Effects of neuromuscular electrical stimulation on patellofemoral pain: A randomized controlled trial.

INTRODUCTION: Patellofemoral Pain (PFP) is a common dysfunction that can compromise the performance of daily activities. Neuromuscular electrical stimulation (NMES) has been proposed as a complementary tool in the therapeutic approach. OBJECTIVE: To analyze the effects of adding NMES to therapeutic exercises in women with PFP. METHODS: Randomized controlled trial involving 34 women with PFP (mean age 23.8 ± 4.1), randomly assigned to two groups: exercises combined with NMES (ESG) and exercises only (ExG). The ExG followed an exercise protocol, while the ESG performed the same exercises combined with NMES. Interventions were performed twice a week for eight weeks. Primary outcome measures included pain and functional disability, while secondary outcomes encompassed electromyographic activity of the quadriceps and hip abductors, along with isokinetic performance. Assessments were performed before the intervention, after 4 and 8 weeks from the start of the protocol and 8 weeks after the conclusion of the treatment. RESULTS: We did not observe difference between the groups in any of the analyzed variables. Both groups showed a reduction in pain and an improvement in functional disability during intragroup comparisons. CONCLUSION: A reduction in pain and an improvement in functional disability were observed; however, there was no additional effect of NMES. TRIAL REGISTRATION: NCT03918863.

Lower limb muscles' thicknesses are weakly associated with dynamic knee valgus during single-leg squat in women with patellofemoral pain.

INTRODUCTION: Patellofemoral pain (PFP) patients often show an altered lower limb alignment during the single-leg squat (SLS). There is evidence that proximal and distal-to-the-knee muscle alterations can modify the lower limb alignment in PFP patients. However, we observed a lack of studies investigating the possible association between the thickness and strength of proximal and distal-to-the-knee muscles and lower limb alignment during SLS in women with PFP. Therefore, this study aimed to investigate the association between the thickness and strength of lower limb muscles and dynamic knee valgus (DKV) during SLS in women with PFP. METHODS: Cross-sectional study, where fifty-five women with PFP were submitted to the following evaluations: (1) muscle thickness (MT) of Gluteus Medius (GMed), Gluteus Maximus (GMax), Vastus Lateralis (VL), and Tibialis Anterior (TA); (2) isometric peak torque of hip abductors, hip external rotators, knee extensors, and foot inversors; and (3) DKV during SLS. RESULTS: There was a significant negative association between GMax's MT and DKV (r = -0.32; p = 0.01), and between TA's MT and DKV (r = -0.28; p = 0.03). No significant correlations were observed between isometric torques and DKV. Regression analysis found that GMax's MT explained 10% of the DKV's variance during SLS. DISCUSSION: Poor lower limb alignment during SLS is weakly associated with proximal and distal-to-the-knee muscle thicknesses, with no association with isometric torque in PFP women. CONCLUSION: Our results suggest that other factors besides strength and muscle thicknesses may explain and improve lower limb alignment in women with PFP.

Analysis of lower limb muscle strength characteristics of amateur runners with patellofemoral pain: A cross-sectional study.

To analyze the lower limb muscle strength characteristics of amateur runners with patellofemoral pain (PFP). Sixty amateur runners (30 in the knee pain group, 30 in the control group) underwent measurements of hip abduction strength, knee extension strength, and knee flexion strength. Additionally, the hamstring/quadriceps ratio and limb strength symmetry index were calculated for all participants. Statistical analyses were conducted using linear mixed models. The hip abduction and knee extensors strength of amateur runners with PFP was significantly lower than that of the control group. The hamstring/quadriceps ratio was significantly higher in the male knee pain group compared to the control group, while no significant difference was found between the female knee pain group and the control group. Furthermore, both the hip abduction strength symmetry index and knee extensors symmetry index were significantly lower in the knee pain group compared to the control group. Amateur runners with PFP exhibit distinct lower limb strength characteristics compared to non-knee pain runners. Additionally, differences in lower limb strength characteristics between male and female amateur runners with PFP were observed. These findings emphasize the importance of considering functional and gender differences in PFP rehabilitation training.

Effect of soft tissue tension around the knee joint on medio-lateral patellar position.

