Rehabilitation after anterior cruciate ligament reconstruction: criteria-based progression through the return-to-sport phase

Changes in isometric mid-thigh pull peak force and symmetry across anterior cruciate ligament reconstruction rehabilitation phases

Background

Whether functionally relevant strength assessments, such as the isometric mid-thigh pull (IMTP), can be used either bilaterally or unilaterally to evaluate and guide rehabilitation progress in those with anterior cruciate ligament reconstruction (ACLR) is under-researched. This study assessed changes in peak force (PF) and asymmetry across 3 phases for bilateral and unilateral IMTP assessments in patients with ACLR. Peak isometric force from the IMTP was compared to peak torque from isokinetic dynamometry as well as against a cohort of healthy, uninjured individuals.

Method

Participants (ACLR, n = 15) completed bilateral and unilateral IMTP assessments at weeks 12 (baseline), 16 (phase 3), and 20 (phase 4) of rehabilitation to evaluate changes in PF and asymmetry. Asymmetry was evaluated using the asymmetry angle. Isometric data from the IMTP were compared to that from an isokinetic dynamometer as well as against a cohort of healthy, uninjured participants (n = 63) allowing for a detailed analysis of limb-specific force production.

Results

The PF during the bilateral IMTP increased for both the injured (0.94 N/kg) and uninjured (0.26 N/kg) limbs from baseline to phase 4, whereas the PF of the injured limb increased by 1.5 N/kg during the unilateral IMTP in the same time frame. Asymmetry values systematically reduced by ∼1% and ∼0.5% for the bilateral and unilateral IMTP tests from baseline to phase 4. Significant differences in PF of the injured limb were evident between those with ACLR and healthy controls across all phases (p = 0.022-0.001). The rate of progression in PF capacity was dependent on test type, amounting to 0.1 and 0.2 body weights per week for the bilateral and unilateral IMTP respectively. Small-to-large correlations (r = 0.12-0.88) were evident between IMTP PF and peak torque from the isokinetic dynamometer as well as between asymmetry metrics from both tests.

Conclusion

The findings suggest that IMTP PF has potential for monitoring changes in PF and asymmetry during the ACLR rehabilitation progress. Both injured limb and uninjured limb show improvement in force-generating capacity, implying a positive adaptation to rehabilitation protocols. The findings highlight that ACLR is a unilateral injury that requires bilateral rehabilitation.

A Rehabilitation Algorithm After Lateral Ankle Sprains in Professional Football (Soccer): An Approach Based on Clinical Practice Guidelines

Lateral ankle sprain (LAS) is one of the most common types of injury in professional football (soccer) players with high risk of recurrence. The rehabilitation after LAS in professional football players is often still time-based and relies on anecdotal experience of clinicans. There is still a lack of utilization of criteria-based rehabilitation concepts after LAS in professional football. The aims of this clinical commentary are (1) to critically discuss the need for criteria-based rehabilitation concepts after LAS in professional football players, (2) to highlight the current lack of these approaches and (3) to present a novel clinical guideline-based rehabilitation algorithm. Short time-loss (15 days) and high recurrence rate (17%) raise the question of trivialization of LAS in professional football. Despite consequences for many stakeholders involved (players, teams, clubs, insurers), there is still a lack of of criteria-based, step-by-step approaches. The use of a criteria-based rehabilitation approach might reduce the high recurrence rate after LAS in professional football players and will lead, in turn, to increased long-term player availability. Practical experiences of he authors demonstrate the feasibility of such an approach. The effectiveness of this novel rehabilitation algorithm remains to be evaluated in future studies. Level of Evidence: 5.

Test-retest reliability and longitudinal validity of drop vertical jump biomechanics during rehabilitation after ACL reconstruction

Hip and knee biomechanics measured during a drop vertical jump (DVJ) can be used to assess patients undergoing rehabilitation after anterior cruciate ligament (ACL) reconstruction. To confidently interpret such data for use as outcome measures, additional information about reliability and validity is required. Therefore, the objective of this study was to estimate the test-retest reliability and longitudinal validity of selected lower limb biomechanics assessed during a DVJ in patients undergoing rehabilitation after ACL reconstruction. Biomechanical analysis of the DVJ in primary unilateral ACL reconstruction patients (22.3 ± 5.5y) were tested twice within 1 week at 6 months post-surgery (n = 46), and again at 12 months post-surgery (n = 36). Peak and initial contact knee angles and moments, hip impulse, vertical ground reaction forces (VGRF), isokinetic knee extension and flexion strength, and global ratings of change (GRC) were assessed. Reliability was evaluated based on the 6-month post-surgery data using intraclass correlation coefficients (ICC2,1), standard errors of measurement and minimum detectable change. Longitudinal validity was evaluated by assessing change from 6 to 12 months, using standardized response means (SRM), and by assessing the correlation (Pearson's r) of change in landing biomechanics with change in strength, and GRC. ICCs ranged from 0.58 to 0.90 for peak knee abduction and flexion moments, 0.44-0.85 for knee flexion and abduction angles, 0.82-0.93 for VGRFs, and 0.42-0.65 for hip impulse. SRMs and correlations of change ranged from 0.00 to 0.50. Reliability and longitudinal validity of DVJ measures varied, ranging from poor-to-excellent; the present results assist in their interpretation when assessed during rehabilitation after ACL reconstruction.

Relationship between Kinesiophobia and Dynamic Postural Stability after Anterior Cruciate Ligament Reconstruction: A Prospective Cohort Study

INTRODUCTION

 Anterior cruciate ligament (ACL) injuries in young, active patients generally require ACL reconstruction (ACLR) to restore mechanical and postural stability. The fear of movement or reinjury (kinesiophobia) has become increasingly recognized in the post-ACLR population; however, the association between restoration of postural stability and kinesiophobia remains largely unknown. The purpose of this study was to investigate changes in mean Tampa Scale of Kinesiophobia-11 (TSK-11), dynamic motion analysis (DMA) scores, and time on the testing platform, as well as any correlation between TSK-11 and mean overall and individual translational and rotational DMA scores during the first 12 months following ACLR.

DESIGN

 Cohort study.

METHODS

 Patients undergoing ACLR were prospectively enrolled and dynamic postural stability and kinesiophobia based on the TSK-11 were collected within 2 days prior to surgery and at 6 and 12 months following ACLR. Dynamic postural stability was quantified by calculating a DMA score, with score calculated in three translational (anterior/posterior [AP], up/down [UD], medial/lateral [ML]) and three rotational (left/right [LR], flexion/extension, and internal/external rotation) independent planes of motions. Correlations between DMA and TSK-11 scores at each time point were analyzed.

RESULTS

 A total of 25 patients meeting inclusion criteria were analyzed. Mean overall DMA and TSK-11 scores increased with each successive testing interval. At 6-month follow-up, a weakly positive association between TSK-11 and DMA scores was appreciated based on overall DMA, AP, UD, ML, and LR. At 12 months, a moderately positive correlation was appreciated between TSK-11 and the translational, but not rotational, planes of motion.

CONCLUSIONS

 Following ACLR, lower level of kinesiophobia were found to be moderately associated with improved dynamic stability, especially in the translation planes of motion.

The Nature of Rehabilitation Programs to Improve Musculoskeletal, Biomechanical, Functional, and Patient-Reported Outcomes in Athletes With ACL Reconstruction: A Scoping Review

CONTEXT

After anterior cruciate ligament (ACL) reconstruction (ACLR), athletes commonly undergo prolonged rehabilitation (eg, 9-12 months), but few actually return to preinjury sports activities. The nature (composition, configuration) of an ACL rehabilitation program (ACL-RP) is an important factor in determining rehabilitation outcomes; however, details about the nature of ACL-RPs are reported inconsistently in research studies. To guide future research reporting to support clinical translation and implementation of ACL-RPs, it is necessary to describe the nature, reporting, and outcomes of ACL-RPs in the current literature.

OBJECTIVE

The purpose of this scoping review was to understand the nature and reporting of various ACL-RPs that address musculoskeletal, biomechanical, functional, or patient-reported outcome measures in adult and pediatric athletes with ACLR.

DATA SOURCES

Articles were selected from searches in 5 electronic databases (PubMed, EbscoHost [MEDLINE, SportDiscus, CINAHL Plus], PROQuest, Cochrane, and Embase).

STUDY SELECTION

Studies were included if they evaluated a post-ACL-RP that implemented strength, balance, plyometric, change of direction running, and/or agility running and included self-reported physical function, quality of life, or pain outcomes.

STUDY DESIGN

Scoping review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) guidelines.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Data were extracted and synthesized to evaluate the reporting of acute program variables (APVs) and exercise descriptors (EDs); 17 studies were included in the final synthesis.

RESULTS

Studies reported between 0% and 67% of the APVs and EDs combined. Only 2 studies were considered to have adequate reporting of both APVs and EDs.

CONCLUSION

Inadequate reporting of APVs and EDs in past studies restricts the translation and implementation of existing research-based ACL-RPs to present-day clinical contexts.

Return to sports after an ACL reconstruction in 2024 - A glass half full? A narrative review

A successful return to sports (RTS) after an anterior cruciate ligament reconstruction (ACLR) is multifactorial, and therefore difficult and challenging. Unfortunately, low percentages of patients RTS, and for those who succeed, one-fifth of patients will sustain a second ACL injury. Over the past years, test batteries were developed to assess whether patients can RTS with a low risk for a second ACL injury risk. Low rates of patients who meet RTS criteria were found, coupled with the insufficiency of current RTS test batteries in predicting second ACL injuries suggesting poor sensitivity. The result of an RTS test is likely to reflect the content of a rehabilitation program, raising critical questions regarding what we are offering patients within the rehabilitation programme. Are we preparing our patients well enough for the high demands of complex situations within pivoting team sports? This narrative review offers insights from key lessons of the last 15 years on 1) RTS testing, 2) the content of rehabilitation, and 3) the RTS continuum, all from a "helicopter perspective".

