Arthritis Foundation Recommendations for ACL Injury Prevention

The Arthritis Foundation has developed a series of working groups called the Osteoarthritis Action Alliance. These groups included experts from various areas related to arthritis, including sports medicine. One of the groups was tasked to develop a set of recommendations for ACL injury prevention as individuals with ACL injury are an increased risk of developing osteoarthritis.
The following link goes to one of the informational flyers that was developed by this working group. It outlines an evidence driven set of guidelines for developing an effective ACL injury prevention program. Also, there are links to current programs that can be accessed online without any associated cost. One of the programs was developed by the UNC Sports Medicine Research Laboratory. We are very excited to have been able to be a part of this process and provide this information for the public.

Arthritis Foundation Flyer on ACL Injury Prevention

A direct link to the PEAKc program is also provided

PEAKc Program

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PEAKcontrol is now Sports Medicine Research Laboratory

We’ve recently changed the website address and name of the PEAK Control blog.

The new blog address is:    smrlunc.wordpress.com

Please be sure to update your bookmarks.  We will still be posting the same type of content on a regular basis.

We have also changed the name of our Facebook page to UNC Sports Medicine Research Laboratory.  Please be sure to check out and “like” the facebook page as we will routinely post different related content to our facebook page.

Enjoy.  DAP

Optimizing Recovery – PREPARE

On my way to the ACSM Health & Fitness Summit #ACSMSummit to present on evidence based strategies to optimize recovery and prevent over-reaching.  Looking forward to sharing this information with the fitness professional community at this wonderful conference.

During this presentation we will discuss the multiple factors that lead to fatigue and ultimately over-reaching / over-training following repeated bouts of strenuous exercise.  We will then discuss the 3R’s system, which focuses on evidence based recovery strategies to maximize the benefits of strenuous exercise and minimize the risk of a catabolic response.  As part of this process we’ve developed the PREPARE score (Planned Recovery to Enhance Performance and Regenerate), which is a survey individuals can take and see their recovery scores in the 3R areas (Re-Fuel, Rest, Retain Movement Efficiency).  The score is meant to help guide individuals optimize their recovery behaviors during strenuous training periods to maximize the anabolic response and minimize the catabolic response of strenuous training regimens.

A PDF copy of the presentation is available.  Enjoy!  DAP

Recovery – PREPARE ACSM Health & Fitness Summit 2013 Handout Low Res

Resources for Real Time Movement Assessment

The importance of assessing movement quality has been discussed in several PEAKc posts over the past year.  Some movement assessment systems involve video analysis (e.g. Landing Error Scoring System) while others can be performed in real-time.  The majority of clinicians may not have the time or resources for video analysis, so to facilitate real-time assessments of movement quality I have uploaded PDF’s of two different real-time movement assessment systems.

• Landing Error Scoring System – Real Time (LESS RT)  Padua_LESS Real Time

• Squat Movement Assessment Hirth_Padua_7 2007

Use of Visual and Verbal Feedback to Improve Lower Extremity Biomechanics, Pain and Function

Reference:

Willy RW, Scholz JP, Davis IS.  Mirror gait retraining for the treatment of patellofemoral pain in female runners.  Clin Biomech (Bristol, Avon). 2012 Dec;27(10):1045-51. doi: 10.1016/j.clinbiomech.2012.07.011.

http://www.ncbi.nlm.nih.gov/pubmed/22917625

What issue was addressed in the study, and why?

Increased contralateral pelvic drop, hip adduction and hip internal rotation are commonly described movement dysfunctions in those with patellofemoral pain (PFP) during functional tasks.  Weakness of the gluteal muscles, which help to stabilize the aforementioned motions, is also observed in those with PFP. However, previous research indicates that isolated hip muscle strengthening is not an effective method for altering lower extremity movement patterns.  Thus, alternative interventions appear to be necessary to ultimately improve these dysfunctional movement patterns.

Real-time feedback using motion analysis has been shown to be an effective means to alter lower extremity movement patterns during running.  In this previous research individual’s lower extremity biomechanics were monitored using an optical motion analysis system while subject’s received real-time feedback on their movement patterns.  A limitation of this research is that it is not clinically feasible to incorporate optical motion analysis equipment for real-time feedback in clinical settings.  Visual feedback using a mirror is a clinically feasible mechanism to provide real-time feedback on lower extremity movement patterns.  However, research has not investigated the effects of visual feedback provided by a mirror on lower extremity biomechanics during running.  Therefore, the purpose of this study was to examine the effects of a 2-week mirror gait retraining intervention on lower extremity biomechanics during running.  In addition, this study investigated whether the effects of mirror gait retraining were transferred to other functional tasks (single leg squatting and stair descent) and retained (1-month and 3 month retention periods).

