Hip passive stiffness is associated with hip kinematics during single-leg squat.

INTRODUCTION: Single-leg squat (SLS) is a test commonly used to assess lower limb function in rehabilitation. Increased hip adduction and internal rotation (IR) is associated with dynamic knee valgus, which is related to hip and knee overload. Proximal and distal factors, such as hip passive stiffness, poor hip muscle strength and excessive foot misalignment may influence hip movement. However, previous studies focus on how proximal and distal factors affected knee joint movement and did not reported the influence on hip joint. OBJECTIVE: This study investigated the association of hip external rotators (ER) strength, hip passive stiffness and shank-forefoot alignment (SFA) with hip adduction and IR during SLS. DESIGN: Cross-sectional study. METHOD: Forty-six health participants of both sexes (23.47 ± 4.29 years, 60.40 ± 11.28 kg, 1.67 ± 8.9 m) had SFA, hip ER torque, hip passive stiffness and hip kinematics assessed. Multiple linear regressions were performed to identify the factors which associated with mean and peak hip adduction and IR movement during SLS. RESULTS: Only hip passive stiffness was associated with mean (R2 = 0.164; Confidence Interval (CI) 95% = [-0.250, -0.048]; p = 0.005) and peak (R2 = 0.116; CI 95% = [-0.223, -0.210]; p = 0.019) hip IR movement. CONCLUSION: Hip passive stiffness was associated with mean and peak hip IR movement during the SLS. These results suggest that individuals with reduced hip passive stiffness may demonstrate increased hip IR movement during SLS.

Correlation between goniometric and photogrammetric assessment of shank-forefoot alignment in athletes.

BACKGROUND: The shank-forefoot alignment (SFA) measurement has been previously developed to enhance the applicability of foot alignment measurement in sports preseason assessment because it is reliable and less time consuming. The use of SFA measurements in the clinical context, usually done with photogrammetry, may be simplified by using the universal goniometer and no longer requiring the image processing step that takes additional time and equipment. OBJECTIVE: Investigate the correlation between the goniometric and photogrammetric assessment of shank-forefoot alignment in athletes. PARTICIPANTS: Thirty volleyball athletes were recruited during a preseason assessment. METHODS: SFA measurements were assessed with a universal goniometer and photogrammetry. For both assessments the participants were positioned in prone with the rearfoot facing up and the ankle actively maintained in 90° of dorsiflexion. The examiner did not have access to the SFA outcome values from both measurements. A second examiner did the bi-dimensional analysis with SIMI MOTION (photogrammetric measure) and read the goniometer measures during the other SFA assessment. Data normality was tested using Shapiro-Wilk test and Pearson was used to determine the correlation between both measurements. RESULTS: A reliability study determined the Intraclass Correlation Coefficient (ICC3,3) for intra-rater reliability of 0.93 for photogrammetry and of 0.81 for goniometry assessment. The correlation (p < 0.001) between these two measurements was 0.71, which indicates a moderate relationship. CONCLUSIONS: This study describes a reliable and practical measurement procedure for shank-forefoot alignment using the universal goniometer that can be easily applied in clinical context.

Correlation between indexes of autonomic maneuvers and heart rate variability in hemodialysis patients.

PURPOSE: The autonomic maneuvers are simple methods to evaluate autonomic balance, but the association between autonomic maneuvers and heart rate variability (HRV) in hemodialysis patients remains unknown. This study aimed to evaluate the correlation between HRV and respiratory sinus arrhythmia (RSA) and Valsalva maneuver (VM) indexes in hemodialysis patients and to compare two methods for RSA indexes acquisitions. METHODS: Forty-eight volunteers on hemodialysis (66.7 % men) were evaluated by VM, RSA, and 24 h Holter monitoring. At the VM, the Valsalva index (VI) was the variable considered. In the RSA, the ratio and difference between the RR intervals of inspiratory and expiratory phase (E:I and E-I, respectively) were considered by traditional form (average of respiratory cycles) and independent respiratory cycles (E:Iindep and E-Iindep). The HRV indexes evaluated were standard deviation of all normal RR intervals (SDNN), standard deviation of sequential 5-min RR interval means (SDANN), root mean square of the successive differences (rMSSD) and percentage of adjacent RR intervals with difference of duration greater than 50 ms (pNN50). RESULTS: The SDNN, SDANN showed significant correlation with all classic indexes of RSA (E:I: r = 0.62, 0.55, respectively, E-I: r = 0.64, 0.57, respectively), E:Iindep (r = 0.59, 0.54, respectively), E-Iindep (r = 0.47, 0.43, respectively) and VI (r = 0.42, 0.34, respectively). Significant correlation of rMSSD with E:I (r = 0.37), E-I (r = 0.41) and E:Iindep (r = 0.34) was also observed. There was no association of any variable with pNN50. Have been show high values for all variables of independent cycles method (p < 0.05). CONCLUSION: The autonomic maneuvers, especially RSA, are useful methods to evaluate cardiac autonomic function in hemodialysis patients. The acquisition of the RSA index by independent cycles should not be used in this population.