Are adjunct treatments effective in improving pain and function when added to exercise therapy in people with patellofemoral pain? A systematic review with meta-analysis and appraisal of the quality of interventions.

OBJECTIVE: To compare the effectiveness of adjunct treatments combined with exercise to exercise alone in people with patellofemoral pain (PFP) and explore the quality of intervention descriptions in randomised controlled trials (RCTs). DESIGN: Systematic review. DATA SOURCES: Seven databases were searched in November 2023. ELIGIBILITY: RCTs that evaluated the effectiveness of any adjunct treatment combined with exercise to exercise alone on self-reported pain and function in people with PFP. RESULTS: We included 45 RCTs (2023 participants), with 25 RCTs (1050 participants) contributing to meta-analyses. Pooled analysis indicated very low-certainty evidence that neuromuscular electrical stimulation or monopolar dielectric diathermy combined with exercise leads to small and large improvements in self-reported pain when compared with exercise alone (standardised mean difference (95% CI)=-0.27 (-0.53 to -0.02) and -2.58 (-4.59 to -0.57), respectively) in the short-term. For self-reported pain and function, very low-certainty evidence indicates that knee taping, whole-body vibration, electromyographic biofeedback and knee brace combined with exercise do not differ from exercise alone. Interventions are poorly described in most RCTs, adjunct treatments scored on average 14/24 and exercise therapy 12/24 in the Template for Intervention Description and Replication checklist. CONCLUSION: Neuromuscular electrical stimulation and monopolar dielectric diathermy combined with exercise seem to improve self-reported pain in people with PFP compared with exercise alone. Knee taping, whole-body vibration, electromyographic biofeedback and knee brace do not offer additional benefits to exercise alone. Most interventions are poorly described, which is detrimental to translating research knowledge into clinical practice. PROSPERO REGISTRATION NUMBER: CRD42020197081.

Effect of augmented feedback on classical ballet jump kinematics: A single-blind randomized controlled trial.

BACKGROUND: Augmented feedback strategies have been demonstrated to enhance jump-related biomechanics. Nevertheless, its effect on classical ballet is still unknown. The purpose of this study was to investigate whether a multimodal augmented feedback session is effective for improving lower limb and trunk kinematics during a classical ballet single-leg jump. METHODS: In a single-blind randomized controlled trial, 36 amateur classical ballet dancers were randomly assigned to either a control group (n = 18) to receive a brief warm-up session, or an augmented feedback group (n = 18) to receive, in addition to a brief warm-up session, a combined visual feedback session associated with verbal instruction. Hip kinematics in the frontal and transversal planes and knee and trunk kinematics in the frontal plane were analysed at baseline, immediate post-intervention, and one-week post-intervention. Intervention effects were analysed using a two-way, mixed model, repeated-measures analysis of variance. RESULTS: No interaction effects were observed, indicating that a single session of multimodal augmented feedback was insufficient to improve lower limb and trunk kinematics during a classical ballet single-leg jump in amateur classical ballet dancers. CONCLUSION: A single session of multimodal augmented feedback should not be used as the sole component in prevention programs intended to improve jump-related kinematics in amateur classical ballet dancers.

Association of Proximal and Distal Factors With Lower Limb Kinematics During a Classical Ballet Jump.

CONTEXT: Excessive dynamic lower limb misalignment may predispose ballet dancers to jump-related injuries. However, it is unknown whether proximal and distal factors influence this movement pattern. The aim of this study was to investigate whether hip abduction strength, foot alignment, and ankle dorsiflexion range of motion (ROM) are associated with peak angles of hip adduction and internal rotation and knee abduction during the preparation and landing phases of a classical ballet jump. DESIGN: Cross-sectional study. METHODS: Forty-one healthy amateur ballet dancers were included. Hip abduction strength was evaluated isometrically using a handheld dynamometer, foot alignment was determined by the shank-forefoot alignment, and weight-bearing ankle dorsiflexion ROM was measured by performing the lunge test. Peak hip and knee angles were analyzed 3-dimensionally during the preparation and landing phases of a single-leg jump. A Pearson correlation matrix was used to investigate the association of hip abduction strength, shank-forefoot alignment, and ankle dorsiflexion ROM with peak angles of hip adduction and internal rotation and knee abduction during the preparation and landing phases of the jump. RESULTS: Greater hip abduction strength was associated with greater peak hip internal rotation angle (r = .43, P < .05), but not with peak hip adduction and knee abduction angles during the preparation phase of the jump. There were no associations of shank-forefoot alignment and ankle dorsiflexion ROM with peak hip and knee angles during the preparation (r = -.23 to .36, P > .05) and landing (r = -.20 to .24, P > .05) phases of the jump. There was no association of hip abduction strength with peak hip and knee angles during the landing phase of the jump (r = -.28 to .16, P > .05). CONCLUSION: Hip abductors strengthening, correction of foot misalignments, and increasing ankle dorsiflexion ROM may not prevent excessive hip and knee movements during a classical ballet single-leg jump in amateur dancers.