Who were the participants in the study?

Ten females completed the study and met the following criteria: self-rated patellar pain of at least a 3 out of 10 scale during running, symptoms must be present during running and at least one other activity (squatting, jumping, kneeling, prolonged sitting, stair descent).  Individuals with patellofemoral instability or other knee related pathologies or history of lower extremity surgery were excluded from the study.

What did the researchers do for this study?

Lower extremity biomechanics were quantified using a motion analysis system during 3 tasks: running, single leg squat, and stair descent.  Lower extremity function was quantified using the Lower Extremity Functional Scale.  Pain was quantified using a visual analog scale.  These measures were take at 4 time periods: pre-training, immediately post-training, 1-month post-training, and 3-months post-training.

Participants who demonstrated abnormal hip motion (greater than 20-deg of peak hip adduction) during running were asked to participate in the mirror gait retraining intervention.  Those who met the criteria participated in a 2-week mirror gait retraining intervention where individuals trained 4 days each week (8 total training session).  The mirror gait retraining intervention was conducted as follows:

• Subjects ran on a treadmill while observing themselves in a full length mirror in front of them (visual feedback).
• During running the subjects received the following verbal cues: “Run with your knees apart with your kneecaps pointing straight ahead” and “Squeeze your buttocks”
• No other concurrent interventions (e.g. stretching, strengthening, etc) were performed
• During the first week of training the amount of visual and verbal feedback was increased each session.
• During the second week of training the amount of visual and verbal feedback were steadily decreased across each session.  This was performed to shift the individual’s dependence from external cues (verbal and mirror feedback) to internal cues and reinforce motor learning of the new movement patterns.  During the sessions when subjects received less feedback they would receive intermittent feedback during the training session.
• The duration of each training session was gradually increased from 15 to 30 minutes over the 2-weeks.
• The participants were instructed to not run outside of their training sessions during the 2-week intervention period.

What new information was learned from this study?

Running Biomechanics:

The following variables were significantly improved immediately following the intervention: peak hip adduction angle, peak thigh adduction angle, peak hip abduction moment, and contralateral pelvic drop.  However, there was no change in hip internal rotation.  After 1-month the following variables remained unchanged from post-test (suggesting successful retention of movement patterns): contralateral pelvic drop, peak thigh adduction moment, and peak hip abduction moment.  Thus, changes in peak hip adduction angle were not retained after 1-month of not performing the intervention.  After 3-months the following variables remained unchanged from post-test (suggesting successful retention of movement patterns): contralateral pelvic drop and peak thigh adduction angle.  Thus, changes in peak thigh adduction angle were not retained after 3-months of not performing the intervention.

Single Leg Squat Biomechanics:

The following variables were significantly improved immediately following the intervention (suggesting successful transfer of the new motor patterns during running to other functional tasks): peak hip adduction angle, peak thigh adduction angle, and peak hip abduction moment.  After 1-month the following variables remained unchanged from post-test: peak hip adduction angle, peak thigh adduction angle, and peak hip abduction moment.  After 3-months the following variables remained unchanged from post-test: peak hip adduction angle and peak thigh adduction angle.  Thus, changes in peak hip and thigh adduction were retained after 1 and 3-months of no training.  However, changes in peak hip abduction were retained after 1-month of no training, but not after 3-months of no training.

Stair Descent Biomechanics

Only peak hip adduction angle was significantly improved immediately following the intervention.  Thus, changes in peak hip adduction angle were transferred from running to stair descent; however, none of the other variables that were changed during running were transferred to stair descent.

Pain and Lower Extremity Function

Both pain and lower extremity function were significantly improved immediately after the intervention.  These improvements were retained at both the 1-month and 3-month follow periods.

What are the clinical applications of this study?

The findings indicate that the 2-week mirror gait re-training program was able to successfully improve hip biomechanics during running.  Also, many of these changes were successfully transferred to other functional tasks (single leg squat and stair descent).  Several of these changes were retained in all tasks.  In general, these findings suggest that the 2-week mirror gait re-training program used in this study was able to facilitate learning a new movement pattern (successful transfer and retention of new movement patterns).

