Movement Quality Assessment of Army Reserve Officers' Training Corps Cadets: A Report of Validity and Normative Data.

INTRODUCTION: Movement quality screening in early-career military populations, like Army Reserve Officers' Training Corps (AROTC) cadets, could decrease the negative impact of musculoskeletal injury observed within the military. Movement quality screening techniques should be valid before being pursued in the field. Normative data describing movement quality of AROTC cadets are also needed. Therefore, the aims of this study were to determine criterion validity of several movement quality assessments and report normative jump-landing kinematics of AROTC cadets. MATERIALS AND METHODS: This cross-sectional research was approved by the Institutional Review Board. As part of a larger study, 20 AROTC cadets (21.3 ± 3.4 years; 1.7 ± 0.1 m; 73.8 ± 14.8 kg) had 3-dimensional (3D) and 2-dimensional (2D) kinematic data collected simultaneously while performing a jump-landing task. Variables of interest were 3D hip and knee sagittal, frontal, and transverse joint angles at maximum knee flexion. An experienced rater calculated sagittal and frontal 2D joint angles at maximum knee flexion. Averages of 2D and 3D angles were calculated to describe normative data and for further data analysis. Bivariate correlations between 3D and 2D variables were used to determine criterion validity. RESULTS: Moderate correlations were found between 2D and 3D hip frontal plane angles (P = .05, r =-0.33), 2D and 3D knee sagittal plane angles (P = .04, r = 0.35), and 2D and 3D knee frontal plane angles (P = .03, r = -0.36). Normative values of knee and hip kinematics demonstrated averages of 17.58° of knee adduction, 16.48° of knee external rotation, 11.57° of hip abduction, 10.76° of hip internal rotation, and 103.47° of knee flexion during landings. However, ranges demonstrated that landing patterns vary within AROTC cadets. CONCLUSIONS: The normative values of 3D jump-landing kinematic data indicate that movement quality varies greatly within AROTC cadets, and some cadets display potentially injurious movements. Therefore, screening movement quality could be beneficial to determine musculoskeletal injury risk in AROTC cadets. Based on the correlations discovered in this study, we recommend the 2D techniques used in this study be researched further as they may serve as alternatives to expensive, timely 3D techniques that could be better utilized in military environments.

The effect of external focus versus internal focus instruction on jump-landing biomechanics in healthy females.

CONTEXT: Different forms of instruction have contributed to favorable results in injury interventions. External focus (EF) instruction may be superior to internal focus (IF) instruction. OBJECTIVE: To investigate the difference in landing biomechanics between participants who received EF versus IF instruction and a control. A secondary aim was to evaluate participant perceptions of focus of attention. DESIGN: Randomized controlled trial. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-one healthy females. EF: N=14; 23.0±2.9yrs; 1.69±0.07m; 64.0±6.8kg; IF: N=15; 22.9±3.2yrs;1.66±0.08m;66.2±12.4kg; Control: N=12; ±2.9yrs; 1.67±0.11m; 74.3±15.1kg. MAIN OUTCOME MEASURES: Participants scoring ≥ five on the LESS and were allocated into EF, IF or control groups. Knee and hip flexion and abduction were collected pre- and post-intervention during five drop vertical jumps. For the intervention, each group was provided separate instructions. In-between the intervention jumps, participants answered: "What strategy were you focusing on when completing the previous jump-landing trials?". Post-intervention minus pre-intervention change scores were calculated and separate 1-way ANOVAs assessed differences in the dependent variables. RESULTS: EF had a greater change in hip and knee flexion angles versus control. There was no significant difference between EF and IF for any variables. There were no significant differences in frontal plane variables. In the EF group, 71.4% were "aligned". In the IF group, 80% of the were "aligned". In the CONT group, 50% were "aligned". CONCLUSIONS: EF instruction may not produce immediate changes in movement compared to IF instruction. Hip and knee flexion were greater in the EF group compared to the control group but was not better than the IF group. Clinicians should provide instruction to patients, but the mode of instruction may not be as critical to see positive biomechanical changes. Patients may not always focus on the instruction being given, therefore the relationship between instruction and patient experience should be further explored.

Standing Pelvic Tilt Is Associated With Dynamic Pelvic Tilt During Running When Measured by 3-Dimensional Motion Capture.

