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Abstract

Total occlusion pressure (TOP) is an important variable to ischaemic exercise training because the optimal pressure of flow restriction (OPR), applied during this exercise modality, is derived from it. Despite the common use of Doppler ultrasound (DU) to determine the TOP, the reproducibility of this assessment was not evaluated yet. Given this, the objective was to evaluate the reproducibility of DU for the measurement of TOP in upper limbs and determine the predictive variables. Thirteen male volunteers attended three times to the laboratory. On the 1st day, we assessed arm circumference (AC), systolic blood pressure (SBP) and diastolic (DBP), and brachial artery TOP. On 2nd and 3rd days, only TOP was assessed. We found a coefficient of variation of 5·6% and an intraclass correlation coefficient of 0·795 for the DU. In the analysis of TOP predictive variables, the Spearman coefficients (R) were 0·813 (SBP), 0·786 (DBP) and 0·388 (AC). Therefore, these results support that DU has good reproducibility for the TOP and that SBP and DBP should be considered to the determination of TOP in upper limbs.

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... Currently, it is known that BFRP needs to be individualized and adequate to limit muscle arterial blood flow partially with a recommended 40-80% of total restriction pressure . Variables such as cuff width, limb circumference, ankle-brachial index, fat and muscle thickness, arterial stiffness, endothelial function, and blood pressure may influence BFRP (Loenneke et al., , 2015Hunt et al., 2016;Jessee et al., 2016;Bezerra de Morais et al., 2017). Doppler ultrasound (Bezerra de Morais et al., 2017), handheld Doppler (Laurentino et al., 2018), pulse oximetry (Zeng et al., 2019), and predictive equations (Hunt et al., 2016) have been proposed to adequately obtain and individually prescribe BFRP to maximize benefits and minimize discomfort/risks during BFR exercise (Singer et al., 2020;Spitz et al., 2020). ...
... Variables such as cuff width, limb circumference, ankle-brachial index, fat and muscle thickness, arterial stiffness, endothelial function, and blood pressure may influence BFRP (Loenneke et al., , 2015Hunt et al., 2016;Jessee et al., 2016;Bezerra de Morais et al., 2017). Doppler ultrasound (Bezerra de Morais et al., 2017), handheld Doppler (Laurentino et al., 2018), pulse oximetry (Zeng et al., 2019), and predictive equations (Hunt et al., 2016) have been proposed to adequately obtain and individually prescribe BFRP to maximize benefits and minimize discomfort/risks during BFR exercise (Singer et al., 2020;Spitz et al., 2020). ...
... Also, BFR training can increase exercise pressor reflex, which is a reflex-mediated cardiovascular response, via engagement of the muscle metaboreflex (Sundblad et al., 2018;Cristina-Oliveira et al., 2020) and cardiac autonomic changes . Additionally, systolic blood pressure is directly proportional to BFRP (Loenneke et al., 2015;Bezerra de Morais et al., 2017), and studies showed SBP to reduce over weeks of BFR training (Cezar et al., 2016;Kambič et al., 2019). ...
Article
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Blood flow restriction (BFR) training combines exercise and partial reduction of muscular blood flow using a pressured cuff. BFR training has been used to increase strength and muscle mass in healthy and clinical populations. A major methodological concern of BFR training is blood flow restriction pressure (BFRP) delivered during an exercise bout. Although some studies increase BFRP throughout a training intervention, it is unclear whether BFRP adjustments are pivotal to maintain an adequate BFR during a training period. While neuromuscular adaptations induced by BFR are widely studied, cardiovascular changes throughout training intervention with BFR and their possible relationship with BFRP are less understood. This study aimed to discuss the need for BFRP adjustment based on cardiovascular outcomes and provide directions for future researches. We conducted a literature review and analyzed 29 studies investigating cardiovascular adaptations following BFR training. Participants in the studies were healthy, middle-aged adults, older adults and clinical patients. Cuff pressure, when adjusted, was increased during the training period. However, cardiovascular outcomes did not provide a plausible rationale for cuff pressure increase. In contrast, avoiding increments in cuff pressure may minimize discomfort, pain and risks associated with BFR interventions, particularly in clinical populations. Given that cardiovascular adaptations induced by BFR training are conflicting, it is challenging to indicate whether increases or decreases in BFRP are needed. Based on the available evidence, we suggest that future studies investigate if maintaining or decreasing cuff pressure makes BFR training safer and/or more comfortable with similar physiological adaptation.
... This is important to establish because, in an effort to save time, some clinicians might apply the LOP from one leg to the contralateral, or the LOP from a physical rehabilitation session to a later session. Further, while the relations between intrinsic characteristics and AOP have been investigated before (Bezerra de Morais et al., 2017;Hunt et al., 2016;Jessee et al., 2016;Loenneke et al., 2012), these relations have not been studied extensively when using the BFR device to measure LOP. ...
... It was hypothesized that LOP would be similar but not identical between days and legs and that it would vary more between days than it would between legs on the same day (Hughes et al., 2018). It was also hypothesized that SBP and thigh circumference would explain a considerable proportion of the variance in LOP as suggested by previous research using AOP measures (Bezerra de Morais et al., 2017;Hunt et al., 2016;Jessee et al., 2016;Loenneke et al., 2012). ...
... SBP, DBP, MAP, PP, and thigh circumference did not demonstrate evidence of a difference between legs or days when averaged across participants, similar to LOP. Thus, given the previously demonstrated relations between these or similar intrinsic characteristics and AOP, it is expected that LOP would not be different as assessed by the LMM (Bezerra de Morais et al., 2017;Hunt et al., 2016;Jessee et al., 2016;Loenneke et al., 2012). Had there been differences in these intrinsic characteristics between days or legs, it is possible that a difference in LOP would have been observed in the LMM as well, especially in light of the strong associations between PP and thigh circumference found in the present study. ...
