Single-limb Squat Research Articles

Classifiers of anterior cruciate ligament status in female and male adolescents using return-to-activity criteria.

A lack of standardization exists for functional tasks in return-to-activity (RTA) guidelines for adolescents with anterior cruciate ligament injury (ACLi). Identifying the variables that discern ACLi status among adolescents is a first step in the creation of such guidelines following surgical reconstruction. This study investigated the use of classification models to discern ACLi status of adolescents with and without injury using spatiotemporal variables from functional tasks typically used in RTA guidelines for adults. Sixty-four adolescents with ACLi and 70 uninjured adolescents completed single-limb hops, lunges, squats, countermovement jumps and drop-vertical jumps. Jumping distances, heights, and depths were collected. Decision trees (DTs) were used to classify ACLi status and were evaluated using the F-measure (F1), kappa statistic (ĸ) and area under the precision-recall curve (PRC). Independent t tests and effect sizes were calculated for each important classifier of the DT models. A five-variable model classified ACLi status with an accuracy of 67.5% (F1 = 0.6842; ĸ = 0.350; PRC = 0.491) with sex as a classifier. Significant differences were found in three of the four spatiotemporal variables (p ≤ 0.002). Separate models then classified ACLi status in males and females with an accuracy of 53.3% (F1 = 0.5882; ĸ = 0.0541; PRC = 0.476) and 76.9% (F1 = 0.7692; ĸ = 0.541; PRC = 0.528), respectively, with significant differences for all variables (p ≤ 0.013). Among the DT models, females were better able to classify ACLi status compared to males, highlighting the importance of sex-specific rehabilitation guidelines for adolescents. Level III.

Changes in dynamic quadriceps angle in patients with chronic ankle instability

Background: Changes in dynamic Quadriceps Angle (Q angle) had been studied in healthy subjects and individuals with other musculoskeletal disorders; however, in chronic ankle instability (CAI), it has not yet been determined. The purpose of this study was to investigate the difference in dynamic Q angle of patients with unilateral chronic ankle instability and those without chronic ankle instability. Methods: One-hundred and four participants with and without chronic ankle instability from both genders aged between 18-30 years, with a BMI range of 17.9-27.3, were enrolled into 2 equal groups; a study group and a control group, with mean values of age of the study and control groups (20.8±2.4) and (20.9±3) years respectively and of BMI (24.1±4.3) and (23.8±2.9) kg/m2 respectively. Dynamic Q angle measurement is carried out using dynamic knee valgus (DKV) through the frontal plane projection angle (FPPA) during single limb squat. Results: A statistically significant difference in FPPA angle was observed between the affected limb of the CAI group and controls (P=0.001). Conclusion: The present study suggested that unilateral CAI display an increased knee valgus, suggesting an additional proximal kinematic alteration and chronic maladaptation in the CAI population.

Lower limb squat biomechanics and select clinical measures in chronic ankle instability

BackgroundIndividuals with chronic ankle instability often present with clinical and biomechanical abnormalities, however squat biomechanics have not been investigated. The purpose of this study was to compare select clinical assessments and squat biomechanics between individuals with and without chronic ankle instability. MethodsFifteen individuals with chronic ankle instability and a matched control group were studied. A weight-bearing dorsiflexion lunge test, foot posture, and an in-line half-kneeling motor control test for core stability were assessed. Lower limb 3D bilateral and unilateral squat biomechanics were captured. Groups, limbs and squat tasks were compared using an alpha of 0.05. FindingsIndividuals with chronic ankle instability had less static weight-bearing dorsiflexion and failed the core stability test more frequently, but did not differ in foot morphology compared to the controls. When squatting, those with chronic ankle instability demonstrated reduced peak ankle dorsiflexion angles and moments in the involved limb (p < 0.04) during single limb squats and had interlimb differences in ankle dorsiflexion angle as well as hip and knee kinetics (p < 0.04) during double limb squats. In those with chronic ankle instability, there was less overall motion, but higher kinetic demands in single limb versus double leg squatting (p < 0.03). InterpretationIndividuals with chronic ankle instability had impaired weight-bearing dorsiflexion and showed impaired core stability more often, which accompanied altered squatting mechanics in both variations. Within the limbs with chronic ankle instability, single limb squats showed lesser kinematic demands but higher kinetic demands than double limb squatting.

