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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.

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.

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.

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.

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.

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.

Purpose: Altered hip strength is a risk factor for lower extremity injury but its relationship to biomechanical dysfunction is debated. Hip strength assessment methods are criticized for using unidirectional, non-weight-bearing positions which may not be representative of athletic activity and may affect comparison to biomechanical analysis of athletic tasks. A weight-bearing task may better represent hip muscle function during these movements. The aim of this study was to identify EMG and force differences for a clinical weight-bearing method of hip strength (the squat-hold) to traditional non-weight-bearing maximal voluntary isometric contractions (MVICs) for hip abduction, extension, and external rotation. Methods: Twenty-nine healthy volunteers (23 female, 6 male; 23.3±5.8 years) performed the squat-hold, sidelying abduction, prone extension, and seated hip external rotation MVICs. The squat-hold was performed by exerting a bilateral, maximal force against a rigid strap encircling both knees in a semi-squatted position. Surface electromyography (EMG) recorded peak activation of the gluteus medius (GMed), gluteus maximus (Gmax), and tensor fascia lata (TFL) and a handheld dynamometer simultaneously measured force during all tasks. Peak activation was compared between the squat-hold and each MVIC using paired t-tests. Force was compared across tasks using a one-way ANOVA. Results: Greater force was observed during the squat-hold than the external rotation MVIC, but abduction and extension MVICs yielded greater force than the squat-hold. GMax activation was higher during the squat-hold than the external rotation task. TFL activation was higher during the abduction MVIC than the squat-hold but GMed activation was similar across tasks. Peak GMax activation was similar between the extension MVIC and squat-hold. Conclusions: Squat-hold force may have been reduced due to altered gluteal moment arms, which affected the length-tension relationship. Clinicians should consider the squat-hold as an alternative assessment of external rotation force, but should continue to assess abduction and extension force with MVICs. Researchers should examine positions optimizing length-tension relationships to better relate motor function and movement patterns.

Si chiama C/2019 Y4 Atlas, avrebbe dovuto dar spettacolo nel mese di maggio, ma le ultime osservazioni mostrano che è in corso un processo di frammentazione del nucleo che potrebbe portarla alla distruzione. L’ha però immortalata per noi lo scorso 2 aprile Giulia Iafrate dell’Inaf di Trieste (autrice, insieme a Conrad Boehm, di questo articolo), producendo un timelapse che la mostra mentre solca il Sistema solare

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.

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.

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.

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.

Background Dynamic knee stability is considered a critical factor in reducing anterior cruciate ligament loads. While the relationships between hamstring force production and anterior cruciate ligament loading are well known in vitro, the influence of hamstring strength to anterior cruciate ligament loading during athletic maneuvers remains unknown. Therefore, the purpose of this study was to determine the influence of hamstring strength on anterior cruciate ligament loading during anticipated sidestep cut. Methods Seventeen recreationally active females were recruited to perform sidestep cutting maneuvers pre/post an acute hamstring strength reduction protocol. Kinematics and kinetics were calculated during the cut and a musculoskeletal model was used to estimate muscle, joint, and anterior cruciate ligament loads. Dependent t-tests were conducted to investigate differences between the two cutting conditions. Findings Anterior cruciate ligament loading increased by 36% due to reduced hamstring strength. This was mostly due to a 44% increase in sagittal plane loading and a 24% increase in frontal plane loading. Post strength reduction sidestep cuts were also performed with decreased anterior tibiofemoral shear force, an outcome that would theoretically reduce anterior cruciate ligament loading. However, the overall decrease in hamstring force production coupled with a more axial hamstring line of action yielded a net increase in anterior cruciate ligament loading. Interpretation These results suggest that decreased hamstring strength significantly increases anterior cruciate ligament loading during anticipated sidestep cutting. Additionally, these results support the premise that preseason screening programs should monitor hamstring strength to identify female athletes with potential deficits and increased injury risk.

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.