Immediate effects of hip strap and foot orthoses on self-reported measures and lower limb kinematics during functional tasks in individuals with patellofemoral osteoarthritis: protocol for a randomised crossover clinical trial.

BACKGROUND: Elevated patellofemoral joint stress has been associated with patellofemoral osteoarthritis (PFOA). Changes in lower limb kinematics, such as excessive femoral adduction and internal rotation and excessive rearfoot eversion during the stance phase of functional activities, may increase patellofemoral stress. There is a lack of studies that assess the effects of interventions for controlling femur and subtalar joint movements during functional activities on self-reported measures in individuals with PFOA. Thus, the primary aim of the study is to determine the immediate effects of the hip strap and foot orthoses during level-ground walking and the single-leg squat test on self-reported outcomes. The secondary aim is to investigate whether the hip strap and foot orthoses result in the kinematic changes that these devices are purported to cause. METHODS: Twenty-nine individuals with PFOA aged 50 years or older will take part in the study. The main outcome is pain intensity. The secondary outcomes are other self-reported measures (global rating of change, acceptable state of symptoms, ease of performance, and confidence) and lower limb kinematics (peak femoral adduction and internal rotation, and peak rearfoot eversion). These outcomes will be assessed during functional tasks performed under three conditions: (i) control condition, (ii) hip strap intervention, and (iii) foot orthoses intervention. To investigate whether these interventions result in the lower limb kinematic changes that they are purported to cause, three-dimensional kinematics of the femur and rearfoot will be captured during each task. Linear mixed models with two fixed factors will be used to test associations between the interventions (control, hip strap, and foot orthoses) and conditions (level-ground walking and single-leg squat test) as well as interactions between the interventions and conditions. DISCUSSION: To the best of the authors' knowledge, this is the first study to evaluate the immediate effects of the hip strap and foot orthoses on self-reported measures and lower limb kinematics during functional tasks in individuals with PFOA. The findings of this study will enable future trials to investigate the effects of these interventions in rehabilitation programmes. TRIAL REGISTRATION: ClinicalTrials.gov NCT04332900 . Registered on 3 April 2020.

Are Altered Kinematics in Runners With Patellofemoral Pain Sex Specific?

BACKGROUND: Altered kinematics have been frequently observed in runners with patellofemoral pain (PFP), and few studies have aimed to understand the influence of sex on kinematics of this population. The aim of this study was to investigate whether altered hip and knee kinematics in runners with PFP are sex specific. HYPOTHESIS: Kinematics will be different between female and male runners with and without PFP. STUDY DESIGN: Case-control study. LEVEL OF EVIDENCE: Level 2. METHODS: Eighty-four runners were divided into 4 groups: 42 runners with PFP (20 women, 22 men) and 42 asymptomatic runners (21 women, 21 men). Three-dimensional gait analyses of the hip in the frontal and transverse plane and the knee in the frontal plane were analyzed at self-selected running speed on a treadmill. One-way analysis of covariance was used to test for differences in kinematic variables between groups. RESULTS: Women with PFP ran with a significantly greater peak hip adduction compared with men with PFP (mean difference [MD] = 4.45°; P = 0.00; effect size [ES] = 0.58) and male control subjects (MD = 4.2°; P = 0.01; ES = 0.54) and greater hip adduction range of motion (ROM) than men with PFP (MD = 3.44°; P = 0.01; ES = 0.49). No significant differences were identified between women with and without PFP. Female control subjects ran with greater peak hip adduction than men with PFP (MD = 5.46°; P < 0.01; ES = 0.58) and male control subjects (MD = 5.21°; P < 0.01; ES = 0.55); greater hip adduction ROM than men with PFP (MD = 4.02°; P = 0.00; ES = 0.52) and male control subjects (MD = 2.91°;P = 0.04; ES = 0.36); and greater peak knee abduction than men with PFP (MD = 3.35°; P = 0.02; ES = 0.44) and male control subjects (MD = 3.69°; P = 0.01; ES = 0.4). CONCLUSION: Women have greater hip adduction than men regardless of the presence of PFP. There were no kinematics difference between women with and without PFP. Comparisons of hip internal rotation between all groups were nonsignificant. CLINICAL RELEVANCE: Altered hip and knee kinematics does not appear to be sex specific in runners with PFP.