Comparing kinematic asymmetry and lateral step-down test scores in healthy, chronic ankle instability, and patellofemoral pain syndrome female basketball players: a cross-sectional study

We aimed to understand whether ankle dorsiflexion range of motion (ROM) and dynamic knee valgus (DKV) kinematic inter-limb asymmetries would be associated with the Lateral Step-Down Test (LSD) in basketball players with chronic ankle instability (CAI), patellofemoral pain (PFP) and healthy controls (HC). An observational cross-sectional study with a between-subject design was employed. Female basketball athletes with CAI (n = 20), PFP (n = 20) and HC (n = 20) were recruited. Ankle dorsiflexion-ROM, DKV angle during a single-limb squat, and LSD quality were measured bilaterally. The Asymmetry index (ASI) was calculated to identify between-limb percentage imbalances. The correlation matrix between the tasks was calculated. Ankle dorsiflexion-ROM was less in the CAI and PFP than in the HC group regardless of limb (p < 0.001). DKV angle was greater in the CAI and PFP than in the HC group bilaterally (p < 0.001). LSDs were similar between the PFP and CAI groups (p = 0.698) but worse than the HC group (p = 0.001). The ASI showed asymmetry across all tasks (p < 0.001), with the greatest asymmetry for the DKV angle. The correlation matrix between tasks on both limbs was significant (p < 0.05). Our findings suggest significant asymmetries in ankle dorsiflexion-ROM and frontal plane knee control are present in female basketball athletes with CAI and PFP, and thus, highlights need to evaluate and reduce limb asymmetries in these populations.

Altered Knee Loading Following Primary ACL Repair versus ACL Reconstruction.

ACL repair (ACL-r) has recently gained renewed clinical interest for treatment of ACL tears. ACL-r has several potential benefits over ACL reconstruction (ACL-R) including maintaining the native ACL innervation and blood supply, no graft site morbidity, and possible improved knee biomechanics and decrease in osteoarthritis. The purpose of this study was to assess for differences in metrics of knee joint loading during a single limb squat task between individuals following a primary ACL-r versus those who underwent a standard ACL-R with a patella bone-tendon-bone autograft. Case Control Study. The ACL-r group [n: 15, age(yrs): 38.8±13.9] sustained a proximal ACL disruption that was amenable to repair, while the ACL-R group [n: 15, age(yrs): 25.60±1.7] underwent primary reconstruction with patella bone-tendon-bone autograft. At 12-weeks post-operation, both groups completed the IKDC questionnaire and biomechanical testing during performance of the single limb squat. Bilateral peak knee extension moment and total knee joint power as a measure of eccentric loading (contraction) during the descent phase of the squat were calculated on the surgical and non-surgical limb and averaged across the middle three of five trials. Participants also completed quadriceps strength testing on both limbs three months after surgery on an isokinetic dynamometer at 60°/sec.LSI (Limb Strength Index) was calculated for all variables. Separate ANCOVAs were performed on each biomechanical variable to examine differences between groups. The ACL-r had a significantly greater peak knee extension moment LSI (ACL-r: 78.46±5.79%; ACL-R: 56.86±5.79%; p=0.019, ηp2=.186) and total knee joint power LSI (ACL-r: 72.47±7.39%; ACL-R: 39.70±7.39%, p=0.006, ηp2=.245) than the ACL-R group. The ACL-r also had a significantly greater quadriceps LSI than the ACL-R group (ACL-r: 66.318±4.61%, ACL-R: 48.03±4.61%, p=0.013, ηp2=.206). Individuals following ACL-r demonstrate increased knee joint loading symmetry during a single leg squat task and greater quadriceps strength symmetry at 12 weeks post-surgery compared to those who underwent ACL-R. 3.