Patellofemoral pain (PFP) is one of the most common sports injuries of the knee joint and has a high persistence and recurrence rate. Medio-lateral patellar position in the knee extension position during contraction is associated with PFP. However, soft tissue tension that most influences the medio-lateral patellar position in the knee extension position during contraction in vivo is unclear. We aimed to clarify the relationship between medio-lateral patellar position and soft tissue tension around the knee joint. Twelve patients with PFP and 20 healthy participants were included. Medio-lateral patellar position and tension of the rectus femoris, vastus lateralis (VL), vastus medialis, iliotibial band (ITB), lateral patellofemoral ligament, and medial patellofemoral ligament were measured during contraction and rest. The tensions of the VL and ITB during contraction and the medio-lateral patellar position at rest were significantly associated with medio-lateral patellar position during contraction (ß = 0.449, 0.354, and 0.393, respectively). In addition, the tension of ITB was significantly associated with the medio-lateral patellar position at rest (ß = 0.646). These relationships were not affected by the presence of PFP. These findings suggest that the patellar position during contraction became more lateral as the tension in the VL and ITB increased, regardless of the presence of PFP. These results may facilitate the prevention and treatment of PFP.

Impairments in peroneal muscle size and activation in individuals with patellofemoral pain in weight-bearing position.

BACKGROUND: Patellofemoral pain (PFP) is characterized by chronic pain in the anterior aspect of the knee during loading activities. Many studies investigating muscle morphology changes for individuals with PFP focus on the proximal joints, however, few studies have investigated muscles of the foot and ankle complex. This study aimed to explore the differences in peroneal muscle size and activation between individuals with PFP and healthy controls using ultrasound imaging in weight-bearing. METHODS: A case-control study in a university lab setting was conducted. Thirty individuals with PFP (age: 20.23 ± 3.30 years, mass: 74.70 ± 27.63 kgs, height: 161.32 ± 11.72 cm) and 30 healthy individuals (age: 20.33 ± 3.37 years, mass: 64.02 ± 11.00 kgs, height: 169.31 ± 9.30 cm) participated. Cross-sectional area (CSA) images of the peroneal muscles were taken in non-weight bearing and weight-bearing positions. The functional activation ratio from lying to single-leg standing (SLS) was calculated. RESULTS: There was a statistically significant (p = 0.041) group (PFP, healthy) by position (non-weight-bearing, weight-bearing) interaction for the peroneal muscle CSA with a Cohen's d effect size of 0.2 in non-weight-bearing position and 0.7 in weight-bearing position. The functional activation ratio for the healthy group was significantly more (p = 0.01) than the PFP group. CONCLUSION: Peroneal muscles were found to be smaller in size in those with PFP compared to the healthy subjects in the weight-bearing SLS position. This study found that those with PFP have lower activation of peroneal muscles in functional position.

Pain and disability were related to Y-balance test but not with proprioception acuity and single-leg triple-hop test in patients with patellofemoral pain: A cross-sectional study.

INTRODUCTION: Patellofemoral pain is a common complaint between physically active subjects. Patients with patellofemoral pain present limitations to performing daily activities. Pain could alter proprioceptive acuity and lead to movement impairment. The aim of this study was to investigate the relationship of pain and disability with proprioception acuity and physical performance in patients with patellofemoral pain. METHODS: Forty-eight patients with patellofemoral pain [age 31.15 (5.91) years; 30 (62.50%) males] were recruited. Data collected included pain intensity, pain duration, disability, joint position sense (JPS) test at 20° and 60° of knee flexion, and physical performance tests (Single-Leg Triple-Hop Test and Y- Balance Test). Spearman's rank correlation coefficient (rs) and 95% confidence intervals (CI) were computed to assess the relationship between the variables. RESULTS: Pain intensity was correlated with Y-Balance Test posteromedial component (rs = -0.32, 95%CI = -0.55 to -0.03, p = 0.029) and the composite score (rs = -0.35, 95%CI = -0.58, -0.07, p = 0.015). Pain duration was correlated with Y-Balance Test posterolateral component (rs = -0.23, 95% CI = -0.53 to -0.01, p = 0.047). Disability was correlated with Y-Balance Test posteromedial component (rs = 0.41, 95% CI = 0.14 to 0.62, p = 0.004). Pain and disability were not correlated with JPS and the Single-Leg Triple-Hop Test. CONCLUSION: Pain and disability were related to Y-Balance Test but not to proprioceptive acuity and Single-Leg Triple-Hop Test in patients with patellofemoral pain.

