Women with patellofemoral pain show changes in trunk and lower limb sagittal movements during single-leg squat and step-down tasks

BACKGROUND

Changes in the trunk and lower limbs' sagittal movements may cause patellofemoral pain (PFP) because they influence the forces acting on this joint.

OBJECTIVES

To compare trunk and lower limb sagittal kinematics between women with and without PFP during functional tests and to verify whether sagittal trunk kinematics are correlated with those of the knees and ankles.

METHODS

A total of 30 women with PFP and 30 asymptomatic women performed single-leg squat (SLS) and step-down (SD) tests and were filmed by a camera in the sagittal plane. The trunk inclination angle, forward knee displacement, and ankle angle were calculated.

RESULTS

The PFP group exhibited less trunk flexion (SLS, p = .006; SD, p = .016) and greater forward knee displacement (SLS, p = .001; SD, p = .004) than the asymptomatic group; there was no significant difference in ankle angle (SLS, p = .074; SD, p = .278). Correlation analysis revealed that decreased trunk flexion was associated with increased forward knee displacement (SLS, r = -0.439, p = .000; SD, r = -0.365, p = .004) and ankle dorsiflexion (SLS, r = -0.339, p = .008; SD, r = -0.356, p = .005).

CONCLUSION

Women with PFP present kinematic alterations of the trunk and knee in the sagittal plane during unipodal activities. Furthermore, the trunk and lower limb sagittal movements were interdependent.

Hip rate of torque development, but not strength, is associated with single-leg squat kinematics in individuals with patellofemoral pain

INTRODUCTION

Isometric hip strength seems to have limited association with frontal plane kinematics in individuals with patellofemoral pain (PFP), but little is known about the association with hip rate of torque development (RTD).

OBJECTIVE

To explore the association of hip strength and RTD with trunk, pelvis, hip, and knee kinematics during a single-leg squat (SLS) in individuals with PFP.

METHODS

Twenty individuals with PFP participated in this study. Hip abductor and extensor strength and RTD (early phase and late phase) were assessed using a hand-held dynamometer. Lateral trunk motion, pelvic drop, hip frontal plane projection angle (HFPPA), and knee frontal plane projection angle (KFPPA) were evaluated during a SLS using a two-dimensional motion analysis.

RESULTS

Lower early and late phase hip abductor RTD were moderately associated with greater HFPPA (early phase: r = -0.501, p = .025; late phase: r = -0.580, p = .007) and KFPPA (early phase: r = -0.536, p = .015; late phase: r = -0.554, p = .011). Lower early phase hip extensor RTD was moderately associated with greater pelvic drop (r = 0.571, p = .009), HFPPA (r = -0.548, p = .012), and KFPPA (r = -0.530, p = .016). Hip abductor and extensor strength were not associated with any kinematic variables (p > .05).

CONCLUSION

Lower hip RTD, but not strength, was associated with greater frontal plane kinematics during a SLS in individuals with PFP, indicating that the ability to produce torque rapidly may be important for kinematic control during functional tasks.

Effects of adding neuromuscular electrical stimulation to functional training on muscle recruitment, pain reduction, and knee joint function in patellofemoral pain syndrome patients

BACKGROUND

Impaired lower extremity motor function and knee pain are common concerns in patients with patellofemoral pain syndrome (PFPS). It is essential to plan therapeutic techniques to therapy PFPS. The objective of this study was to determine the effect of neuromuscular electrical stimulation (NMES) combined with functional training on pain, lower extremity function and muscle recruitment in patients with PFPS.

METHODS

Twenty-four PFPS patients (male-13, female-11) were selected to conduct this study finally. Two groups were formed: the control group (n = 12) which included functional training only and the experimental group (n = 12) which functional training along with NMES-in both groups interventions were performed for 45 minutes/session, 3 days/weeks for 6 weeks. The functional training consisted of warm-up activities, strength training, balance training, and relaxation activities. All patients were evaluated with surface electromyography testing system for the root mean square and integrated electromyography of vastus medial oblique (VMO), vastus lateralis (VL), and VMO/VL ratio, visual analog scores (VAS) for pain, and Kujala functional score for knee joint function before and after 6 weeks. Normality was tested for all outcome variables using Shapiro-Wilk test. Nonparametric (Mann-Whitney U test and Wilcoxon signed-rank test) tests were used to analyze data. A 2-way analysis of variance with repeated measures (group*time) was applied to analyze the data.