Effectiveness of adjunctive treatment combined with exercise therapy for patellofemoral pain: a protocol for a systematic review with network meta-analysis of randomised controlled trials.

INTRODUCTION: Patellofemoral pain (PFP) is a chronic condition that affects up to 25% of the general population and has a negative impact on functionality and quality of life due to the high levels of pain experienced by these patients. In order to improve pain and function, rehabilitation programmes that combine adjunctive treatments with exercise therapy are often used in research and clinical settings. However, despite the variety of adjunctive treatments available, their effectiveness when compared with exercise therapy has yet to be elucidated. Thus, the aim of this study is to evaluate the effectiveness of adjunctive treatments plus exercise therapy versus exercise therapy, and determine the relative efficacy of different types of adjunctive treatments plus exercise therapy for individuals with PFP. METHODS AND ANALYSIS: A systematic review and network meta-analysis will be conducted based on the Cochrane Collaboration recommendations and reported in line with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. We will search Embase, PubMed (MEDLINE), CENTRAL, CINAHL, PEDro, SPORTDiscus, Web of Science and OpenGrey. It will be included randomised controlled trials that compared adjunctive treatment plus exercise therapy to placebo adjunctive treatment plus exercise therapy or exercise therapy. The outcomes of interest will be pain and function, with no restrictions on language, setting or year of publication. Study selection will be performed by two independent reviewers, based on the eligibility criteria. Risk of bias will be assessed using the Physiotherapy Evidence Database scale and the evidence summarised via the Grading of Recommendation, Assessment, Development and Evaluation approach. A Bayesian network meta-analysis will be performed to compare the efficacy of different adjunctive treatments plus exercise therapy. Consistency between direct and indirect comparisons will be assessed. ETHICS AND DISSEMINATION: No ethical statement will be required for this systematic review and meta-analysis. The findings will be published in a relevant international peer-reviewed journal and presented at conferences. PROSPERO REGISTRATION NUMBER: CRD42020197081.

Frontal plane biomechanics during single-leg squat and hip strength in patients with isolated patellofemoral osteoarthritis compared to matched controls: A cross-sectional study.

The patellofemoral compartment of the knee is the most frequently affected by osteoarthritis. However, there is a lack of biomechanics studies on patellofemoral osteoarthritis (PFOA). This study's purpose was to compare the frontal plane biomechanics of the trunk and lower limb during the single-leg squat and isometric hip abductor torque in individuals with isolated PFOA and controls. Frontal plane kinematics during the single-leg squat were evaluated using a three-dimensional (3-D) motion analysis system. Isometric hip abductor torque was determined using a handheld dynamometer. Twenty individuals participated in the study (10 with PFOA and 10 controls). No significant differences between groups were found regarding age (mean ± SD, PFOA group = 51.8 ± 6.9 versus control group = 47.8 ± 5.5; mean difference = 4, 95% confidence interval [CI] = -1.9 to 9.9, p = 0.20) or body mass index (PFOA group = 27.6 ± 2.2 versus control group = 25.5 ± 2.5; mean difference = 2.1, 95% confidence interval [CI] = -0.1 to 4.3, p = 0.06). Compared to control, the PFOA group presented greater hip adduction in the descending and ascending phases of the single-leg squat at 45° (mean difference [95% CI] = 6.44° [0.39-12.48°], p = 0.04; mean difference [95% CI] = 5.33° [0.24-10.42°], p = 0.045, respectively) and 60° (mean difference [95% CI] = 8.44° [2.15-14.73°], p = 0.01; mean difference [95% CI] = 7.58° [2.1-13.06°], p = 0.009, respectively) of knee flexion. No significant differences between groups were found for the frontal plane kinematics of the trunk, pelvis or knee (p > 0.05). The PFOA group exhibited lower isometric hip abductor torque (mean difference [95% CI] = -0.34 Nm/kg [-0.67 to -0.01 Nm/kg], p = 0.04). The individuals with PFOA presented greater hip adduction than the control group, which could increase lateral patellofemoral joint stress at 45° and 60° of knee flexion in the descending and ascending phases of the single-leg squat. These individuals also exhibited hip abductor weakness in comparison to healthy controls.