Adolescent Athletes Demonstrate Inferior Objective Profiles at the Time of Return to Sport After ACLR Compared With Healthy Controls.

Background:Athletes display persistent muscle deficits and altered limb-loading mechanics at the time of return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR).Purpose:To compare an objective profile of adolescent athletes at RTS after ACLR to matched healthy controls.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Included were 124 participants; 62 patients who underwent ACLR (15.4 ± 1.7 years) and 62 healthy controls (15.3 ± 1.7 years). Motion capture and force plates were used to capture joint motions during jump landing (JL) and single-limb squat (SLS) tasks. Energy absorption contribution (EAC) was calculated, and repeated-measures analysis of variance was used to assess for EAC differences between groups. Participants completed an International Knee Documentation Committee (IKDC) Subjective Knee Form, and isokinetic quadriceps and hamstring strength testing was performed on each limb. Independent t tests were run to examine age, height, weight, and IKDC scores as well as compare differences between groups for quadriceps and hamstring strength.Results:A significant group × joint interaction was found for JL (P < .001) and SLS (P < .001). For JL, patients who underwent ACLR utilized significantly greater hip (P < .001) and significantly less knee (P < .001) EAC on the surgical limb compared with controls. During SLS, patients who underwent ACLR utilized significantly greater hip (P < .001) and significantly less knee (P < .001) EAC on the surgical limb compared with controls. The ACLR cohort demonstrated lower IKDC scores (P < .001) and significantly lower quadriceps strength on the surgical limb (P < .001) than controls. There were no differences in surgical limb hamstring strength between the ACLR cohort and healthy controls (P = .701).Conclusion:Compared with matched healthy controls, the participants who underwent ACLR in this study demonstrated an inferior objective profile at RTS, consisting of deficits in surgical limb loading, self-reported outcomes, and strength.

Hyperalgesia affects muscle activity and knee range of motion during a single-limb mini squat in individuals with knee osteoarthritis: a cross-sectional study

BackgroundThe effect of hyperalgesia on functionality remains uncertain for individuals with knee osteoarthritis (KOA). This study aimed examine the clinical measures and hyperalgesia’s effect on muscle activity, knee range of motion (ROM) and postural control during the single-leg mini squat (SLMS) in individuals with KOA, determining the correlation between variables.MethodsIn this cross-sectional study, 60 individuals, 30 healthy (HG, 57.4 ± 6.86 years), and 30 with mild to moderate KOA (KOAG, 59.4 ± 5.46 years) were evaluated by the visual analog scale (VAS), Western Ontario and McMaster Universities Index (WOMAC), and the pressure pain threshold (PPT) in subcutaneous, myotomal, and sclerotomal structures. Muscle activity, knee ROM and postural control were assessed during a SLMS. The analyses were performed in the two phases of the SLMS. Phase 1 - during descending movement (eccentric contraction), Phase 2 - during ascending movement (concentric contraction). Analysis of covariance was applied for each variable separately, using weight as a co-variable. We used Spearman’s test for determining the correlation.ResultsThere was no difference between groups for age, height, and postural control (p > 0.059), but KOAG presented the highest values for VAS and WOMAC (p = 0.000). In addition, EMG activity was higher in KOAG for gastrocnemius medialis and tibialis anterior muscles during phase 1 (p < 0.027), and for gastrocnemius medialis and gluteus medius muscles during phase 2 (p < 0.007), and reduced values for PPT and knee ROM (p = 0.000). Also, the correlations between PPT with muscle activity and postural control were moderate (rho< 0.482), while strong relationships were observed between some PPT points with VAS and WOMAC (rho> 0.507).ConclusionHyperalgesia affects the functionality during a single-limb mini squat. There is an important correlation between hyperalgesia and muscle activity, postural control, and clinical measures in individuals with KOA.