Article
Objective Assess lower-extremity blood flow restricted exercise (BFR) limb occlusion pressure (LOP) variability and identify related intrinsic characteristics using a portable Delphi BFR system. Design Repeated measures. Setting Laboratory. Participants Forty-two healthy males (n = 25) and females (n = 17) (25.8 ± 5.2 y, 1.76 ±0 .09 m, 78.9 ± 14.9 kg) completed two visits. Brachial artery blood pressure, thigh circumferences (TC), and LOP were measured supine. Main outcome measures Linear mixed-effects models (LMM) and generalizability theory were used to evaluate LOP between legs and days, determine intrinsic characteristic relations, and assess random variance components. Results LOP was not different between legs (p = .730) or days (p = .916; grand mean = 183.7 mmHg [178.4, 189.1]). LOP varied significantly between participants (p = .011, standard error = 47.3 mmHg). 47% of LOP variance was between participants, 18% and 6% was within participants between days and legs, respectively, and 28% was associated with random error. The relative error variance was 14.4 mmHg. Pulse pressure (PP) (p = .005) and TC (p = .040) were positively associated with LOP. A LMM including PP and TC predicted LOP with a mean absolute difference of 11.1 mmHg [9.7, 12.6] compared to measured LOP. Conclusions The relative error variance suggests that clinicians should measure LOP consistently for each patient to ensure BFR safety and effectiveness.
... Calculation of arterial occlusive pressure (AOP) involves determination of the pressure required to fully occlude arterial flow to the involved limb (AORN Recommended Practices Committee, 2007). This is most often achieved using Doppler ultrasound (Bezerra de Morais et al., 2016) and can be used to prescribe pressure at a relative percentage of AOP to standardise the level of occlusion across cohorts (Laurentino et al., 2012;Hughes et al., 2017;. ...
... In this study, the pneumatic tourniquet system appeared to have high reproducibility (>0.953) with a COV of less than 2.97% across all the body positions examined. These findings are similar to a recent study examining the reliability of Doppler ultrasound for calculating total AOP in the upper limbs (Bezerra de Morais et al., 2016). The authors calculated AOP using Doppler ultrasound in 13 male volunteers across three repeated measures, reporting an ICC of 0.795 and a COV of 5.6%. ...
Article
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Background Total arterial occlusive pressure (AOP) is used to prescribe pressures for surgery, blood flow restriction exercise (BFRE) and ischemic preconditioning (IPC). AOP is often measured in a supine position; however, the influence of body position on AOP measurement is unknown and may influence level of occlusion in different positions during BFR and IPC. The aim of this study was therefore to investigate the influence of body position on AOP. Methods Fifty healthy individuals (age = 29 ± 6 y) underwent AOP measurements on the dominant lower-limb in supine, seated and standing positions in a randomised order. AOP was measured automatically using the Delfi Personalised Tourniquet System device, with each measurement separated by 5 min of rest. Results Arterial occlusive pressure was significantly lower in the supine position compared to the seated position (187.00 ± 32.5 vs 204.00 ± 28.5 mmHg, p < 0.001) and standing position (187.00 ± 32.5 vs 241.50 ± 49.3 mmHg, p < 0.001). AOP was significantly higher in the standing position compared to the seated position (241.50 ± 49.3 vs 204.00 ± 28.5 mmHg, p < 0.001). Discussion Arterial occlusive pressure measurement is body position dependent, thus for accurate prescription of occlusion pressure during surgery, BFR and IPC, AOP should be measured in the position intended for subsequent application of occlusion.
... A recent study found a significant correlation between the brachial artery occlusion pressure measurements performed over 3 nonconsecutive days, using a Doppler US (ICC = 0.795). The authors concluded that the measurement was reliable with a CV of 5.6% (2). Despite the correlation found, it is insufficient to appropriately compare 2 measurements, because the correlation coefficient is a measure of the strength of the relationship between 2 variables, not of the agreement between them (3). ...
... It is known that blood flow increases during the exercise and the arterial occlusion pressure may change across repetitions (1); however, setting the pressure off of resting arterial occlusion pressure is presently a standard practice. In addition, the measurements were performed only at one time point; nonetheless, this measurement has demonstrated good reproducibility in the determination of arterial occlusion pressure level by the Doppler US over several days (2). ...
Article
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Laurentino, GC, Loenneke, JP, Mouser, JG, Buckner, SL, Counts, BR, Dankel, SJ, Jessee, MB, Mattocks, KT, Iared, W, Tavares, LD, Teixeira, EL, and Tricoli, V. Validity of the handheld Doppler to determine lower-limb blood flow restriction pressure for exercise protocols. J Strength Cond Res XX(X): 000-000, 2018-Handheld (HH) Doppler is frequently used for determining the arterial occlusion pressure during blood flow restriction exercises; however, it is unknown whether the blood flow is occluded when the auscultatory signal is no longer present. The purpose of this study was to assess the validity between the HH Doppler and the Doppler ultrasound (US) measurements for determining the arterial occlusion pressure in healthy men. Thirty-five participants underwent 2 arterial occlusion pressure measurements. In the first measure, a pressure cuff (17.5 cm wide) was placed at the most proximal region of the thigh and the pulse of posterior tibial artery was detected using an HH Doppler probe. The cuff was inflated until the auscultatory pulse was no longer detected. After 10 minutes of rest, the procedure was repeated with the Doppler US probe placed on the superficial femoral artery. The cuff was inflated up to the point at which the femoral arterial blood flow was interrupted. The point at which the auscultatory pulse and blood flow were no longer detected was deemed the arterial occlusion pressure. There were no significant differences in arterial occlusion pressure level between the HH Doppler and the Doppler US (133 [±18] vs. 135 [±17] mm Hg, p = 0.168). There was a significant correlation (r = 0.938, p = 0.168), reasonable agreement, and a total error of the estimate of 6.0 mm Hg between measurements. Arterial occlusion pressure level determined by the HH Doppler and the Doppler US was similar, providing evidence that the HH Doppler is a valid and practical method.
... Moreover, the cuff pressure is of particular importance, as it is intended to induce the above mentioned mechanisms that, in turn, promote the desired physiological adaptations without potential harmful consequences (e.g., adverse cardiovascular events) (65,113). However, the supposed optimal cuff pressure is influenced by various moderator variables (113), e.g., (a) cuff width (41,81), (b) cuff material (18), (c) cuff shape (43,121), (d) individual's blood pressure (17,41,58) (e) individual limb characteristics (e.g., circumferences), (12,58), (f) body position (36,98), (g) position of the cuff tube (100), and (h) initial restriction pressure (45,46,114). Therefore, it is recommended to set the cuff pressure relative to these moderator variables (16,77,89). ...