Interventions used by Brazilian physiotherapists in the rehabilitation of patellofemoral pain: A web-based survey.

BACKGROUND: No studies have evaluated whether interventions used by Brazilian physiotherapists for the treatment of patellofemoral pain (PFP) are in line with the best existing scientific evidence. OBJECTIVES: Identify the interventions most commonly used by Brazilian physiotherapists for the rehabilitation of PFP and determine whether characteristics of physiotherapists and knowledge regarding evidence-based practice (EBP) influence the choice of interventions. DESIGN: Cross-sectional web-based survey. METHODS: Brazilian physiotherapists who treat patients with PFP participated in the study. Characteristics of the participants, information regarding EBP and interventions used in the treatment of PFP were collected through an online questionnaire. Descriptive analysis of the data was performed. Logistic regression analysis was employed to investigate associations between the interventions and both the characteristics of the physiotherapists and their knowledge regarding EBP. RESULTS: One hundred and ninety-four physiotherapists completed the questionnaire, 97.4% of whom reported using combined hip and quadriceps strengthening exercises, whereas only 25.3% reported using foot orthoses. A significant number of physiotherapists also reported using interventions that are not recommended (such as patellar mobilization, lumbar, hip and knee mobilization/manipulation and biophysical agents). Physiotherapists with a master's or doctoral degree and those who were aware of clinical practice guidelines were respectively 2.57-fold and 3.81-fold more likely to use recommended interventions. CONCLUSION: Most Brazilian physiotherapists choose interventions that are in line with current scientific evidence. However, a significant number also use interventions that are not recommended for the treatment of PFP.

Association of Ankle Dorsiflexion and Landing Forces in Jumping Athletes.

BACKGROUND: Dorsiflexion range of motion restriction has been associated with patellar tendinopathy, but the mechanisms of how dorsiflexion restriction could contribute to knee overload remain unknown. HYPOTHESIS: Peak ankle dorsiflexion and ankle dorsiflexion excursion are negatively associated with peak vertical ground-reaction force (vGRF) and loading rate, and with peak patellar tendon force and loading rate, and positively associated with peak ankle plantar flexor moment. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 4. METHODS: Kinematic and kinetic data of 26 healthy recreational jumping athletes were measured during a single-leg drop vertical jump. Pearson's correlation coefficients were calculated to establish the association between peak ankle dorsiflexion and ankle dorsiflexion excursion with peak vGRF and vGRF loading rate, with peak patellar tendon force and patellar tendon force loading rate, and with peak ankle plantar flexor moment. RESULTS: Ankle dorsiflexion excursion negatively correlated with peak vGRF loading rate (r = -0.49; P = 0.011) and positively correlated with peak ankle flexor plantar moment (r = 0.52; P = 0.006). In addition, there was a positive correlation between peak ankle dorsiflexion and peak vGRF (r = 0.39; P = 0.05). CONCLUSION: Ankle kinematics are associated with vGRF loading rate, ankle flexor plantar moment and peak vGRF influencing knee loads, but no association was observed between ankle kinematics and patellar tendon loads. CLINICAL RELEVANCE: These results suggest that increasing ankle dorsiflexion excursion may be an important strategy to reduce lower limb loads during landings but should not be viewed as the main factor for reducing patellar tendon force.

Adding muscle power exercises to a strength training program for people with patellofemoral pain: protocol of a randomized controlled trial.