Assessing quadriceps strength in patellofemoral pain patients: A study on the reliability and validity of a low-cost strain-gauge for clinical practice.

BACKGROUND: Patellofemoral pain (PFP) is a common knee complaint affecting diverse populations both acutely and chronically. Quadriceps muscle weakness is one possible aetiology, but current devices for measuring muscle strength (isokinetic dynamometer [ID] and hand-held dynamometers [HHD]) are frequently too expensive (e.g., ID) or lack reliability (e.g., HHD) for practitioners, especially in under-resourced settings. There is a need to evaluate a low-cost device to manage rehabilitation of people with PFP. METHODS: Isometric quadriceps strength of participants aged 18-35 years (total [n = 33], control group [n = 17] and PFP group [n = 16]) were evaluated on an isokinetic dynamometer and a commercially available strain gauge at baseline and after an 8-week non-standardised intervention. RESULTS: The strain gauge showed high absolute and relative reliability (intraclass correlation coefficient = 0.89-0.99; typical error of measurement = 3.9-10.4%). Clinically meaningful difference scores (12.2-45 Nm) were greater than the typical error of measurement, implying sufficient sensitivity of the strain gauge to measure true changes in isometric quadricep strength. Strong to very strong correlations were evident between the strain gauge and isokinetic dynamometer torque measurements (r = 0.88-0.90, SEE = 0.05-0.07 Nm), but slope values (ß = 0.65-0.77) indicated that torque from the strain gauge was lower than that obtained from the isokinetic dynamometer. An average systematic bias of 16.3-28.8 Nm was evident in favour of the isokinetic dynamometer, with no statistically significant between-group differences apparent between baseline and follow-up testing. CONCLUSION: The present commercially available strain gauge is reliable and sensitive enough to detect clinically meaningful differences in quadriceps strength of both healthy individuals and those with PFP. However, the strain gauge lacks validity and therefore cannot replace isokinetic dynamometry. Given the low cost and excellent reliability, the strain gauge can be a valuable tool to assess quadriceps muscle deficits and track rehabilitation progress in people with PFP.

The effect of marathon running on the lower extremity kinematics and muscle activities during walking and running tasks.

Patellofemoral pain syndrome (PFPS) is a common injury among runners, and it is thought that abnormal lower extremity biomechanics contribute to its development. However, the relationship between biomechanical changes after a marathon and PFPS injury remains limited. This study aims to investigate whether differences in knee and hip kinematics and lower extremity muscle activities exist in recreational runners before and after a marathon. Additionally, it aims to explore the relationship between these biomechanical changes and the development of PFPS injury. 12 recreational runners participated in the study. Kinematics and muscle activities of the lower extremity were recorded during walking (5 km/h) and running (10 km/h) tasks within 24 hours before and within 5 hours after a marathon. After the marathon, there was a significant decrease in peak knee flexion (walking: p = 0.006; running: p = 0.006) and an increase in peak hip internal rotation (walking: p = 0.026; running: p = 0.015) during the stance phase of both walking and running compared to before the marathon. The study demonstrates a decrease in knee flexion and an increase in hip internal rotation during the stance phase of gait tasks after completing a marathon, which may increase the risk of developing PFPS injury.

Relationship between exacerbating patellofemoral pain and dynamic knee valgus in females with patellofemoral pain after a patellofemoral joint loading protocol: A cross-sectional.