... From a methodological point of view, specific equipment (e.g., pneumatic cuffs and Doppler ultrasound) and appropriate skills are required to set a personalized cuff pressure in relation to the subjects' individual AOP. Commonly, the AOP is determined using pneumatic cuffs that are inflated incrementally until the arterial blood flow distal to the cuffs is no longer present (e.g., at the posterior tibial or radial artery for the lower or upper limbs, respectively) (12,17,80). In this respect, valid measuring devices to quantify the arterial blood flow, such as Doppler ultrasound or pulse oximetry, are required to determine the optimal cuff pressure for BFR training (52,122). ...
Article
Bielitzki, R, Behrendt, T, Behrens, M, and Schega, L. Current techniques used for practical blood flow restriction training: a systematic review. J Strength Cond Res XX(X): 000-000, 2021-The purpose of this article was to systematically review the available scientific evidence on current methods used for practical blood flow restriction (pBFR) training together with application characteristics as well as advantages and disadvantages of each technique. A literature search was conducted in different databases (PubMed, Web of Science, Scopus, and Cochrane Library) for the period from January 2000 to December 2020. Inclusion criteria for this review were (a) original research involving humans, (b) the use of elastic wraps or nonpneumatic cuffs, and (c) articles written in English. Of 26 studies included and reviewed, 15 were conducted using an acute intervention (11 in the lower body and 4 in the upper body), and 11 were performed with a chronic intervention (8 in the lower body, 1 in the upper body, and 2 in both the upper and the lower body). Three pBFR techniques could be identified: (a) based on the perceptual response (perceived pressure technique), (b) based on the overlap of the cuff (absolute and relative overlap technique), and (c) based on the cuffs' maximal tensile strength (maximal cuff elasticity technique). In conclusion, the perceived pressure technique is simple, valid for the first application, and can be used independently of the cuffs' material properties, but is less reliable within a person over time. The absolute and relative overlap technique as well as the maximal cuff elasticity technique might be applied more reliably due to markings, but require a cuff with constant material properties over time.
... TOP is a measure that shows good reproducibility 20 and was determined according to the previous studies 5,20 . Briefly, the brachial artery blood flow of a dominant arm was detected by an ultrasound model SonoAceR3 (Samsung Medison -South Korea), by Power Doppler Technique -with 12 MHz linear transducers placed in the flexor crease of the elbow. ...
... TOP is a measure that shows good reproducibility 20 and was determined according to the previous studies 5,20 . Briefly, the brachial artery blood flow of a dominant arm was detected by an ultrasound model SonoAceR3 (Samsung Medison -South Korea), by Power Doppler Technique -with 12 MHz linear transducers placed in the flexor crease of the elbow. ...
Article
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Aim: To investigate the neuromuscular fatigue and recovery after an intermittent isometric handgrip exercise (IIHE) executed until failure with different blood flow restriction (BFR) conditions (free flow, partial and total vascular restriction). Methods: Thirteen healthy men carried out an IIHE at 45% of maximum voluntary isometric force (MVIF) until failure with total restriction (TR), partial restriction (PR) or free flow (FF). The rate of force development (RFD) was extracted from the MIVF over the time intervals of 0-30, 0-50, 0-100, and 0-200ms and normalized by MVIF [relative RFD (RFDr)]. Results: The RFDr decreased significantly (p<0.01) after the IIHE in all BFR conditions and time intervals studied, remaining lower for five minutes. The medians of the RFDr in FF condition were significantly lower (p=0.01) at 30ms (1.56 %MVIF·s⁻¹) and 50ms (1.70 %MVIF·s⁻¹) when compared to TR at 30ms (2.34 %MVIF·s⁻¹) and 50ms (2.63 %MVIF·s⁻¹) in minute 1 post failure. Conclusions: These results show that, regardless of the blood flow restriction level, there is no RFD recovery five minutes after an exhaustive IIHE. When the task was executed with FF, the reduction of the RFD was greater when compared with the TR condition.
... Second, few studies on IPC were concerned with individualizing the occlusion level. It has been proposed that a sufficient occlusion pressure to completely block blood flow should be applied to the member undergoing IPC (11) , but the use of arbitrary pressures may induce different stimuli between subjects due to individual factors such as limb circumference and systemic blood pressure (18,19) . Nevertheless, even if the usage of arbitrary pressure is enough to totally occlude the blood flow in all subjects (20) , the occlusion level may exceed by far the minimum amount necessary to fully occlude blood flow in some participants, thus raising the perception of pain or discomfort during IPC. ...
... During TOP determination, the Doppler transducer will be positioned at the mean distance between the medial malleolus of the tibia and the Achilles tendon. The pressure cuff (Aneroid sphygmomanometer Premium, Duque de Caxias-RJ; cuff width 20 cm) will be positioned around the sub-inguinal region in the non-dominant upper thigh and inflated based on a prior protocol (18) . TOP will be defined as the pressure at the time when arterial pulse is abolished, which will be indicated by the absence of auscultatory signal. ...
Article
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Background: Ischemic preconditioning (IPC) has been used to improve exercise performance, but its role in protecting against exercise-induced muscle damage (EIMD) is still unclear. Objective: To investigate the effects of IPC on the indirect markers of EIMD when compared to placebo. Methods: 30 healthy young men, with no recent experience in lower limb strength training, will be recruited. Subjects will be allocated randomly into two groups: IPC or placebo. The IPC group will undergo 4 x 5 min of occlusion (with individualized total occlusion pressure), interspersed with 5 min of reperfusion. The placebo group will be submitted to the same protocol, but with minimum pressure (10mmHg) being applied during the occlusion period. After the interventions, volunteers will be submitted to muscle damage induced by isokinetic exercise (10 sets of 12 maximum eccentric repetitions) in the non-dominant femoral quadriceps. The primary outcome will be isometric peak torque, measured both before and up to 72 hours after exercise. Secondary outcomes include rate of torque development, muscle soreness, knee range of motion, thigh circumference and blood levels of creatine kinase. Discussion: The results of this trial will indicate whether the effects of IPC are superior to placebo in the protection against EIMD. Study registry: This protocol was published on the Registro Brasileiro de Ensaios Clínicos (REBEC) with the registration number RBR- 8brxg7. Keywords: Blood Flow Restriction; Prevention; Eccentric Exercise; Muscle Recovery; Placebo Effect.