Rehabilitation and Return to Play Protocols After Anterior Cruciate Ligament Reconstruction in Soccer Players: A Systematic Review

BACKGROUND

Rehabilitation after anterior cruciate ligament ACL reconstruction (ACLR) is crucial for safe return to play (RTP) and reducing the chances of a reinjury. Yet, there is no consensus on the ideal functional tests to assess rehabilitation progress in soccer players after ACLR.

PURPOSE

The primary objective was to highlight the existing gap in the literature concerning the most effective standardized rehabilitation protocols and testing for facilitating successful RTP among soccer players.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review using PubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) was conducted. Inclusion criteria encompassed original studies (level of evidence 1-4) that examined rehabilitation protocols, metrics of knee rehabilitation, and clinical outcomes after ACLR in soccer players.

RESULTS

This review incorporated 23 studies, predominantly retrospective case series, with a total number of 874 soccer players who underwent ACLR and rehabiliation. 5 (21.7%) studies utilized an accelerated rehabilitation protocol, while 7 (30.4%) of studies utilized a criterion-based rehabilitation. A wide heterogeneity of data was extracted including functional tests of rehabilitation and RTP such as strength test batteries, hop test batteries, and movement quality assessments. Of the 23 selected studies, 2 (8.7%) used all 3 test batteries, 8 (34.8%) used 2 test batteries, 12 (52.2%) used 1 test battery, and 1 (4.3%) used 0 of the test batteries. The mean time between surgery and RTP ranged from 3 to 8 months with only 2 (8.7%) studies reporting complications after ACLR. Lastly, out of the total studies examined, 9 (39.1%) assessed patient-reported outcome measures (PROMs), all of which demonstrated significant improvement from the initial assessment to the final follow up.

CONCLUSION

Soccer-specific rehabilitation after ACLR lacks standardization. Even though many studies have assessed protocols for optimal RTP and reduced secondary ACL injuries, there is a gap in the literature regarding the most effective protocols and RTP testing. The methodology reported by Kyritsis et al could serve as a foundation for future prospective randomized multicenter studies to establish a standard rehabilitation protocol and enable a successful return to soccer.

The Seated Trunk Control Test: Investigation of Reliability and Known-Groups Validity Using Individuals Post-Anterior Cruciate Ligament Reconstruction

CONTEXT

Decreased trunk neuromuscular control is a risk factor for both upper- and lower-extremity injuries, yet there are few reliable and valid clinical tests to identify deficits.

OBJECTIVE

The purpose of this study was to determine the reliability and known-groups validity of a novel clinical test, the seated trunk control test (STCT).

DESIGN

Cross-sectional reliability and known-groups validity study.

SETTING

Laboratory.

PARTICIPANTS

89 unique participants: 34 were 3 months postoperative anterior cruciate ligament reconstruction (ACLR) and 55 healthy controls.

METHODS

For the STCT, participants sat on a balance board with their eyes closed for three 30-second trials while investigators counted balance errors. Intraclass correlations (ICCs) were used to assess interrater reliability (N = 20) and test-retest reliability (N = 40). To assess known-groups validity, independent t tests were used to compare STCT errors at 3 months post-ACLR with healthy matched controls (N = 34/group). Area under a receiver operating characteristic curve identified an optimal cutoff for distinguishing between groups.

RESULTS

The STCT had perfect interrater reliability (ICC2,3 = 1.00) and good test-retest reliability (ICC3,3 = .79; 95% confidence interval = .61-.89). The ACLR group made significantly more errors on the STCT (mean [SD] = 15.5 [5.4]) than controls (mean [SD] = 8.2 [4.1]; P < .001, Cohen d = 1.52). The STCT's ability to distinguish between groups was excellent (area under a ROC curve = 0.86). A cutoff of 12 errors maximized sensitivity (76%) and specificity (85%).

CONCLUSIONS

The STCT is reliable between raters and across days. It also has excellent ability to distinguish between individuals with a recent ACLR and healthy matched controls, which provides initial evidence to suggest that the STCT may be clinically useful for identifying deficits in trunk neuromuscular control.

Are inter-limb differences in change of direction velocity and angle associated with inter-limb differences in kinematics and kinetics following anterior cruciate ligament reconstruction?

BACKGROUND

Quantifying inter-limb differences in kinematics and kinetics during change of direction is proposed as a means of monitoring rehabilitation following anterior cruciate ligament reconstruction (ACLR). Velocity and centre of mass (CoM) deflection angle are fundamental task descriptors that influence kinematics and kinetics during change of direction. Inter-limb differences in approach velocity and CoM deflection angle have been identified following ACLR and may contribute to the presence of inter-limb differences in kinematics and kinetics during change of direction.

RESEARCH QUESTION

The aim of this study was to quantify the proportion of variance in kinematic and kinetic inter-limb differences attributable to inter-limb differences in approach velocity and centre of mass deflection angle during a change of direction task.

METHODS

A cohort of 192 patients (male, 23.8 ± 3.6 years, 6.3 ± 0.4 months post primary ACLR) completed a pre-planned 90° change of direction task on both their operated and non-operated limb. Inter-limb differences in approach velocity and CoM deflection angle were calculated alongside lower-extremity kinematic and kinetic variables. The relationship between inter-limb differences in task-level variables and inter-limb differences in kinematic and kinetic variables was examined using linear regression models. Kinematic and kinetic inter-limb differences were adjusted for inter-limb differences in approach velocity and CoM deflection angle. Adjusted and unadjusted inter-limb differences were submitted to one sample t-tests.

RESULTS

Inter-limb differences in approach velocity and centre of mass deflection angle explained 3 - 60% of the variance in kinematic and kinetic inter-limb differences. Statistical inferences remained consistent between adjusted and unadjusted conditions with the exception of hip flexion angle.

SIGNIFICANCE

Inter-limb differences in task-level features explain a large proportion of the variance in inter-limb differences in several kinematic and kinetic variables. Accounting for this variation reduced the magnitude of kinematic and kinetic inter-limb differences comparable to those previously observed in normative cohorts.

Telerehabilitation to Address the Rehabilitation Gap in Anterior Cruciate Ligament Care: Survey of Physical Therapists/Care Providers

Background

While the importance of structured rehabilitation following anterior cruciate ligament reconstruction (ACLR), particularly in the return-to-sport phase, is known, for most patients, supervised physical therapy is often completed before this time point. The recent emergence of telerehabilitation and other digital health interventions has the potential to address this "rehabilitation gap."

Methods

The study was conducted as a cross-section, online survey collecting qualitative and quantitative data from open and closed questions. Inclusion criteria included local qualified physical therapists or other professionals working with ACLR patients.

Results

Eighty-three percent of respondents experienced a "rehabilitation gap" with their ACLR patients. Few reported currently utilizing apps or websites (9.74%). The majority (41/58) reported experience with telerehabilitation, and 84% felt that there was a role for digital rehabilitation strategies to address the "rehabilitation gap." The vast majority (94.74%) of participants felt that standard commercial insurance did not permit sufficient rehabilitation.

Discussion

While the majority of our respondents acknowledged the existence of a "rehabilitation gap," as well as familiarity with and confidence in telerehabilitation, few were using this technique at the time of our survey. This suggests an opportunity for development in this space.

Predicting Leg Forces and Knee Moments Using Inertial Measurement Units: An In Vitro Study

We compared the ability of seven machine learning algorithms to use wearable inertial measurement unit (IMU) data to identify the severe knee loading cycles known to induce microdamage associated with anterior cruciate ligament rupture. Sixteen cadaveric knee specimens, dissected free of skin and muscle, were mounted in a rig simulating standardized jump landings. One IMU was located above and the other below the knee, the applied three-dimensional action and reaction loads were measured via six-axis load cells, and the three-dimensional knee kinematics were also recorded by a laboratory motion capture system. Machine learning algorithms were used to predict the knee moments and the tibial and femur vertical forces; 13 knees were utilized for training each model, while three were used for testing its accuracy (i.e., normalized root-mean-square error) and reliability (Bland-Altman limits of agreement). The results showed the models predicted force and knee moment values with acceptable levels of error and, although several models exhibited some form of bias, acceptable reliability. Further research will be needed to determine whether these types of models can be modified to attenuate the inevitable in vivo soft tissue motion artifact associated with highly dynamic activities like jump landings.

The effectiveness of physical therapy in the rehabilitation of patients after arthroscopy of the knee joint

OBJECTIVE

Aim: To determine the effectiveness of physical therapy on the functional state of law enforcement officers' knee joints after surgical intervention.

PATIENTS AND METHODS

Materials and Methods: The research involved law enforcement officers from different units of the National Police of Ukraine (n = 56) who had suffered knee joint injuries in the line of duty, and underwent surgical intervention and rehabilitation procedures.

RESULTS

Results: It was found that 78.2 % of respondents had suffered knee joint ligament injuries as a result of falls during rapid movement, while 43.9 % were in full gear (armored protection, helmet, etc.). It was determined that after surgical intervention, the functional state of the knee joint of law enforcement officers who followed the recommendations of physical therapy specialists and systematically performed special sets of physical exercises was significantly different (p < 0.001). Worse results were noted in people who partially followed the recommendations of rehabilitation therapists and performed part of the prescribed procedures and physical exercises.

CONCLUSION

Conclusions: The effectiveness of the complex use of physical rehabilitation means for restoring the functioning of the knee joint after surgical intervention, which included arthroscopy, partial menisectomy of the damaged areas, debridement, vaporization of damaged cartilage, etc. was revealed. The positive effect of physical exercises on the functional state of the knee joint was proven. The sets of exercises that are advisable to use to restore the functioning of the knee joint were determined.

New prediction equations for knee isokinetic strength in young and middle-aged non-athletes

BACKGROUND

This study aimed to develop alternative prediction equations to predict isokinetic muscle strength at 60°/s based on anthropometric characteristics, including body mass, height, age, and sex for young and middle-aged non-athlete populations.