Standing pelvic tilt (PT) is related to biomechanics linked with increased risk of injury such as dynamic knee valgus. However, there is limited evidence on how standing PT relates to dynamic PT and whether the palpation meter (PALM), a tool to measure standing PT, is valid against 3-dimensional (3D) motion analysis. The purposes of this study were to (1) determine the criterion validity of the PALM for measuring standing PT and (2) identify the relationship between standing PT and dynamic PT during running. Participants (n = 25; 10 males and 15 females) had their standing PT measured by the PALM and 3D motion analysis. Dynamic PT variables were defined at initial contact and toe off. No relationship between the 2 tools was found. Significant large positive relationships between standing PT and PT at initial contact (r = .751, N = 25, P < .001) and PT at toe off (r = .761, N = 25, P < .001) were found. Since no relationship was found between standing PT measured by the PALM and 3D motion analysis, the PALM is not a valid alternative to 3D motion analysis. Clinicians may be able to measure standing PT and gain valuable information on dynamic PT, allowing clinicians to quickly assess whether further biomechanical testing is needed.

Reliability and criterion validity of two-dimensional movement assessments in those with patellofemoral pain.

OBJECTIVES: Determine criterion validity and intra/inter-rater reliability of 2-dimensional (2D) knee frontal plane projection angle (kFPPA), hip frontal plane projection angle (hFPPA), and dynamic valgus index (DVI) during forward step-downs in those with patellofemoral pain (PFP). DESIGN: Cross-sectional. SETTING: University research laboratory. PARTICIPANTS: 39 participants with PFP (34.18 ± 7.41years, 170± .1 cm, 81.03 ± 19.36 kg, duration of pain: 68.67 ± 85.08months, anterior knee pain scale: 80.49 ± 7.87, visual analog scale:2.08 ± 2.02) MAIN OUTCOME MEASURES: Average 3D hip and knee sagittal, frontal, and transverse joint angles and 2D kFPPA, hFPPA, and DVI at maximum knee flexion were variables of interest. 3D DVI was calculated as the sum of hip and knee frontal and transverse angles. 2D kFPPA, hFPPA, and DVI were calculated by two raters independently on two occasions. RESULTS: Intra- and inter-rater reliability of all 2D angles were excellent. kFPPA was moderately correlated to 3D knee transverse angles. hFPPA was moderately correlated to 3D hip frontal and transverse angles and largely correlated to 3D DVI. 2D DVI was moderately correlated to hip transverse angles. CONCLUSION: kFPPA, hFPPA, and DVI are reliable. hFPPA may be reflective of 3D hip and knee frontal and transverse motion during forward step-downs in those with PFP.

Measurement Properties of Clinically Accessible Movement Assessment Tools for Analyzing Jump Landings: A Systematic Review.

CONTEXT: Lower-extremity musculoskeletal injury is commonly associated with poor movement patterns at the trunk, hip, and knee. Efforts have been focused on identifying poor lower-extremity movement using clinically friendly movement assessments, such as rubrics and 2D measures. Assessments used clinically or for research should have acceptable measurement properties, such as reliability and validity. However, the literature on reliability and validity of movement assessments to analyze jump landings has not been summarized. OBJECTIVE: To systematically review measurement properties of rubrics and 2D measurements that aim to classify movement quality during jump landings. EVIDENCE ACQUISITION: The search strategy was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The search was performed in PubMed, SPORTDiscus, and Web of Science databases. The COnsensus-based Standards for the selection of health Measurement INstruments multiphase procedure was used to extract relevant data, evaluate methodological quality of each study, score the results of each movement assessment, and synthesize the evidence. EVIDENCE SYNTHESIS: Twenty-two studies were included after applying eligibility criteria. Reliability and construct validity of the landing error scoring system were acceptable. Criterion validity of 2D knee flexion angle and medial knee displacement is acceptable. Reliability of 2D knee ankle separation ratio and knee frontal plane projection angle are acceptable. CONCLUSION: The landing error scoring system is a valid way to determine poor movement quality and injury risk. Measures of 2D knee flexion angle and medial knee displacement are valid alternatives for 3D knee flexion angle and knee abduction moment, respectively. Knee ankle separation ratio and knee frontal plane projection angle are reliable but lack validity justifying their clinical use.

Measurement Properties of Clinically Accessible Movement Assessment Tools for Analyzing Single-Leg Squats and Step-Downs: A Systematic Review.