... 3,17,27,37,46,48,79 Currently, it is recommended that individual occlusion pressures be calculated as a percentage of the total arterial occlusion pressure (AOP), with individual protocols ranging from 60% to 80%. 35,40,69,84 The gold standard method of measuring AOP and true occlusion is Doppler ultrasound, 6,9,29,56,66 although recent investigations have begun to assess the feasibility of pulse oximetry as a lower maintenance alternative. 77,84 A previous method in the literature attempted to predict the AOP as a percentage of the brachial systolic blood pressure. ...
Article
Full-text available
Background Low-load blood flow restriction (BFR) training has attracted attention as a potentially effective method of perioperative clinical rehabilitation for patients undergoing orthopaedic procedures. Purpose To (1) compare the effectiveness of low-load BFR training in conjunction with a standard rehabilitation protocol, pre- and postoperatively, and non-BFR interventions in patients undergoing anterior cruciate ligament reconstruction (ACLR) and (2) evaluate protocols for implementing BFR perioperatively for patients undergoing ACLR. Study Design Systematic review; Level of evidence, 2. Methods A systematic review of the 3 medical literature databases was conducted to identify all level 1 and 2 clinical trials published since 1990 on BFR in patients undergoing ACLR. Patient demographics from included studies were pooled. Outcome data were documented, including muscle strength and size, and perceived pain and exertion. A descriptive analysis of outcomes from BFR and non-BFR interventions was performed. Results A total of 6 studies (154 patients; 66.2% male; mean ± SD age, 24.2 ± 3.68 years) were included. Of these, 2 studies examined low-load BFR as a preoperative intervention, 1 of which observed a significant increase in muscle isometric endurance ( P = .014), surface electromyography of the vastus medialis ( P < .001), and muscle blood flow to the vastus lateralis at final follow-up ( P < .001) as compared with patients undergoing sham BFR. Four studies investigated low-load BFR as a postoperative intervention, and they observed significant benefits in muscle hypertrophy, as measured by cross-sectional area; strength, as measured by extensor torque; and subjective outcomes, as measured by subjective knee pain during session, over traditional low-load resistance training (all P < .05). BFR occlusion periods ranged from 3 to 5 minutes, with rest periods ranging from 45 seconds to 3 minutes. Conclusion This systematic review found evidence on the topic of BFR rehabilitation after ACLR to be sparse and heterogeneous likely because of the relatively recent onset of its popularity. While a few authors have demonstrated the potential strength and hypertrophy benefits of perioperative BFR, future investigations with standardized outcomes, long-term follow-up, and more robust sample sizes are required to draw more definitive conclusions.
... First, an incremental increase in pressure by 50 mmHg, which was due to time constraints, may have decreased accuracy of LOP for the Delfi units. However, previous studies also used approximately 40-50 mmHg increments to observe total occlusion pressure with their BFR units (1). Second, our study design included a short rest period between applications of the different units. ...
Article
The purpose of this study was to compare the standing lower extremity limb occlusion pressure (LOP) between two units. It was hypothesized that the Delfi unit, which utilizes a wider cuff (11.5 cm), would require significantly less LOP as compared to the KAASTU unit, which utilizes a narrow cuff (5 cm). Twenty-nine healthy participants (22 men, 7 women) mean age 24 years old (± 1.7 SD) volunteered. The procedure was identical for each cuff, completed with 5 minutes of rest in between. The cuff was placed on the proximal left thigh in the standing position. The initial pressure was set to 50 mmHg and then increased in 50 mmHg increments until complete arterial occlusion was achieved or the unit went to its maximum pressure. Arterial blood flow was determined by a mobile ultrasound measured at the left popliteal artery. Paired samples t-tests were used to determine differences in LOP (mmHg) between the Delfi and KAATSU unit cuffs. Significant differences were observed between the cuffs (wide: 239.4 mmHg vs. narrow: 500 mmHg; p < 0.001). We were able to achieve complete arterial occlusion with the wide cuff. The KAATSU unit reached maximum pressure with all participants, therefore we were unable to achieve complete arterial occlusion with the narrow cuff. Although achieving complete arterial occlusion is not indicated or safe for BFR training, relative pressures are used and determined as a percentage of LOP. Our study found that the relative pressure of the wide cuff is lower than the narrow cuff.
... First, an incremental increase in pressure by 50 mmHg, which was due to time constraints, may have decreased accuracy of LOP for the Delfi units. However, previous studies also used approximately 40-50 mmHg increments to observe total occlusion pressure with their BFR units (1). Second, our study design included a short rest period between applications of the different units. ...
Article
Full-text available
The purpose of this study was to compare the standing lower extremity limb occlusion pressure (LOP) between two units. It was hypothesized that the Delfi unit, which utilizes a wider cuff (11.5 cm), would require significantly less LOP as compared to the KAASTU unit, which utilizes a narrow cuff (5 cm). Twenty-nine healthy participants (22 men, 7 women) mean age 24 years old (± 1.7 SD) volunteered. The procedure was identical for each cuff, completed with 5 minutes of rest in between. The cuff was placed on the proximal left thigh in the standing position. The initial pressure was set to 50 mmHg and then increased in 50 mmHg increments until complete arterial occlusion was achieved or the unit went to its maximum pressure. Arterial blood flow was determined by a mobile ultrasound measured at the left popliteal artery. Paired samples t-tests were used to determine differences in LOP (mmHg) between the Delfi and KAATSU unit cuffs. Significant differences were observed between the cuffs (wide: 239.4 mmHg vs. narrow: 500 mmHg; p < 0.001). We were able to achieve complete arterial occlusion with the wide cuff. The KAATSU unit reached maximum pressure with all participants, therefore we were unable to achieve complete arterial occlusion with the narrow cuff. Although achieving complete arterial occlusion is not indicated or safe for BFR training, relative pressures are used and determined as a percentage of LOP. Our study found that the relative pressure of the wide cuff is lower than the narrow cuff.
