Physiological and Hemodynamic Effects of Blood Flow Restriction Training on Quadriceps.
It is known that the greater weekly physical exertion the lower the death risk because of myocardial infarction (5). High-intensity resistance training (RT) is considered as one of the main strategies in the prevention of cardiovascular diseases, and it has been shown as one of the factors for improving primary and secondary disease prevention (5). In addition to the hemodynamic advantages and the reduced risk of death, the high-intensity RT also improves physiological factors.
However, it is apparent that individuals with some pathology or some type of a lesion are limited biomechanically when performing maximum exertion. Because of this, the Japanese developed a technique of RT so that people with a limitation for maximum exertion can have the same benefits of those who train at high-intensity. For example, the Kaatsu training or low-intensity RT with blood flow restriction (BFR) (4,5) is purported to provide benefits of high-intensity RT.
Low-intensity RT coupled with BFR alters various hemodynamic and physiological factors in the human body, such as double product (DP), lactate (La), oxygen saturation ([O.sub.2]), systolic blood pressure (SBP), and diastolic blood pressure (DBP) (5,6,11). In addition to being a technique used for cardiovascular improvement and in some cases for rehabilitation (6,7), the Kaatsu technique also benefits force-generating capacity and endurance.
It is already known that RT with BFR can generate hypertrophy and some hemodynamic changes (7,8,11,13), but few studies have been done with large muscle groups. Thus, the aim of the present study is to verify the physiological and hemodynamic effects of vascular occlusion in the acute squatting exercise.
The subjects in this study consisted of 30 men who were healthy and physically active recreational bodybuilders for at least 6 months. They had no metabolic complications or ostheomyoarticular issues (Table 1). Ten subjects were randomly placed into three different groups: (a) low-intensity with BFR (LI); (b) high-intensity without BFR (HI); and (c) control (CON).
The subjects made four visits to the UniCEUB with a 48-hr interval. The time was standardized from 11:00 a.m. to 12:00 a.m. in order to minimize circadian variations. The 1st day was to sign a consent form and sample characterization, the 2nd day was for the 1RM test, the 3rd day was for retesting 1RM and protocol familiarization, and the 4th day consisted of carrying out the training. The control group visited the UniCEUB two times. The 1st visit was for sample characterization and the 2nd consisted of data collection at rest.
To characterize the sample, the subjects' age in yrs, height and weight measured to the nearest 0 to 5 cm and 0 to 1 kg, respectively, using a stadiometer and Filizola[R] scale (Industria Filizola S/A, Brasil). Body mass index (BMI) was calculated as kilogram and square meter, fat percentage was determined using the 7 skinfolds of Jackson and Pollock (9) and Siri (10) formula (Table 1). The 1RM test and retesting was done using the protocol of Uchida et al. (11). The 1RM protocol was used to predetermine the load that was used on the training day, the 30% LI group of 1RM, and the 70% HI group of 1RM.
The training protocol used was adapted from Araujo et al. (1) and the exercise was the squat. The LI group performed 6 sets, 10 to 15 reps with a 90-sec recovery interval at 30% of 1RM. The BFR was performed bilaterally with pressure between 140 and 160 mmHg using the Kaatsu Master equipment (Kaatsu Global Inc., USA). The equipment was mounted with the individual standing, positioning in the proximal part of the thighs just below the gluteal fold and inguinal ligament. The HI group performed 6 sets, 10 to 15 reps with a 90-sec recovery interval at 70% of 1RM.
When the subjects arrived in the laboratory, they remained at rest for 15 min to collect the following variables: (a) Systolic blood pressure (SBP) and Diastolic blood pressure (DBP) using the auscultatory method with results expressed in mercury millimetres (mmHg); (b) Double product (DP) (1); (c) Oximetry (MD by Rossmax, SB100, Taiwan); and (d) Lactate (ROCHE DIAGNOSTICS, Accutrend Lactate, USA). The measurements were taken at the pre-training moment (T0), immediately after training (T1), and after the 15-min recovery (T2). This research was approved by the ethics committee of the University Educational Center of Brasilia (CEUB), and all subjects signed the informed consent form.
All analyses were performed using the SPSS 22 (IBM Corporation, Armonk, NY, USA, 24.0). The normality of the data was verified using the Shapiro-Wilk test. A 3 x 3 mixed factorial ANOVA was used to evaluate SBP, DBP, DP, Oximetry, and Lactate. The Bonferroni post-hoc was used to verify the differences between the groups. We adopted P[less than or equal to]0.05 as the level of statistical significance.
Table 1 shows the mean and standard deviation of the sample characterization data divided by groups.
Table 2 presents the means [+ or -] standard deviations of the physiological measurements in the three moments.