In addition to improved movement patterns, pain and lower extremity function were also improved.  These findings suggest that improvements in pain and function may be associated with lower extremity movement pattern modifications.

Use of verbal feedback in combination with mirror gait retraining may be an important adjunct to a comprehensive and integrated intervention strategy to improve lower extremity biomechanics in those with PFP and altered hip biomechanics.

What are the limitations of the study, and what areas should be considered for future research?

There was no control group utilized in this study.  Thus, it is not clear if changes in lower extremity biomechanics, pain, and lower extremity function were due to the intervention.  However, these findings provide initial evidence to suggest that the intervention utilized in this study may have clinical merit and warrants further investigation.

Myofascial Trigger Points in the Gluteus Medius and Quadratus Lumborum in those with Patellofemoral Pain

Reference:

Roach S, Sorenson E, Headley B, San Juan JG.  Prevalence of myofascial trigger points in the hip in patellofemoral pain.  Archives of Physical Medicine and Rehabilitation 2012 Nov 2. pii: S0003-9993(12)01079-9. doi: 10.1016/j.apmr.2012.10.022. [Epub ahead of print]

http://www.ncbi.nlm.nih.gov/pubmed/23127304

What issue was addressed in the study, and why?

Dysfunction of the hip abductor and external rotator muscles is frequently associated with  patellofemoral pain (PFP).  Hip muscle dysfunction is believed to allow for greater hip adduction and internal rotation, thus contributing to medial knee displacement (knee valgus collapse) during functional tasks and ultimately increased patellofemoral contact pressure.  However, the underlying factors associated with hip muscle dysfunction are not clear.

The presence of myofascial trigger points (MTrPs) may contribute to hip muscle dysfunction; however, previous research has not investigated whether MTrPs are actually present in those with PFP.  Therefore, the purpose of this study was to determine the prevalence of of MTrPs in the gluteus medius and quadratus lumborum of individuals with and without PFP.  A secondary purpose was to determine the effects of a single bout of trigger point pressure release therapy on hip muscle strength.

Who were the participants in the study?

A total of 52 participants were enrolled in the study

• Patellofemoral Pain (PFP) group (n=26): reported general anterior, anterior/medial knee or retropatellar pain for 1 month or longer associated with prolonged sitting, stair ascent/descent, sports, and/or running.
• Control group (n=26): no previous history of PFP

What did the researchers do for this study?

The dominant leg of all participants was assessed for the following:

• Peak isometric strength during hip abduction
• Presence of MTrPs in the gluteus medius
  • 3 locations within the gluteus medius were assessed: 1) proximal to greater trochanter and inferior to iliac crest; 2) anterior to first location (previously described), deep to the iliac creast; 3) posterior to the tensor fascia latae
  • Presence of MTrPs in the quadratus lumborum
    • Assessed in a side lying position with palpation over the lateral third of the lumbar transverse processes

Criteria for identifying the presence of a trigger point included localized taut bands with tenderness, and the presence of a jump sign.

After the initial testing session, the PFP group participants were randomly assigned to a treatment group or sham-control group.  Those PFP group participants assigned to the treatment group received approximately 60-seconds of direct manual pressure over each identified MTrP.  Those in the sham-control group did not receive actual direct pressure over their identified MTrPs, but rather the investigator gently laid their hands over the lateral hip for 60-seconds.

What new information was learned from this study?

Prevalence of MTrPs and strength comparisons between PFP and Control subjects:

The prevalence of MTrP’s was significantly greater in the gluteus medius and quadratus lumborum muscles for the PFP compared to control subjects.  Also, peak isometric hip abduction strength was significantly less in the PFP compared to control subjects.

• 97% of PFP subjects demonstrated gluteus medius MTrPs compared to only 23% of control subjects
• 87% of PFP subjects demonstrated bilateral quadratus lumborum MTrPs compared to only 13% of control subjects
  • 93% of PFP subjects demonstrated contralateral side quadratus lumborum MTrPs
    

Trigger Point Release Therapy:

A single bout of trigger point release therapy did not influence peak isometric hip abduction strength in the PFP subjects.

What are the clinical applications of this study?

MTrPs are more prevalent in the gluteus medius and quadratus lumborum muscles of those with PFP compared to healthy, control subjects.  The presence of MTrPs is also associated with decreased peak isometric hip abduction strength in PFP compared to healthy, control subjects.  These findings suggest that presence of MTrPs in the gluteus medius and quadratus lumborum muscles may be a factor to consider in the prevention and rehabilitation of PFP.  It is possible that MTrPs need be effectively treated to ultimately restore normal gluteus medius and quadratus lumborum function in those with PFP or at risk for PFP.