BACKGROUND: Strong evidence supports the proximal combined with quadriceps strengthening for patellofemoral pain (PFP) rehabilitation. However, most reported rehabilitation programs do not follow specific exercise prescription recommendations or do not provide adequate details for replication in clinical practice. Furthermore, people with PFP have power deficits in hip and knee muscles and it remains unknown whether the addition of power exercises would result in superior or more consistent outcomes. Therefore, this study is designed to verify whether the benefits of a rehabilitation program addressing proximal and knee muscles comprising power and strength exercises are greater than those of a program consisting of strength exercises only. METHOD: This study will be a randomized controlled trial that will be conducted at university facilities. A minimum of 74 people with PFP between the ages of 18 and 45 years will be included. The experimental group will engage in a 12-week resistance training program focusing on proximal and knee muscles using power and strength exercises. The control group will engage in a 12-week resistance training program focusing on proximal and knee muscles using strength exercises only. Primary outcomes will be pain intensity and physical function; and secondary outcomes will be kinesiophobia, self-reported improvement, quality of life, peak hip and knee torque, and hip and knee rate of force development. The primary outcomes will be evaluated at baseline, and after 6 weeks, 12 weeks, 3 months, 6 months, and 1 year. The secondary outcomes will be evaluated at baseline and immediately after the interventions. Therapists and participants will not be blinded to group allocation. DISCUSSION: This randomized clinical trial will investigate if adding power exercises to a progressive resistance training may lead to more consistent outcomes for PFP rehabilitation. The study will provide additional knowledge to support rehabilitation programs for people with PFP. TRIAL REGISTRATION: ClinicalTrials.gov NCT03985254. Registered on 26 August 2019.

Impaired muscle capacity of the hip and knee in individuals with isolated patellofemoral osteoarthritis: a cross-sectional study.

AIMS: The aims of this study were to compare the capacity of the knee and hip muscles between individuals with and without isolated patellofemoral osteoarthritis (PFOA) and to evaluate the impact of PFOA on pain, stiffness, and physical function. METHODS: This cross-sectional study evaluated muscle capacity of the hip and knee using an isokinetic dynamometer. The isokinetic variables used in the statistical analysis were peak torque, total work, and average power. Pain, stiffness, and physical function were assessed using questionnaires. RESULTS: A total of 26 individuals participated in the study (13 with PFOA and 13 controls). The PFOA group exhibited lower peak torque, total work, and average power for knee extension and flexion in the concentric mode (p ⩽ 0.01) as well as lower peak torque and total work for knee extension (p ⩽ 0.005) and lower total work for knee flexion (p = 0.05) in the eccentric mode. The PFOA group exhibited lower peak torque of the extensor, abductor, adductor, and internal rotator muscles of the hip (p ⩽ 0.05), less total work of the abductor and adductor muscles (p ⩽ 0.04), and lower average power of eccentric adduction of the hip (p = 0.01) compared with the healthy controls. Compared with the control group, the PFOA group had a higher level of pain, stiffness, and compromised physical functioning self-reported (p ⩽ 0.005). CONCLUSION: Participants with PFOA exhibited impairments regarding muscle capacity of the hip and knee, higher level of pain and stiffness as well as compromised physical functioning in comparison with healthy controls.

Are hip and knee kinematics and training load characteristics relate to pain intensity and physical function level in runners with Patellofemoral Pain?

BACKGROUND: Patellofemoral pain (PFP) is the most common running-related injury. Altered hip and knee kinematics and increases in weekly distance and running pace are often associated with PFP development and exacerbation. RESEARCH QUESTION: Are altered movements and training load characteristics (weekly distance and running pace) relate to pain intensity or physical function level in runners with PFP? METHODS: Forty recreational runners with PFP (20 males and 20 females) participated in this cross-sectional observational study. Three-dimensional hip and knee kinematics were quantified during the stance phase of running. Weekly distance was defined as the average weekly kilometers of running and running pace as the average pace of the activity measured as minutes per kilometer. A visual analogue scale was used to evaluate worst knee pain during the last week. The anterior knee pain scale (AKPS) was used to evaluate knee functional score. A Pearson correlation matrix was used to investigate the association between each dependent variable (worst pain in the last week and AKPS score) and the independent variables (knee and hip kinematics, weekly distance and running pace). RESULTS: There was no significantly correlation between kinematic variables, pain and functional score for both males and females separately and combined. Weekly distance (km/week) was found to positively correlate to pain intensity (r = 0.452; p < 0.05) in females with PFP. A simple linear regression revealed that weekly distance was significant predictor emerged of pain in females with PFP. Females exhibited significantly greater peak hip adduction and hip adduction ROM than the males and males had significantly greater running pace compared to females. SIGNIFICANCE: Weekly distance should be considered in the clinical context during rehabilitation of PFP in females runners aiming at pain reduction.