... The transducer (5 to 10 MHZ) of a portable vascular Doppler (DV 2001, MEDPEJ, Ribeirão Preto, Brazil) will be positioned at the ankle at a mean distance between medial malleolus and calcaneus tendon to capture the Table 2 Treatment protocol performed by the high-intensity resistance exercise group and blood flow restriction exercise group (adapted from Bryk et al. [15], The interval between sets will be 30 s and between exercises will be 2 min *Load is 60% of the 1-repetition maximum + The load will be adjusted every 3 weeks to maintain an effort perception between 6 and 7 on the Borg scale ‡ Load is 10% of the 1-repetition maximum auscultatory signal of the posterior tibial artery. A manufactured pneumatic cuff (10 cm width and 80 cm length) will be positioned on the proximal end of the thigh [31,33] and inflated based on a previous protocol [34]. The TRP will be readjusted every 3 weeks. ...
Article
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Background Knee osteoarthritis (OA) is characterized by chronic pain, physical dysfunction, and reduced quality of life. Low-load resistance exercises with blood flow restriction (BFR) have presented results similar to those of high-intensity resistance exercise (HIRE) without BFR provided that the exercise volume in both is paired. However, it is unclear whether BFR exercise with reduced load and volume generates clinical improvements similar to those of HIRE. The aim of the proposed study is to evaluate the effects of BFR resistance exercise with very low load and low volume against HIRE in patients with knee OA for the outcomes of knee pain, muscle performance, physical function, disease severity, quality of life, perceived exertion during the exercises, adherence, and patient satisfaction with treatment. Methods This two-arm, prospectively registered, randomized controlled trial with blinded assessors and volunteers will involve 64 patients with knee OA. Two weekly treatment sessions will be provided for 12 weeks. Patients will perform very low-load (10% of 1-RM) and low-volume BFR exercise or HIRE (60% of 1-RM) for strengthening thigh muscles. The primary outcome will be the knee pain measured after 12 weeks of treatment. The secondary outcomes include knee pain 6 months after randomization, physical function, disease severity, quality of life, muscle performance, knee pain and perceived exertion during exercise, adherence, and patient satisfaction with treatment. Discussion If the improvements in the outcomes are similar in the two groups, BFR exercise with reduced load and volume may be an interesting alternative in the treatment of knee OA, especially when exercises with high loads generate joint pain. Trial registration Registro Brasileiro de Ensaios Clínicos (REBEC), RBR-6pcrfm. Registered on July 10, 2018.
... When administering BFR/KAATSU training, methods to obtain the pressure vary. For instance, the application of doppler ultrasound has shown reproducibility (Bezerra de Morais et al., 2017) and both the doppler ultrasound (Masri et al., 2016) and devices set to determine limb occlusion pressure (McEwan et al., 2019) have been advocated. For those unable to afford/ operate doppler ultrasound, pulse oximeters have shown potential in determining occlusion pressure within the upper extremity (Zeng et al., 2019;Lima-Soares et al., 2020). ...
Article
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Purpose: The purpose of the study was to explore how individuals in the United States of America applied BFR/KAATSU devices and administered BFR/KAATSU training. In addition, the study sought to examine safety topics related to BFR/KAATSU training. Methods: The study was completed using survey research. Subjects were recruited through Facebook, email, and word of mouth. The survey was developed, piloted, and finally deployed March 22, 2021-April 21, 2021. Results: In total, 148 consented to the research; 108 completed the survey, and of those 108, 70 indicated current use with BFR/KAATSU equipment. Professions represented included athletic training, personal training, physical therapy, and strength and conditioning. Among those currently using BFR/KAATSU training (n = 70), the following results were found. The most common devices used were inflatable devices (n = 43, 61.4%). Education completed prior to device administration was formal (n = 39, 55.7%) and/or self-directed (n = 37, 52.9%). Barriers were faced by 29 (41.4%) when trying to enact training. Techniques and parameters varied during application. Screening processes were used (n = 50, 71.4%) prior to training. The devices were used to determine restrictive pressure (n = 31, 44.3%), and a supine position was used most when determining initial restrictive pressure (n = 33, 47.1%). For subsequent restrictive pressure measurements, respondents repeated the same method used initially (n = 38, 54.3%). Workload was often defined as the length of time under tension/load (n = 22, 31.4%) and exercise was directly supervised (n = 52, 74.3%). Adverse effects included bruising, lightheadedness, and cramping (n = 15, 21.4%). The devices have also been applied on those with pathology (n = 16, 22.9%). Conclusion: Those using blood flow restriction/KAATSU devices came from several professions and used an assortment of devices for BFR/KAATSU training. Individuals applied devices using a variety of parameters on populations for which efficacy has and has not been well defined.
... In laboratorial and clinical settings, the use of Doppler ultrasound equipment has been considered the gold standard method to determine AOP (15,23,1,12). An alternative method to determine the AOP is through a sonographic handheld Doppler equipment (18,28); however, the use of Doppler equipment, even as handheld, is inherently limited to the technical expertise needed to assess AOP. ...
Article
Lima-Soares, F, Pessoa, KA, Torres Cabido, CE, Lauver, J, Cholewa, J, Rossi, FE, and Zanchi, NE. Determining the arterial occlusion pressure for blood flow restriction: pulse oximeter as a new method compared with a handheld Doppler. J Strength Cond Res XX(X): 000-000, 2020-In laboratorial and clinical settings, the use of Doppler ultrasound equipment has been considered the gold standard method to determine arterial occlusion pressure (AOP). However, the use of Doppler equipment is inherently limited to the technical expertise needed to perform AOP measurements. To overcome the technical difficulties of the use of Doppler equipment use in the determination of AOP, a simpler and less subjective methodology would be helpful for blood flow restriction (BFR) practitioners. In this regard, portable pulse oximetry has been largely used in clinical practice for measuring systolic pressures, as well as loss or recovery of pulse, with results similar to those observed with the use of Doppler equipment. For such purposes, the AOP from young male and female subjects was evaluated after different body positions (standing, seated, and supine positions). Loss of capillary blood flow or AOP was readily determined by simple visual inspection for the pulse oximeter and loss of sound for the Doppler equipment. The results presented herein strongly suggest the use of the portable pulse oximetry equipment as reliable, when compared with the handheld Doppler (seated K = 0.962, standing K = 0.845, and supine K = 0.963 and seated rs = 0.980, standing rs = 0.958, and supine rs = 0.955). Because AOP measurement by pulse oximetry is relatively easier to perform and financially more accessible than handheld Doppler equipment, BFR practitioners may benefit from this new methodology to measure AOP, thus determining individualized restriction pressures.