METHODS

Three hundred and thirty-two healthy non-athletic participants (174 females, 158 males) between 20 and 59 years underwent a 60°/s isokinetic knee joint concentric contraction test. Forty people were randomly selected for retesting to assess the reliability of the isokinetic instrument. Multivariate linear regression was used to establish extension peak torque (EPT) and flexion peak torque (FPT) prediction equations. Sixty extra participants were used individually to validate the prediction equations, and Bland Altman plots were constructed to assess the agreement of predicted values with actual measurements.

RESULTS

The result demonstrated that the instrument we used has excellent reliability. The multivariable linear regression model showed that body mass, age, and sex were significant predictors of PT (EPT: Adjusted R2 = 0.804, p < 0.001; FPT: Adjusted R2 = 0.705, p < 0.001). Furthermore, the equations we established had higher prediction accuracy than those of Gross et al. and Harbo et al. CONCLUSION: The equations developed in this study provided relatively low bias, thus providing a more suitable reference value for the knee isokinetic strength of young and middle-aged non-athletes.

Accelerometer-assessed physical activity patterns during the first two years after a non-surgically treated ACL injury

OBJECTIVES

To describe physical activity patterns and analyze changes during the first two years after a non-surgically treated ACL injury, and to assess correlations between accelerometer-assessed physical activity and self-reported knee function and knee-related quality of life.

DESIGN

Prospective cohort study.

PARTICIPANTS

128 patients (61 females, 25.2 ± 7.1 years) with acute ACL injury.

MAIN OUTCOME MEASURES

Physical activity patterns were measured with accelerometry. Self-reported knee function was assessed using the International Knee Documentation Committee Subjective Knee Form, and knee-related quality of life was assessed using the Anterior Cruciate Ligament Quality of Life questionnaire.

RESULTS

Moderate to vigorous physical activity (MVPA) and steps per day increased from baseline to 3 months (p < .001), with no further increase from 3 to 24 months (p > .05). Time in MVPA did not correlate to patient-reported outcome measures at 3, 6, 12, or 24 months (p > .05).

CONCLUSIONS

Physical activity increased from acute phase to 3 months after non-surgically treated ACL injury, but almost one in four patients did not reach recommended levels of physical activity. Physical activity did not correlate with knee function or quality of life. Patients may need improved support to return to physical activity after ACL injury.

LEVEL OF EVIDENCE

Level II.

TRIAL REGISTRATION

NCT02931084.

Resistance wheel running improves contractile strength, but not metabolic capacity, in a murine model of volumetric muscle loss injury

The primary objective of this study was to determine if low- or high-resistance voluntary wheel running leads to functional improvements in muscle strength (i.e., isometric and isokinetic torque) and metabolic function (i.e., permeabilized fibre bundle mitochondrial respiration) after a volumetric muscle loss (VML) injury. C57BL/6J mice were randomized into one of four experimental groups at age 12 weeks: uninjured control, VML untreated (VML), low-resistance wheel running (VML-LR) and high-resistance wheel running (VML-HR). All mice, excluding the uninjured, were subject to a unilateral VML injury to the plantar flexor muscles and wheel running began 3 days post-VML. At 8 weeks post-VML, peak isometric torque was greater in uninjured compared to all VML-injured groups, but both VML-LR and VML-HR had greater (∼32%) peak isometric torque compared to VML. All VML-injured groups had less isokinetic torque compared to uninjured, and there was no statistical difference among VML, VML-LR and VML-HR. No differences in cumulative running distance were observed between VML-LR and VML-HR groups. Because adaptations in VML-HR peak isometric torque were attributed to greater gastrocnemius muscle mass, atrophy- and hypertrophy-related protein content and post-translational modifications were explored via immunoblot; however, results were inconclusive. Permeabilized fibre bundle mitochondrial oxygen consumption was 22% greater in uninjured compared to VML, but there was no statistical difference among VML, VML-LR and VML-HR. Furthermore, neither wheel running group demonstrated a change in the relative protein content of the mitochondrial biogenesis transcription factor, peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α). These results indicate that resistance wheel running alone only has modest benefits in the VML-injured muscle. NEW FINDINGS: What is the central question of the study? Does initiation of a resistance wheel running regimen following volumetric muscle loss (VML) improve the functional capacity of skeletal muscle? What is the main finding and its importance? Resistance wheel running led to greater muscle mass and strength in mice with a VML injury but did not result in a full recovery. Neither low- nor high-resistance wheel running was associated with a change in permeabilized muscle fibre respiration despite runners having greater whole-body treadmill endurance capacity, suggesting resilience to metabolic adaptations in VML-injured muscle. Resistance wheel running may be a suitable adjuvant rehabilitation strategy, but alone does not fully mitigate VML pathology.

Comparison between the effect of immersive virtual reality training versus conventional rehabilitation on limb loading and functional outcomes in patients after anterior cruciate ligament reconstruction: A prospective randomized controlled trial

Purpose

Anterior cruciate ligament injury (ACL) commonly occurs during sporting events. It causes pain, instability and reduction in range of movement of the knee which results in altered balance, reduced strength as well as loading to the involved knee. The challenge to get the patient back to competitive sports level much depends on the rehabilitation process. Post ACLR rehabilitation is challenging due to the long rehabilitation time as well as boring repetitive exercises. The aim of this study is to compare between the effectiveness of using immersive virtual reality (PlayStation VR) in addition to the conventional rehabilitation as an aid in rehabilitation of patients after ACLR in terms of objective functional assessment and pain and subjective knee function scoring.

Methods

This randomised controlled trial was undertaken in a tertiary hospital in Malaysia from July 2019 until July 2020. Thirty patients were randomised into a group undergoing purely conventional rehabilitation (Group 1) and a group undergoing both conventional rehabilitation and immersive virtual reality assisted rehabilitation (Group 2). The immersive virtual reality assisted rehabilitation was started at 3 months post operatively for 3 months duration. Limb loading, balance, range of motion, functional hop tests of the knee, pain and subjective scoring of the knee with the International Knee Documentation Committee (IKDC) Scores were measured preoperatively and at 6 months.

Results

There were significant differences in terms of improvement of pain scores (p = 0.012) as well as IKDC Scores (p = 0.024) in Group 2 as compared to Group 1. However, there were no significant differences with regards to limb loading, balance, range of motion and functional hop tests of the knee (p > 0.05). No adverse events were observed during the study period.

Conclusion

Immersive virtual reality can be used as an adjunct in rehabilitation of patients after ACL reconstruction in terms of improving their pain as well as their subjective knee evaluation. Large randomised control trial is recommended to further investigate the efficacy.

Evaluating a Wearable Solution for Measuring Lower Extremity Asymmetry During Landing

Purpose

Force plates can be used to monitor landing asymmetries during rehabilitation, but they are not widely available. Accelerometer-based wearable technology may be a more feasible solution. The purpose of this article was to determine the agreement between impact accelerations measured with force plates and accelerometer-derived measures of (1) centre of mass (COM) acceleration and (2) tibial acceleration asymmetries during bilateral landings.

Method

Participants completed three countermovement jumps (CMJ) and three squat jumps (SJ) on dual force plates with triaxial accelerometers attached to each tibia and lower back, near the COM. Bland and Altman 95% limits of agreement (95% LOA) were calculated.

Results

19 adults (n = 11; 58% women, n = 8; 42% men) participated in the study. The mean differences between impact and COM accelerations were 0.24 g (95% LOA: -1.34 g to 1.82 g) and 0.38 g (95% LOA: -1.15 to 1.91 g) for the CMJ and SJ, respectively. The mean differences between the impact and tibial acceleration-based lower limb asymmetries in the CMJ and SJ were -6% (95% LOA: -32% to 19%) and 0% (95% LOA: -45% to 45%), respectively.

Conclusions

Our findings show acceptable agreement between impact acceleration and accelerometer-based COM acceleration and lack of agreement between impact accelerations and accelerometer-based tibial acceleration asymmetries. COM acceleration could be used to quantify landing impacts during rehabilitation, but we do not consider the accelerometer-based asymmetry measures to be a suitable alternative for force plate-based measures. Future work should focus on determining normative values for lower extremity asymmetries during landing tasks.

Post-Operative Modified All-Inside ACL Reconstruction Technique's Clinical Outcomes and Isokinetic Strength Assessments

BACKGROUND AND OBJECTIVE

Anterior cruciate ligament (ACL) injuries are very common among the athletic population. ACL reconstruction (ACLR) performed because of these injuries is one of the procedures performed by orthopedic surgeons using different grafting methods. This study aims to compare the data related to post-operative 6-month isokinetic strength values, strength-related asymmetry rates, time parameters, and joint angle in athletes who underwent ACLR with the Modified All-inside (4ST) technique, on both the healthy knee (HK) and the ACLR-applied sides.

MATERIALS AND METHODS

A total of 20 athletes from various sports on whom the 4ST ACLR technique had been applied by the same surgeon were evaluated retrospectively. Lysholm, Tegner, and International Knee Documentation Committee (IKDC) scores of the patients were obtained pre-operative and at 6 months post-operative. Isokinetic knee extension (Ex) and flexion (Flx) strengths on the HK and ACLR sides of the patients were evaluated with a series of four different angular velocities (60, 180, 240, and 300°/s). In addition to peak torque (PT) and hamstring/quadriceps ratio (H/Q) parameters, the findings were also evaluated with additional parameters such as joint angle at peak torque (JAPT), time to peak torque (TPT), reciprocal delay (RD), and endurance ratio (ER).

RESULTS

There was a significant improvement in the mean Lysholm, Tegner, and IKDC scores after surgery compared with pre-operative levels (p < 0.05). As for PT values, there were significant differences in favor of the HK in the 60, 180, and 300°/s Ex phases (p < 0.05). In terms of the H/Q and (hamstring/hamstring)/(quadriceps/quadriceps) (HH/QQ) ratios, there were significant differences at 300°/s (p < 0.05). In terms of JAPT, there were significant differences in the 300°/s Ex and 180°/s Flx phases (p < 0.05). In terms of TPT, there were significant differences in the 300°/s Ex phase (p < 0.05). In terms of RD and ER, no significant difference was observed between the HK and ACLR sides at any angular velocity.