The present study examined the acute effects of the squatting exercise performed with and without BFR on DP, La, oximetry, SBP, and DBP in normotensive young subjects. The main finding was that there was only a significant difference between groups in the oximetry variable.
The ischemia caused by BFR can generate an increase in the metabolites concentration stimulating the muscular hypertrophy and less vasodilatation (6,11). Although the LI group had a significant lower result at moment T1 for [O.sub.2] than the HI group, there was no significant difference between the exercise groups at the moment T2 for La. Our results corroborate with the study of Tanimoto et al. (11) who found a significant difference in the moments post and 15 min after the exercise in relation to the pre-exercise moment.
In addition to the aforementioned factors, a reduction in [O.sub.2] caused by BFR may alter intramuscular oxygenation, increase the metabolic concentration (e.g., La) that produces more acidic and anabolic environment in addition to lowering the pH, and increase blood pressure via muscle metaboreflex (5,8,13).
The exercise protocols promoted an increase in DP in T1 and T2 moments on DP, but no differences were observed between the protocols. The results of Tanimoto et al. (11) and Vieira et al. (13) are in agreement with the present study. For practical applications of this variable, perhaps the important thing is to get to exhaustion with or without BFR.
The changes in SBP and DBP are explained because to the maximum effort during the protocols, in which the oxygen supply of the muscles was reduced causing accumulation of local metabolites, stimulation of chemoreceptors, increased HR and cardiac contractility (8). However, the individuals may not have actually performed a maximum effort, as the DBP at T1 moment did not show a significant difference in relation to the T0 moment in both exercise groups.
This result goes against the findings of Neto et al. (7) who found a significant difference in the SBP pre-exercise and 20 min after exercise in the high-intensity protocol, as well as the pre-exercise with 10 and 20 min after exercise in DBP in the low-intensity protocol with BFR. The findings of Neto et al. (7) are in agreement with Maior et al. (3) who found significant differences between post-exercise and rest in both SBP and DBP in both exercise groups.
Neto et al. (7) also found significant difference in SBP but only after 30 min of post-exercise rest in the group that underwent training with low-intensity and BFR, which goes against our study that found this difference immediately after exercise. Perhaps the protocol used by Neto et al. (7) was not the most appropriate, taking into account that the study used upper and lower limbs, agonist muscles and antagonists.
The SBP results in both exercise groups in T2 were significantly lower in relation to T1. This finding can be explained because of an increase in nitric oxide synthase that promotes positive changes in the endothelium (7). Or, it could also be due to the decreased cardiac output that was not completely compensated by the increase in systemic peripheral vascular resistance (3,9).
The present study found that lactate was significantly higher in both exercise groups at T1 and T2 moments compared to T0. The accumulation of lactate is related to the release of growth hormone and muscle hypertrophy (8,11). Individuals who for some reason cannot train intensively can use a lower intensity plus BFR to produce the same benefits.
Vieira et al. (13) found similar hemodynamic changes in young and older subjects. But, as the researchers pointed out, they would not know if it would be possible to extrapolate such findings to large muscle groups. Our study has confirmed such findings in young people with the second exercise that more recruits muscles, the squatting (12).
Some results that were not significant must have occurred because to the choice of the intensity protocols, or even the chosen exercise, which demands a great physical effort (5). Thereby, comparing results in the BFR area of research is a difficult task, since different researchers use different protocols, either in the exercise, in the intensity, or in the moments of variables collected. It is suggested for future studies that there is collection of oxygen saturation for BRF confirmation, the identification of different exercises, and the formalization of a BFR protocol type.
The squatting exercise with or without BFR improved the subjects' hemodynamics variables and increased the production of metabolic sub-products during exercise. For some reason, therefore, if a person cannot perform a high-intensity exercise, then a low-intensity exercise can be used with BFR to get the same results as a high-intensity exercise.
We would like to thank the "Centro Universitario de Brasilia, UniCEUB" for your remarkable support on this article.
