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.

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.

Effects of cold water immersion on lower extremity joint biomechanics during running.

The purpose of this study was to identify the influence of cryotherapy on lower extremity running biomechanics. Twenty-six healthy male volunteers were randomised into two intervention groups: cold water (cold water at ~11°C) or tepid water (tepid water at ~26°C). They were required to run at 4.0 ± 0.2 m · s(-1) before and after they underwent water immersion for 20 min. Differences between pre- and post-intervention were used to compare the influence of water intervention during running. Peak joint angles, peak joint moments, peak ground reaction forces (GRF) and contact time (CT) were calculated using three-dimensional gait analysis. Independent t-tests were applied with a significant alpha level set at 0.05. Decreased peak propulsive and vertical GRF, decreased plantarflexion moments, increased hip flexion angle and longer CT were observed following cold water immersion. Although cold water immersion (cryotherapy) affected the running movement, none of the alterations have been related to running biomechanical patterns associated with injuries. Therefore, our results indicated that cold water immersion appears safe prior to running activities.

Obese children experience higher plantar pressure and lower foot sensitivity than non-obese.

BACKGROUND: Children obesity is a risk factor for several dysfunctions and diseases, with negative effects on the morphology of the locomotor system, plantar pressure and body stability. A relationship between postural control and sensorimotor information has been assumed. However, there is few data on the effects of children obesity on the availability of sensorial information from the foot during standing. METHODS: Twenty obese and twenty non-obese children were evaluated for foot sensitivity and plantar pressure during unipedal and bipedal stance. Data were compared between obese and non-obese participants, between foot regions and between legs. FINDINGS: Obese children experiences higher plantar pressure and have lower foot sensitivity than non-obese. Additionally, obese children had similar sensitivity for different foot regions, as compared to the non-obese. INTERPRETATION: Children obesity negatively influences foot sensitivity. Bipedal stance seemed more sensitive to differentiate between obese and non-obese. Higher plantar pressure and lower foot sensitivity in obese children may affect performance of weight bearing activities, contribute to higher risk of foot injuries and have potential implication for children footwear design and clinical physical examination.