CONCLUSIONS

Although differences were observed in PT values, particularly in the Ex phase, this did not cause a significant change in H/Q ratios. Similar results were observed for additional parameters such as JAPT, TPT, RD, and ER. The results show that this ACLR technique can be used in athletes in view of strength gain and a return to sports.

The Longitudinal Neurophysiological Adaptation of a Division I Female Lacrosse Player Following Anterior Cruciate Rupture and Repair: A Case Report

Background

Neurophysiological adaptation following anterior cruciate ligament (ACL) rupture and repair (ACLR) is critical in establishing neural pathways during the rehabilitation process. However, there is limited objective measures available to assess neurological and physiological markers of rehabilitation.

Purpose

To investigate the innovative use of quantitative electroencephalography (qEEG) to monitor the longitudinal change in brain and central nervous systems activity while measuring musculoskeletal function during an anterior cruciate ligament repair rehabilitation.

Case Description

A 19 year-old, right-handed, Division I NCAA female lacrosse midfielder suffered an anterior cruciate ligament rupture, with a tear to the posterior horn of the lateral meniscus of the right knee. Arthroscopic reconstruction utilizing a hamstring autograft and a 5% lateral meniscectomy was performed. An evidence-based ACLR rehabilitation protocol was implemented while using qEEG.

Outcomes

Central nervous system, brain performance and musculoskeletal functional biomarkers were monitored longitudinally at three separate time points following anterior cruciate injury: twenty-four hours post ACL rupture, one month and 10 months following ACLR surgery. Biological markers of stress, recovery, brain workload, attention and physiological arousal levels yielded elevated stress determinants in the acute stages of injury and were accompanied with noted brain alterations. Brain and musculoskeletal dysfunction longitudinally reveal a neurophysiological acute compensation and recovering accommodations from time point one to three. Biological responses to stress, brain workload, arousal, attention and brain connectivity all improved over time.

Discussion

The neurophysiological responses following acute ACL rupture demonstrates significant dysfunction and asymmetries neurocognitively and physiologically. Initial qEEG assessments revealed hypoconnectivity and brain state dysregulation. Progressive enhanced brain efficiency and functional task progressions associated with ACLR rehabilitation had notable simultaneous improvements. There may be a role for monitoring CNS/brain state throughout rehabilitation and return to play. Future studies should investigate the use of qEEG and neurophysiological properties in tandem during the rehabilitation progression and return to play.

Recurrence quantification analysis of isokinetic strength tests: A comparison of the anterior cruciate ligament reconstructed and the uninjured limb

BACKGROUND

Despite widespread use of return to sport testing following anterior cruciate ligament reconstruction, studies suggest inadequacy in current testing criteria, such as limb symmetry index calculations, to determine athletes' readiness to return to play. Recurrence quantification analysis, an emerging non-linear data analysis tool, may reveal subtle neuromuscular differences between the injured and uninjured limb that are not captured by traditional testing. We hypothesized that isokinetic torque curve data of the injured limb would demonstrate lower determinism and entropy as compared to the uninjured limb.

METHODS

102 patients (44 M, 58F, 10 ± 1 months post-anterior cruciate ligament reconstruction) underwent isokinetic quadriceps strength testing using a HumacNorm dynamometer. Patients completed maximum effort knee extension and flexion at 60°/sec. Data were post-processed with a MATLAB CRQA Graphical User Interface and determinism and entropy values were extracted. Paired-sample t-tests (α = 0.05) were used to compare data from the injured and uninjured limb.

FINDINGS

Determinism and entropy values in the torque curves were lower in the injured limb than the uninjured limb (p < 0.001). Our findings indicate there is less predictability and complexity present in the torque signals of injured limbs.

INTERPRETATION

Recurrence quantification analysis can be used to assess neuromuscular differences between limbs in patients who have undergone anterior cruciate ligament reconstruction. Our findings offer further evidence that there are changes to the neuromuscular system which persist following reconstruction. Further investigation is needed to establish thresholds of determinism and entropy values needed for safe return to sport and to evaluate the utility of recurrence quantification analysis as a return to sport criterion.

Hip Abductor and External Rotator Strengths Correlate With Hop Symmetry in Men Athletes 2 Years After Anterior Cruciate Ligament Reconstruction

CONTEXT

Hip muscle strength and hop performance limb symmetries after anterior cruciate ligament reconstruction (ACLR) are not well studied. This study aimed to determine the differences in hip abductors' (ABD) and external rotators' (ER) muscle strength measures between limbs, and the relationship between hip ABD and ER muscle strengths and hop performance limb symmetry indices (LSIs) 2 years after ACLR.

DESIGN

Cross-sectional study.

METHODS

Forty (level I/II) men athletes 2 years after unilateral ACLR completed 4 single-legged hop tests and involved hip ABD and ER strength testing (maximum voluntary isometric contraction [MVIC]; isokinetic peak torque [PKTQ] at 60°, 180°, and 300°/s; and isotonic peak velocity at 75% of their MVICs). Muscle strength measures were normalized to body mass, and hop performances were reported as LSIs. Paired t test was used to determine strength differences between limbs, and the Pearson correlation coefficient was used to assess the relationship between involved hip muscle strength measures and hop performance LSIs.

RESULTS

Hip ER-MVIC (involved: 60.26 [12.01], uninvolved: 63.68 [13.17] N·m/kg) and ER eccentric PKTQ at 60°/s (involved: 32.59 [9.28]; uninvolved: 35.73 [10.50] N·m/kg) were significantly different between limbs (P ≤ .018). Single-hop LSI correlated with hip ER-PKTQ at 180°/s (r = .354) and 300°/s (r = .324, P ≤ .041), while triple-hop LSI correlated with hip ER-MVIC (r = .320), concentric ER-PKTQ at 180°/s (r = .355), eccentric ER-PKTQ at 60°/s (r = .314), and hip ABD-PKTQ at 60°/s (r = .364) and 300°/s (r = .336, P ≤ .049).

CONCLUSIONS

Men athletes demonstrated symmetrical hop performance and hip muscle strengths, except for ER hip's MVIC and isokinetic eccentric peak torque at 60°/s 2 years after ACLR. Hop performance LSIs had a few, yet positive moderate relationships with involved hip ABDs and ER strength measures. This may indicate that hip ABD and ER muscle strength measures contribute to athletes' hop performances 2 years after ACLR. Post-ACLR rehabilitation programs might incorporate hip muscle strengthening training to improve athletes' functional performances.

Beyond guidelines: A qualitative clinical stakeholder study of optimal management of anterior cruciate ligament rehabilitation

AIMS

This study gathered expert perspectives in the management of anterior cruciate ligament (ACL) rehabilitation to explore current practice, variations in care and optimal management strategies.

MATERIALS AND METHODS

This was a qualitative semi-structured interview study. The participants' experiences were considered in terms of their roles as employees, managers, clinicians and professional gatekeepers. Purposive and snowball sampling were used to recruit physiotherapists and orthopaedic surgeons. Participants were included if they had a proven record in clinical management or research involving ACL patients. Persons were excluded if they could not speak English. Interviews were conducted in person, via skype or over the phone at a time convenient to the participant. Data was analysed using a framework analysis and critical realist approach.

RESULTS

Results included 24 interviews that were conducted with 19 physiotherapists and 5 surgeons. Themes of variation in current care and optimal care were explored including subthemes of patient centred practice, evidence based medicine, resources, self-management, multidisciplinary teamwork, training and expertise were explored. Participant's perceptions of current care were that it was a location 'lottery' that significantly varied for patients across the UK.

CONCLUSIONS

Stakeholders identified that optimal management should be patient centred and incorporate adequate equipment, specific training for physiotherapists and a closely communicating multidisciplinary team. Research is needed to explore cost effective models of optimal rehabilitation that include return to sport strategies.

The use of physical function capacity measures in the management of lower limb tendinopathy: A scoping review of expert recommendations

BACKGROUND

Physical function capacity measures are recommended as outcome measures for people with lower limb tendinopathy.

OBJECTIVE

(i) Explore measures of physical function capacity recommended by experts in lower limb tendinopathy (ii) the context they were used, (ii) identify recommended criteria for exercise progression and return to sport or activity.

DESIGN

Scoping Review.

METHOD

Three databases were searched using keywords for lower limb tendinopathy and physical function capacity to identify studies that outlined a progressive exercise rehabilitation program. A 15-item tool was used for data extraction.

RESULTS

26 studies were included, only eight recommended a physical function capacity measure. There were 10 physical function capacity measures identified for a range of lower limb tendinopathies including patellar (50%), Achilles (13%), proximal hamstring (13%), gluteal (13%), combined patellar and Achilles (13%). Pain was the most common criterion that was used to determine the progression of rehabilitation (96%), with physical function capacity measures rarely used (12%).

CONCLUSION

Physical function capacity measures are used infrequently across expert recommended exercise rehabilitation programs. There remains a high reliance on pain as the criterion for progression of exercises during rehabilitation. There is a need to develop measures of physical function capacity to better inform and progress rehabilitation.

Pre- and Post-Operative Hamstring Autograft ACL Reconstruction Isokinetic Knee Strength Assessments of Recreational Athletes

Background and Objectives: Anterior cruciate ligament (ACL) injuries are common injuries with a high incidence among people with high physical activity levels. Therefore, ACL reconstruction (ACLR) is one of the most common surgical procedures performed in sports medicine. This study aims to compare the pre- and 6-month post-operative isokinetic knee strengths in healthy (HK) and ACL knees of patients who underwent semitendinous/gracilis (ST/G) ACLR. Materials and Methods: A retrospective cohort of 21 recreational athletes who underwent ST/G ACLR by the same surgeon were evaluated. The pre- and 6-month post-operative isokinetic knee extension (Ex) and flexion (Flx) strengths of the HK and ACLR patients were evaluated in a series consisting of three different angular velocities (60, 180 and 240°/s). Of all the findings, peak torque (PT) and hamstring/quadriceps (H/Q) parameters were evaluated. Results: There was a significant improvement in post-operative Lysholm, Tegner and IKDC scores compared to pre-operative scores (p < 0.05). There were significant differences in pre-operative and post-operative knee Ex and Flx strengths at angular velocities of 60°, 180° and 240°/s in both the ACLR and HK groups (p < 0.001). There was no significance at 240°/s Flx for ACLR (p > 0.05). As for H/Q ratios, there was a significant difference between pre- and post-operative values only at 60°/s angular velocity in both ACLR and HC (p < 0.005). Conclusions: The pre-operative and 6-month post-operative results of the ST/G ACLR showed that there was a high level of recovery, particularly in quadriceps strength, while the increase in strength was less in the hamstring. The significance observed at 60°/s in H/Q ratios was within normal ranges. It can be argued that the ST/G ACLR method is feasible for people with high physical activity levels and for athletes.

