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.

Hip Joint Biomechanical Parameters and Their Relationship With the Esthetic Functional Performance of the Développé à la Seconde Movement in Classical Ballet Dancers.

Développé à la seconde is a classic ballet movement that requires the maintenance of a high hip joint range of motion (ROM) and muscle strength. However, the contribution of these hip joint biomechanical parameters to this movement's esthetic performance is unclear. Therefore, this study evaluated hip joint biomechanical characteristics of 21 experienced ballet dancers (15-29 y old) and verified the relationship between these variables with the développé à la seconde static and dynamic performance. Correlations between age, ballet practice time, gluteus maximus and gluteus medius thicknesses, ROM, and muscle strength with absolute and relative static and dynamic performances were verified. Flexors, extensors, and internal rotators peak strength and external rotation ROM were highly correlated with absolute and relative static performances (0.5-0.7). Flexors and extensors strength and external and internal rotation ROM showed the highest correlations with the développé dynamic performance (0.49-0.67). Flexor strength and flexor and internal rotation ROM predicted 26% to 41% of this movement's static and dynamic performances. Thus, from a biomechanical perspective, clinical assessment of hip strength and ROM may be used to predict the quality of the ballet dancers' performance of the développé à la seconde and guide classical ballet training.

Can we replace exercises targeted on core/hip muscles by exercises targeted on leg/foot muscles in women with patellofemoral pain? A randomized controlled trial.

OBJECTIVE: To verify the effects of replacing exercises targeted on core/hip muscles by exercises targeted on leg/foot muscles in a rehabilitation program for patellofemoral pain (PFP). DESIGN: Randomized Controlled Trial. PARTICIPANTS: Fifty women with PFP. METHODS: PFP participants were randomized into the standard rehabilitation group (SRG, n = 25) or distal exercise group (DEG, n = 25). Knee pain, patient-reported function, dynamic knee valgus and muscle strength were measured at baseline and after six and twelve weeks of the program start. RESULTS: SRG and DEG presented similar responses to rehabilitation (except for muscle strengthening). Knee pain reduced after 6 weeks (SRG: -37.7%, ES = 1.23; DEG: -30%, ES = 0.93) and 12 weeks (SRG: -47.4%, ES = 1.53; DEG: -43.3%, ES = 1.46). Patient-reported function improved after 6 weeks (SRG: +7.3%, ES = 0.45; DEG: +3.8%, ES = 0.22) and 12 weeks (SRG: +14.1%, ES = 0.80; DEG: +8.8%, ES = 0.50). Dynamic knee valgus reduced after 12 weeks (SRG: -29.7%, ES = 0.38; DEG: -34.5%, ES = 0.32). Both groups experienced increases in knee extension strength (SRG: +9%, ES = 0.28; DEG: +6%, ES = -0.29), but only SRG had strength gains for hip abduction (+10%, ES = 0.36) and extension (+11%, ES = 0.44). CONCLUSION: Exercises targeted on core/hip muscles can be replaced by exercises targeted on leg/foot muscles in a lower limb exercise-based rehabilitation program for women with PFP. CLINICAL TRIAL REGISTRATION: NCT03663595.

Proximal and distal muscle thickness is different in women with patellofemoral pain but is not associated with knee frontal plane projection angle.

OBJECTIVE: The aim of this study was to compare proximal and distal muscle thickness between patellofemoral pain (PFP) and asymptomatic women (CG) and to verify the possible association between morphology and lower limb alignment during single leg-squat. METHODS: Thirty women (PFP, n = 15 and CG, n = 15) performed the following evaluations: (i) muscle thickness of external oblique (EO), gluteus medius (GMed), tensor fascia latae (TFL), peroneus (PER) and tibialis anterior (TA); (ii) knee frontal plane projection angle (FPPA) during single-leg squat. RESULTS: Compared with the CG, PFP showed: (1) smaller GMed (-10.02%; p = 0.04; effect size = 0.82), greater TFL (+18.44%; p = 0.02; effect size = 0.92) and PER (+14.23%; p = 0.02; effect size = 0.87) muscle thickness and greater knee FPPA during single-leg squat (+31.8%; p = 0.04; effect size = 1.12). No differences were observed in EO (+7.17%; p = 0.37; effect size = 0.34) and TA (-1.35%; p = 0.81; effect size = 0.12) muscle thickness. Additionally, we failed to observe significant associations between muscle morphology and knee FPPA in both groups. CONCLUSION: PFP patients showed alterations in proximal and distal muscle thickness, despite the lack of association with poor lower limb alignment. Prospective studies are necessary to determine if differences in muscle morphology are the cause or the consequence of PFP and to confirm the absence of relationship with lower limb alignment.

Effects of neuromuscular electrical stimulation and low-level laser therapy on neuromuscular parameters and health status in elderly women with knee osteoarthritis: A randomized trial.