BAZETT-JONES, D. M., S. C. COBB, W. E. HUDDLESTON, K. M. O’CONNOR, B. S. AMSTRONG, and J. E. EARL-BOEHM. Effect of Patellofemoral Pain on Strength and Mechanics after an Exhaustive Run. Med. Sci. Sports Exerc., Vol. 45, No. 7, pp. 1331–1339, 2013. Purpose: To investigate the effects of an exhaustive run on trunk and lower extremity strength and mechanics in patients with and without patellofemoral pain (PFP), we hypothesized that strength would decrease and mechanics would change after the exhaustive run. Methods: Nineteen subjects with PFP and 19 controls participated (10 men and 9 women per group). Lower extremity and trunk mechanics during running, body mass–normalized strength, and pain assessments before and after an exhaustive run were quantified. A repeated-measures ANOVA was used to assess group differences and exhaustion-related changes (P G 0.05), with t-test post hoc analyses performed when significant interactions were identified (P G 0.0125). Results: Pain significantly increased with the exhaustive run in the PFP group (P = 0.021). Hip strength was reduced after the exhaustive run, more so in those with PFP (abduction: before = 0.384 T 0.08, after = 0.314 T 0.08, P G 0.001; external rotation: before = 0.113 T 0.02, after = 0.090 T 0.02, P G 0.001). Persons with PFP also demonstrated increased knee flexion (before = 41.6 -T 5.5-, after = 46.9 -T 7.5-, P G 0.001), hip flexion (before = 30.4 -T 6.8-, after = 42.5 -T 9.7-, P G 0.001), and anterior pelvic tilt (before = 7.2 -T 5.1-, after = 13.3 -T 6.7-, P = 0.001) after the exhaustive run compared to controls. Trunk flexion increased in both PFP (before = 13.09 -T 6.2-, after = 16.31 -T 5.3-, P G 0.001) and control (before = 1393 -T 4.7-, after = 15.99 -T 5.9-, P G 0.001) groups. Hip extension (before = j2.09 T 0.49 NImIkg j1 ,a fter =j2.49 T 0.54 NImIkg j1 , P = 0.002) moments increased only in subjects with PFP. Conclusions: Exhaustive running results in reduced hip strength in subjects with PFP; however, this did not result in changes to hip internal rotation or adduction kinematics. Kinematic and kinetic changes after the exhaustive run are more indicative of compensatory changes to reduce pain. Increasing trunk flexion during running might provide pain

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.

Context: Lower extremity overuse injuries are associated with gluteus medius (GMed) weakness. Understanding the activation of muscles about the hip during strengthening exercises is important for rehabilitation. Objective: To compare the electromyographic activity produced by the gluteus medius (GMed), tensor fascia latae (TFL), anterior hip flexors (AHF), and gluteus maximus (GMax) during 3 hip-strengthening exercises: hip abduction (ABD), hip abduction with external rotation (ABD-ER), and clamshell (CLAM) exercises. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Twenty healthy runners (9 men, 11 women; age = 25.45 ± 5.80 years, height = 1.71 ± 0.07 m, mass = 64.43 ± 7.75 kg) participated. Intervention(s): A weight equal to 5% body mass was affixed to the ankle for the ABD and ABD-ER exercises, and an equivalent load was affixed for the CLAM exercise. A pressure biofeedback unit was placed beneath the trunk to provide positional feedback. Main Outcome Measure(s): Surface electromyography (root mean square normalized to maximal voluntary isometric contraction) was recorded over the GMed, TFL, AHF, and GMax. Results: Three 1-way, repeated-measures analyses of variance indicated differences for muscle activity among the ABD (F3,57 = 25.903, P Conclusions: The ABD exercise is preferred if targeted activation of the GMed is a goal. Activation of the other muscles in the ABD-ER and CLAM exercises exceeded that of GMed, which might indicate the exercises are less appropriate when the primary goal is the GMed activation and strengthening.