RESULTS

A significant increases (P < .001) root mean square and integrated electromyography of VMO, VMO/VL ratio, and Kujala score in both groups, For VAS scores, significant decreases was observed in both groups. When both groups were compared, greater improvement (P < .05) was observed in the experimental group in comparison the control group for both knee pain, lower extremity function and muscle recruitment. However, there was no difference in VL muscle recruitment between the 2 groups.

CONCLUSIONS

Functional training and NMES combined with functional training are helpful to improve pain, knee function and muscle recruitment of PFPS patients. NMES combined with functional training was more effective compared to the control group. This may help clinical trialists to use different NMES to synchronize other interventions in future studies to enhance rehabilitation efficacy in PFPS patients through passive training versus active stimulation.

Effectiveness of Interventions Aimed at Changing Movement Patterns in People With Patellofemoral Pain: A Systematic Review With Network Meta-analysis

OBJECTIVE: To summarize the effectiveness of interventions for changing movement during weight-bearing functional tasks in people with patellofemoral pain (PFP). DESIGN: Systematic review with network meta-analysis (NMA). LITERATURE SEARCH: Medline, Embase, CINAHL, SPORTDiscus, and Cochrane Library were searched from inception up to May 2023. STUDY SELECTION CRITERIA: Randomized controlled trials involving people with PFP and nonsurgical, nonpharmacological interventions on task kinematics were included. DATA SYNTHESIS: NMA was conducted for frontal knee movement data, and pairwise meta-analysis was used to pool data when NMA was not possible. Reduced movements were those changes that indicated movements occurring with less amplitude. The GRADE approach was used to grade the certainty of the evidence. RESULTS: Thirty-seven trials were included (n = 1235 participants). Combining knee/hip exercises with internal feedback had the strongest effect on reducing frontal knee movements (standardized mean difference [SMD] from NMA = -2.66; GRADE: moderate evidence). On pairwise comparisons, the same combination of interventions reduced frontal hip movements (SMD = -0.47; GRADE: moderate evidence) and increased sagittal knee movements (SMD = 1.03; GRADE: moderate evidence), with no effects on sagittal hip movements (GRADE: very low evidence), compared to knee/hip exercises alone. There was no effect for single applications of braces on the frontal knee movement (GRADE: very low evidence) and taping on movements of the knee, hip, and ankle (GRADE: very low to low evidence) compared to no intervention. CONCLUSION: Knee/hip exercises combined with internal feedback techniques may change knee and hip movements in people with PFP. The combination of these interventions can reduce frontal knee and hip movements, and can increase sagittal knee movements. J Orthop Sports Phys Ther 2023;53(12):1-13. Epub 14 September 2023. doi:10.2519/jospt.2023.11956.

Activation, strength, and resistance: Which variables predict the kinematics of women with and without patellofemoral pain?

INTRODUCTION

Investigating the possible relationship between neuromuscular changes and movement alterations could help to describe the mechanisms underlying patellofemoral pain (PFP).

OBJECTIVE

To investigate whether activation and muscle strength of the trunk and lower limb and muscle resistance of the trunk predict the knee frontal and trunk sagittal kinematics in women with and without PFP.

METHOD

Sixty women (PFP, n = 30; asymptomatic, n = 30) underwent the single-leg squat test to collect electromyographic and kinematic data. Activation of transversus abdominis/internal oblique, gluteus medius (GMed), and vastus medialis oblique (VMO); knee frontal and trunk sagittal angles were analyzed. Participants also underwent maximal isometric tests to determine lateral trunk, hip abductor, and knee extensor torques and performed a lateral trunk resistance test. Multiple regression was used to determine predictive models.

RESULTS

In the PFP group, knee frontal angle (R2 = 0.39, p = 0.001) was predicted by GMed activation (β = 0.23, p = 0.000) and hip abductor torque (β = 0.08, p = 0.022). No variable was able to predict trunk sagittal kinematics in this group. In the asymptomatics, knee frontal angle (R2 = 0.16, p = 0.029) was predicted by hip abductor torque (β = 0.07, p = 0.029), while trunk sagittal angle (R2 = 0.24, p = 0.024) was predicted by VMO activation (β = 0.12, p = 0.016).