OBJECTIVE: The aim of the present study is to 1) the effect of exacerbating patellofemoral pain (PFP) on dynamic knee valgus (DKV) 2) the relationship between exacerbating PFP and DKV in females with patellofemoral pain. DESIGN: Cross-sectional study. METHODS: Sixty women with PFP were recruited from the orthopedic clinics. We evaluated pain intensity and DKV in two conditions without (condition 1) and with (condition 2) PFJ loading during the single-leg squat (SLS) task. The MANOVA test was used to compare pain intensity and DKV angle between the two conditions. Furthermore, the Pearson correlation was used to examine the correlation between pain intensity with DKV angle. RESULTS: The MANOVA analysis showed that pain intensity (P < 0.000, η2 = 0.623) and DKV angle (P < 0.000, η2 = 0.544) with a medium effect size significantly increased after PFJ loading. Furthermore, an excellent positive correlation was observed between an increase in pain intensity and DKV angle (P < 0.000, r = 0.840). CONCLUSION: It seems that after the PFJ loading protocol and the subsequent pain exacerbation, the neuromuscular biomechanics of the lower limb are deficits. As a result, the stabilizing muscles activation decreases and increases the lower limb movement in the frontal plane.

Effects of high frequency strengthening on pain sensitivity and function in female runners with chronic patellofemoral pain.

OBJECTIVE: To investigate the effects of a high frequency strengthening program on function, pain, and pain sensitization in female runners with chronic patellofemoral pain (PFP). DESIGN: Cross-sectional study. SETTING: University laboratory. PARTICIPANTS: Thirty female runners (mean age 32 ± 8.1 years) with chronic PFP completed an 8-week home strengthening program. MAIN OUTCOME MEASURES: Variables assessed at baseline, 8-weeks, and 12 weeks included single leg step down test (SLSD), pain, Anterior Knee Pain Scale (AKPS), University of Wisconsin Running Injury and Recovery Index (UWRI), and quantitative sensory testing. RESULTS: There was large and statistically significant improvement at 8 and 12 weeks for average knee pain (ηp2 = 0.334, p < 0.001), worst knee pain (ηp2 = 0.351, p < 0.001), SLSD (ηp2 = 0.161, p = 0.001), AKPS (ηp2 = 0.463, p < 0.001), and UWRI (ηp2 = 0.366, p < 0.001). A medium to large effect and statistically significant improvement in pressure pain threshold testing was found for all local and remote structures (ηp2 range, 0.110 to 0.293, range p < 0.001 to p = 0.009) at 8 and 12 weeks. CONCLUSIONS: There was a significant decrease in local and remote hyperalgesia via mechanical and thermal pain sensitivity testing in female runners with chronic PFP. There was a large effect and significant improvement in self-reported pain and function.

Immediate Improvements in Patellofemoral Pain Are Associated With Sagittal Plane Movement Training to Improve Use of Gluteus Maximus Muscle During Single Limb Landing.

OBJECTIVE: The authors sought to examine the immediate effects of movement training aimed at improving use of gluteus maximus (GMAX) in the sagittal plane on hip internal rotation and self-reported patellofemoral pain (PFP) during single-limb landing. METHODS: Seventeen females with PFP participated. Lower extremity kinematics and kinetics, GMAX activation, and self-reported PFP were obtained before and after a single-session movement training program aimed at increasing the use of GMAX. Dependent variables of interest included self-reported PFP, average GMAX activation, average hip extensor moment, and peak hip internal rotation. Post-training changes were evaluated using paired t tests and Wilcoxon signed rank tests. RESULTS: Following movement training, self-reported PFP decreased significantly (mean [standard deviation]) (3.9 [1.1] vs 0.8 [1.3] on a 0-10 scale). Additionally, significant increases were observed for the average hip extensor moment (0.6 [0.3] vs 1.8 [0.4] Nm/kg) and average GMAX activation (41.0% [18.3] vs 51.6% [25.7] maximum voluntary isometric contraction), whereas peak hip internal rotation decreased significantly (8.5 degrees [5.8] vs 6.0 degrees [5.3]). CONCLUSION: Movement training aimed at improving the use of GMAX in the sagittal plane resulted in clinically relevant changes in self-reported pain, GMAX activation, and hip kinetics and kinematics. Improving the use of GMAX during movement merits consideration when designing rehabilitation programs for females with PFP. IMPACT: The current study highlights the clinical utility of movement training for persons with PFP and provides a biomechanical rationale for its use as a potential intervention in this population.

Gait retraining for runners with patellofemoral pain: A protocol for systematic review and meta-analysis.