Interventions used for Rehabilitation and Prevention of Patellar Tendinopathy in athletes: a survey of Brazilian Sports Physical Therapists.

OBJECTIVES: (1) To identify the type and frequency of interventions used by Brazilian physical therapists to treat and prevent the occurrence of patellar tendinopathy in athletes and the criteria used to return to sport; (2) to compare the interventions used to the grade of recommendation of current evidence. METHODS: Design: cross-sectional study. SETTING: online survey throughout sports physical therapy association. PARTICIPANTS: Physical therapists who were invited to complete a structured questionnaire. MAIN OUTCOME MEASURES: Interventions more frequently used for treating and preventing PT in athletes and the criteria used to define return to sport. RESULTS: One-hundred and twenty-one physical therapists participated in this study. Quadriceps eccentric strengthening (75.2%), education (61.2%) and lower limb joint/lumbo-pelvic stabilization/hamstrings stretching (59.5%) were more frequently cited for prevention purposes, while lower limb joint stabilization (81.8%), education (80.2%) and myofascial release (78.5%) were more frequently reported for treatment. The majority of the physical therapists based their decision of athlete discharge on a combination of pain intensity, function and functional test results (44.6%). CONCLUSION: There was inconsistency between interventions used in clinical practice and interventions recommended by the best available evidence.

Acute Effects of Hip Mobilization With Movement Technique on Pain and Biomechanics in Females With Patellofemoral Pain: A Randomized, Placebo-Controlled Trial.

CONTEXT: People with patellofemoral pain (PFP) present altered lower-limb movements during some activities. Perhaps, joint misalignment in the hip is one of the reasons for altered movement patterns in people with PFP. Some mobilization techniques have been designed to address joint misalignments. OBJECTIVE: To investigate the acute effects of hip mobilization with movement (MWM) technique on pain and biomechanics during squats and jumps in females with and without PFP. DESIGN: Randomized, placebo-controlled trial. SETTING: Movement analysis laboratory. PATIENTS: Fifty-six physically active females (28 with PFP and 28 asymptomatic) were divided into 4 groups: experimental group with PFP, sham group with PFP, experimental group without PFP, and sham group without PFP. INTERVENTION(S): The experimental groups received MWM for the hip, and the sham groups received sham mobilization. MAIN OUTCOME MEASURES: Pain, trunk, and lower-limb kinematics, and hip and knee kinetics during single-leg squats and landings. RESULTS: After the interventions, no difference between groups was found for pain. The PFP experimental group decreased hip internal rotation during squats compared with the PFP sham group (P = .03). There was no other significant difference between PFP groups for kinematic or kinetic outcomes during squats, as well as for any outcome during landings. There was no difference between asymptomatic groups for any of the outcomes in any of the tasks. CONCLUSIONS: Hip mobilization was ineffective to reduce pain in people with PFP. Hip MWM may contribute to dynamic lower-limb realignment in females with PFP by decreasing hip internal rotation during squats. Therefore, hip MWM could be potentially useful as a complementary intervention for patients with PFP.

People with patellofemoral pain have impaired functional performance, that is correlated to hip muscle capacity.