CONTEXT: Poor lower-extremity biomechanics are predictive of increased risk of injury. Clinicians analyze the single-leg squat (SLS) and step-down (SD) with rubrics and 2D assessments to identify these poor lower-extremity biomechanics. However, evidence on measurement properties of movement assessment tools is not strongly outlined. Measurement properties must be established before movement assessment tools are recommended for clinical use. OBJECTIVE: The purpose of this study was to systematically review the evidence on measurement properties of rubrics and 2D assessments used to analyze an SLS and SD. EVIDENCE ACQUISITION: The search strategy was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The search was performed in PubMed, SPORTDiscus, and Web of Science databases. The COnsensus-based Standards for the selection of health Measurement INstruments multiphase procedure was used to extract relevant data, evaluate methodological quality of each study, score the results of each movement assessment, and synthesize the evidence. EVIDENCE SYNTHESIS: A total of 44 studies were included after applying eligibility criteria. Reliability and construct validity of knee frontal plane projection angle was acceptable, but criterion validity was unacceptable. Reliability of the Chmielewski rubric was unacceptable. Content validity of the knee-medial-foot and pelvic drop rubrics was acceptable. The remaining rubrics and 2D measurements had inconclusive or conflicting results regarding reliability and validity. CONCLUSIONS: Knee frontal plane projection angle is reliable for analyzing the SLS and SD; however, it does not serve as a substitute for 3D motion analysis. The Chmielewski rubric is not recommended for assessing the SLS or SD as it may be unreliable. Most movement assessment tools yield indeterminate results. Within the literature, standardized names, procedures, and reporting of movement assessment tool reliability and validity are inconsistent.

The injury risk profile of an Army Reserve Officers' Training Corps population: A preliminary descriptive study.

OBJECTIVES: Army Reserve Officers' Training Corps (ROTC) prepares cadets for military service where lower extremity injuries can occur. The Landing Error Scoring System (LESS), Functional Movement Screen (FMS) and Y-Balance (YBAL) have not been used to evaluate injury risk in the ROTC. Higher physical fitness lowers injury risk in basic training recruits, it is unknown if previous high school sport participation affects injury risk in the ROTC. The purpose of this study was to evaluation the LESS, FMS, YBAL and high school sport participation in the ROTC. DESIGN: Descriptive study. SETTING: University. PARTICIPANTS: 78 ROTC (49 males, 29 females; 19.7 ± 2.3yrs; 1.71 ± 10.1 m; 62.5 ± 21.2 kg). MAIN OUTCOME MEASURES: LESS, FMS, YBAL and sports participation were collected and scores were calculated. Means, standard deviation and range were reported for each test. Distribution of scores within injury risk categories were evaluated. Sport participation frequency was reported. RESULTS: The mean LESS and FMS scores were 7.1 ± 2.1 and 14.6 ± 2.1, respectively. The average YBAL composite score was 90.2% ± 12.0. 68% were poor on the LESS. 46.1% were high risk on the FMS. 69.2% were high risk on the YBAL composite. Seventy-seven percent reported at least one year of participation in high school sports. CONCLUSIONS: ROTC population demonstrated poor jump landing mechanics and were high risk on the YBAL composite.

REPORT-PFP: a consensus from the International Patellofemoral Research Network to improve REPORTing of quantitative PatelloFemoral Pain studies.

Patellofemoral pain is a common and often debilitating musculoskeletal condition. Clinical translation and evidence synthesis of patellofemoral pain research are compromised by heterogenous and often inadequately reported study details. This consensus statement and associated checklist provides standards for REPORTing of quantitative PatelloFemoral Pain (REPORT-PFP) research to enhance clinical translation and evidence synthesis, and support clinician engagement with research and data collection. A three-stage Delphi process was initiated at the 2015 International Patellofemoral Research Network (iPFRN) retreat. An initial e-Delphi activity (n=24) generated topics and items, which were refined at the 2017 iPFRN retreat, and voted on prior to and following the 2019 iPFRN retreat (n=51 current and past retreat participants). Voting criteria included 'strongly recommended' (essential), 'recommended' (encouraged) and uncertain/unsure. An item was included in the checklist if ≥70% respondents voted 'recommended'. Items receiving ≥70% votes for 'strongly recommended' were labelled as such. The final REPORT-PFP checklist includes 31 items (11 strongly recommended, 20 recommended), covering (i) demographics (n=2,4); (ii) baseline symptoms and previous treatments (n=3,7); (iii) outcome measures (2,4); (iv) outcomes measure description (n=1,2); (v) clinical trial methodology (0,3) and (vi) reporting study results (n=3,0). The REPORT-PFP checklist is ready to be used by researchers and clinicians. Strong stakeholder engagement from clinical academics during development means consistent application by the international patellofemoral pain research community is likely. Checklist adherence will improve research accessibility for clinicians and enhance future evidence synthesis.

Foot joint coupling variability differences between habitual rearfoot and forefoot runners prior to and following an exhaustive run.