... In the following day, blood pressure and the pressure necessary to total restriction (TRP -total restriction pressure) of brachial artery flow was determined, and the volunteers were familiarized with MVIC and IIHE. Total restriction pressure determination TRP of the brachial artery flow is a measure that shows good reproducibility and was determined according to the previous study (13). Briefly, the brachial artery blood flow of the dominant arm was detected by an ultrasound model SonoAceR3 (Samsung Medison -South Korea), by Power Doppler Technique -with 12 MHz linear transducers placed in the flexor crease of the elbow. ...
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... Right after, the Doppler transducer was positioned on the posterior tibial artery (mean distance between the medial malleolus of the tibia and the Achilles tendon), while the nylon cuff (20 cm wide; Aneroid sphygmomanometer Premium) was positioned around the subinguinal region with the cuff bladder on the medial portion of the thigh, covering the femoral artery. 39 The cuff bladder was manually inflated based on a prior protocol, 4 and TOP was defined as the minimum pressure required to abolish the arterial pulse. ...
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... The average of the 5 values required to occlude brachial artery blood velocity were recorded as the AOP. Using the Statistical Package for the Social Sciences Software Version 13.0 (SPSS Inc., Chicago, IL) a twoway repeated measures ANOVA indicated that in-house AOP measurements were consistent for each day(Table 2) stable across days(Table 3), and precise (COV = 2.81%), and are in line with the literature[72]. ...
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Background: The resistance training with blood flow restriction (BFR) presents results in strength gain and muscle hypertrophy. However, there are no data that evaluate the long-term adaptation of the autonomic nervous system and its influence on the performance, especially with eccentric contractions. Objective: To perform a systematic autonomous monitoring during eccentric training with BFR at different loads and to correlate them with possible changes in the performance METHODS: This is a 4-arms, randomized controlled and single blind trial. Sixty men were randomized in four groups: low and high load eccentric exercise (LL and HL); LL and HL with BFR (LL-BFR and HL-BFR). The participants underwent 18 sessions of eccentric exercise for the dominant quadriceps femoris muscle in the isokinetic dynamometer. The performance (strength through isometric, concentric and eccentric peaks torque on the isokinetic dynamometer and Single-leg Hop Test) was evaluated one week before, in the fourth week and one week after the end of the training program. Heart rate variability (HRV) through vagal and global indices was evaluated daily for 15 minutes before each session. Results: there was a significant correlation between performance and HRV for LL and HL-BFR groups, with an increase in parasympathetic indices in the first group and an increase in performance in the second group. Conclusion: HRV indices are correlated with performance. However, in the LL group, there was an increase in parasympathetic indices without repercussions on performance while, in the HL-BFR group, there was an increase in performance and no repercussion in the autonomic indices. This article is protected by copyright. All rights reserved.
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Picón-Martínez, M.; Chulvi-Medrano, I.; Alonso-Aubin D.A. (2019). Uso del entrenamiento con restricción del flujo sanguíneo en España: Un estudio transversal.
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Blood flow restriction (BFR) training is increasing in popularity in the fitness and rehabilitation settings due to its role in optimizing muscle mass and strength as well as cardiovascular capacity, function, and a host of other benefits. However, despite the interest in this area of research, there are likely some perceived barriers that practitioners must overcome to effectively implement this modality into practice. These barriers include determining appropriate BFR training pressures, access to appropriate BFR training technologies for relevant demographics based on the current evidence, a comprehensive and systematic approach to medical screening for safe practice and strategies to mitigate excessive perceptual demands of BFR training to foster long-term compliance. This manuscript attempts to discuss each of these barriers and provides evidence-based strategies and direction to guide clinical practice and future research.
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Background The precise calculation of arterial occlusive pressure is essential to accurately prescribe individualized pressures during blood flow restriction training. Arterial occlusion pressure in the lower limb varies significantly between different body positions while similar reports for the upper limb are lacking. Hypothesis Body position has a significant effect in upper limb arterial occlusive pressure. Using cuffs with manual pump and a handheld Doppler ultrasound can be a reliable method to determine upper limb arterial blood flow restriction. Study Design A randomized repeated measures design. Level of Evidence Level 3. Methods Forty-two healthy participants (age mean ± SD = 28.1 ± 7.7 years) completed measurements in supine, seated, and standing position by 3 blinded raters. A cuff with a manual pump and a handheld acoustic ultrasound were used. The Wilcoxon signed-rank test with Bonferroni correction was used to analyze differences between body positions. A within-subject coefficient of variation and an intraclass correlation coefficient (ICC) test were used to calculate reproducibility and reliability, respectively. Results A significantly higher upper limb arterial occlusive pressure was found in seated compared with supine position ( P < 0.031) and in supine compared with standing position ( P < 0.031) in all raters. An ICC of 0.894 (95% CI = 0.824-0.939, P < 0.001) was found in supine, 0.973 (95% CI = 0.955-0.985, P < 0.001) in seated, and 0.984 (95% CI = 0.973-0.991, P < 0.001) in standing position. ICC for test-retest reliability was found 0.90 (95% CI = 0.814-0.946, P < 0.001), 0.873 (95% CI = 0.762-0.93, P < 0.001), and 0.858 (95% CI = 0.737-0.923, P < 0.001) in the supine, seated, and standing position, respectively. Conclusion Upper limb arterial occlusive pressure was significantly dependent on body position. The method showed excellent interrater reliability and repeatability between different days. Clinical Relevance Prescription of individualized pressures during blood flow restriction training requires measurement of upper limb arterial occlusive pressure in the appropriate position. The use of occlusion cuffs with a manual pump and a handheld Doppler ultrasound showed excellent reliability; however, the increased measurement error compared with the differences in arterial occlusive pressure between certain positions should be carefully considered for the clinical application of the method. Strength of Recommendations Taxonomy (SORT) B.