Single leg drop jump performance identifies functional deficit in collegiate athletes who have returned to sports after ACL reconstruction: A case-control study

Despite its apparent functional importance, there is a general lack of data in explosive strength in individuals recovering from an anterior cruciate ligament reconstruction (ACLR). Hence, we wonder if single leg drop jump (SLDJ) can be an effective testing since drop jump is a commonly used testing which rely on adequate development of explosive strength and stretch shortening cycle function. The purpose of this study was to determine if SLDJ test can identify functional deficit in collegiate athletes who have returned to sports (RTS) after ACLR when comparing it with the common return to sport testing. Nine collegiate athletes who had undergone a unilateral ACLR and returned to their primary sport with at least 10 months post-surgery were recruited and assigned into the injured group and compared with 9 matched non-injured athletes as the control group. Both groups underwent an identical battery testing in 1 session with the sequence of first modified star excursion balance test (SEBT), second single hop and bound test, third SLDJ and lastly 1 repetition maximum (1RM) single leg press. A 2-way mixed model analysis of variance showed that there is no significant interaction effect on common RTS testing which include modified SEBT, single hop and bound tests, and 1RM single leg press, but significant interaction effect on SLDJ jump height (P = .03), reactive strength index (P = .03) and mean propulsion force (P = .03). For the injured group, ACLR leg jump height (10.35 ± 2.71 cm) was significantly lower than non-ACLR leg (12.86 ± 3.51 cm) with a mean difference of 2.51 (95% confidence interval [CI]: 0.55-4.47). ACLR leg reactive strength index (0.29 ± 0.10 m/s) was significantly < non-ACLR leg (0.39 ± 0.16 m/s) with a mean difference of 0.1 (95% CI: 0.03-0.17) and ACLR leg mean propulsion force (1087.49 ± 287.26 N) was significantly < non-ACLR leg (1157.40 ± 299.80 N) with a mean difference of 69.91 (95% CI: 16.04 to 123.78). SLDJ was able to identify jump height, reactive strength and propulsion force deficit in the involved limb of collegiate athletes who have returned to sports after ACLR.

Time-loss and recurrence of lateral ligament ankle sprains in male elite football: A systematic review and meta-analysis

A literature search was conducted to systematically review and meta-analyze time-loss and recurrence rate of lateral ankle sprains (LAS) in male professional football players. Six electronic databases (PubMed, Scopus, Web of Science, PEDRO, CINAHL, and Cochrane) were searched independently, separately both for time-loss and recurrence from inception until April 30, 2021. In addition, reference lists were screened manually to find additional literature. Cohort studies, case reports, case-control studies and RCT in English language of male professional football players (aged more than 16 years) for which data on time-loss or recurrence rates of LAS were available were included. A total of 13 (recurrence) and 12 (time-loss) studies met the inclusion criteria. The total sample size of the recurrence studies was 36,201 participants (44,404 overall initial injuries; 7944 initial ankle sprain [AS] injuries, 1193 recurrent AS injuries). 16,442 professional football players (4893 initial AS injuries; 748 recurrent AS injuries) were meta-analyzed. A recurrence rate of 17.11% (95% CI: 13.31-20.92%; df = 12; Q = 19.53; I² = 38.57%) based on the random-effects model was determined. A total of 7736 participants were part of the time-loss studies (35,888 total injuries; 4848 total ankle injuries; 3370 AS injuries). Out of the 7736 participants, 7337 participants met the inclusion criteria with a total of 3346 AS injuries. The average time-loss was 15 days (weighted mean: 15.92; median: 14.95; min: 9.55; max: 52.9). We determined a priori considerable heterogeneity (CI: 18.15-22.08; df = 11; Q = 158; I² = 93%), so that the data on time-loss are only presented descriptively. There is an average time-loss of 15 days per LAS and a recurrence rate of 17%. LAS is one of the most common types of injury with higher recurrence rates than ACL injuries (9%-12%) in professional football players. Nevertheless, the focus of research in recent years has been mostly on ACL injuries. However, the high recurrence rates and long-term consequences show the necessity for research in the field of LAS in elite football. Yet, heterogeneous data lead to difficulties concerning the aspect of comparability.

Knee Strength Assessment and Clinical Evaluation Could Predict Return to Running after Anterior Cruciate Ligament Reconstruction Using Patellar Tendon Procedure

BACKGROUND AND OBJECTIVES

Muscle knee strength is a major parameter that allows return to running. Isokinetic strength parameters may predict return to running 4 months after ACLR using the bone-patellar-tendon-bone procedure.

MATERIALS AND METHODS

The isokinetic knee strength of 216 patients (24.5 ± 5 years) was measured 4 months after surgery, and progressive return to running was allowed. The effectiveness of return to running was reported at 6 months. Return to running prediction was established using multivariate logistic regression. Predictive parameters were presented with a ROC curve area to define the best cut-off, with sensibility (Se) and specificity (Sp).

RESULTS

A model was established, including the limb symmetry index (LSI), and 103 patients (47.6%) were able to run between the fourth and the sixth month after surgery. These patients presented significantly fewer knee complications, a better Lysholm score, a better Quadriceps and Hamstring LSI and better quadriceps strength reported for body weight on the operated limb. The best model was established including the Quadriceps and Hamstring LSI at 60°/s and the Lysholm score. The cut-off for Quadriceps LSI was 60% (ROC curve area: 0.847; Se: 77.5%; Sp: 77%), for Hamstring LSI 90% (ROC curve area: 0.716; Se: 65.7%; Sp: 60.2%) and for Lyshom score 97 points (ROC curve area: 0.691; Se: 65%; Sp: 66%).

CONCLUSION

Four months after ACLR using a bone-patellar-tendon-bone procedure, the Quadriceps and Hamstring LSI associated to the Lysholm score could help make the decision to allow return to running.

Interventions for increasing return to sport rates after an anterior cruciate ligament reconstruction surgery: A systematic review

Background

An injury followed by surgery poses many challenges to an athlete, one of which is rehabilitation, with the goal of returning to sport. While total restoration of physical abilities is a primary goal for most athletes, psychosocial factors also play an important role in the success of an athlete's return to sport (RTS). The purpose of this review was to examine the effectiveness of exercise and psychosocial interventions on RTS rates, which might be one of the most important outcomes for elite athletes.

Methods

To carry out this review, PubMed, SAGE Journals, Web of Science, SPORTDiscus, ScienceDirect, and Google Scholar databases were searched from inception to July 2022. The inclusion criteria consisted exercise or psychosocial intervention for athletes after anterior cruciate ligament reconstruction (ACLR), with reporting RTS rates as an outcome.

Results

From 1032 identified articles, four reports (N = 130) met inclusion criteria, all of which examined the recovery after ACLR. The mean MINORS score for the included studies was 16.3 ± 6.1, of which non-comparative studies scored 11.0 ± 1.4, while comparative studies scored 21.5 ± 0.7. There were consistent findings for benefits of exercise and psychosocial interventions on RTS rates. Return to preinjury rates in the reviewed studies vary between 63 and 95% with lower % observed in female athletes and with shorter follow-up. Interventional studies reporting RTS rates with a larger sample size and longer follow-up are needed.

Conclusion

Physical and psychological function, as well as social support can be influenced by appropriate interventions, indicating future work on rehabilitation programs for return to preinjury might consider taking the holistic approach addressing those.

Angle-specific analysis of knee strength deficits after ACL reconstruction with patellar and hamstring tendon autografts

After anterior cruciate ligament reconstruction (ACLR) there are differences in the neuromuscular deficits observed in patients with bone-patellar tendon-bone (BPTB) and with hamstring tendon (HT) autografts. Differences in knee extensor and flexor strength are commonly reported, but analyses have largely focused on peak torque metrics despite the requirement to generate torque through range when returning to sport. The aim of this study was to investigate the angle-specific strength and strength asymmetry differences between BPTB and HT around the time of return to play after ACLR. A total of 357 male field sport athletes with either a BPTB (n=297) or an HT (n=60) autograft underwent concentric knee flexor and extensor isokinetic strength testing nine months post-ACLR. Angle-specific torques were compared between grafts and limbs using 1D Statistical Parametric Mapping and discrete-point variables. Inter-limb extensor torque asymmetry was greater in BTPB than HT at knee angles of >30° (p=0.001, peak d=5.53), with flexor torque asymmetry lower in BPTB than HT at flexion angles of >25° (p=0.001, peak d=2.68). Angle of maximum asymmetry and angle of operated limb peak torque differed in knee extension for BPTB (p<0.001, d=0.32) but not HT, whereas knee flexion angle of maximum asymmetry and operated limb peak torque differed in both BTPB (p<0.001, d=0.75) and HT (p<0.001, d=0.43). Graft type affected extensor torque at knee angles of 67-85° and flexor torque at knee angles of 27-85°. Angle-specific strength analysis may inform the rehabilitation process and improve rehabilitation and return-to-play decision making strategies in comparison to the use of peak torque values alone.

Correlations Between Preseason Functional Test Scores and Game Performance in Female Collegiate Volleyball Players

Background

Functional tests (FT) are assessment tools that attempt to evaluate balance, flexibility, strength, power, speed, or agility through performance of gross motor skills. FT are frequently administered by coaches or sports medicine professionals to evaluate athletic ability, to predict performance, to identify athletes at risk for injury, or to evaluate an athlete's ability to return to sport after injury. Functional tests which can provide accurate or predictive information regarding athletic ability would be advantageous to coaching staffs or medical professionals.