Unfortunately, a single bout of trigger point release therapy was not sufficient to restore peak isometric hip abduction strength in those with PFP.  It is not clear if the presence of MTrPs was reduced following the single bout of trigger point release therapy as this was not reported by the authors.  The authors indicate that “it was expected that the MTrP compression discomfort would significantly decrease” with the intervention; however, this did not appear to be verified.  Thus, future research is needed to determine if a single bout of trigger point release therapy that effectively eliminates the presence of MTrPs is sufficient to restore muscle strength.

What are the limitations of the study, and what areas should be considered for future research?

It is not clear if the investigators were blinded to the group membership (PFP or control) of the study participants.  If tester blinding was not performed then this may introduce bias into the MTrP prevalence results.

An isolated, single bout of trigger point release therapy may not be sufficient to restore normal muscle function.  Rather a systematic and integrated approach utilizing techniques for muscle inhibition, lengthening, and activation may be required to restore normal muscle function in those with MTrPs.  Future research is needed to examine this approach to restoring normal muscle function in those with MTrPs.

Impact of Diet on Game Performance

Reference:

Souglis AG, Chryssanthopoulos C, Travlos AK, Zorzou AE, Gissis I, Papadopoulos C, Sotiropoulos A (2012) The effect of high vs. low carbohydrate diets on distances covered in soccer, Journal of Strength and Conditioning Research, doi: 10.1519/JSC.0b013e3182792147

http://www.ncbi.nlm.nih.gov/pubmed/23168373

A summary of this recent article can be accessed at the following blog site:

http://www.scienceofsocceronline.com/2012/12/does-diet-affect-match-performance.html

 Brief Summary:

In short, the researchers compared the effects of a high carbohydrate diet to a low carbohydrate diet on measures of work load during a soccer match.  Players consumed either the high (8 g CHO per Kg body mass) or low (3 CHO per Kg body mass) carbohydrate diet for 3.5 days prior to a scheduled game.  An estimated energy and macronutrient content of the prescribed diets during the intervention period for a 70-Kg player is listed below.

	High CHO Diet	Low CHO Diet
Total Kcal	2869	2873
Carbohydrate (g)	565	212
Fat (g)	44	95
Protein (g)	85	95

Distances traveled during the match were recorded using GPS devices.  Players who consumed high carbohydrate diets traveled significantly greater distances during the soccer match compared to those who consumed a low carbohydrate diet:

• Total distance covered over entire game: 13% greater in high carbohydrate players
• Total distance covered in first half: 12% greater in high carbohydrate players
• Total distance covered in second half: 16% greater in high carbohydrate players

These findings provide insight into the importance of diet / nutrition to actual game related performance.

Increasing muscle flexibility through eccentric training – a systematic literature review

Reference:

O’Sullivan K, McAuliffe S, DeBurca N.  The effects of eccentric training on lower limb flexibility: a systematic review.  British Journal of Sports Medicine 46(12):838-45, 2012.  doi: 10.1136/bjsports-2011-090835

http://www.ncbi.nlm.nih.gov/pubmed/22522590

What issue was addressed in the study, and why?

Lower extremity muscle flexibility is often reduced in those suffering from lower extremity musculoskeletal injury.  Static stretching is a commonly used exercise to improve muscle flexibility; however, several research studies indicate that static stretching is not effective at reducing future injury risk, post-exercise muscle soreness, or improving performance.  Thus, isolated static stretching is effective in improving flexibility; however, this does not appear to translate to reduced injury risk.

Animal based research demonstrates that eccentric training results in new sarcomeres to be created and aligned in series (sarcomerogenesis), thus facilitating greater muscle length and flexibility.  In addition, eccentric training has been shown to increase muscle force and alter the muscle’s length-tension curve by allowing peak torque to be produced at longer muscle lengths.  Due to these combined benefits (improved flexibility, peak force production, and ability to produce peak torque at longer muscle lengths), eccentric training has been proposed as an alternative method to improve muscle flexibility.  However, it is not clear if there is sufficient research from human subjects to support eccentric training as an effective method for improving lower extremity muscle flexibility.

Who were the participants in the study?