As joint coupling variability has been associated with running-related lower extremity injury, the purpose of this study was to identify how variability within the foot may be different between forefoot (FFS) and rearfoot strike (RFS) runners. Identifying typical variability in uninjured runners may contribute to understanding of ideal coordination associated with running foot strike patterns. Fifteen FFS and 15 RFS runners performed a maximal-effort 5 km treadmill run. A 7-segment foot model identified 6 functional articulations (rearfoot, medial and lateral midfoot and forefoot, and 1st metatarsophalangeal) for analysis. Beginning and end of the run motion capture data were analyzed. Vector coding was used to calculate 6 joint couples. Standard deviations of the coupling angles were used to identify variability within subphases of stance (loading, mid-stance, terminal, and pre-swing). Mixed between-within subjects ANOVAs compared differences between the foot strikes, pre and post run. Increased variability was identified within medial foot coupling for FFS and within lateral foot coupling for RFS during loading and mid-stance. The exhaustive run increased variability during mid-stance for both groups. Interpretation. Joint coupling variability profiles for FFS and RFS runners suggest different foot regions have varying coordination needs which should be considered when comparing the strike patterns.

Exploring the Pain in Patellofemoral Pain: A Systematic Review and Meta-Analysis Examining Signs of Central Sensitization.

BACKGROUND: Patellofemoral pain (PFP) has high recurrence rates and minimal long-term treatment success. Central sensitization refers to dysfunctional pain modulation that occurs when nociceptive neurons become hyperresponsive. Researchers in this area of PFP have been increasingly productive in the past decade. OBJECTIVE: To determine whether evidence supports manifestations of central sensitization in individuals with PFP. DATA SOURCES: We searched MeSH terms for quantitative sensory testing (QST) pressure pain thresholds (PPTs), conditioned pain modulation (CPM), temporal summation, sensitization, hyperalgesia, and anterior knee pain or PFP in PubMed, SPORTDiscus, CINAHL, Academic Search Complete, and EBSCOhost. STUDY SELECTION: Peer-reviewed studies that were written in English and published between 2005 and 2020 and investigated QST or pain mapping in a sample with PFP were included in this review. DATA EXTRACTION: The initial search yielded 140 articles. After duplicates were removed, 78 abstracts were reviewed. The full text of 21 studies was examined, and we included 15 studies in our evaluation: 6 in the meta-analysis, 4 in the systematic review, and 5 in both the meta-analysis and systematic review. DATA SYNTHESIS: A random-effects meta-analysis was conducted for 4 QST variables (local PPTs, remote PPTs, CPM, temporal summation). Strong evidence supported lower local and remote PPTs, impaired CPM, and facilitated temporal summation in individuals with PFP compared with pain-free individuals. Evidence for heat and cold pain thresholds was conflicting. Pain mapping demonstrated expanding pain patterns associated with long duration of PFP symptoms. CONCLUSIONS: Signs of central sensitization were present in individuals with PFP, indicating altered pain modulation. The etiologic and treatment models of PFP should reflect the current body of evidence regarding central sensitization. Signs of central sensitization should be monitored clinically, and treatments with central effects should be considered as part of a multimodal plan of care.

The effects of military style ruck marching on lower extremity loading and muscular, physiological and perceived exertion in ROTC cadets.

Military ruck marching with load carriage increases ground reaction forces, which are related to bone stress injuries (BSI). This study's purpose was to examine whether a ruck march increases impact loading and to describe muscular, physiological and perceived exertion in Army Reserve Officer Training Corps (ROTC) cadets. Secondary purposes examined relationships among loading changes after the ruck march and baseline characteristics. Fifteen Army ROTC cadets performed a 4-mile march. Lower extremity loading and muscular, physiological and perceived exertion were measured pre- and post-march. Results indicated significant increases in peak impact force and loading rate and decreases in ankle dorsiflexion and plantarflexion strength. Factors that might have been related to changes seen in lower extremity loading did not yield any compelling relationships to explain those changes. In conclusion, the ruck march led to increased peak impact force and loading rate, which have been shown to be related to the risk of BSI. Practitioner summary: This study examined ROTC cadets ankle strength and lower extremity loading before and after a ruck march. We found that lower extremity loading increased after the march, and ankle dorsiflexion (DF) strength decreased, despite the cadets not feeling fatigued. These changes are consistent with risk factors for bone stress injuries. Abbreviations: BSI: bone stress injury; ROTC: Reserve Officer Training Corps; PIF: peak impact force; LR: loading rate; RPE: rate of perceived exertion; APFT: Army physical fitness test; DF: dorsiflexors; PF: plantar-flexors; INV: invertors; EV: evertors; HHD: handheld dynamometer; %HRmax: percentage of maximum heart rate.