OBJECTIVE: To determine the effects of neuromuscular electrical stimulation and low-level laser therapy on neuromuscular parameters and health status in elderly subjects with knee osteoarthritis. DESIGN: A randomized evaluator-blinded clinical trial. SUBJECTS: Forty-five elderly women with knee osteoarthritis. METHODS: Subjects were randomized into 1 of the following 3 intervention groups: electrical stimulation group (18-32 min pulsed current, stimulation frequency 80 Hz, pulse duration 400 µs, stimulation intensity 40% of maximal isometric voluntary contraction), laser group (dose 4-6 J per point, 6 points at the knee joint) or combined group (electrical stimulation plus laser therapy). The outcomes included muscle thickness and anatomical cross-sectional area (ultrasonography), knee extensors' electrical activity (electromyography), torque (dynamometry) and health status (Western Ontario and McMaster Universities Osteoarthritis Index). All groups underwent a 4-week control period (without intervention) followed by an 8-week intervention period. RESULTS: Muscle thickness and anatomical cross-sectional area increased in the electrical stimulation and combined groups. All groups presented similar improvements in torque, electrical activity and health status. CONCLUSION: Electrical stimulation alone or in combination with laser therapy generated positive effects on all evaluated parameters. Laser therapy increased health status and electrical activity, but had no effect on muscle mass.

Effects of neuromuscular electrical stimulation and low-level laser therapy on the muscle architecture and functional capacity in elderly patients with knee osteoarthritis: a randomized controlled trial.

OBJECTIVES: To determine the effects of low-level laser therapy in combination with neuromuscular electrical stimulation on the muscle architecture and functional capacity of elderly patients with knee osteoarthritis. DESIGN: A randomized, evaluator-blinded clinical trial with sequential allocation of patients to three different treatment groups. SETTING: Exercise Research Laboratory. SUBJECTS: A total of 45 elderly females with knee osteoarthritis, 2-4 osteoarthritis degrees, aged 66-75 years. INTERVENTION: Participants were randomized into one of the following three intervention groups: electrical stimulation group (18-32 minutes of pulsed current, stimulation frequency of 80 Hz, pulse duration of 200 µs and stimulation intensity fixed near the maximal tolerated), laser group (low-level laser therapy dose of 4-6 J per point, six points at the knee joint) or combined group (electrical stimulation and low-level laser therapy). All groups underwent a four-week control period (without intervention) followed by an eight-week intervention period. MAIN MEASURES: The muscle thickness, pennation angle and fascicle length were assessed by ultrasonography, and the functional capacity was assessed using the 6-minute walk test and the Timed Up and Go Test. RESULTS: After intervention, only the electrical stimulation and combined groups exhibited significant increases in the muscle thickness (27%-29%) and pennation angle (24%-34%) values. The three groups exhibited increased performance on the walk test (5%-9%). However, no significant differences in terms of functional improvements were observed between the groups. CONCLUSIONS: Neuromuscular electrical stimulation reduced the deleterious effects of osteoarthritis on the quadriceps structure. Low-level laser therapy did not potentiate the effects of electrical stimulation on the evaluated parameters.

Inibição muscular dos extensores do joelho em sujeitos acometidos por condromalácia patelar e osteoartrite do joelho - um estudo de revisão sistemática / Knee extensor muscle inhibition in subjects with chondromalacia patellae and knee osteoarthritis - a systematic review

A inibição muscular (IM) tem sido reportada como um dos fatores associados à fraqueza muscular presente na osteoartrite (OA) e condromalácia patelar (CP), sendo inclusive associada com a etiologia e a progressão. Entretanto, parece existir uma lacuna na literatura em relação a estudos de revisão que avaliaram o grau de IM de sujeitos acometidos por CP e OA. O objetivo do estudo foi reunir os resultados de estudos que investigaram o grau de IM na OA e CP e identificar possíveis diferenças na IM que estejam associadas aos estágios do processo degenerativo. Foram incluídos nesta revisão sistemática estudos transversais e/ou experimentais publicados nas bases de dados PubMed, Scopus, SciELO e Cochrane entre 1990 e 2010 que avaliaram a IM por meio da técnica de interpolação de abalo publicados. Os dados referentes à população, protocolo de IM, qualidade dos estudos e resultados de IM foram sumariados e apresentados em Tabelas. Para análise da qualidade, utilizou-se a escala de PEDro. Após a aplicação dos critérios de inclusão, 13 artigos foram incluídos na revisão sistemática (OA=9 e CP=4). A partir da análise dos dados, observou-se uma IM maior na CP em comparação à OA. Contudo, a variabilidade metodológica e a falta de informações sobre os protocolos de IM indicam a necessidade de novos estudos experimentais a fim de que se possa determinar com maior precisão a relação entre a IM e as doenças degenerativas articulares.

Muscle inhibition (MI) has been reported as one of the factors associated with muscle weakness present in osteoarthritis (OA) and chondromalacia patellae (CP), including being associated with the etiology and progression. However, there seems to be a gap in the literature regarding the review studies that assessed the degree of IM subjects affected by CP and OA. The main objective of study was bringing together the results of studies that investigated the degree of OA in the MI and CP and to identify possible differences in IM which are linked to stages of the degenerative process. We included cross-sectional and/or experimental studies published in the databases PubMed, Scopus, SciELO and Cochrane between 1990 and 2010 that evaluated the MI through interpolation twitch techniques. Data on population characteristics, MI protocol, quality of studies and MI results were summarized and presented in Tables. For quality analysis, it was used the scale PEDro. After applying the inclusion criteria, 13 articles were included in the systematic review (OA=9 and CP=4). Based on the analysis of the data, there MI>CP compared to OA. However, the variability of protocols, as well as the lack of information about the IM protocols, indicates the need for further experimental studies in order that we can determine more precisely the relationship between IM and degenerative joint diseases.