 athletes (51%) met the return to sport criteria for both qualitative tests (hop and hold and LESS).

87 athletes (55%) rehabilitated with a sports physical therapist, but only 45 of them (52%) had return to sport measurements with their primary physical therapist performed. Conversely 71 athletes (45%) rehabbed with non-sports physical therapists, with only 24 of them (34%) having return to sport testing performed.
The results from this survey of ACLR rehab and return to sport practices from Dutch physical therapists revealed fairly low adherence to published (and freely available) ACLR guidelines with only 52% of pivoting athletes formally tested by their primary physical therapist on the readiness to return to sport following ACLR.

What was quite surprising was only 23% of ACLR athletes were tested by their usual treating physical therapist with advice that was consistent with Dutch guidelines. And only 16% of all ACLR patients included in this study passed all of the 9 testing criteria points.

These results are slightly better than a similar study conducted in Australia by Ebert et al (2017) who found that only 5% of their ACLR patients at 12 months post-op were receiving rehab that was consisted with evidence-based practice guidelines by (
van Melick et al 2016).

The problem with such low numbers of ACLR patients meeting rehab standards and passing return to sport criteria, is that it has been consistently shown that not passing a battery of return to sport tests carries an elevated chance of 2nd ACL injury in the next 1-2 years upon return to sport (Webster & Hewett 2018, Grindem et al 2016 and Kyritsis et al 2016).
Even though this is just one study on ACLR practices on a group of Dutch physical therapists, the findings unfortunately would not be that dissimilar to what is happening worldwide. On top of the findings from this paper, and Ebert et al 2017, Greenberg et al 2018 reported that 55% of clinicians surveyed only used manual muscle testing to determine quadriceps strength in ACLR patients during ACLR rehab!

Despite these low numbers and worrying trends with inadequate ACLR rehab and return to sport testing, its important that we keep striving to improve our management of ACLR patients, particularly when determining when the athlete is ready to return to play.

There are no doubt some pretty major barriers to implementing “best practice” for ACLR return to play testing. Having access to isokinetic strength testing is just one major hurdle for the vast majority of clinicians and patients. Also having access to reliable, inexpensive technology to measure vertical jump heights is also another major hurdle. Then to have the time and space to implement them in a timely fashion is another.

There would be many more barriers, including lack of knowledge of how to structure an appropriate rehab plan over 9-12 months. Typically physiotherapists have a great skillset to get the ACLR patient through the first 3 months, but beyond that stage when people are looking to return to running, jumping, training and sport, the process can be much more complicate – especially for the early career clinician. This is why collaboration with exercise professionals is a must!

Unfortunately, I don’t have all the answers to overcome all of these barriers but importantly, we all need to try our best and not just accept that the person is 12 months post-op and the surgeon says they are good to return to sport. This is simply not good enough.

This is why Randall Cooper and I have worked on developing the Melbourne ACL Rehab Guide into a clinician friendly checklist of tests that require very little cost to the patient and very little equipment to the clinician. It’s not perfect, but it certainly is better than doing nothing.

If you’re interested in learning more about ACLR rehab and what the Melbourne ACL Rehab Guide looks like in real time, take our ACLR Masterclass today by clicking on the link

The below paper is full text reference for your own reading. References cited throughout this article can be found in the reference section of this paper

Research Review 1

van Melick N, van Rijn L, Nijhuis-van der Sanden MWG, Hoogeboom TJ, van Cingel REH. Fatigue affects quality of movement more in ACL-reconstructed soccer players than in healthy soccer players. Knee Surg Sports Traumatol Arthrosc. 2019 Feb;27(2):549-555. doi: 10.1007/s00167-018-5149-2. Epub 2018 Sep 27. PMID: 30259146; PMCID: PMC6394549.

Davies GJ, McCarty E, Provencher M et al (2017) ACL return to sport guidelines and criteria. Curr Rev Musculoskelet Med 10(3):307–314

Gokeler A, Welling W, Zaffagnini S et al (2017) Development of a test battery to enhance safe return to sports after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Artrosc 25(1):192–199

van Melick N, van Cingel RE, Brooijmans F et al (2016) Evidencebased clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus. Br J Sports Med 50(24):1506–1515
Gustavsson A, Neeter C, Thomeé P et al (2006) A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstruction. Knee Surg Sports Traumatol Arthrosc 14(8):778–788

Research Review 2



We recently hosted our latest Insights Episode. Watch the recording through the link below
Click Here

Thanks for reading and staying up to date. I look forward to sharing more in the future.

If you enjoyed the reviews, I'd be grateful if you told your colleagues about the Learn.Physio Journal Club.

Stay Tuned for our Next Issue

If you would like to check out our previous Research Review Issues
Click Here

Check out our Insights Interviews
Click Here

You are receiving this email because you signed up to our Free Journal Club to receive research reviews, webinar invites and early access to our Masterclasses

Click here to unsubscribe from this list
Copyright © *|CURRENT_YEAR|* *|LIST:COMPANY|*, All rights reserved.

Our mailing address is:

Want to change how you receive these emails?
You can update your preferences or unsubscribe from this list.