Purpose

The primary purpose of this study was to identify correlations between preseason FT scores and in-season game statistics in a cohort of female collegiate level volleyball (VB) players. A secondary purpose was to present FT descriptive data for this cohort based on level of competition, player position, and starter status.

Study Design

prospective cohort; correlational.

Methods

One hundred and thirty-one female collegiate VB players representing three levels of competition completed four FT [standing long jump (SLJ), single-leg hop (SLH), lower extremity functional test (LEFT), and the Y-Balance Test - Lower Quarter (YBT-LQ)] at the start of the preseason. Player statistics were collected from team records at the completion of the season.

Results

Starters performed significantly better on all tests. There were moderate negative correlations between LEFT scores and game statistics for liberos, defensive specialists, and outside hitters. There were moderate positive correlations between YBT-LQ composite scores and game statistics for liberos, defensive specialists, hitters, and middle blockers. There were also low to moderate level positive correlations between SLJ and SLH scores and game performance for outside hitters. There were low to moderate level positive correlations between SLH scores and game performance for middle blockers and opposite side hitters.

Conclusions

The results of this study indicate that there are low to moderate correlations between some preseason functional test scores and some game statistics. The SLJ, SLH, LEFT, and YBT-LQ tests may help coaches with talent identification and/or may influence training strategies.

Level of Evidence

3.

Is There an Association in Young Patients Between Quadriceps or Hamstring Strength After ACL Reconstruction and Graft Rupture?

Background:

Younger patients who sustain anterior cruciate ligament (ACL) ruptures are at high risk for reinjury after ACL reconstruction. Restoring muscle strength before return to sports (RTS) is regarded as an important factor in reducing the reinjury risk, and quadriceps and hamstring strength assessment is commonly included in RTS testing. However, it is not clear whether reduced strength is a risk factor for subsequent graft rupture in this patient population.

Purpose:

To investigate the association between quadriceps and hamstring strength at 12 months after primary ACL reconstruction and ACL graft rupture in young patients.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

The cohort consisted of 210 patients (100 men and 110 women) who were younger than 20 years at the time of primary ACL reconstruction with a hamstring tendon autograft and who had no previous contralateral ACL injury. Isokinetic strength testing (60 and 180 deg/s) of knee flexors and extensors was performed at 12 months postoperatively, and the limb symmetry index (LSI) for each strength outcome was calculated. RTS rates and the incidence of further ACL graft ruptures were recorded.

Results:

Measures of central tendency (mean and median) of LSI values ranged from 88 to 98. The percentage of patients with LSI ≥90 was 57% to 69% for quadriceps strength and 45% to 47% for hamstring strength. Overall, 19 patients (9%) sustained an ACL graft rupture. No significant differences were found between the patients who sustained an ACL graft rupture and those who did not in terms of quadriceps and hamstring strength at 12 months. No significant associations were found between achieving LSI ≥90 for quadriceps peak torque and subsequent ACL graft rupture.

Conclusion:

In young patients who underwent an ACL reconstruction, no association was noted between quadriceps and hamstring strength at 12 months postoperatively and subsequent graft ruptures. The role of strength testing as part of the RTS criteria after ACL reconstruction, and specifically the use of limb symmetry thresholds, warrants further investigation and clarification.

Psychological Patient-reported outcome measure after anterior cruciate ligament reconstruction: Evaluation of subcategory in ACL-Return to Sport after Injury (ACL-RSI) scale

BACKGROUND

It has been recognized that psychological factors influence the return to sports after anterior cruciate ligament reconstruction (ACLR). The ACL-return to sports after injury (RSI) scale was developed based on subcategories of emotions, confidence in physical performance and risk appraisal. However, it has not been clarified describing which is the most influential psychological factor of the ACL-RSI scale.

HYPOTHESIS

Risk appraisal is the most influent for return to sports in the subcategories of the ACL-RSI scale.

PATIENTS AND METHODS

A total of 85 competitive patients who had undergone ACLR were evaluated at 6, 12 and 24 months after surgery. They were classified the return to sports (RTS) group and non-return to sports (NRTS) group. Evaluations were several clinical and functional scores including Cincinnati knee rating system, Knee Osteoarthritis Outcome Score (KOOS), Lysholm score, limitation in activities of daily living (ADL) and sports which estimated by Visual Analog Scale (VAS) score, Isokinetic Muscle Strength (quadriceps and hamstrings), single hop test and anterior laxity. They were investigated their relationship with the ACL-RSI scale including each subcategory.

RESULTS

The total ACL-RSI scale significantly improved at each point. Of the subcategories, only risk appraisal was not significantly different at each point (p=0.21 and p=0.13). There was a significant difference at 24 months after ACLR between the RTS group and NRTS group. In terms of risk appraisal, compared with emotion and performance confidence, the difference in the mean value was the most divergent (RTS group: 55.9±22.7 and NRTS group: 23.8±19.3) and took time to improve through 24 months. Among various clinical and functional scores, there were significant differences in the VAS score for sports, KOOS-symptoms, sports and QOL, Cincinnati Knee Rating System-cut, and single hop test values between two groups. Of these, the KOOS-QOL and VAS score for sports showed particularly strong correlations with ACL-RSI risk appraisal (r=0.75 and -0.68, respectively).

CONCLUSION

Of the ACL-RSI scale, risk appraisal took the longest time to improve and strongly affected the return to sports. The KOOS-QOL and VAS score for sports were most strongly correlated with the ACL-RSI risk appraisal. It seems that it is important to reduce the psychological risk as soon as possible after ACL injury in ACLR patients.

LEVEL OF EVIDENCE

II.

Effects of lead leg selection on bilateral landing force-time characteristics: Return to sport testing implications

We quantified the effect of lead leg selection on landing force-time characteristics during a vertical drop landing (VDL) initiated with a step-off. Plyometric-trained subjects (male: n = 8; female: n = 5; age =23 ± 3.3 years; body mass =74.4 ± 11.2 kg) performed 6 step-off-initiated VDLs from a 45-cm box (n = 3/lead leg). Pooled and lead leg stratified between-limb comparisons of limb-specific initial ground contact timing, peak vertical ground reaction force (Fz_peak ), and early landing-phase impulse (Impulse_100ms ) were assessed by a two-factor, within-subject ANOVA, and limb symmetry indexes were calculated (α = 0.05). Pooled data showed that the lead leg made contact prior to the trail leg and contributed a greater fraction to Fz_peak compared with the trail leg. Stratifying trials by lead leg selection led to significant between-limb differences in Fz_peak (p < 0.05) and Impulse_100ms (p < 0.01) with the right leg leading but not with the left leg leading. Lead leg selection in step-off-initiated VDLs influenced landing performance and limb symmetry indexes of variables associated with lower limb injury risk, suggesting the need to control for lead leg selection in these tasks. A step-off may not be a suitable technique to initiate landing tasks when assessing limb symmetry.

Biomechanical asymmetries differ between autograft types during unplanned change of direction after ACL reconstruction

Nine months after anterior cruciate ligament (ACL) reconstruction, athletes who undergo surgery using a bone-patellar-tendon-bone (BPTB) autograft demonstrate higher loading asymmetries during vertical jumping than those with a hamstring tendon (HT) autograft. These asymmetries may transfer into sporting movements with a greater ACL injury risk. The aim of this study was to compare between-limb asymmetries in knee mechanics and task performance during an unplanned 90° change-of-direction (CoD) task in male field sport athletes reconstructed with BPTB or HT autografts. Seventy-eight male multidirectional field sport athletes with either a BPTB (n = 39) or HT (n = 39) autograft completed maximal unplanned CoD trials in a three-dimensional motion capture laboratory at approximately 9 months post-surgery. A mixed-model 2x2 ANOVA (autograft type x limb) was used to compare variables related to ACL injury risk (e.g., internal knee moments) and performance (e.g., completion time) between autografts and limbs. Statistical parametric mapping was used for a waveform comparison throughout stance, supplemented with a discrete point analyses of peak knee moments and performance variables. Interaction effects were found at the knee joint, with BPTB demonstrating greater asymmetries than HT in knee extension moment (p < 0.001); resultant ground reaction force (p < 0.001); peak knee external rotation moment (p = 0.04); and knee adduction (p = 0.05), medial rotation (p < 0.001), and flexion (p < 0.001) angles. No differences were found between autografts for any performance variable. BPTB demonstrated greater lower-limb biomechanical asymmetries than HT during CoD, which may influence knee loading and longer-term outcomes and should thus be targeted during rehabilitation prior to return to play.

Anatomical and Neuromuscular Factors Associated to Non-Contact Anterior Cruciate Ligament Injury

The majority of anterior cruciate ligament (ACL) injuries occur during non-contact mechanisms. Knowledge of the risk factors would be relevant to help prevent athletes’ injuries. We aimed to study risk factors associated with non-contact ACL injuries in a population of athletes after ACL reconstruction. From a cohort of 307 athletes, two populations were compared according to the non-contact or contact mechanism of ACL injury. Gender, age and body mass index (BMI) were reported. Passive knee alignment (valgus and extension), knee laxity (KT-1000 test), and isokinetic knee strength were measured on the non-injured limb. The relationship between these factors and the non-contact sport mechanism was established with models using logistic regression analysis for the population and after selection of gender and cut-offs of age, BMI and knee laxity calculated from Receiver Operating Characteristics curve area and Youden index. Age, BMI, antero-posterior laxity, isokinetic knee strength, passive knee valgus and passive knee extension were associated with non-contact ACL injury. According to the multivariate model, a non-contact ACL injury was associated with non-modifiable factors, age (OR: 1.05; p = 0.001), passive knee extension (OR: 1.14; p = 0.001), and with one modifiable factor (Hamstring strength: OR: 0.27; p = 0.01). For women, only passive knee valgus was reported (OR: 1.27; p = 0.01). Age, passive knee extension and weak Hamstring strength were associated with a non-contact ACL injury. Hamstring strengthening could be proposed to prevent ACL injury in young male athletes or in case of knee laxity.