Context Patellofemoral pain (PFP) is the most common injury in running and jumping athletes. Randomized controlled trials suggest that incorporating hip and core strengthening (HIP) with knee-focused rehabilitation (KNEE) improves PFP outcomes. However, no randomized controlled trials have, to our knowledge, directly compared HIP and KNEE programs. Objective To compare PFP pain, function, hip- and knee-muscle strength, and core endurance between KNEE and HIP protocols after 6 weeks of rehabilitation. We hypothesized greater improvements in (1) pain and function, (2) hip strength and core endurance for patients with PFP involved in the HIP protocol, and (3) knee strength for patients involved in the KNEE protocol. Design Randomized controlled clinical trial. Setting Four clinical research laboratories in Calgary, Alberta; Chicago, Illinois; Milwaukee, Wisconsin; and Augusta, Georgia. Patients or Other Participants Of 721 patients with PFP screened, 199 (27.6%) met the inclusion criteria (66 men [31.2%], 133 women [66.8%], age = 29.0 ± 7.1 years, height = 170.4 ± 9.4 cm, weight = 67.6 ± 13.5 kg). Intervention(s) Patients with PFP were randomly assigned to a 6-week KNEE or HIP protocol. Main Outcome Measure(s) Primary variables were self-reported visual analog scale and Anterior Knee Pain Scale measures, which were conducted weekly. Secondary variables were muscle strength and core endurance measured at baseline and at 6 weeks. Results Compared with baseline, both the visual analog scale and the Anterior Knee Pain Scale improved for patients with PFP in both the HIP and KNEE protocols (P < .001), but the visual analog scale scores for those in the HIP protocol were reduced 1 week earlier than in the KNEE group. Both groups increased in strength (P < .001), but those in the HIP protocol gained more in hip-abductor (P = .01) and -extensor (P = .01) strength and posterior core endurance (P = .05) compared with the KNEE group. Conclusions Both the HIP and KNEE rehabilitation protocols produced improvements in PFP, function, and strength over 6 weeks. Although outcomes were similar, the HIP protocol resulted in earlier resolution of pain and greater overall gains in strength compared with the KNEE protocol.

Objectives The primary purpose of this study was to compare hip strength in males with and without patellofemoral pain (PFP). The secondary purpose was to compare knee strength in males with and without PFP. Design Secondary analysis of cross-sectional data for males with and without PFP from a larger randomized controlled trial examining hip and core versus knee-muscle strengthening for the treatment of PFP. Setting Laboratory setting. Participants Sixty-six males with PFP and 36 controls. Main outcome measures Peak isometric force for the hip abductors, external rotators, internal rotators, extensors, and knee extensors expressed as a percentage of body mass (%BM). Results No differences existed with respect to any of the hip strength measures ( P > .05). Males with PFP demonstrated almost 17% less knee extensor strength than controls (mean difference = 7.3 %BM; 95% confidence interval, 1.3–13.4 %BM; t = 2.41; P = .02). Conclusions Unlike females, males with PFP did not demonstrate hip muscle weakness. However, differences did exist with knee extensor strength. These data provide preliminary evidence for the potential need for sex-specific interventions for individuals with PFP.