Functional Outcomes and Psychological Benefits of Active Video Games in the Rehabilitation of Lateral Ankle Sprains: A Case Report.

CONTEXT: The use of active video games (AVG) as a treatment modality in the rehabilitation context is increasing. However, little is known about the functional outcomes and psychological benefits of such rehabilitation in college athletes with lateral ankle sprains (LASs). OBJECTIVE: To examine functional outcomes and psychological benefits of AVG-aided rehabilitation program for LAS. DESIGN: A mixed-methods, single-subject case series design. SETTING: College athletic training clinic. PATIENTS: Two female college soccer players who sustained LAS (grades I and II) during sport participation. INTERVENTION: A 4-week balance training program. One patient completed balance exercises using AVG, whereas the other patient completed traditional balance exercises. MAIN OUTCOME MEASURES: Several validated instruments were used to evaluate different functional outcomes and psychological factors: balance (Balance Error Scoring System, Star Excursion Balance Test), rehabilitation adherence (Rehabilitation Adherence Measure for Athletic Training), foot and ankle function (Foot and Ankle Ability Measure), perceptions of pain (Visual Analog Scale for pain), perceived readiness to return to sport (Injury-Psychological Readiness to Return to Sport Scale), and mood (Brunel Mood Scale). RESULTS: It appears that the balance training protocols (AVG and traditional balance exercises) were equally effective in restoring patient's balance to functional levels. Despite very individualistic processes of rehabilitation, the participants' perceived pain, perceived readiness to return to sport, and mood states were closely linked with objective and subjective functional measures of progress. CONCLUSIONS: Based on the results, AVG has the potential to provide more versatility into the static and dynamic postural control exercises typically used following acute LAS. Moreover, the current results support the existing psychological and biopsychosocial theoretical conceptualizations of athletes' responses to injuries and rehabilitation process.

The Prioritized Research Agenda for the Athletic Training Profession: A Report From the Strategic Alliance Research Agenda Task Force.

CONTEXT: Athletic trainers (ATs) must be equipped with evidence to inform their clinical practice. A systematic, inclusive, and continuous process for exploring research priorities is vital to the success of ATs and, more importantly, their patients' positive outcomes. OBJECTIVE: To identify research priorities and unify research with clinical practice to improve patient care and advance the profession. DESIGN: Mixed-methods study. SETTING: Focus groups and a Web-based survey. PATIENTS OR OTHER PARTICIPANTS: A total of 87 ATs (43 men [49.4%], 44 women [50.6%]; age = 40 ± 11 years; experience = 18 ± 11 years) participated in focus groups. Of the 49 332 e-mails sent, 580 were undeliverable, 5131 ATs started the survey (access rate = 10.5%), and 4514 agreed to participate (response rate = 9.3%). MAIN OUTCOME MEASURE(S): Our study consisted of 6 focus-group sessions, a content-expert review, and a Web-based survey. Themes from the focus groups were used to develop the research priorities and survey instrument. We used the 25-item validated survey to determine whether the research priorities and findings of the focus groups were generalizable. Endorsement of research priorities and recommendations was achieved when respondents indicated they agreed or strongly agreed. RESULTS: Respondents endorsed 5 research priorities: health care competency (n = 4438/4493, 98.8%), vitality of the profession (n = 4319/4455, 96.9%), health professions education (n = 3966/4419, 89.8%), health care economics (n = 4246/4425, 96.0%), and health information technology (n = 3893/4438, 87.7%). We also made the following recommendations: (1) develop funding initiatives that align with the agenda, (2) develop postdoctoral fellowships focused on clinical research, (3) facilitate collaborative relationships between clinicians and researchers, and (4) make research evidence more readily available and more applicable. CONCLUSIONS: Using a systematic and inclusive process, we developed a prioritized research agenda for the athletic training profession. The agenda was endorsed by the leaders of each Strategic Alliance organization and adopted as the Athletic Training Research Agenda.

Quantitative and qualitative assessment of frontal plane knee motion in males and females: A reliability and validity study.