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Introduction Exercise with blood flow restriction (BFR) is emerging as an effective modality for improving muscular function in clinical and athletic populations. Selection of cuff pressure is critical because it should maximize metabolic stress without completely occluding blood flow or compromising user safety. It is unknown how cuff pressures determined at rest influence blood flow hemodynamics during exercise. Purpose We evaluated changes in blood flow and tissue perfusion before, during, and after exercise with BFR. Methods Ten males performed rhythmic handgrip exercise (30 contractions, 30% MVC) at 0%, 60%, 80%, 100%, and 120% of limb occlusion pressure (LOP). Brachial artery blood flow and tissue saturation were assessed using Doppler ultrasound and near-infrared spectroscopy, respectively. Results At rest blood flow generally decreased with increased pressure (0% > 60% ≈ 80% > 100% ≈ 120% LOP). During 60% and 80% LOP conditions, blood flow increased during exercise from rest and decreased after exercise (all P < 0.05). Compared to 0% LOP, relative blood flow at 60% and 80% LOP decreased by 22–47% at rest, 22–48% during exercise, and 52–71% after exercise (all P < 0.05). Increased LOP decreased tissue saturation during exercise with BFR (P < 0.05). Heart rate, mean arterial pressure, and cardiac output did not differ across LOP. Conclusion At pressures below LOP the cardiovascular system overcame the external pressure and increased blood flow to exercising muscles. Relative reductions in blood flow at rest were similar to those during exercise. Thus, the relative occlusion measured at rest approximated the degree of occlusion during exercise. Moderate cuff pressures increased metabolic stress without completely occluding blood flow.
Thesis
Introdução: Desordens musculoesqueléticas são comuns e podem comprometer a função, o desempenho físico e a qualidade de vida. Dentre as intervenções utilizadas no manejo de desordens musculoesqueléticas, as modalidades de restrição de fluxo sanguíneo (RFS) vêm ganhando espaço na literatura científica. Objetivos: Essa tese teve o propósito de investigar os aspectos fisiológicos, os métodos de prescrição e as aplicações clínicas de modalidades de RFS em diferentes desordens musculoesqueléticas. Métodos e resultados: As modalidades de RFS consideradas foram a RFS passiva (sem exercício concomitante), o pré-condicionamento isquêmico (PCI) e a RFS combinada ao exercício. Como desordens musculoesqueléticas foram consideradas condições que causassem prejuízo funcional, tais como perda de força e de massa muscular, dano muscular induzido por exercício, fadiga muscular e osteoartrite (OA) de joelho. A presente tese é composta por introdução, três capítulos referentes às modalidades de RFS, e considerações finais. Os capítulos 1, 2 e 3 versam, respectivamente, sobre RFS passiva, PCI e RFS combinada ao exercício, e são compostos de sete artigos científicos envolvendo três desenhos de estudo: revisão sistemática (com e sem meta-análise), revisão narrativa e ensaio clínico aleatorizado. O capítulo 1 é uma revisão sistemática (artigo 1) sobre os efeitos da RFS passiva para minimizar perdas de força e de massa muscular (hipotrofia por desuso) em indivíduos submetidos a restrições na descarga de peso em membros inferiores. No capítulo 1 observamos que embora potencialmente útil, o alto risco de viés apresentado nos estudos originais limita a indicação de RFS passiva como modalidade eficaz contra a redução de força e de massa muscular induzida por imobilismo. O capítulo 2 é um ensaio clínico controlado e aleatorizado (artigo 2) que investigou os efeitos do PCI na proteção contra o dano muscular induzido por exercício (DMIE) em pessoas saudáveis. O artigo 2 apontou que o PCI não foi superior ao sham para proteger contra o DMIE. O capítulo 3 aborda aspectos fisiológicos, metodológicos e clínicos da RFS combinada ao exercício físico. O primeiro manuscrito do capítulo 3 (artigo 3) é uma revisão sistemática com meta-análise que analisou a excitação muscular (por eletromiografia de superfície) durante exercício resistido com RFS. O artigo 3 indicou que a excitação muscular durante o exercício de baixa carga com RFS foi maior que durante exercício de carga pareada sem RFS somente quando a falha muscular não foi alcançada. Adicionalmente, exercício de baixa carga com RFS apresentou menor excitação muscular que exercício de alta carga, independentemente de alcançar ou não a falha voluntária. O segundo manuscrito do capítulo 3 (artigo 4) é uma revisão sistemática com meta-análise que mostrou uma viii antecipação da falha muscular durante exercícios de baixa carga com altas pressões de RFS, mas não com baixas pressões. O terceiro manuscrito do capítulo 3 (artigo 5) é uma revisão narrativa que discute a possível necessidade de ajustar a pressão de RFS ao longo das semanas de treinamento. No artigo 5 observamos que a literatura é contraditória, o que dificulta recomendar se tais ajustes na pressão de RFS são necessários. O artigo 6 é um protocolo de ensaio clínico aleatorizado proposto para investigar os efeitos do exercício de baixa carga e volume total reduzido com RFS versus treinamento de alta carga sem RFS no tratamento da OA de joelho. O artigo 7 é o ensaio clínico aleatorizado que apresenta os resultados do protocolo (artigo 6) e mostrou que o treinamento de baixa carga com volume total reduzido e com RFS teve efeito similar ao treinamento de alta carga sem RFS na dor no joelho, desempenho muscular, função física e qualidade de vida de pacientes com OA de joelho, embora a magnitude nos ganhos de força tenha sido maior após treino de alta carga. Conclusões: De forma geral, com exceção do PCI para proteger contra o DMIE, as modalidades de RFS são potencialmente úteis no manejo das disfunções musculoesqueléticas aqui estudadas. Adicionalmente, concluímos que é necessário avançar no entendimento dos mecanismos fisiológicos e no estudo dos métodos de prescrição das diferentes modalidades de restrição de fluxo sanguíneo.