INTRODUCTION: Patellofemoral pain (PFP) is highly prevalent in runners. Physical therapies were proved to be effective in the treatment of PFP. Gait retraining is an important method of physical therapy, but its effectiveness and safety for PFP remained controversial. Previous review suggests gait retraining in the treatment of PFP warrants consideration. However, recent publications of randomized controlled studies and case series studies indicated the positive effect of gait retraining in clinical and functional outcomes, which re-raise the focus of gait retraining. This paper will systematically review the available evidence, assessing the safety and effectiveness for the use of gait retraining for runners with PEP. METHOD AND ANALYSIS: A systematic review of relevant studies in Pubmed, Embase, SCOPUS, and Cochrane Library were synthesized. Inclusion criteria are studies evaluating clinical outcomes (i.e., changes to pain and/or function) following running retraining interventions in symptomatic running populations; Studies with less than 10 participants in total or in the running retraining intervention group were excluded. The primary outcomes measured will be pain score, Lower extremity functional scale and training related injuries or complications. Review Manager (Revman Version 5.3) software will be used for data synthesis, sensitivity analysis, meta regression, subgroup analysis and risk of bias assessment. A funnel plot will be developed to evaluate reporting bias and Begg and Egger tests will be used to assess funnel plot symmetries. We will use the Grading of Recommendations Assessment, Development and Evaluation system to assess the quality of evidence. ETHICS AND DISSEMINATION: Our aim is to publish this systematic review in a peer-reviewed journal. Our findings will provide information about the safety of gait retraining and their effect on reliving pain and improving function of lower limb on runners with PEP. This review will not require ethical approval as there are no issues about participant privacy.

Knee flexor strength, rate of torque development and flexibility in women and men with patellofemoral pain: Relationship with pain and the performance in the single leg bridge test.

OBJECTIVES: To investigate the relationship between: (1) knee flexor strength, rate of torque development (RTD), and flexibility with pain level; (2) knee flexor strength and RTD with the performance in the single leg bridge test (SLBT) in women and men with patellofemoral pain (PFP). DESIGN: Cross-sectional. SETTING: Laboratory-based study. PARTICIPANTS: 39 women and 36 men with PFP. MAIN OUTCOME MEASURES: Knee flexor strength, RTD, and flexibility; performance in the SLBT, current, and worst pain level. RESULTS: Moderate to strong significant negative relationships were identified between the current pain level with knee flexor strength (r = -0.57 to -0.34) and flexibility (r = -0.44 to -0.35); and between knee flexor strength and RTD with the performance in the SLBT (r = 0.34 to 0.57) in women and men with PFP. Knee flexor RTD was not related to any pain level and no significant relationships were identified between the worst pain level with knee flexor strength and flexibility in women and men with PFP. CONCLUSIONS: Our results support the potential value of assessing knee flexor strength and flexibility in women and men with PFP. The SLBT may be a useful tool to assess knee flexor muscle capacity in individuals with PFP in a clinical setting.

Effects of gait retraining with focus on impact versus gait retraining with focus on cadence on pain, function and lower limb kinematics in runners with patellofemoral pain: Protocol of a randomized, blinded, parallel group trial with 6-month follow-up.

Patellofemoral pain (PFP) is one of the most prevalent injuries in runners. Unfortunately, a substantial part of injured athletes do not recover fully from PFP in the long-term. Although previous studies have shown positive effects of gait retraining in this condition, retraining protocols often lack clinical applicability because they are time-consuming, costly for patients and require a treadmill. The primary objective of this study will be to compare the effects of two different two-week partially supervised gait retraining programs, with a control intervention; on pain, function and lower limb kinematics of runners with PFP. It will be a single-blind randomized clinical trial with six-month follow-up. The study will be composed of three groups: a group focusing on impact (group A), a group focusing on cadence (group B), and a control group that will not perform any intervention (group C). The primary outcome measure will be pain assessed using the Visual Analog Pain scale during running. Secondary outcomes will include pain during daily activities (usual), symptoms assessed using the Patellofemoral Disorders Scale and lower limb running kinematics in the frontal (contralateral pelvic drop; hip adduction) and sagittal planes (foot inclination; tibia inclination; ankle dorsiflexion; knee flexion) assessed using the MyoResearch 3.14-MyoVideo (Noraxon U.S.A. Inc.). The study outcomes will be evaluated before (t0), immediately after (t2), and six months (t24) after starting the protocol. Our hypothesis is that both partially supervised gait retraining programs will be more effective in reducing pain, improving symptoms, and modifying lower limb kinematics during running compared with the control group, and that the positive effects from these programs will persist for six months. Also, we believe that one gait retraining group will not be superior to the other. Results from this study will help improve care in runners with PFP, while maximizing clinical applicability as well as time and cost-effectiveness.