BACKGROUND: The aim was to determine reliability and validity of frontal plane projection angle (FPPA) and visual assessments (VA) in both males and females. METHODS: Fifty-four participants (30 females) performed lateral step-downs while kinematics were recorded by two-dimensional and three-dimensional analyses. Two raters viewed the videos, extracted images, and measured the FPPA (quantitative). Using the videos, the raters also categorized (qualitative VA) each participant's motion as demonstrating dynamic valgus (>10° valgus), dynamic varus (>10° varus), or no change. Reliability was assessed for FPPA and VA using intraclass correlation coefficients and Kappa, respectively. Validity was determined by comparing the FPPA to three-dimensional measures (Pearson correlations) and comparing the VA to both FPPA and standard reference 3D kinematics (Kappa). RESULTS: FPPA showed good-excellent reliability (ICC = 0.850-0.998). VA showed minimal-moderate reliability (κ = 0.370-0.766). The FPPA showed large correlations (r = -0.514-0.531) with hip adduction in both sexes but only a moderate relationship with knee abduction in males (r = 0.427-0.445). VA showed no-weak (κ = 0.153-0.475) and weak-moderate (κ = 0.455-0.698) agreement compared to FPPA and no-weak (κ = -0.300-0.183) and no-minimal (κ = -0.078-0.027) disagreement compared to the reference standard 3D kinematics in males and females, respectively. CONCLUSION: The quantitative FPPA is more reliable and valid than qualitative VA of frontal knee plane motion.

Treatment Success of Hip and Core or Knee Strengthening for Patellofemoral Pain: Development of Clinical Prediction Rules.

CONTEXT: Patellofemoral pain (PFP) is a common injury that interferes with quality of life and physical activity. Clinical subgroups of patients may exist, one of which is caused by proximal muscle dysfunction. OBJECTIVES: To develop clinical prediction rules that predict a positive outcome after either a hip and core- or knee-focused strengthening program for individuals with PFP. DESIGN: Secondary analysis of data from a randomized control trial. SETTING: Four university laboratories. PATIENTS OR OTHER PARTICIPANTS: A total of 199 participants with PFP. INTERVENTION(S): Participants were randomly allocated to either a hip and core-focused (n = 111) or knee-focused (n = 88) rehabilitation group for a 6-week program. MAIN OUTCOME MEASURE(S): Demographics, self-reported knee pain (visual analog scale) and function (Anterior Knee Pain Scale), hip strength, abdominal muscle endurance, and hip range of motion were evaluated at baseline. Treatment success was defined as a decrease in visual analog scale score by ≥2 cm or an increase in the Anterior Knee Pain Scale score by ≥8 points or both. Bivariate relationships between the outcome (treatment success) and the predictor variables were explored, followed by a forward stepwise logistic regression to predict a successful outcome. RESULTS: Patients with more pain, better function, greater lateral core endurance, and less anterior core endurance were more likely to have a successful outcome after hip and core strengthening (88% sensitivity and 54% specificity). Patients with lower weight, weaker hip internal rotation, stronger hip extension, and greater trunk-extension endurance were more likely to have success after knee strengthening (82% sensitivity and 58% specificity). CONCLUSION: The patients with PFP who have more baseline pain and yet maintain a high level of function may experience additional benefit from hip and core strengthening. The clinical prediction rules from this study remain in the developmental phase and should be applied with caution until externally validated.

Acute Responses of Strength and Running Mechanics to Increasing and Decreasing Pain in Patients With Patellofemoral Pain.

CONTEXT: Patellofemoral pain (PFP) is typically exacerbated by repetitive activities that load the patellofemoral joint, such as running. Understanding the mediating effects of changes in pain in individuals with PFP might inform injury progression, rehabilitation, or both. OBJECTIVE: To investigate the effects of changing pain on muscular strength and running biomechanics in those with PFP. DESIGN: Crossover study. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Seventeen participants (10 men, 7 women) with PFP. INTERVENTION(S): Each participant completed knee pain-reducing and pain-inducing protocols in random order. The pain-reducing protocol consisted of 15 minutes of transcutaneous electric nerve stimulation (TENS) around the patella. The pain-inducing protocol was sets of 20 repeated single-legged squats (RSLS). Participants completed RSLS sets until either their pain was within at least 1 cm of their pain during an exhaustive run or they reached 10 sets. MAIN OUTCOME MEASURE(S): Pain, isometric hip and trunk strength, and running mechanics were assessed before and after the protocols. Dependent variables were pain, normalized strength (abduction, extension, external rotation, lateral trunk flexion), and peak lower extremity kinematics and kinetics in all planes. Pain scores were analyzed using a Friedman test. Strength and mechanical variables were analyzed using repeated-measures analyses of variance. The α level was set at P < .05. RESULTS: Pain was decreased after the TENS (pretest: 3.10 ± 1.95, posttest: 1.89 ± 2.33) and increased after the RSLS (baseline: 3.10 ± 1.95, posttest: 4.38 ± 2.40) protocols (each P < .05). The RSLS protocol resulted in a decrease in hip-extension strength (baseline: 0.355 ± 0.08 kg/kg, posttest: 0.309 ± 0.09 kg/kg; P < .001). Peak plantar-flexion angle was decreased after RSLS (baseline: -13.97° ± 6.41°, posttest: -12.84° ± 6.45°; P = .003). Peak hip-extension (pretest: -2.31 ± 0.46) and hip-abduction (pretest: -2.02 ± 0.35) moments decreased after both the TENS (extension: -2.15 ± 0.48 Nm/kg, P = .015; abduction: -1.91 ± 0.33 Nm/kg, P = .015) and RSLS (extension: -2.18 ± 0.52 Nm/kg, P = .003; abduction: -1.87 ± 0.36 Nm/kg, P = .039) protocols. CONCLUSIONS: This study presents a novel and effective method of increasing pain in persons with PFP. Functionally increased pain after RSLS coincides with reduced hip-extensor muscle strength and decreased plantar-flexion angle during running. The TENS treatment decreased pain during running in those with PFP but failed to influence strength. Hip moments were reduced by both protocols, which may demonstrate that acute increases or decreases in pain cause runners to change their mechanics.