Context: Identification of impaired balance as a risk factor for lower extremity injury regardless of injury history has led to subsequent investigation of variables that may adversely affect balance in healthy individuals. Objectives: To investigate the relationship among core and lower extremity muscle function, foot posture, and balance. Design: Descriptive laboratory study. Setting: Musculoskeletal injury biomechanics laboratory. Patients or Other Participants: A total of 108 individuals (40 men, 68 women; age = 22.8 ± 4.7 years, height = 168.5 ± 10.4 cm, mass = 69.9 ± 13.3 kg) participated in the study. Main Outcome Measure(s): Core endurance was assessed during 1 time-to-failure trial, and isometric hip and ankle strength were assessed using a handheld dynamometer and isokinetic dynamometer, respectively. Foot structure was quantified using the digital photographic measurement method. Single-limb–stance time to boundary was assessed using a force plate during an eyes-closed condition. Hierarchical multiple regression analyses were performed to predict balance using lower extremity strength, foot posture, and core endurance. Results: Foot posture (β = −0.22, P = .03) and ankle-inversion strength (β = −0.29, P = .006) predicted mediolateral balance. Increasing arch posture and ankle-inversion strength were associated with decreased mediolateral single-limb–stance balance. Conclusions: Increasing arch height was associated with decreased mediolateral control of single-limb stance. The relationship between time to boundary and injury risk, however, has not been explored. Therefore, the relationship between increasing arch height and injury due to postural instability cannot be determined from this study. If authors of future prospective studies identify a relationship between decreased time to boundary and increased injury risk, foot structure may be an important variable to assess during preparticipation physical examinations. The relationship between increasing ankle-inversion strength and decreased balance may require additional study to further elucidate the relationship between ankle strength and balance.

Patellofemoral pain (PFP) is often seen in physically active individuals and may account for 25–40% of all knee problems seen in a sports injury clinic.1 ,2 Patellofemoral-related problems occur more frequently in women than in men.3 PFP is characterised by diffuse pain over the anterior aspect of the knee and aggravated by activities that increase patellofemoral joint (PFJ) compressive forces, such as squatting, ascending and descending stairs and prolonged sitting, as well as repetitive activities such as running. It, therefore, has a debilitating effect on sufferers’ daily lives by reducing their ability to perform sporting and work-related activities pain free. Dye has described PFP as an orthopaedic enigma, and it is one of the most challenging pathologies to manage.4 Alarmingly, a high number of individuals with PFP have recurrent or chronic pain.5 While physiotherapy interventions for PFP have proven effective compared with sham treatments, treatment results can be disappointing in a proportion of patients. This variability in treatment results may be due to the fact that the underlying factors that contribute to the development of PFP are not being addressed, or are not the same for all patients with PFP. The mission of the 3rd International Patellofemoral Research Retreat was to improve our understanding concerning the factors that contribute to the development and consequently to the treatment of PFP. The 3rd International Patellofemoral Research Retreat was held in Vancouver, Canada, in September 2013, for 3 days: from 18 September to 21 September. After peer-review for scientific merit and relevance to the retreat, 58 abstracts were accepted for the retreat (39 podiums, 8 posters and 11 thematic posters). The podium and poster presentations were grouped into three categories: (1) natural history of PFP and local factors that influence PFP, (2) trunk and distal factors that influence PFP and …

A key to understanding potential anterior cruciate ligament injury mechanisms is to determine joint loading characteristics associated with an injury-causing event. However, direct measurement of anterior cruciate ligament loading during athletic tasks is invasive. Thus, previous research has been unable to study the association between neuromuscular variables and anterior cruciate ligament loading. Therefore, the purpose of this study was to determine the influence of movement anticipation on anterior cruciate ligament loading using a musculoskeletal modeling approach.Twenty healthy recreationally active females were recruited to perform anticipated and unanticipated sidestep cutting. Three-dimensional kinematics and kinetics of the right leg were calculated. Muscle, joint and anterior cruciate ligament forces were then estimated using a musculoskeletal model. Dependent t-tests were conducted to investigate differences between the two cutting conditions.ACL loading significantly increased during unanticipated sidestep cutting (p0.05). This increase was primarily due to a significant increase in the sagittal plane ACL loading, which contributed 62% of the total loading. Frontal plane ACL loading contributed 26% and transverse plane ACL loading contributed 12%.These results suggest that anterior cruciate ligament loading resulted from a multifaceted interaction of the sagittal plane shear forces (i.e., quadriceps, hamstrings, and tibiofemoral), as well as the frontal and transverse plane knee moments. Additionally, the results of this study confirm the hypothesis in the current literature that unanticipated movements such as sidestep cutting increase anterior cruciate ligament loading.