Anteromedial versus posterolateral hip musculature strengthening with dose-controlled in women with patellofemoral pain: A randomized controlled trial.

OBJECTIVE: To compare the effectiveness of adding anteromedial versus posterolateral hip musculature strengthening to knee strengthening in women with patellofemoral pain (PFP). DESIGN: Randomized controlled trial. SETTING: University physiotherapy clinic. PARTICIPANTS: Fifty-two women with PFP were randomized to receive either anteromedial (AMHG) or posterolateral (PLHG) hip musculature strengthening. MAIN OUTCOME MEASURES: The primary outcomes were pain intensity by the numeric pain rating scale and function by the Anterior Knee Pain Scale in six weeks. Secondary outcomes were pain and function at six months, global perceived effect at six weeks and six months, pain in step down, isometric torque of abductors, adductors and hip rotators measured with hand-held dynamometer, and dynamic knee valgus by step down in six weeks. RESULTS: Both groups showed improvement in primary outcomes; however, no differences were found between groups in pain intensity and function in six weeks and the secondary outcomes. Group x time interaction found superior gains in abductor strength in the PLHG and increase in the strength of the adductors and internal rotators in AMHG. CONCLUSION: There was no difference between the addition of anteromedial or posterolateral hip musculature strengthening to knee strengthening in improving pain and function in women with PFP.

Static and Dynamic Quadriceps Stretching Exercises in Patients With Patellofemoral Pain: A Randomized Controlled Trial.

BACKGROUND: Limited data are available on the effect of stretching exercise in patients with patellofemoral pain (PFP) who have inflexible quadriceps, which is one of the various causes of PFP syndrome. This study compares quadriceps flexibility, strength, muscle activation time, and patient-reported outcomes after static and dynamic quadriceps stretching exercises in patients with PFP who had inflexible quadriceps. HYPOTHESIS: Quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes would improve with dynamic quadriceps stretching as compared with static quadriceps stretching exercises. STUDY DESIGN: Randomized controlled trial. LEVEL OF EVIDENCE: Level 2. METHODS: Of the 44 patients included in the study, 20 performed static stretching and 24 performed dynamic stretching. Quadriceps flexibility was assessed by measuring the knee flexion angle during knee flexion in the prone position (the Ely test). Muscle strength and muscle activation time were measured using an isokinetic device. The patient-reported outcomes were evaluated using the visual analogue scale for pain and anterior knee pain scale. RESULTS: No significant differences in quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes in the involved knees were found between the 2 groups (P values > 0.05). CONCLUSION: Quadriceps flexibility and strength, muscle activation time, and patient-reported outcomes in patients with PFP who had inflexible quadriceps showed no significant differences between the static and dynamic quadriceps stretching exercise groups. CLINICAL RELEVANCE: Both static and dynamic stretching exercises may be effective for improving pain and function in patients with PFP who have inflexible quadriceps.

The Effect of Diacutaneous Fibrolysis on Local and Widespread Hyperalgesia and Muscle Length in Patients With Patellofemoral Pain Syndrome: Secondary Analysis of a Pretest-Posttest Clinical Trial.