Development of new cartilage lesions after ACL reconstruction is associated with abnormal knee rotation

PURPOSE

The purpose of this study is to examine the association between the development of articular cartilage pathology and knee rotation after single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Seventeen patients that underwent single-bundle ACL reconstruction and did not have any cartilage lesions at the time of surgery based on the Outerbridge classification or meniscal injury that required meniscectomy > 20% were examined by MRI and in the biomechanics laboratory at a 6-year minimum follow-up. Cartilage lesions that occurred after reconstruction were graded on MRI according to a modified Noyes scale. For cartilage evaluation, the lateral and medial femoral condyles were divided into 9 segments each (lateral, central, and medial third and each third was divided into anterior, central, and posterior segment). Tibial rotation during a pivoting task was measured with optoelectronic motion analysis system and side-to-side differences of tibial rotation between the reconstructed and contralateral intact knees were calculated. The association between the total modified Noyes scale score (outcome variable) and side-to-side differences of tibial rotation after controlling for meniscectomy and meniscal repair was investigated with hierarchical regression models.

RESULTS

Side-to-side difference of tibial rotation was associated with total modified Noyes scale score (p = 0.015, β = 0.667, adjusted R² = 42.1%). All patients developed new cartilage lesions in MRI located mainly at the central region of the lateral femoral condyle and less frequently in the central and anterior regions of the medial femoral condyle.

CONCLUSION

Abnormally increased tibial rotation that persists after ACL-R is significantly associated with the development of new articular cartilage lesions at mean 8.4 years after reconstruction which were located mainly at the central region of the LFC and secondarily in the central and anterior regions of the MFC (more superficial lesions). These findings suggest that there is emerging evidence that abnormal rotational kinematics is a potential risk factor for the pathogenesis and onset of posttraumatic articular cartilage degeneration after ACLR.

LEVEL OF EVIDENCE

IV.

The Effects of Virtual Reality Nonphysical Mental Training on Coordination and Skill Transfer in Healthy Adults

CONTEXT

Mental training is a promising method to improve motor skills. However, transfer of these improvements to different skills or functional activities is still unclear. The purpose of this study was to investigate the effects of mental balance training programs on motor coordination and skill transfer.

DESIGN

Randomized controlled trial.

METHODS

Fifty-seven healthy adults (28 females and 29 males) aged between 18 and 25 years participated in this study. Participants were randomly assigned to 3 groups: virtual reality (VR) mental training group, conventional mental training group, and control group. The training program included action observation and motor imagery practice with balance exercise videos. The VR mental training group trained with a VR head-mounted display and the conventional mental training group trained with a nonimmersive computer monitor for 30 minutes, 3 days per week, for 4 weeks. Coordination skills were tested with 2 separate custom-made obstacle course tests (OCT-1 and OCT-2). OCT tests included crouching, turning, leaning, stepping over, changing direction, walking on various surfaces, or using repeated hand and arm movement tasks. OCT-1 was used to investigate the effects of mental exercises on coordination skills, and OCT-2 to investigate transfer effects for novel tasks. Test time (total and corrected) and error types (minor, major, and total) were recorded. Touching an obstacle without changing its position was classified as a minor error, and changing its position was a major error.

RESULTS

OCT-1 test time and number of errors significantly decreased in the VR mental training and conventional mental training groups, but not in the control group. The number of minor errors was only decreased in the VR mental training group. For OCT-2, total and corrected time were not significantly different between the groups. However, both training groups were significantly superior to the control group for all types of errors.

CONCLUSIONS

Our findings suggest that both training interventions can significantly improve coordination and skill transfer test results. In addition, VR mental training may have some advantages over conventional mental training. These findings are promising for the use of mental training for prevention and rehabilitation in special populations.

On-Field Tests for Patients After Anterior Cruciate Ligament Reconstruction: A Scoping Review

Background:

After anterior cruciate ligament reconstruction (ACLR), a patient’s physical capacities, such as (repeated) sprint performance, agility performance, and intermittent endurance performance, are often reduced because of detraining effects. Monitoring the progression of these physical capacities is essential for specific training goals before patients return to complex team sports.

Purpose:

To map the existing literature regarding on-field tests for (repeated) sprint performance, agility performance, and intermittent endurance performance in patients after ACLR.

Study Design:

Scoping review; Level of evidence, 4.

Methods:

A search was performed in 4 electronic databases, PubMed, Embase, CINAHL, and PsycInfo, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for scoping reviews.

Results:

There were 11 studies that met the inclusion criteria and described a total of 14 on-field tests for patients after ACLR. Overall, 2 tests were described for sprint performance, 11 tests were related to agility performance, and 1 test was performed for intermittent endurance performance.

Conclusion:

The results of this scoping review provide an overview of on-field tests to monitor sport-specific progression and to set performance-specific training goals for patients after ACLR before returning to complex team sports.

A Compound Hop Index for Assessing Soccer Players' Performance

Athletes regularly have to pass a series of tests, among which one of the most frequently used functional performance measures are single-leg hop tests. As the collected individual results of tests constitute a large amount of data, strategies to decrease the amount of data without reducing the number of performed tests are being searched for. Therefore, the study aimed to present an effective method to reduce the hop-test battery data to a single score, namely, the Compound Hop Index (CHI) in the example of a soccer team. A male, first-league soccer team performed a battery of commonly used single-leg hop tests, including single hop and triple hop for distance tests and the six-meter timed hop test. Gathered data, including Limb Symmetry Indexes of the three tests, normalized to body height for the single- and triple-hop-tests distance separately for right and left legs, and the time of the six-meter timed hop test separately for right and left legs were standardized to z-scores. Consecutively, the z-scores were averaged and formed CHI. The developed CHI represents a novel score derived from the average of z-scores that significantly reduces, clarifies, and organizes the hop performance-measures data.

[Judging movement quality in patients who sustained a knee ligament injury: a systematic review]

BACKGROUND

 Knee joint injury statistics are dominated by ruptures of the capsular ligament structures. Post-traumatic deficits in dynamic movement patterns are assessed quantitatively as well as qualitatively. The aim of this review was to compile tools that are used to assess the quality of movement after knee ligament injuries in adults.

METHODS

 A systematic search for original papers was carried out in the following primary sources: Ovid, PubMed, Scopus and Web of Science. Both conservative and surgical treatment options were considered. PROSPERO registration of the study protocol: CRD42020175359.

RESULTS

 A total of 1153 papers were identified. Eleven original papers from four different working groups were included in this work. All papers assessed the quality of movement in adults after anterior cruciate ligament (ACL) injury. A total of 348 (70 deficient, 278 reconstructed) patients after an ACL injury and 119 adults with an intact ACL were examined in the studies included.

CONCLUSION

 It is possible to assess movement quality after a knee ligament injury with a low temporal and technical effort. The changes recorded result in a functional valgus, which, based on the study results, may be further differentiated into isolated knee valgus, medial collapse or postural collapse.

Limb preference impacts single-leg forward hop limb symmetry index values following ACL reconstruction

Following anterior cruciate ligament (ACL) reconstruction limb dominance for performing tasks is not considered when making rehabilitation progression decisions. The purpose of this study was to determine if strength and functional outcomes differ between individuals who injured their preferred or nonpreferred jumping limb and to determine if these same outcomes differ between individuals who injured their preferred or nonpreferred limb used to kick a ball. A secondary purpose was to determine the association of quadriceps strength and single-leg forward hop performance with patient self-reported function. Forty individuals with ACL reconstruction (age = 20.0 ± 4.6 years, height = 174.2 ± 12.7 cm, mass = 71.2 ± 12.7 kg, time since surgery = 5.3 ± 0.8 months) were included in the study. Primary outcome measures included, International Knee Documentation Committee Subjective Knee Form (IKDC) scores, quadriceps limb symmetry index (LSI) values, and single-leg forward hop LSI values. Limb preference was defined two ways, kicking a ball and performing a unilateral jump. There were no significant differences between groups based on injury to the preferred limb to kick a ball for any of the outcome variables. Individuals who injured their nonpreferred jumping limb demonstrated significantly (p = 0.05, d = 0.77) lower single-leg forward hop LSI values (81.1% ± 19.5%) compared to individuals who injured their preferred jumping limb (94.1% ± 12.6%), but demonstrated no differences in IKDC scores or quadriceps LSI values. Quadriceps LSI and single-leg forward hop LSI explained 73% of the variance in IKDC scores, but quadriceps LSI had the strongest association (r = 0.790). These findings suggests that limb preference influences single forward hop LSI values and should be considered following ACL reconstruction.

Establishing Reference Values for Isometric Knee Extension and Flexion Strength

Single-joint isometric and isokinetic knee strength assessment plays an important role in strength and conditioning, physical therapy, and rehabilitation. The literature, however, lacks absolute reference values. We systematically reviewed the available studies that assessed isometric knee strength. Two scientific databases (PubMed and PEDro) were searched for the papers that are published from the inception of the field to the end of 2019. We included studies that involved participants of both genders and different age groups, regardless of the study design, that involved isometric knee extension and/or flexion measurement. The extracted data were converted to body-mass-normalized values. Moreover, the data were grouped according to the knee angle condition (extended, mid-range, and flexed). A meta-analysis was performed on 13,893 participants from 411 studies. In adult healthy males, the pooled 95% confidence intervals (CI) for knee extension were 1.34–2.23Nm/kg for extended knee angle, 2.92–3.45Nm/kg for mid-range knee angle, and 2.50–3.06Nm/kg for flexed knee angle, while the CIs for flexion were 0.85–1.20, 1.15–1.62, and 0.96–1.54Nm/kg, respectively. Adult females consistently showed lower strength than adult male subgroups (e.g., the CIs for knee extension were 1.01–1.50, 2.08–2.74, and 2.04–2.71Nm/kg for extended, mid-range, and flexed knee angle condition). Older adults consistently showed lower values than adults (e.g., pooled CIs for mid-range knee angle were 1.74–2.16Nm/kg (male) and 1.40–1.64Nm/kg (female) for extension, and 0.69–0.89Nm/kg (male) and 0.46–0.81Nm/kg (female) for flexion). Reliable normative for athletes could not be calculated due to limited number of studies for individual sports.