A systematic literature review was performed using the following search terms:

• eccentric
• strength OR training
• flexib* OR range of motion OR fascicle

Only randomized clinical trials which compared eccentric training on measures of lower extremity muscle flexibility to either no intervention, or a different intervention, were selected for inclusion in this systematic literature.  A total of 530 potential relevant articles were retrieved.  A total of 6 articles ultimately met the inclusion criteria and were included in this review.

What did the researchers do for this study?

Two independent research assessed the methodologic quality of each included study using the PEDro scale.  Individual study quality was classified as “high” (PEDro = greater than 6 out of 10), “fair” (PEDro = between 4-5 out of 10),  or “poor” (PEDro = less than 4 out of 10) based on the study’s PEDro score.

The following lower extremity muscle groups were investigated in those studies included in the systematic literature review:

• quadriceps (2 studies)
• calf (2 studies)
• hamstrings (2 studies)

Two different measures of muscle flexibility were measured in those studies included in the systematic literature review:

• range of motion (goniometric assessment of joint motion)
• fascicle length (diagnostic ultrasound assessment of muscle fascicle length)

What new information was learned from this study?

All 6 studies were rated as “high” quality based on their PEDro scores.  All of these studies revealed consistent evidence that eccentric training increases range of motion, or fascicle length, or both across all of the muscle groups studied.

There were a wide variety of eccentric training protocols used across the 6 studies.  A summary of the eccentric training protocols used is listed below:

• Duration of eccentric training: 6 to 10 weeks
• Repetitions: 6 to 10 repetitions
• Sets: 1 to 6 sets
• Duration of eccentric contraction: 3 to 6 seconds
• Training load: 50 to 100% of eccentric 1 RM

Based on these findings, eccentric training is an effective means of improving lower extremity muscle flexibility, assessed by either joint range of motion or muscle fascicle length.  This finding is consistent across the different muscle groups assessed and eccentric training protocols utilized across the 6 studies included in this systematic literature review.

What are the clinical applications of this study?

The magnitude of change in muscle flexibility when performing eccentric training appears to be similar to the improvement seen when performing static stretching.  Thus, eccentric training does not appear to be more effective than static stretching.  However, given the added benefits of eccentric training (increased peak torque, ability to generate peak torque at longer muscle lengths) it may be considered a viable supplement to other forms of flexibility training.

The training duration required to achieve increased muscle flexibility following eccentric training is not clear.  The shortest duration training period was 6-weeks in the included studies.  However, animal research has shown that sarcomerogenesis begins to occur after 10 days of eccentric training.  It is also unclear how long flexibility gains are maintained after ceasing eccentric training.  Future research is needed to better investigate these aspects of eccentric training on muscle flexibility.

What are the limitations of the study, and what areas should be considered for future research?

All of the included studies utilized healthy, uninjured participants.  Thus, these findings cannot be generalized to individuals who suffer from a musculoskeletal injury.  It is known that eccentric training can facilitate increased post-exercise soreness, thus eccentric training may not be an appropriate modality for improving flexibility in those with musculoskeletal injury.

At this point in time there are no specific parameters that can be recommended for improving muscle flexibility using eccentric training.  Future research is needed to investigate the optimal training parameters (duration, repetitions, sets, eccentric contraction time, training load, frequency, etc) for improving muscle flexibility.

Is there a link between musculoskeletal injury risk and neurocognitive function?

Over the last few years research has showed an association between neurocognitive test scores and lower extremity musculoskeletal injury risk.  Specifically, decreased neurocognitive scores were observed in those individuals who had suffered lower extremity injury.  These studies have sparked discussion within the research community to better understand the potential relationship between neurocognitive function and lower extremity injury risk.  It is theorized that decreased neurocognitive function may result in poor spatial awareness, slower reaction time, and altered decision making which may facilitate an elevated injury risk.

At this point a cause and effect relationship cannot be established between neurocognitive function and lower extremity injury risk as there is still more research required to better understand this relationship.  However, the current data do suggest that neurocognitive function may be a factor to consider when assessing an individual’s overall injury risk profile.  This information should be along with other data that have also been shown to be related to injury risk, such as movement efficiency, prior injury history, and body mass index.  In addition, neurocognitive function may also be a factor to consider in the rehabilitation and  return to play decision making process, especially in cases of traumatic injury that have resulted in significant time loss.

An overview of the current research examining the relationship between neurocognitive function and musculoskeletal injury can be found at:

http://lowerextremityreview.com/news/in-the-moment-sports-medicine/brains-and-sprains-is-there-an-extremity-concussion-link

Decreased Gluteus Maximus Activation Following Hip Joint Effusion – Presence of Arthrogenic Muscle Inhibition?