Individuals With Patellofemoral Pain Have Less Hip Flexibility Than Controls Regardless of Treatment Outcome.

OBJECTIVE: To examine differences in hip flexibility before and after a 6-week muscle strengthening program between those with patellofemoral pain (PFP) and healthy controls. DESIGN: Single-blind, multicentered, randomized controlled trial. SETTING: Four clinical research laboratories. SUBJECTS: Physically active individuals (199 PFP and 38 controls). INTERVENTIONS: Patellofemoral pain and control subjects were randomized into either a hip-focused or a knee-focused muscle strengthening treatment program. MAIN OUTCOME MEASURES: Pain-visual analog scale (centimeter), function-Anterior Knee Pain Scale (points), flexibility-passive goniometry (degrees): hip adduction (HADD), hip external rotation (HER), hip internal rotation (HIR), total hip rotation (HROT), hip extension (HEXT) were measured before and after the muscle strengthening treatment program. RESULTS: Subjects with patellofemoral pain who successfully completed the treatment program (n = 153) had 65%, 25%, 18%, and 12% less HADD, HER, HROT, and HIR ranges of motion (ROMs), respectively, than controls (P < 0.05). Patellofemoral pain subjects who did not successfully complete the program (n = 41) had 134%, 31%, 22%, and 13% less HADD, HER, HROT, and HIR ROMs, respectively, than controls (P < 0.05). All subjects increased their HIR, HROT, and HEXT ROMs pretest to posttest (P < 0.05), but by less than 2 degree. CONCLUSIONS: Individuals with PFP had less hip flexibility than controls regardless of treatment outcome or time. After the 6-week muscle strengthening program, and regardless of treatment success, PFP and control subjects experienced a small but clinically insignificant improvement in hip flexibility. CLINICAL RELEVANCE: Hip ROM should be considered as a targeted area of focus in a rehabilitation program for physically active individuals with PFP.

Lasting Improvement of Patient-Reported Outcomes 6 Months After Patellofemoral Pain Rehabilitation.

BACKGROUND/OBJECTIVE: Hip- and knee-muscle-strengthening programs are effective in improving short-term patient-reported and disease-oriented outcomes in individuals with patellofemoral pain (PFP), but few to no data exist on moderate- to long-term postrehabilitative outcomes. The first purpose of the study was to assess differences in pain, function, strength, and core endurance in individuals with PFP before, after, and 6 mo after successful hip- or knee-muscle-strengthening rehabilitation. The second purpose was to prospectively follow these subjects for PFP recurrence at 6, 12, and 24 mo postrehabilitation. METHODS: For 24 mo postrehabilitation, 157 physically active subjects with PFP who reported treatment success were followed. At 6 mo postrehabilitation, pain, function, hip and knee strength, and core endurance were measured. At 6, 12, 18, and 24 mo, PFP recurrence was measured via electronic surveys. RESULTS: Sixty-eight subjects (43%) returned to the laboratory at 6 mo. Regardless of rehabilitation program, subjects experienced significant improvements in pain and function, strength, and core endurance pre- to postrehabilitation and maintained improvements in pain and function 6 mo postrehabilitation (Visual Analog Scale/Pain-pre 5.12 ± 1.33, post 1.28 ± 1.14, 6 mo 1.68 ± 2.16 cm, P < .05; Anterior Knee Pain Scale/Function-pre 76.38 ± 8.42, post 92.77 ± 7.36, 6 mo 90.27 ± 9.46 points, P < .05). Over the 24 mo postrehabilitation, 5.10% of subjects who responded to the surveys reported PFP recurrence. CONCLUSIONS: The findings support implementing a hip-or knee-muscle-strengthening program for the treatment of PFP. Both programs improve pain, function, strength, and core endurance in the short term with moderate- and long-term benefits of improved pain and function and low PFP recurrence.