The effect of time-to-boundary minima selection and stability limit definition was investigated during eyes open and eyes closed condition single-limb stance postural stability. Anteroposterior and mediolateral time-to-boundary were computed using the mean and standard deviation (SD) of all time-to-boundary minima during a trial, and the mean and SD of only the 10 absolute time-to-boundary minima. Time-to-boundary with rectangular, trapezoidal, and multisegmented polygon defined stability limits were also calculated. Spearman’s rank correlation coefficient test results revealed significant medium-large correlations between anteroposterior and mediolateral time-to-boundary scores calculated using both the mean and SD of the 10 absolute time-to-boundary minima and of all the time-to-boundary minima. Friedman test results revealed significant mediolateral time-to-boundary differences between boundary shape definitions. Follow-up Wilcoxon signed rank test results revealed significant differences between the rectangular boundary shape and both the trapezoidal and multisegmented polygon shapes during the eyes open and eyes closed conditions when both the mean and the SD of the time-to-boundary minima were used to represent postural stability. Significant differences were also revealed between the trapezoidal and multisegmented polygon definitions during the eyes open condition when the SD of the time-to-boundary minima was used to represent postural stability. Based on these findings, the overall results (i.e., stable versus unstable participants or groups) of studies computing postural stability using different minima selection can be compared. With respect to boundary shape, the trapezoid or multisegmented polygon shapes may be more appropriate than the rectangular shape as they more closely represent the anatomical shape of the stance foot.

This paper shows how the risk of price declines in stock market investments can be reduced by using a sequential signal system to determine when to buy or sell. The signals are based on growth rates in long-leading indexes and in broad stock price indexes. Tests of the method during the past 20 years or more are shown for Australia, France, Germany, Japan, the UK and the USA. In some instances the reduction in risk (measured in terms of volatility of rates of return) is achieved at the cost of a lower average rate of return, but in other cases the average rate of return may be significantly higher than that obtained by a simple buy-and-hold strategy.

Altered expression of dystrophin led to a reduction in the myocardial PCr to ATP ratio in MD carriers and BMD patients. Decreased myocardial PCr was also observed in the mouse model of MD, themdx mouse, which had decreased myocardial glucose uptake in response to insulin and during ischaemia, with increased susceptibility to ischaemic damage. However, utrophin transgene expression corrected the functional and metabolic abnormalities in the dystrophin-deficient mouse heart. To our knowledge, this is the first report of beneficial effects resulting from the expression of a dystrophin-related transgene in heart, making the findings important for the use of gene therapy in the treatment of cardiomyopathy in dystrophic patients.

This report describes and analyzes a practical system which will assist financial analysts and portfolio managers to maximize the annual rate of return in their asset-allocation program when choosing between stocks, short-term bills and long-term bonds. The level and stability of the total rates of return (from capital gain or loss and dividends or interest) are compared for various investment strategies. Our objective is achieved by developing, with the aid of new long-leading indexes, a method of forecasting the beginning and end of major bull markets in stock prices. During bear-market periods the choice between short-term bills and long-term bonds is governed by signals from a leading index of inflation. The paper reports the findings for Australia, Japan, the United Kingdom, the United States and West Germany.

Background: Chronic heart failure (CHF) is associated with abnormalities of skeletal muscle metabolism. This may be due to impaired oxygen delivery as a result of endothelial dysfunction. Aims: We postulated that ascorbic acid would improve oxygen delivery to exercising muscle and improve skeletal muscle metabolism. Methods: We studied skeletal muscle metabolism using 31P magnetic resonance spectroscopy in 39 CHF patients. Endothelial function was assessed by changes in pulse wave velocity. Subjects were randomised to receive 4g ascorbic acid daily for 4weeks in a placebo-controlled double-blind study. Results: Ascorbic acid significantly increased phosphocreatine utilization during exercise. In addition, glycolytic ATP synthesis increased in the ascorbic acid group (change in rate of ATP synthesis at 1min −0.21±0.76 with placebo, 2.06±0.60 following ascorbic acid; p