OBJECTIVE: To (i) compare objective function in a range of tasks between people with and without patellofemoral pain (PFP); and (ii) evaluate the relationship of objective function with hip muscle capacity and self-reported function in people with PFP. DESIGN: Cross-sectional. SETTINGS: Laboratory. PARTICIPANTS: Thirty-two physically active people (16 with PFP and 16 controls). MAIN OUTCOME MEASURES: Functional assessments included stair climbing (time), single-legged chair stand (repetitions), step down (repetitions), forward hop for distance and side hop (repetitions). Hip abductor and extensor capacity assessments included power, endurance, isometric and dynamic strength. Self-reported function included the Kujala scale and Patellofemoral sub-scale of the Knee injury and Osteoarthritis Outcome Score (KOOS-PF). RESULTS: The PFP group was 15% slower climbing stairs (effect size [ES] = 0.90), performed 12% fewer chair stands (ES = 0.62) and forward hopped 20% shorter (ES = 0.79) compared to controls. Lower hip muscle strength and power correlated with lower objective function (r = 0.52-0.78). Lower Kujala scores correlated with longer stair climbing time (r = -0.53). CONCLUSION: People with PFP have objective functional impairments, that are associated with reduced hip muscle capacity, indicating progressive resistance training may be beneficial. Absence of a strong correlation between self-reported, and objective, function indicates assessment of both when treating people with PFP is warranted.

Relationship between the architecture and function of ankle plantar flexors with Achilles tendon morphology in ballet dancers.

Achilles tendinopathy is the most frequent foot overuse injury in ballet dancers and knowledge of clinically modifiable factors related to tendon structure in a population at risk, such as ballet dancers, would be important for the development of preventive programs. Therefore, the present study aimed to assess relationships of gastrocnemius muscle architecture and ankle plantar flexors function with Achilles tendon morphology in ballet dancers. Fifty-four measures from 27 ballet dancers were collected. Tendon morphology (thickness, echogenicity, hypoechoic areas and neovascularisation) and muscle architecture (thickness, pennation angle and fascicle length) were evaluated using ultrasonography; ankle plantar flexors torque was evaluated using hand-held dynamometry, flexibility was evaluated in maximal weight-bearing ankle dorsiflexion position using inclinometer, and endurance was evaluated using the heel rise test. Ankle plantar flexors torque and medial gastrocnemius muscle architecture (thickness, pennation angle and fascicle length) are associated with Achilles tendon thickness in ballet dancers (r2 = 0.24, p = 0.008). Ankle plantar flexors torque and medial gastrocnemius muscle fascicle length are also associated with the echogenicity of the Achilles tendon (r2 = 0.13, p = 0.03). These findings call attention to the potential importance of ankle plantar flexors muscle force in healthy ballet dancers for the prevention of alterations in Achilles tendon structure.

Patellofemoral joint stress measured across three different running techniques.

BACKGROUND: Patellofemoral pain (PFP) is the most common running-related injury. It has been shown in previous studies that gait retraining may have a beneficial effect on patellofemoral joint stress (PFJS). RESEARCH QUESTION: Is there a reduction of PFJS across 4 running conditions: 1. runner's typical rearfoot strike pattern, 2. forefoot landing, 3. step rate increase by 10% and 4. forward trunk lean? METHODS: Nineteen healthy runners (28.05 ± 5.03 years; 26.58 ± 8.85 km/week, 6.00 ± 4.51 years of running experience) completed one running trial for each condition, at the same subject-specific comfortable speed on a treadmill. Kinetic and kinematic data were collected and measures of hip, knee and ankle joint moments and PFJS were calculated. RESULTS: Compared to rearfoot strike condition, peak PFJS and PFJS-time integral per step were significantly (P < 0.01) lower during forefoot landing and step rate increase conditions. PFJS per kilometer was significantly reduced for forefoot landing (17.01%; P < 0.01) and increased step rate (12.90%; P = 0.003). Forward trunk lean technique showed no significant differences in peak PFJS (P = 0.187), PFJS-time integral per step (P = 0.815) and PFJS per kilometer (P = 0.077) compared to rearfoot strike pattern. INTERPRETATION: The comparison between techniques revealed greater reductions on PFJS by forefoot landing, followed by 10% step rate increase condition. These changes were the result of different lower limb movement strategies across the 2 running conditions. We conclude that compared to a rearfoot strike pattern, both a forefoot landing and step rate increase result in lower cumulative PFJS joint stress in healthy runners, with the forefoot landing being the most effective. These running technique modifications could be recommended to reduce PFJS loads and may have implications for PFP prevention.