CONTEXT: Localized and widespread hyperalgesia has been observed in patients with patellofemoral pain. Diacutaneous fibrolysis (DF) has shown to be effective in reducing pain in several musculoskeletal conditions including patellofemoral pain syndrome, but no studies have evaluated the effects of this technique in reducing localized and widespread hyperalgesia. OBJECTIVE: To assess the effect of DF on the pressure pain threshold and muscle length tests in patients with patellofemoral pain syndrome. DESIGN: A single-group, pretest-posttest clinical trial. SETTING: University of Zaragoza. PARTICIPANTS: Forty-six subjects with patellofemoral pain (20 males and 26 females: age 27.8 [6.9] y). INTERVENTION: Three sessions of DF. MAIN OUTCOME MEASURES: Pressure pain threshold using a handheld pressure algometer (4 sites around the knee, on tibialis anterior muscle, and one remote site on the upper contralateral limb); muscle length test of the iliotibial band, rectus femoris, and hamstring muscles; and patient-perceived treatment effect score. RESULTS: The application of 3 sessions of DF significantly increased the pressure pain threshold in all sites at posttreatment evaluation (P < .001) and at a 1-week follow-up (P < .001). A significant increase in muscle length was also observed at the posttreatment evaluation (P < .001) and 1-week follow-up (P < .001). Ninety-seven percent of the patients reported subjective improvement at posttreatment and at 1-week follow-up. CONCLUSION: This study found that local and widespread hyperalgesia was significantly reduced after 3 sessions of diacutaneous fibrolysis and at the 1-week follow-up. A significant improvement on muscle length tests was also observed, with high clinical satisfaction among patients.

Influence of symptom frequency and severity on hip abductor strength and endurance in individuals with patellofemoral pain.

OBJECTIVE: To compare clinical measures of hip abductor strength and endurance of individuals with patellofemoral pain with more severe symptoms to those with less severe symptoms. DESIGN: Cross-sectional. SETTINGS: Laboratory. PARTICIPANTS: Sixty participants with patellofemoral pain were divided three times into 2 groups according to three symptomatology criteria: functional capacity, pain frequency and pain severity. MAIN OUTCOME MEASURES: Isometric strength evaluated using a hand-held dynamometer, endurance using maximum number of repetitions and maximum holding time, functional capacity using the Anterior Knee Pain Scale, pain frequency using a 2-category scale ("Less frequent" = 1-2 times a week; "More frequent" = >3 times a week) and pain severity using Numeric Pain Rating Scales. RESULTS: Participants with more frequent symptoms and with more severe pain were significantly weaker (10%, p = 0.04 and 16%, p = 0.001, respectively), and had less isometric (17%, p = 0.02 and 24%, p = 0.002, respectively) and dynamic (13%, p = 0.02 and 23%, p = 0.007, respectively) endurance compared to those with less pronounced symptoms. CONCLUSION: Our study highlighted that hip abductor strength and endurance deficits are more pronounced in individuals with more severe and frequent pain.

Internal and external focus show similar effect on the gait kinematics in patients with patellofemoral pain: A randomised controlled trial.

PURPOSE: The purpose of this study was to examine how attentional focus during training influences the effects of a 6-week hip-knee strength training program on pain, function, strength, and kinematics in males and females with Patellofemoral pain (PFP). METHODS: Seventy-five males and females with PFP were randomly allocated to a group that trained with an internal focus (n = 25), a group that trained with an external focus (n = 25), or a control group (n = 25). All patients completed testing before (baseline) and after (posttest) the 6-week period. The primary outcome was pain, assessed by Visual Analog Scale (VAS). The secondary outcomes were function, hip muscles strength and lower extremity kinematics, assessed by Kujala Questionnaire, handheld dynamometer and a 2-D motion capture, respectively. All outcomes were measured at the baseline and after the 6-week intervention. Analysis of covariance was used to compare posttest outcomes among the groups while accounting for group differences in baseline performance. RESULTS: The hip-knee strengthening exercises resulted in improved knee valgus (ES(95 % CI) = 0.43(0.26 to 0.75), p = 0.03), and external rotator strength (ES(95 % CI) = 0.51(0.12 to 0.78), p = 0.03) for males and females who trained with an external compared to internal focus. CONCLUSIONS: Our findings indicate that males and females with PFP may benefit from completing a hip-knee strengthening training program with an external focus vs. an internal focus. Physical therapists and clinicians should consider using instructions that promote an external focus when implementing hip-knee strengthening training programs with PFP patients. This result could be strengthened or re-enforced by larger studies with longer follow up.

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.