The vascular system exhibits altered growth, calcium responses and metabolism during hypertension. To relate such changes, we compared histological, tension and metabolic responses in the aorta from 32-week-old spontaneously hypertensive rats (SHRs), normotensive Wistar-Kyoto (WKY) rats, and SHRs treated with Verapamil (V) and ACE-inhibitor, Trandolapril (T) as well as a combination of the two treatments (C). Vascular hypertrophy was apparent in the SHRs. Contractile responses induced by 50 mmol/1 KCl and 2.5 mmol/1 Ca2+ were significantly lower in the SHR (64.4 mN/mm2 vs. 49.2 mN/mm2), but an associated increase in Ca2+ -sensitivity (EC50 of extracellular Ca2+ (mumol/1): SHR, 456 vs. WKY, 616) normalised tension generating ability. All treatments led to significant decreases in blood pressure, although only T and C treated animals became normotensive with concomitant normalisation of vascular hypertrophy. An increase in oxygen consumption was apparent in the SHR aorta, which was associated with significant differences in the activities of key metabolic enzymes. Anti-hypertensive treatment normalised many of the metabolic parameters, with the C therapy being the most efficacious. We conclude that the treatment of hypertension by combined therapy leads to a better normalisation of structural, contractile, and metabolic parameters in the SHR, than either treatment alone and that metabolic changes with the pathology are resolved with appropriate therapy.

The increased use of creatine by athletes as a dietary supplement to improve their physical performance assumes that increased serum creatine levels will increase intracellular skeletal muscle creatine. Despite this common assumption, skeletal muscle creatine uptake awaits full characterization. Consequently, we have investigated 14 C-labelled creatine uptake in isolated, incubated rat soleus (type I) muscle preparations at 37 °C. We found that the apparent K m for creatine uptake was 73 μM and the V max was 77 nmol h -1 gww -1 . Creatine uptake was 82% inhibited by 2 mM β-guanidinopropionic acid, the structural analogue of creatine. In addition, a decrease in buffer Na + concentration, from 145 to 25 mM, reduced the rate of 14 C-labelled creatine uptake by 77%, indicating that uptake is largely Na + -dependent in soleus muscle. Insulin had no effect on the rate of creatine uptake in vitro. The total creatine content was 34% lower, but the rate of creatine uptake in the presence of 100 μM extracellular creatine was 45% higher, in soleus than in extensor digitorum longus (type II) muscle. However, at 1 mM extracellular creatine, the maximal rate of uptake was not significantly different for the two muscle types, implying that soleus muscle has a lower K m for creatine uptake. We suggest that intracellular creatine levels may play a role in the regulation of skeletal muscle creatine uptake.

This chapter discusses that 31P NMR allows measurement of changes in creatine phosphate (PCr) during muscle stimulation and metabolic manipulation as well as in diseased muscle. The ratio of PCr to Adenosine Tri Phosphate (ATP) reflects the status of cellular energetics. This ratio changes from tissue to tissue under normal healthy conditions and is, therefore, an indication of tissue type. Skeletal muscle has the largest ratio followed by heart, whilst the ratio is lowest in vascular smooth muscle. The PCr/ATP ratio also changes within tissues to give an index of tissue function or disease. Creatine analogues can affect the muscle PCr. The chronic and acute changes seen in the energetic profile of the tissue exposed to 3-guanidinopropionic acid (β-GPA) further explains the importance of PCr in muscle function. The PCr metabolism is important to normal cellular function and that as such it is tightly regulated in muscular tissue.