Reference:

Freeman S, Mascia A, McGill S.  Arthrogenic neuromusculature inhibition: A foundational investigation of existence in the hip joint.  Clinical Biomechanics 2012 Dec 20. pii: S0268-0033(12)00271-9. doi: 10.1016/j.clinbiomech.2012.11.014. [Epub ahead of print]

http://www.ncbi.nlm.nih.gov/pubmed/23261019

What issue was addressed in the study, and why?

Arthrogenic muscle inhibition (AMI) is a reflexive inhibition of musculature surrounding a joint due to pain and/or joint effusion.  AMI results in reduced voluntary muscle activation and ultimately decreases in muscle force output.  AMI has been repeatedly shown to occur in the quadriceps muscles following knee joint injury or effusion.  It is possible that other joints and muscles may also experience AMI, similar to the knee joint and quadriceps muscles.

The gluteus maximus is theorized to be weakened and inhibited in those with lower extremity injury.   However, the neurophysiologic mechanism for this is not yet understood.  It is possible that the gluteus maximus may experience AMI in the presence of hip joint injury or effusion; however, this has not been previously investigated.  Therefore, the purpose of this study was to examine the effects of simulated hip joint effusion on voluntary gluteus maximus muscle activation.  It was theorized that the presence of hip joint effusion would cause facilitate AMI of the gluteus maximus, thereby result in decreased voluntary gluteus maximus muscle activation.

Who were the participants in the study?

A control (9 healthy participants) and intervention (12 participants who complained of hip pain and dysfunction and demonstrated findings of hip labral pathology during physical examination) group of participants were utilized in the study.

What did the researchers do for this study?

Surface EMG electrodes were attached to the gluteus maximus muscle of all subjects to measure the activation amplitude during 4 different exercises: 1) supine pelvic bridge, 2) prone hip extension, 3) active straight leg raise, 4) active hip abduction.

Both intervention and control groups were tested pre-intervention and post-intervention.  The intervention group subjects had a sterile saline solution injected into their pathologic hip joint until the point of near full capsular distension.  The control group subjects rested between test sessions and did not receive an injection.

What new information was learned from this study?

The intervention group demonstrated significantly decreased gluteus maximus activation during the supine pelvic bridge and prone hip extension exercises.  There were no such changes during the active straight leg raise and active hip abduction exercises for the intervention group.  No changes were observed in the control group between pre- and post-intervention measures of gluteus maximus activation.

Decreases in gluteus maximus activation of intervention group subjects was isolated to the side of the injection/joint effusion as there were no changes in contralateral gluteus maximus activation.  Thus, these findings indicate that voluntary activation of the gluteus maximus muscle is decreased following hip joint effusion.

What are the clinical applications of this study?

These findings extend previous research demonstrating the presence of AMI in the quadriceps muscle group following knee joint effusion and suggest a similar phenomenon occurs at the hip joint.  Decreased gluteus maximus activation following hip joint effusion may result reduced force output/strength, which may alter normal lower extremity biomechanics.  Interventions aimed to reduce AMI of the gluteus maximus following hip joint injury/effusion may be required to fully restore normal gluteal muscle function.  Research has not investigated specific interventions to combat AMI of the gluteus maximus; however, research investigating quadriceps AMI suggests that the following are important components and may be considered for treatment of gluteus maximus AMI:

• Pain and effusion control (cryotherapy)
• TENS (transcutaneous electrical stimulation) to stimulate spinal reflexive pathways
• NMES (neuromuscular electrical stimulation) to stimulate inhibited muscles
• TMS (transcranial magetic stimulation) to increase cortical motor excitability

What are the limitations of the study, and what areas should be considered for future research?

Only voluntary activation of the gluteus maximus was quantified.   Previous research investigating AMI of the quadriceps utilized electrical stimulation to examine the H-reflex, which is analogous to the spinal stretch reflex.  Thus, while AMI of the gluteus maximus appears to occur following hip joint effusion, the specific neural pathways by which AMI results cannot be determined through this study.  Future research examining the specific neural pathways and mechanisms for gluteus maximus AMI post joint effusion is needed to better establish effective therapeutic interventions.

Research is needed to identify targeted interventions to combat gluteus maximus AMI.  In addition, it is important that these interventions be part of an integrated rehabilitation strategy to restore neuromuscular control and movement efficiency once gluteus maximus activation deficits have been restored.