Rehabilitation after ACL injury and reconstruction from the patients' perspective

OBJECTIVES

To describe and compare patients' appraisal of the rehabilitation and adherence to the rehabilitation program after acute ACL injury treated with (ACLR) or without (non-ACLR) reconstruction.

DESIGN

Prospective cohort study.

PARTICIPANTS

275 patients (143 females; mean age 25 ± 7 years) with acute ACL injury, of whom 166 patients had ACLR within 24 months.

MAIN OUTCOME

Adherence to rehabilitation was assessed using the modified Sports Injury Rehabilitation Adherence Scale (SIRAS).

RESULTS

Appraisal of rehabilitation was higher in the post-ACLR group compared to the non-ACLR group at 3 months (91% compared to 70% scored rehabilitation as necessary, p = 0.025) and at 6 months (87% compared to 70% scored it as necessary, p = 0.017). SIRAS score did not differ between 3 and 6 months for the non-ACLR group (median (IQR) 13 (2) vs 13 (2)) or the post-ACLR group (14 (1) vs 14 (2), p > 0.05). The post-ACLR group had a higher SIRAS score than the non-ACLR group at 3 and 6 months (p ≤ 0.001).

CONCLUSION

Patients treated with ACLR reported valuing their rehabilitation more and rated greater adherence to the rehabilitation programme than non-surgically treated patients. As rehabilitation is essential for good knee function, strategies to improve adherence after non-ACLR treatment should be implemented.

LEVEL OF EVIDENCE

Prospective cohort study, level II.

Vertical jump impulse deficits persist from six to nine months after ACL reconstruction

Later-stage rehabilitation following anterior cruciate ligament (ACL) reconstruction (ACLR) provides a valuable opportunity to target performance deficits before return to sport. This study aimed to: (1) evaluate bilateral counter-movement jump (CMJ) phase-specific impulse and isokinetic strength inter-limb asymmetry progression from 6 to 9 months post-ACLR; and (2) examine the extent to which individual changes in strength asymmetry could explain changes in impulse asymmetry. Male athletes (n = 44) with a hamstring tendon or bone-patellar tendon-bone autograft were tested 6 and 9 months post-ACLR. Two-way mixed-model ANOVAs were used to identify inter-session and inter-graft differences in CMJ phase-specific impulse asymmetries and knee isokinetic flexor and extensor strength asymmetries, as well as in absolute impulse and strength values of independent (ACLR/uninvolved) limbs. Linear regression models were used to assess the relationship between changes in impulse asymmetry and strength asymmetry. Reductions in strength asymmetry arose from improved ACLR-limb performance, whereas concentric impulse asymmetry reduced consequent to decreased uninvolved-limb performance and eccentric deceleration impulses decreased bilaterally. Graft type did not modulate findings. Changes in strength asymmetry had little or no ability to explain changes in impulse asymmetry. Consideration of approaches that may influence persisting deficits observed bi-laterally throughout vertical jumping performance post-ACLR may enhance rehabilitation practice.

A comparison of kinematic demands placed on the knee and hip during two ACL return-to-sport screening maneuvers and an agility test

OBJECTIVES

This study's purpose was to compare the kinematic demands placed on the knee and the hip during various biomechanical tests.

DESIGN

Retrospective cross-sectional design.

SETTING

A university research laboratory.

PARTICIPANTS

The study sample consisted of 70 NCAA Division I female athletes.

MAIN OUTCOME MEASURES

During the performance of three test maneuvers, a drop vertical jump (DVJ), single leg cross over hop (COH) and modified T-test (AT), the hip and knee joint angles at maximum knee valgus were obtained from marker displacement data collected using a 20-camera motion analysis system. A linear mixed model was used to compare the effect of test on joint angle.

RESULTS

A significant difference (p < 0.001) in the frontal and sagittal plane position of the knee and hip was noted between the DVJ, COH, and AT tests at maximum knee valgus.

CONCLUSIONS

The DVJ, COH, and AT maneuvers do not appear to place the same kinematic stress on the knee, supporting the need for the development of return to sport tests that mimic on field demands.

Correlations of Single-Leg Performance Tests to Patient-Reported Outcomes After Primary Anterior Cruciate Ligament Reconstruction

OBJECTIVE

To determine the relationship between patient-reported outcomes (PROs) to the single-leg step-down test (SLSD) and the Y-balance anterior reach (YB-A) 6 months after primary anterior cruciate ligament reconstruction (ACLR).

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Sixty-six patients 6 months after ACLR participated.

INTERVENTIONS

Patients performed the SLSD, YB-A, and completed PROs after ACLR.

MAIN OUTCOME MEASURES

Patients completed the International Knee Documentation Committee Score (IKDC), the Lysholm Activity Scale, the Tampa Scale of Kinesiophobia (TSK-11), and the Knee Injury and Osteoarthritis Outcome Score (KOOS)-Symptom, -Sport, and -Quality of Life (QOL) subscales. The SLSD requires subjects to complete as many single-leg step-downs as possible in 60 seconds, and the YB-A involves reaching anteriorly on a single limb. Pearson product moment correlations were used to assess relationships between the YB-A and SLSD performance to each PRO.

RESULTS

Single-leg step-down test symmetry was significantly correlated with the TSK-11 (r = -0.70), KOOS-Sport (r = 0.40), -Symptom (r = 0.46), and -QOL (r = 0.42). The YB-A symmetry was significantly correlated with the KOOS-Symptom (r = 0.30) and KOOS-Sport (r = 0.30).

CONCLUSIONS

Single-leg step-down test performance demonstrated stronger relationships to patient-reported knee function than the YB-A. Furthermore, the SLSD symmetry was strongly correlated with fear of movement. The SLSD provides a robust method for clinicians to assess dynamic knee function and may aid in identifying patients who could benefit from intervention to reduce fear of movement or reinjury.

Bilateral Hidden Isokinetic Quadriceps Performance before and after MPFL Reconstruction in Pediatric Patients

We perform prospective study to evaluate the isokinetic performance of quadriceps before and 1 year after medial patella-femoral ligament (MPFL) reconstruction with the adductor magnus tendon in the case of recurrent patellar dislocation. The present study is the first to describe the isokinetic function of the quadriceps of the involved and uninvolved extremity, in such a wide range. The MPFL is a crucial passive stabilizer of patella and, along with the conditions of the anatomical shape of the femoral-patellar joint and the function of quadriceps, influences the overall patellar stability. However, only a few studies have examined indirectly or directly the function of quadriceps. A total of 27 patients (average age at surgery was 15.8 years) with recurrent monolateral patellar dislocation were treated with MPFL reconstruction using the adductor magnus tendon. In the study group, healthy and operated quadriceps were evaluated for the following parameters at the velocities of 60 and 180 deg/s before surgery and in the follow-up examination: peak torque, peak torque to body weight, time to peak torque, peak torque angle, torque in 30 degree of the knee flexion (TQ 30 degree), and the torque in the first 180 milliseconds (TQ 180). Preoperative patellar instability and its normalization after MPFL reconstruction have no impact on the isokinetic quadriceps index value which depends on the time and degree of inactivity as well as implementation of appropriate physiotherapy. The increase in the quadriceps muscle strength of a healthy limb is responsible for the persistence of muscle isokinetic imbalance after MPFL reconstruction in pediatric patients. This is a level 2b study.

Effects of a Competitive Soccer Match on Jump Performance and Interlimb Asymmetries in Elite Academy Soccer Players

ABSTRACT

Bromley, T, Turner, A, Read, P, Lake, J, Maloney, S, Chavda, S, and Bishop, C. Effects of a competitive soccer match on jump performance and interlimb asymmetries in elite academy soccer players. J Strength Cond Res 35(6): 1707-1714, 2021-The purpose of this study was to investigate the effects of a competitive soccer match on jump performance and interlimb asymmetries over incremental time points during a 72-hour period. Fourteen elite adolescent players from a professional English category 3 academy performed single-leg countermovement jumps pre, post, 24-, 48-, and 72-hour post-match on a single force platform. Eccentric impulse, concentric impulse, peak propulsive force, jump height, peak landing force, and landing impulse were monitored throughout. Interlimb asymmetries were also calculated for each metric as the percentage difference between limbs. Significant negative changes (p < 0.05) in jump performance were noted for all metrics at all time points, with the exception of jump height. Interlimb asymmetries were metric-dependent and showed very large increases, specifically post-match, with a trend to reduce back toward baseline values at the 48-hour time point for propulsive-based metrics. Asymmetries for landing metrics did not peak until the 24-hour time point and again reduced toward baseline at 48-hour time point. This study highlights the importance of monitoring distinct jump metrics, as jump height alone was not sensitive enough to show significant changes in jump performance. However, interlimb asymmetries were sensitive to fatigue with very large increases post-match. More frequent monitoring of asymmetries could enable practitioners to determine whether existing imbalances are also associated with reductions in physical performance or increased injury risk.

New Frontiers of Body Composition in Sport

The body composition phenotype of an athlete displays the complex interaction among genotype, physiological and metabolic demands of a sport, diet, and physical training. Observational studies dominate the literature and describe the sport-specific physique characteristics (size, shape, and composition) of adult athletes by gender and levels of competition. Limited data reveal how body composition measurements can benefit an athlete. Thus, the objective is to identify purposeful measurements of body composition, notably fat and lean muscle masses, and determine their impact on the health and performance of athletes. Areas of interest include relationships among total and regional body composition measurements, muscle function, sport-specific performance, risk of injury, return to sport after injury, and identification of activity-induced fluid shifts. Discussion includes the application of specific uses of dual X-ray absorptiometry and bioelectrical impedance including an emphasis on the need to minimize measurement errors and standardize protocols, and highlights opportunities for future research. This focus on functional body composition can benefit the health and optimize the performance of an athlete.