CONCLUSION

Kinematics is predicted by the muscles acting in the respective planes, such that hip abductors capacities are related to the knee frontal alignment in both groups, and that of the VMO is related to the trunk sagittal alignment only in asymptomatic women.

Comparisons of musculoskeletal injuries among three different modalities of Taekwondo (Kyorugi, Poomsae, and Shibum): a one-year follow-up prospective epidemiologic study

The purpose of the study was to report the injury rates and characteristics (body location, type, mechanism, and severity) of musculoskeletal injuries in Kyorugi, Poomsae, and Shibum. A total of 137 Korean collegiate Taekwondo players - Kyorugi (n = 44), Poomsae (n = 46), and Shibum (n = 47) - were prospectively studied in 2019. Injury rates per 1,000 athlete-exposures (AEs) and time-exposures (TEs) during training and competition were calculated. Additionally, body location, type, mechanism, and severity of injury were analysed. The highest injury rate was recorded in Poomsae (172.0/1,000 AEs and 79.5/1,000 TEs) followed by Kyorugi (47.1/1,000 AEs and 25.9/1,000 TEs) and Shibum (57.5/1,000 AEs and 17.0/1,000 TEs). The frequently injured body location was the thigh (Kyorugi = 17%; Poomsae = 25%; Shibum = 18%). The common injury types were muscle cramps/spasms in Kyorugi (33%) and Poomsae (59%), and sprain in Shibum (41%). The common injury mechanisms were gradual onset in Kyorugi (40%) and Shibum (49%), and non-contact trauma in Poomsae (91%). Regarding the severity, the number of days from the injury onset to recovery > 1 week were higher in the order of Kyorugi (78%), Shibum (54%), and Poomsae (28%). Our data provide preliminary evidence that different injury prevention strategies should be applied to each modality of Taekwondo.

Patellofemoral Pain Syndrome Risk Associated with Squats: A Systematic Review

Patellofemoral pain syndrome (PFPS) is highly prevalent; it can cause severe pain and evolve into progressive functional loss, leading to difficulties performing daily tasks such as climbing and descending stairs and squatting. This systematic review aimed to find evidence, in the literature, of squat movements that can cause or worsen PFPS. This work was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, and its protocol was registered in PROSPERO (CRD42019128711). From the 6570 collected records, 37 were included. From these 37 articles, 27 present a causal relationship between knee flexion and PFPS, 8 describe a relationship, considering the greater existence of muscle contractions, and one article did not describe this relationship in its results. The main limitations stem from the fact that different studies used different evaluation parameters to compare the force exerted on the patellofemoral joint. Furthermore, most studies are focused on sports populations. After analysing the included works, it was concluded that all squat exercises can cause tension overload in the knee, especially with a knee flexion between 60° and 90° degrees. The main causal/worsening factors of PFPS symptoms are the knee translocation forward the toes (on the same body side) when flexing the knee, and the muscle imbalance between the thigh muscles.

Feasibility of Superimposed Neuromuscular Electrical Stimulation to the Gluteus Medius During a Resistance Training Program

CONTEXT

Gluteus medius (GMed) weakness is a common impairment seen across multiple lower-extremity pathologies. Greater GMed weakness is moderately associated with greater frontal plane motion, often termed dynamic knee valgus during functional tasks which may increase risk of lower-extremity injury. Neuromuscular electrical stimulation (NMES) superimposed to targeted muscles has emerged in clinical practice; however, NMES superimposed to the GMed in unknown. It is essential to assess the safety, credibility, and expectancy of NMES superimposed to the GMed prior to implementation in clinical practice. The objective of this study was to evaluate feasibility, safety, credibility, and expectancy of improvement with a 2-week intervention with or without NMES to the GMed in females with dynamic knee valgus.

DESIGN

Feasibility study.

METHODS

A total of 22 adult females with dynamic knee valgus (age = 21.8 [1.4] y, mass = 76.9 [18.8] kg, height = 1.7 [0.1] m) completed a 2-week intervention with NMES or a sham treatment superimposed to the GMed during all therapeutic exercises. Feasibility was assessed by recruitment and completion rate, while safety was assessed by the total number of adverse events. Treatment credibility and expectancy was assessed with the Credibility Expectancy Questionnaire. Mixed-measure analysis of variance were used for statistical analysis (P ≤ .05).