Effect of simulated rehabilitation on hip joint loading during single limb squat in patients with hip dysplasia

Rehabilitation for patients with developmental dysplasia of the hip (DDH) addresses modifiable factors in an effort to reduce symptoms and prevent or delay the development of osteoarthritis, yet its effect on joint mechanics remains unknown. Our objective was to establish how rehabilitation (muscle strengthening and movement training), simulated with a musculoskeletal model and probabilistic analyses, alters hip joint reaction forces (JRF) in patients with DDH during a single limb squat. In four patients with DDH, hip abductor strengthening was simulated by increasing the maximum isometric force value between 0 and 32.6% and movement training was simulated by decreasing the hip adduction angle between 0 and 10° relative to baseline. 2,000 Monte Carlo simulations were performed separately to simulate strengthening and movement training, from which 99% confidence bounds and sensitivity factors were calculated. Our results indicated that simulated movement training aimed at decreasing hip adduction had a substantially larger influence on hip JRF than strengthening, as indicated by 99% confidence bounds of the resultant JRF (0.88 ± 0.55 xBW vs. 0.31 ± 0.12 xBW, respectively). Relative to baseline, movement training that resulted in a 10° decrease in hip adduction decreased the resultant JRF by 0.78 ± 0.65 xBW, while strengthening the abductors by 17.6% increased resultant JRF by 0.18 ± 0.06 xBW. To our knowledge, these results are the first to provide evidence pertaining to the effect of rehabilitation on joint mechanics in patients with DDH and can be used to inform more targeted interventions.

CONSISTENCY OF DYNAMIC KNEE VALGUS KINEMATICS AND PAIN ACROSS FUNCTIONAL TASKS IN FEMALES WITH PATELLOFEMORAL PAIN: A CROSS-SECTIONAL STUDY.

Dynamic knee valgus has been associated with patellofemoral pain (PFP) during high-level tasks, however, repeated lower-level stresses may be an alternative pain mechanism. The primary purpose of the current study was to examine the consistency of dynamic knee valgus and task-elicited pain demonstrated by females with PFP across four common functional tasks (stair ascent, stair descent, sit-to-stand, and stand-to-sit). A secondary purpose was to assess the correlation between the clinical test of single-limb squat and functional tasks. Females with patellofemoral pain will demonstrate a positive relationship in magnitude of dynamic knee valgus and task-elicited pain across functional tasks. Individuals who demonstrated greater dynamic knee valgus and task-elicited pain during the clinical test of single-limb squat would demonstrate greater dynamic knee valgus and task elicited pain during stair ascent/descent and sit-to-stand/stand-to-sit tasks. Cross-sectional study; secondary analysis of a feasibility intervention study. Twenty-three women with patellofemoral pain (age: 21.8 SD 3.7 years; BMI: 22.2 SD 2.0 kg/m2) participated. Three-dimensional kinematic data were captured during task completion. Hip and knee frontal and transverse plane angles at 45 ° of knee flexion, and pain using a visual analog scale, were assessed during single-limb squat, stair ascent/descent, and sit-to-stand. Pearson product-moment correlation coefficients were calculated to examine between-task relationships for each variable at the pre-intervention assessment. Correlation coefficients between tasks ranged from 0.23-0.76 for hip frontal plane measures (7/10 significant relationships, p<0.02), 0.31-0.90 for hip transverse plane measures (7/10 significant, p<0.01), 0.87-0.95 for knee frontal plane measures (10/10 significant, p<0.01), and 0.54-0.86 for knee transverse plane measures (10/10 significant, p<0.01). Correlations spanned 0.59-0.85 for pain during tasks (10/10 significant, p<0.01). Females with patellofemoral pain demonstrated positive correlations in dynamic knee valgus kinematics and task-elicited pain across five tasks. Movement and pain during the clinical test of single-limb squat test also was correlated with movement and pain during the functional tasks of stair ascent/descent and sit-to-stand. Level 2b.