Clinically measured hip muscle capacity deficits in people with patellofemoral pain.

OBJECTIVE: To evaluate differences in clinical measures of hip abductor and extensor capacity (strength, endurance and power) in people with patellofemoral pain (PFP) compared to asymptomatic controls. DESIGN: Cross-sectional. SETTINGS: Laboratory. PARTICIPANTS: Thirty-two physically active people (16 with PFP and 16 controls). MAIN OUTCOME MEASURES: Strength was evaluated isometrically using a hand-held dynamometer and dynamically using 10 repetitions maximum (10RM) tests. Power was assessed using a linear position transducer. Endurance was assessed using maximum number of repetitions. RESULTS: The PFP group had significant deficits compared to the control group in isometric strength (21-25%) for hip abduction (ES = 0.98) and extension (ES = 0.85); in 10RM (15-18%) for hip abduction (ES = 0.72) and extension (ES = 0.85); and in power (24-31%) for hip abduction (ES = 0.80), and extension (ES = 0.94). No difference was identified for hip abduction and extension in endurance tests. CONCLUSION: Clinical assessments can identify deficits in isometric and dynamic hip strength, as well as power in people with PFP. Hip muscle capacity deficits in people with PFP including strength and power highlight a potential need for more progressive resistance training in this population.

Comparison of the effects of fatigue on kinematics and muscle activation between men and women after anterior cruciate ligament reconstruction.

OBJECTIVES: Studies comparing the effects of fatigue between men and women after anterior cruciate ligament (ACL) reconstruction are lacking. The purpose of this study was to compare the effects of muscle fatigue on trunk, pelvis and lower limb kinematics and on lower limb muscle activation between male and female athletes who underwent ACL reconstruction. DESIGN: Cross-sectional study. SETTING: Laboratory setting. PARTICIPANTS: Fourteen recreational athletes (7 males and 7 females) with unilateral ACL reconstruction participated of this study. MAIN OUTCOME MEASURES: Trunk, pelvis and lower limb kinematics and muscle activation of the vastus lateralis, gluteus medius and gluteus maximus were evaluated during a single-leg drop vertical jump landing before and after a fatigue protocol. RESULTS: Females had greater peak knee abduction after fatigue in relation to before fatigue (P = 0.008), and in relation to men after fatigue (P = 0.011). Also, in females, peak knee abduction was greater in the reconstructed limb in relation to the non-reconstructed limb after fatigue (P = 0.029). Males showed a greater mean amplitude of activation of the vastus lateralis muscle after fatigue in relation to before fatigue (P < 0.001). CONCLUSIONS: Muscle fatigue produced kinematic alterations that have been shown to increase the risk for a second ACL injury in female athletes.

Relationship between rearfoot, tibia and femur kinematics in runners with and without patellofemoral pain.

BACKGROUND: Patellofemoral pain (PFP) is the most common running overuse injury. Excessive rearfoot eversion is commonly considered as a PFP risk factor and the relationship between ankle-foot complex movement and lower limb may be involved with this dysfunction. The purpose of this study was to evaluate the correlation between rearfoot eversion with tibia and femur kinematics in frontal and transverse planes during running in individuals with and without PFP. The secondary purpose was to compare the lower limb kinematics between runners with and without PFP. METHODS: Fifty-four recreational runners were divided into 2 groups: healthy runners (CG, n = 27) and runners with patellofemoral pain (PFPG, n = 27). Kinematics during running were assessed using three-dimensional motion analysis system. Pearson's correlation coefficients (r) were calculated to establish the correlation of rearfoot eversion with tibial and femur movements. FINDINGS: Greater peak rearfoot eversion was correlated with greater peak femur adduction in PFP runners. Greater peak rearfoot eversion was correlated with greater peak tibial internal rotation and tibial adduction in the PFPG and CG. Additionally, greater peak rearfoot eversion was correlated with greater tibial internal rotation range of motion in the PFPG and CG. No significant differences were found between the PFPG and CG for all kinematics variables. INTERPRETATION: Correlation between greater rearfoot eversion and greater peak hip adduction in the PFPG might be related to PFP persistence in runners with excessive rearfoot eversion, and indicates that treatment strategies aimed at controlling the movement of the rearfoot could help modify the symptoms.