RESULTS

Recruitment was completed in 5 months with 100% completion rate and no adverse events. There was no difference in treatment credibility between groups (NMES = 23.7 [2.3], sham = 21.7 [3.4], P = .12); however, the NMES group demonstrated a greater expectancy score (NMES = 20.0 [3.8], sham = 15.9 [5.1], P = .045).

CONCLUSION

Resistance training with NMES superimposed to the GMed is a feasible and safe intervention that resulted in greater expectance of success. Clinicians may consider superimposing NMES to the gluteal muscles when addressing muscle weakness in individuals with dynamic knee valgus.

Gluteal Central Activation in Females With Patellofemoral Pain: A Preliminary Study

CONTEXT

Lesser hip muscle strength is commonly observed in females with patellofemoral pain (PFP) compared with females without PFP and is associated with poor subjective function and single-leg squat (SLS) biomechanics. Hip muscle weakness is theorized to be related to PFP, suggesting centrally mediated muscle inhibition may influence the observed weakness. The central activation ratio (CAR) is a common metric used to quantify muscle inhibition via burst superimposition. However, gluteal inhibition has yet to be evaluated using this approach in females with PFP. The study objectives are to (1) describe gluteal activation in the context of subjective function, hip strength, and squatting biomechanics and (2) examine the relationship of gluteal activation with subjective function and squatting biomechanics in females with PFP.

DESIGN

Cross-sectional.

METHODS

Seven females with PFP (age = 22.8 [3.6] y; mass = 69.4 [18.0] kg; height = 1.67 [0.05] m, duration of pain = 6-96 mo) completed this study. Subjective function was assessed with the Anterior Knee Pain Scale, while fear-avoidance beliefs were assessed with the Fear-Avoidance Belief Questionnaire physical activity and work subscales. Biomechanical function was assessed with peak hip and knee angles and moments in the sagittal and frontal planes during SLS. Gluteus medius (GMed) and gluteus maximus (GMax) activation were assessed with the CAR. Descriptive statistics were calculated, and relationships between variables were assessed with Spearman rho correlations.

RESULTS

The CAR of GMed and GMax was 90.5% (8.1%) and 84.0% (6.3%), respectively. Lesser GMed CAR was strongly associated with greater hip adduction during SLS (ρ = -.775, P = .02) and greater fear-avoidance beliefs-physical activity subscale (ρ = -.764, P = .018).

CONCLUSION

We found a wide range in GMed and GMax activation across females with PFP. Lesser GMed activation was associated with greater hip adduction during SLS and fear of physical activity, suggesting that gluteal inhibition should be assessed in patients with PFP.

Patients with chronic unilateral anterior knee pain experience bilateral deficits in quadriceps function and lower quarter flexibility: a cross-sectional study

Background: Little is known about how chronic unilateral anterior knee pain (AKP) affects bilateral quadriceps function and lower quarter flexibility. Objective: To determine if patients with chronic unilateral AKP present bilateral deficits in quadriceps function and lower quarter flexibility. Methods: Twenty-two patients with chronic unilateral AKP (pain duration: 48.6 months) and 22 matched healthy controls were evaluated. Pain perception and functional outcomes were obtained. Knee joint and thigh circumferences, quadriceps subcutaneous tissue thickness and function (i.e. maximal and explosive strength, activation, and endurance), and lower quarter flexibility (i.e. hamstrings and iliopsoas/rectus femoris muscle) in both legs were compared across conditions. Results: Knee joint and thigh circumferences, and quadriceps subcutaneous tissue thickness were not different between conditions (P ≥ .39). Compared with matched healthy controls, patients with chronic unilateral AKP showed: 1) greater pain perception (0.0 versus 4.4 cm, P < .0001); 2) a lower score for functional outcomes (79.6 versus 53.9, P < .0001); 3) less bilateral quadriceps maximal (3.5 versus 2.8 Nm/kg, P < .0001) and explosive (10.8 versus 8.7 Nm/kg/s, P = .01) strength, activation (0.95 versus 0.83, P < .0001), and endurance (1.66 versus 1.52 Nm/kg, P = .02); and 4) less bilateral hamstrings (86.8 versus 72.6°, P = .002) and iliopsoas/rectus femoris (11.6 versus 7.8°, P < .05) flexibility. Conclusion: Patients with chronic unilateral AKP (without knee joint effusion or quadriceps muscle atrophy) appear to have bilateral deficits in quadriceps function and lower quarter flexibility, which should be addressed with pain reduction.