Relationship Between Isometric Hip Torque With Three Kinematic Tests in Soccer Players

Introduction: Hip muscle strength has a good component to improve the execution of movement preventing excessive knee movements, such as dynamic valgus, which is a factor related to ACL injuries, however, the relationship between isometric torque and dynamic valgus is not yet well established. Functional tests that resemble sports have been used for movement analysis and possible injury minimizing factor. Objectives: To compare the knee medialization peak in three kinematic tests with different demands, and its correlation with the isometric torque of the abductors and hip extensors. Methods: The isometric torque was collected by the Lafayette hand dynamometer. Two-dimensional kinematics were used to evaluate three functional tests of different requirements, Single Limb Squat, Lateral Step Down Test and Single Leg Drop Landing Tests. For comparison between values we used the Student T test and for correlation the Spearman test, with p Results: No significant differences were found between the three right kinematic tests, different from the left. And no relationship was established between the isometric hip torque and none of the three kinematic tests. Conclusion: There is no correlation between the dynamic knee valgus peak during different tests. It is concluded that the isometric torque test does not seem to be as sensitive when related to functional tests, but it has good applicability for comparing strength between limbs.

Landing biomechanics are not immediately altered by a single-dose patellar tendon isometric exercise protocol in male athletes with patellar tendinopathy: A single-blinded randomized cross-over trial

ObjectivesTo a) determine the acute effects of a single-dose patellar tendon isometric exercise protocol on involved limb landing biomechanics in individuals with patellar tendinopathy and asymptomatic patellar tendon pathology, and b) determine if individuals with patellar tendinopathy demonstrated changes in pain following a single-dose patellar tendon isometric exercise protocol. DesignSingle-blinded randomized cross-over trial. SettingLaboratory; Participants28 young male athletes with symptomatic (n = 13, age: 19.62 ± 1.61) and asymptomatic (n = 15, age: 21.13 ± 1.88) patellar tendinopathy. Main outcome measuresParticipants completed a single-dose patellar tendon isometric exercise protocol and a sham-TENS protocol, randomized and separated by 7–10 days. Pain-levels during a single-limb decline squat (SLDS) and three-dimensional biomechanics were collected during a double-limb jump-landing task before and after each intervention protocol. A mixed-model repeated measures ANOVA was conducted to compare change scores for all dependent variables. ResultsThere were no group × intervention interactions for change in pain (F(1, 26) = 0.555, p = 0.463). There was one significant group × intervention interaction for vertical ground reaction force (VGRF) (F(1, 26) = 5.33, p = 0.029). However, post-hoc testing with Bonferroni correction demonstrated no statistical significance for group (SYM: t = −1.679, p = 0.119; ASYM: t = −1.7, p = 0.107) or intervention condition (isometric: t = −2.58, p = 0.016; sham-TENS: 0.72, p = 0.460). There were no further significant group × intervention interactions (p > 0.05). ConclusionsA single-dose patellar tendon isometric exercise protocol did not have acute effects on landing biomechanics or pain levels in male athletes with patellar tendinopathy or asymptomatic patellar tendon pathology.

Neuromuscular Electrical Stimulation Primes Feedback Control During a Novel Single Leg Task

FMRI studies support that neuromuscular electrical stimulation can modulate the excitability of the somatosensory cortex. We studied whether practice and electrical stimulation of the quadriceps would enhance learning during a weight-bearing task. 20 healthy individuals (10 male) and 8 control subjects participated in a 2-day study. Day 1 consisted of a pretest, a training session, and a post-test; day 2 consisted of a pretest, 2 bouts of electrical stimulation to the quadriceps muscles, and a post-test. The single limb squat task was performed at varying knee resistance and target velocities and a random unexpected perturbation was administered. Feedforward error was calculated during a 50 ms time window before the unexpected event. Feedback error was calculated during a 150 ms window after the unexpected event. Peak error score decreased by 2.98 degrees (p < 0.001) immediately following training. Error was improved by 1.78 degrees (p < 0.001) during the feedforward phase and 1.44 degrees (p < 0.001) during the feedback phase. All subjects plateaued after day 1; except for the electrical stimulation group that showed a decrease of 1.206 degrees during the perturbed cycles (p = 0.024). Electrical stimulation triggered additional learning, beyond practice, during the unexpected event at a latency associated with the transcortical reflex.

