Correlation Between HRV and Performance in Eccentric Resistance Training Associated With Partial Blood Flow Restriction
Condition: Exercise
Study type: Interventional

Summary: 
      Studies on resistance training (RT) associated with blood flow restriction (BFR) is an
      alternative method of gaining strength and hypertrophy muscle. However, there is a gap
      correlated to autonomic repercussion of BFR and performance. Thus, it becomes relevant to
      investigate this type of training in post-exercise. Objective: investigate and compare
      autonomic and performance responses of 6 weeks of eccentric RT with different intensities
      associated or not to BFR in healthy youngsters. Method: This is a randomized clinical trial
      including 60 healthy men aged 18-35 years, divided into four groups according to exercise
      intensity and BFR: 80% without BFR, 40% without BFR, 80% with BFR and 40% with BFR. Exercise
      intensity will be determined by the peak of excentric torque on the isokinetic dynamometry
      method and by the BFR, as being 40% of the intensity required for the complete examination of
      the blood flow evaluated by Doppler. Participants will do an eccentric femoral quadriceps
      muscle exercise session on the isokinetic dynamometer according to the previously randomized
      group. For recovery analyzes, it will be used: the root-mean-square of the successive normal
      sinus RR interval difference (rMSSD); high frequency (HF) ms²; HF(nu) and the standard
      deviation of instantaneous beat-to-beat interval variability (SD1). For performance, it will
      be used the single leg hop test.

      For data analysis of the population profile, the descriptive statistical method will be used
      and the results will be presented with values of means, standard deviations, median and
      confidence interval. Initially, participants from all study groups will be dichotomized at
      each performance outcome (muscle strength test on the isokinetic dynamometer and vertical
      jump test) as "improvement" or "without improvement" in order to demonstrate the behavior of
      the responses obtained during the training, that is, whether the individual responded to the
      RT or not. It is worth mentioning that this qualitative analysis will be performed
      considering the data obtained from the initial, intermediate and final evaluation.

      The dichotomization of the results of the functional tests will be performed by the typical
      error of the sample measurement for each test. It will be considered as "improvement" if the
      participant presents gains in tests above the typical error of the measure. The values
      obtained from the initial, intermediate and final evaluation will be analyzed independently.

      Subsequently, the weekly average of the vagal indices (rMSSD, HF and SD1) will be performed
      in the baseline moment and after 6 weeks of RT moment of each study group. In the sequence,
      the performance parameters will be correlated with the autonomic parameters in the respective
      groups. Pearson or Spearman correlation test will be used according to the normality of the
      data. The level of significance will be p <0.05 for all tests. The statistical program SPSS
      (Statistical Package for the Social Sciences) will be used for the analyzes.
    


Intervention name(s): Blood flow restriction
Intervention type(s): Other
Intervention description(s): an alternative method to produce strength and muscle hypertrophy with lower intensities
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Other
Keywords: resistance training; vascular occlusion; performance; autonomic nervous system; recovery of physiological function