PAIN, FUNCTION, AND STRENGTH OUTCOMES FOR MALES AND FEMALES WITH PATELLOFEMORAL PAIN WHO PARTICIPATE IN EITHER A HIP/CORE- OR KNEE-BASED REHABILITATION PROGRAM.

BACKGROUND: Hip exercise has been recommended for females with patellofemoral pain (PFP). It is unknown if males with PFP will benefit from a similar treatment strategy. HYPOTHESES/PURPOSE: The purpose of this study was to compare improvements in pain, function, and strength between males and females with PFP who participated in either a hip/core or knee rehabilitation program. The directional hypothesis was that females would respond more favorably to the hip/core rehabilitation program and males to the knee program. STUDY DESIGN: Randomized-controlled clinical trial. METHODS: Patients were randomly assigned to a six-week hip/core or knee rehabilitation program. Visual analog scale (VAS), Anterior Knee Pain Scale (AKPS), and hip and knee isometric strength were collected before and after subjects completed the rehabilitation program. Data were analyzed using an intention-to-treat basis. Separate mixed-model analyses of variance (ANOVA) with repeated measures were used to determine changes in VAS and AKPS and strength changes for subjects classified as treatment responders (successful outcome) and non-responders (unsuccessful outcome). RESULTS: Regardless of sex or rehabilitation group, VAS (F1,181=206.5; p<.0001) and AKPS (F1,181 = 160.4; p < 0.0001) scores improved. All treatment responders demonstrated improved hip abductor (F1,122 = 6.6; p = 0.007), hip extensor (F1,122 = 19.3; p < 0.0001), and knee extensor (F1,122 = 16.0; p < 0.0001) strength. A trend (F1,122 = 3.6; p = 0.06) existed for an effect of sex on hip external rotator strength change. Males demonstrated a 15.4% increase compared to a 5.0% increase for females. All treatment non-responders had minimal and non-significant (p > 0.05) strength changes. CONCLUSION: On average, males and females with PFP benefitted from either a hip/core or knee rehabilitation program. Subjects with successful outcomes likely had hip and knee weakness that responded well to the intervention. These males and females had similar and meaningful improvements in hip extensor and knee extensor strength. Only males had relevant changes in hip external rotator strength. Clinicians should consider a subgroup of males who may benefit from hip extensor and external rotator exercise and females who may benefit from hip extensor exercise. LEVEL OF EVIDENCE: 2b.

Functional Movement Screen Factorial Validity and Measurement Invariance Across Sex Among Collegiate Student-Athletes.

Gnacinski, SL, Cornell, DJ, Meyer, BB, Arvinen-Barrow, M, and Earl-Boehm, JE. Functional Movement Screen factorial validity and measurement invariance across sex among collegiate student-athletes. J Strength Cond Res 30(12): 3388-3395, 2016-The Functional Movement Screen (FMS) is a screening tool used to evaluate functional movement quality and subsequent musculoskeletal injury risk. Despite recent research on the factorial validity of the FMS, no confirmatory factor analysis (CFA) has been conducted to examine measurement invariance across sex among student-athletes. The primary purpose of the current study was to confirm the factor structure of the FMS measurement model in a collegiate student-athlete population. It was hypothesized that the 1-factor model would demonstrate better model fit than the recently proposed 2-factor model. The secondary purpose of the study was to examine FMS measurement invariance across sex using the previously identified measurement model. It was hypothesized that FMS measurement invariance would hold across sex. Male (n = 88) and female (n = 88) collegiate student-athletes completed FMS screening during the off-season. Factorial validity was examined using CFA procedures, and model parameters were estimated using maximum likelihood estimation. Measurement invariance was examined by comparison of fit indices between hierarchically constrained models. Results revealed support for both the 1- and the 2-factor models; however, the 2-factor model failed to fit the data significantly better than the 1-factor model. Results also indicated that measurement invariance did not hold across sex, indicating that the FMS sum score construct is not measured equivalently in male and female populations. Collectively, results provide evidence for the use of the unidimensional FMS sum score among collegiate student-athletes, yet prompt caution because it relates to the evaluation of sex differences in sum or movement pattern scores.