Iliotibial band syndrome rehabilitation in female runners: a pilot randomized study

BackgroundIliotibial band syndrome (ITBS) carries marked morbidity in runners. Its management is not standardized and lacks evidence base. We evaluated the effectiveness of three different exercises programs in reducing ITBS symptoms.MethodsPatients were divided into three equal treatment groups: ITB stretching (group A), conventional exercise (group B), and experimental hip strengthening exercise (group C). Numeric pain rating scale (NPRS; every week), lower extremity functional scale (LEFS; every 2 weeks), dynamometer (DN; weeks 0, 2, 4, 6, 8), single-limb mini squat (SLMS; week 0, 8), and Y-balance test™ (YBT), between and within group’s differences were evaluated using ANOVA model.ResultsTwenty-four female runners (age 19–45 years) were included into one of three groups (A, B, and C). Statistical significance (p < 0.05) within group C was observed for composite YBT and DN for injured and non-injured leg, the YBT (injured leg for the posterior medial), LEFS, NPRS, and the SLMS. Statistical significance (p < 0.05) was found between group A and group C. The stretching group exhibited statistically significant (p < 0.05) YBT anterior reach for the injured/non-injured leg and the LEFS.ConclusionThere were no statistical differences between the three groups. The subjects who underwent experimental hip strengthening exercises consistently showed improvements in outcome measures, and never scored less than the other two groups.Trial registrationClinicalTrials.gov identifier (NCT number): NCT0229615

Myotonic dystrophy type 1 alters muscle twitch properties, spinal reflexes, and perturbation-induced trans-cortical reflexes.

Neurophysiologic biomarkers are needed for clinical trials of therapies for myotonic dystrophy (DM1). We characterized muscle properties, spinal reflexes (H-reflexes), and trans-cortical long-latency reflexes (LLRs) in a cohort with mild/moderate DM1. Twenty-four people with DM1 and 25 matched controls underwent assessment of tibial nerve H-reflexes and soleus muscle twitch properties. Quadriceps LLRs were elicited by delivering an unexpected perturbation during a single-limb squat (SLS) visuomotor tracking task. DM1 was associated with decreased H-reflex depression. The efficacy of doublet stimulation was enhanced, yielding an elevated double-single twitch ratio. DM1 participants demonstrated greater error during the SLS task. DM1 individuals with the least-robust LLR responses showed the greatest loss of spinal H-reflex depression. DM1 is associated with abnormalities of muscle twitch properties. Co-occurring alterations of spinal and trans-cortical reflex properties underscore the central nervous system manifestations of this disorder and may assist in gauging efficacy during clinical trials.

The relationship between single-limb squat and jump-cut kinematics

ABSTRACT No objective criteria exist for progressing athletes into cutting manoeuvres following ACL reconstruction (ACLR). The purpose of this study was to evaluate the relationship between a jump-cut task (JC) and the single-limb squat (SLS) in both ACLR and healthy controls. Case-control, laboratory based. Twenty-three participants with a history of ACLR (Age = 21 ± 3 years; Height = 174.5 ± 7.2 cm; Mass = 76.2 ± 9.9 kg) and 23 healthy controls participants (Age = 21 ± 3 years; Height = 173.8 ± 9.2 cm; Mass = 75.0 ± 10.5 kg) were included. Kinematics were collected bilaterally. Correlations between tasks were evaluated for kinematics. Independent sample t-tests were used to evaluate differences between groups for each dependent variable. Peak trunk rotation and medial knee displacement were strongly correlated (p < 0.001, r2 = 0.63), between tasks. ACLR group performed SLS and JC tasks with less sagittal plane motion compared to healthy controls (p < 0.05). Lack of frontal and transverse plane control during SLS resulted in positions of increased lateral trunk flexion, hip adduction, and medial knee displacement during JC. The SLS may be considered for use as a clinical predictor of JC during rehabilitation following ACLR.