The relationship between substrate and metabolism in vascular smooth muscle has been investigated by studying the acute energetic effects caused by the creatine analogue beta-guanidinopropionic acid (beta-GPA) on porcine carotid arteries using 31P-nuclear magnetic resonance (NMR). Porcine carotid arteries were superfused for 12 h with Krebs-Henseleit buffer at 22 degrees C, containing 50 mM beta-GPA, and either 11 mM glucose or 5 mM pyruvate as substrate. beta-GPA enters the cells and becomes phosphorylated by creatine kinase to produce beta-GPA-P. Perfusion with beta-GPA leads to the formation of NMR observable beta-GPA-P (after 2.5 h). The appearance of beta-GPA-P with time was significantly greater when glucose was used as substrate. To differentiate between oxidative and glycolytic metabolism in the phosphorylation of beta-GPA, 1 mM cyanide was included in the perfusion buffer containing 50 mM beta-GPA and 11 mM glucose. No phosphocreatine (PCr) was observed with these conditions, and there was a small but significant decrease in ATP concentration ([ATP]) compared with glucose perfusion without cyanide (0.56 +/- 0.02 to 0.47 +/- 0.02 mumol/g wet wt), that was greater than the concentration with pyruvate as substrate (0.25 +/- 0.03 mumol/g wet wt). Thus the [ATP] during cyanide treatment is maintained with glycolytic metabolism. Despite the relatively high [ATP], accumulation of beta-GPA-P only occurred over a much slower time course ( > 10 h) than without cyanide.(ABSTRACT TRUNCATED AT 250 WORDS)

The action of the creatine analogue beta-guanidinopropionic acid (beta-GPA) was examined in rat heart mitochondria and in isolated cardiomyocytes or fibres which were permeabilized with the non-ionic detergent saponin to determine the kinetics of mitochondrial creatine kinase for beta-GPA. Fibres and myocytes were subjected to increasing [ADP] in the presence and absence of beta-GPA or creatine, whereas isolated mitochondria received a similar protocol with increasing [ATP]. In isolated mitochondria given ATP, there was a stimulation of respiration by creatine, but no significant stimulation of respiration by beta-GPA. Further studies on fibres from control and beta-GPA-fed rats also found that beta-GPA is not utilized by the mitochondria, as evidenced by a lack of beta-GPA-stimulated respiration (Km for ADP = 142 +/- 23 microM) compared with control (Km for ADP from 161 +/- 23 microM), but no significant change in Vmax. Therefore the rat heart mitochondria are not responsive to beta-GPA as compared with creatine. Interestingly, the fibres from beta-GPA-fed rats had no creatine- or beta-GPA-stimulated respiration (Km for ADP = 57.3 +/- 7.2 microM for control, 54.2 +/- 7.2 microM with creatine, and 53.5 +/- 7.8 microM with beta-GPA). The mitochondria prepared from the hearts of rats exposed for 10 weeks to 1% beta-GPA in their diet had a significant decrease in Vmax. and a significant decrease in Km for ADP. Thus the hearts from beta-GPA-fed animals may be pathologic, due to a disruption of the creatine kinase energy circuit.

This article attempts to identify and describe the main characteristics of Australia'a business cycles during the period 1949 to 7984 with the aid of leading, coincident, and lagging indicators, using the methodology of the International Economic lndicator project at the Center for lnternational Business Cycle Research, Columbia University, New York. The methodology to identify Australia's classical cycle and growth cycle chronologies is discussed. Reviews are made of the lead-lag patterns of, first, both chronologies in relation to the specific cycles of the individual coincident indicators, and second, the growth chronology in relation to the leading and lagging indicators. Australia's growth cycle chronology is compared with the chronology of other countries, notably of United States, United Kingdom, and Japan. The general uses of an indicator analysis are reviewed. An appendix compares the reference cycle chronologies previously available for Australia and the indicators used to obtain them.

This paper exploits recently developed statistical techniques to examine the causal patterns in lag relationships between changes in wages and consumer prices. The analysis uses quarterly data for selected periods and a total historical sample period 1954-82. Causation has generally been unidirectional from wages to prices. However, for the first half of the 1970s bidirectional causation was detected, though the causation from wages to prices was statistically more significant. Brief consideration is given to some policy implications of the results.