Address for correspondence: Professor Sacha Clael, Faculty of Physical Education, University of Brasilia, Universidade de Brasilia, Campus Darcy Ribeiro, Asa Norte, Brazil, Email: email@example.com
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Marcio Rabelo Mota (1,2), Julia Ester Cavalcante da Fonseca, Samuel Barbosa Mezavila Abdelmur, Mateus Medeiros Leite, Alessandro Oliveira Silva, Renata Aparecida Elias Dantas, Sacha Clael (3)
(1) University Center of Brasilia--UniCEUB, Brasilia, Brazil, (2) University Center of Anapolis--UniEVANGELICA, Anapolis, Goiania, (3) Faculty of Physical Education, University of Brasilia --UnB, Brasilia, Brazil
Table 1. Descriptive Data of the Subjects. LI HI (n = 10) (n = 10) Age (yrs) 27.20 [+ or -] 6.89 24.50 [+ or -] 6.00 Weight (kg) 82.43 [+ or -] 16.28 78.68 [+ or -] 8.14 Height (m) 1.75 [+ or -] 0.77 1.79 [+ or -] 0.70 BMI (kg*[m.sup.-2]) 26.26 [+ or -] 3.18 24.57 [+ or -] 2.18 Body Fat (%) 14.20 [+ or -] 5.30 13.33 [+ or -] 5.12 Control (n = 10) Age (yrs) 21.20 [+ or -] 2.70 Weight (kg) 79.76 [+ or -] 10.52 Height (m) 1.78 [+ or -] 0.75 BMI (kg*[m.sup.-2]) 25.20 [+ or -] 3.13 Body Fat (%) 15.72 [+ or -] 6.01 BMI = Body Mass Index, HI = High Intensity Group, LI = Low Intensity Group, CON = Control Group, kg = kilograms, m = meters, % = percentage Table 2. Physiological Comparison between the Three Moments. T0 LI HI DP 8994.80 [+ or -] 2254.78 9252.40 [+ or -] 1406.33 La 2.21 [+ or -] 0.83 2.32 [+ or -] 0.73 [O.sub.2] 96.00 [+ or -] 1.56 94.80 [+ or -] 0.92 SBP 124.50 [+ or -] 9.12 122.90 [+ or -] 8.70 DBP 65.00 [+ or -] 6.53 67.70 [+ or -] 8.56 T0 CON DP 7110.80 [+ or -] 961.14 ([dagger][section]) La 4.67 [+ or -] 0.80 ([dagger][section]) [O.sub.2] 96.60 [+ or -] 1.50 ([section]) SBP 116.50 [+ or -] 4.33 DBP 67.20 [+ or -] 4.39 T1 LI DP 22927.28 [+ or -] 3587.40 (*) La 7.66 [+ or -] 3.04 (*) [O.sub.2] 93.60 [+ or -] 0.84 (*) SBP 158.80 [+ or -] 19.19 (*) DBP 69.90 [+ or -] 9.42 T1 HI DP 26271.80 [+ or -] 4310.95 (*) La 9.37 [+ or -] 2.83 (*) [O.sub.2] 95.90 [+ or -] 1.91 ([dagger]) SBP 160.60 [+ or -] 18.56 (*) DBP 72.50 [+ or -] 7.72 T1 CON DP 7386.00 [+ or -] 1419.76t ([dagger][section]) La 4.05 [+ or -] 1.22t ([dagger][section]) [O.sub.2] 97.40 [+ or -] 1.43 ([dagger]) SBP 118.00 [+ or -] 4.21t ([dagger][section]) DBP 66.00 [+ or -] 7.00 T2 LI DP 11390.70 [+ or -] 3318.35 (*[dagger]) La 5.82 [+ or -] 1.37 (*) [O.sub.2] 95.00 [+ or -] 0.47 SBP 125.30 [+ or -] 18.02 ([dagger]) DBP 71.20 [+ or -] 8.88 (*) T2 HI DP 10520.10 [+ or -] 2423.95 (*[dagger]) La 6.06 [+ or -] 2.22 (*[dagger]) [O.sub.2] 95.60 [+ or -] 2.46 SBP 116.80 [+ or -] 8.93 ([dagger]) DBP 67.70 [+ or -] 5.83 T2 CON DP 7019.20 [+ or -] 1134.32t ([dagger][section]) La 3.39 [+ or -] 0.87t ([dagger][section]) [O.sub.2] 95.40 [+ or -] 2.41 SBP 114.60 [+ or -] 5.00 DBP 65.00 [+ or -] 5.27 T0 = pretest, T1 = posttest, T2 = 15 minutes after test, HI = High Intensity Group, LI = Low Intensity Group, CON = Control Group, DP = Double Product, La = Lactate, O2 = Oximetry, SBP = Systolic Blood Pressure, DBP = Diastolic Blood Pressure, (*) Significant difference intragroup regarding T0 (P[less than or equal to]0.05). ([dagger]) Significant difference intragroup regarding T2 (P[less than or equal to]0.05). tSignificant difference regarding LI (P[less than or equal to]0.05), ([section])Significant difference regarding HI (P[less than or equal to]0.05)
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|Author:||Mota, Marcio Rabelo; da Fonseca, Julia Ester Cavalcante; Abdelmur, Samuel Barbosa Mezavila; Leite, M|
|Publication:||Journal of Exercise Physiology Online|
|Date:||Jun 1, 2018|
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