Test-retest reliability and minimum detectable change for various frontal plane projection angles during dynamic tasks

ObjectiveEstablish between-day test-retest reliability metrics for 2-dimensional frontal plane projection angles (FPPAs) during the lateral step-down (LSD), single-limb squat (SLS), single-limb landing (SLL), and drop vertical jump (DVJ). DesignTest-retest reliability study. SettingUniversity laboratory. Participants20 healthy adults (12 female, age = 23.60 ± 1.93 years old, body mass index = 24.26 ± 2.54 kg/m2) were tested on 2 separate occasions 7–14 days apart. Main outcome measuresIntraclass correlation coefficients (ICC), standard errors of the measurement (SEM), and minimal detectable change (MDC) values across the LSD, SLS, SLL, and DVJ for the following body region variables: trunk, trunk on pelvis, pelvis, hip, thigh to vertical, knee, and shank to vertical. ResultsThere was moderate-to-substantial between-day test-retest reliability for nearly all body regions across all tasks (ICC = 0.65–0.96). SEM values varied across body regions and tasks (0.9–3.5°). MDCs were variable (2.3–9.8°). Of the body regions, MDCs were largest for the knee and hip. By task, MDCs were lowest for the LSD. ConclusionsThis study identified between-day test-retest reliability metrics for 2-dimensional FPPAs across a variety of body regions during commonly assessed clinical tasks. These data allow clinicians and researchers to more confidently assess true change between assessments or over time.

Reliability of Single Limb Squat and Lateral Step Down Assessment in Novice and Expert Clinicians

The single limb squat (SLS) and lateral step down (LSD) are common lower extremity tests used to assess gross lower extremity strength and motor control. PURPOSE: To compare intra-rater reliability of lower extremity tests between novice and expert clinicians between sessions. METHODS: Six licensed physical therapists (3 “novice” and 3 “expert”) rated 20 frontal plane video recordings of healthy adults who participated in a previous study performing the SLS and LSD. The sample size required to find a kappa of at least 0.50 with a 95% confidence interval of ±0.40 was estimated to be 18. Novice physical therapists were operationally defined as those within 3 years of initial licensure. Expert physical therapists were licensed for at least 10 years and held a board certification in either orthopedics or sports. Prior to data collection, clinicians practiced rating the SLS and LSD on a separate set of recordings. Kappa statistics were calculated based on previous reported formula and interpreted using a standard index. If bias or prevalence indices were above 0.5, the prevalence-adjusted bias-adjusted kappa (PABAK) was calculated. RESULTS: For the SLS, intra-rater reliability of all raters, except one, had moderate reliability or better. For the LSD, most raters had substantial reliability except for two raters, one novice and one expert, who had fair and moderate reliability, respectively. CONCLUSIONS: Our findings suggest using the SLS to assess lower limb strength and control given its higher reliability in novice and experts. The SLS rating was based on knee movement, while LSD was based on trunk, arm, pelvis, knee, and foot. The higher reliability on SLS than LSD may be due to evaluating only one component rather than several simultaneously.Table 1: Intra-rater reliability of single leg squat and lateral step down test performance by novice and expert raters; kappa (95% confidence interval)

Alterations in Center of Pressure During Single-Limb Loading in Individuals with Patellofemoral Pain.

Altered foot loading during weightbearing is suggested to play a role in the development of patellofemoral pain (PFP). This study aimed to determine foot-loading characteristics associated with PFP by assessing center of pressure (COP) during single-limb loading in individuals with PFP compared with noninjured controls. Thirty recreationally active patients with PFP and 30 noninjured control participants had barefoot plantar pressure assessed during single-limb squats (SLSs) from which COP parameters (COP velocity and COP index) were obtained. Groups were compared using independent t tests. Individuals with PFP demonstrated a greater COP index (P = .042), indicating a more lateral foot-loading pattern, and exhibited increased overall COP velocity (P = .013) and anteroposterior COP velocity during SLSs compared with control participants (P = .033). Greater lateral foot loading and increased COP velocity during SLSs demonstrated by individuals with PFP may indicate reduced dynamic balance in this patient group, which may be implicated in the development of PFP.

DOES A COMBINED INTRA-ARTICULAR AND EXTRA-ARTICULAR ACL RECONSTRUCTION EFFECT EXTERNAL KNEE VALGUS MOMENT ASYMMETRY?

Introduction: Peak external knee valgus moment can predict future ACL injury and is, often times, asymmetric following anatomic intra-articular ACL reconstruction. The purpose of this study is to evaluate the external knee valgus moment during a drop landing and a single limb squat 2 years following an iliotibial band (ITB) intra-articular and extra-articular physeal-sparing ACL reconstruction. Methods: Fourteen study subjects (mean age: 14.3 ± 2.6 yrs) who had previously undergone a physeal-sparing ACL reconstruction, as originally described by McIntosh using an ITB autograft, were enrolled in this IRB-approved study. All subjects were seen at a minimum of 24 months after surgery (mean follow-up: 55.0 ± 28.9 mos) and clinical, radiographic, and patient reported outcomes were collected. During functional testing, subjects underwent drop landing (DL) and unilateral squat (US) tasks. Isokinetic muscle strength of the hip and knee was collected using an isokinetic dynamometer at 60°/s. Paired student’s t-tests evaluated differences between affected (AFF) and unaffected (UNAFF) limbs. Results: During a drop landing, the AFF limb, compared to the UNAFF limb, did not demonstrate a difference in external knee valgus moment (0.50° vs. 0.51°, p=0.736). However, in the AFF limb, the mean knee peak knee valgus angle was 2.8 degrees less than the UNAFF limb during a drop landing (p=0.039). This difference was not considered within the range of a minimal clinical difference (MCD) of 5.1 degrees. Similar trends were found during a single limb squat with no significant difference seen in peak knee valgus moment between AFF and UNAFF (0.14° vs. 0.07°, p=0.150) with a statistical, yet not minimal clinical difference, in knee valgus angle at 45° squat position (-2.4° vs. 0.7°, p=0.033; MCD = 5.2). Thus, no asymmetry in peak knee valgus moment during a drop landing or a single limb squat following an ITB intra- and extra-articular ACL reconstruction was observed. In this series at 2 years’ post-op, the Pedi-IKDC and HSS Pedi-FABS were 96.54 ± 5 and 22.6 ± 5, respectively. Subjects demonstrated return to pre-operative Tegner Activity scores (8.42 vs. 8.17, p=0.33). Normalized hip abduction strength was significantly stronger in AFF (1.05 Nm/kg) vs. UNAFF (0.93 Nm/kg, p=0.02). Conclusion: Overall, there were no clinically significant differences, or asymmetry, in functional knee valgus in subjects following combined intra- and extra-articular iliotibial band ACL reconstruction during a drop landing or single leg squat. Young athletes can be expected to return to pre-operative activity levels and demonstrate appropriate knee valgus control following this physeal-sparing ACL reconstruction.

Clinical movement assessments do not differ between collegiate athletes with and without chronic ankle instability

ObjectivesTo determine if overall Landing Error Scoring System-17 (LESS-17) and Fusionetics scores differ between collegiate athletes with and without chronic ankle instability (CAI). We also aimed to determine if the rate of specific movement errors during the LESS-17 and Fusionetics differed between the groups. DesignCase-Control. SettingClinical Sports Medicine Facility. ParticipantsNinety-nine athletes from six Division I NCAA sports were eligible for the investigation. Forty-nine of those participants were classified as having CAI and fifty were classified as uninjured controls. Main outcome measuresAn overall Lower Extremity Fusionetics score and individual task scores were calculated based on movement errors made during a double limb, double-limb with heel lift, and single limb squat. A LESS-17 score was calculated based on movement errors made during a 30 cm drop jump. ResultsNo differences were found between groups for the LESS-17 (p = 0.51), overall Lower Extremity Fusionetics (p = 0.49), and individual Fusionetics tasks (p > 0.36). More individuals with CAI made an uncontrolled trunk movement during a single-limb squat than uninjured controls (p < 0.01). ConclusionsOverall movement quality, as assessed by the LESS-17 and Fusionetics, did not differ between collegiate athletes with and without CAI. The rate of making specific movement errors also did not differ between groups.