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We examined the effects of detraining after blood flow-restricted (BFR) low-load elastic band training on muscle size and arterial stiffness in older women. Fourteen women were divided into BFR training (BFR-T) or non-BFR training (CON-T). Each group participated in 12 weeks of arm curl and press down training using an elastic band either with (BFR-T) or without BFR (CON-T). Muscle cross-sectional area (CSA) and maximum voluntary isometric contraction (MVIC) for upper arms and cardio-ankle vascular index (CAVI) were evaluated before and after the 12-week training period and also after 12 weeks of detraining. CSA and MVIC were higher at post and detraining (CSA: 16.3% (p < 0.01) and 6.9% (p < 0.01) for elbow flexion and 17.1% (p < 0.01) and 8.7% (p > 0.05) for elbow extension; MVIC: 7.3 and 3.9% (both p > 0.05) for elbow flexion and 17.6 and 15.1% (both p < 0.01) for elbow extension) than at pre for the BFR-T, but not for the CON-T. There was no change in CAVI for the two groups. Increased muscle strength/size following 12 weeks of elastic band BFR-T was well maintained with a low risk of arterial stiffness after 12 weeks of detraining in older women.
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IntroductionOur aim was to evaluate the safety and efficacy of a low-intensity resistance training program combined with partial blow flow restriction (BFR training) in a cohort of patients with polymyositis (PM) and dermatomyositis (DM).Methods In total, 13 patients with PM and DM completed a 12-week twice a week low-intensity (that is, 30% one-repetition-maximum (1RM)) resistance exercise training program combined with partial blood flow restriction (BFR). Assessments of muscle strength, physical function, quadriceps cross sectional (CSA) area, health-related quality of life, and clinical and laboratory parameters were assessed at baseline and after the intervention.ResultsThe BFR training program was effective in increasing the maximal dynamic strength in both the leg-press (19.6%, P <0.001) and knee-extension exercises (25.2% P <0.001), as well as in the timed-stands (15.1%, P <0.001) and timed-up-and-go test (¿4.5%, P =0.002). Quadriceps CSA was also significantly increased after the intervention (4.57%, P =0.01). Similarly, all of the components of the Short Form-36 Health Survey, the Health Assessment Questionnaire scores, and the patient- and physician reported Visual Analogue Scale were significantly improved after training (P <0.05). Importantly, no clinical evidence or any other self-reported adverse event were found. Laboratory parameters (creatine kinase and aldolase) were also unchanged (P >0.05) after the intervention.Conclusions We demonstrated that a 12-week supervised low-intensity resistance training program associated with partial blood flow restriction may be safe and effective in improving muscle strength and function as well as muscle mass and health-related quality of life in patients with PM and DM.Trial registrationClinicaltrials.gov NCT01501019. Registered November 29, 2011.
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The assessment of endothelial function as brachial artery flow-mediated vasodilatation is a widely used technique that determines the effect of risk factor intervention and may have the potential to predict the clinical benefit of antiatherogenic therapy. Previous studies suggest that flow-mediated dilation is greater using the upper-arm occlusion technique, but no data are available to compare intertester reliability between technicians. This study was undertaken to compare the amount of hyperemia between upper and lower occlusion techniques and to determine reproducibility between testers. Nineteen healthy adults, ages 25 to 50, were included in the study. Brachial artery vasodilatation was measured 1 and 3 minutes post cuff deflation and was compared with the baseline and expressed as a percent change. There was a tester effect in the percent change in diameter across all measurements. The results of this study reveal inconsistencies between testers when using a blood pressure cuff to induce hyperemia for the assessment of endothelial function through brachial artery flow-mediated vasodilation. However, upper arm as compared to lower arm blood pressure cuff occlusion results in significantly greater hyperemia and vasodilatation, even though there was a difference in measurements between testers.
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We performed a prospective study to determine the effects of introducing low-load muscular training with moderate restriction of blood flow during the first 16 weeks after reconstruction of the anterior cruciate ligament. 44 subjects (average age 29 (18-52) years) were randomized into a group that trained restriction of blood flow (group R, n = 22) and a group that trained without restriction (group N, n = 22). Both groups followed the same training schedule. Evaluations of knee extensor and flexor torques before surgery and 16 weeks after it showed a significant increase in muscular strength in group R as compared to group N. The preoperative/16-week postoperative ratio of the cross-sectional area of the knee extensor muscles showed a statistically significant enlargement in group R as compared to group N. 16 weeks after surgery, the short diameters of type 1 and type 2 fibers of M. vastus lateralis tended to be larger in group R (n = 8) than in group N (n = 8), although the differences were not significant. These findings show that low-load resistance muscular training during moderate restriction of blood flow is an effective exercise for early muscular training after reconstruction of the anterior cruciate ligament.
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We investigated the hemodynamic and hormonal responses to a short-term low-intensity resistance exercise (STLIRE) with the reduction of muscle blood flow. Eleven untrained men performed bilateral leg extension exercise under the reduction of muscle blood flow of the proximal end of both legs pressure-applied by a specially designed belt (a banding pressure of 1.3 times higher than resting systolic blood pressure, 160-180 mmHg), named as Kaatsu. The intensity of STLIRE was 20% of one repetition maximum. The subjects performed 30 repetitions, and after a 20-seconds rest, they performed three sets again until exhaustion. The superficial femoral arterial blood flow and hemodynamic parameters were measured by using the ultrasound and impedance cardiography. Serum concentrations of growth hormone (GH), vascular endothelial growth factor (VEGF), noradrenaline (NE), insulin-like growth factor (IGF)-1, ghrelin, and lactate were also measured. Under the conditions with Kaatsu, the arterial flow was reduced to about 30% of the control. STLIRE with Kaatsu significantly increased GH (0.11+/-0.03 to 8.6+/-1.1 ng/ml, P < 0.01), IGF-1 (210+/-40 to 236+/-56 ng/ml, P < 0.01), and VEGF (41+/-13 to 103+/-38 pg/ml, P < 0.05). The increase in GH was related to neither NE nor lactate, but the increase in VEGF was related to that in lactate (r = 0.57, P < 0.05). Ghrelin did not change during the exercise. The maximal heart rate (HR) and blood pressure (BP) in STLIRE with Kaatsu were higher than that without Kaatsu. Stroke volume (SV) was lower due to the decrease of the venous return by Kaatsu, but, total peripheral resistance (TPR) did not change significantly. These results suggest that STLIRE with Kaatsu significantly stimulates the exercise-induced GH, IGF, and VEGF responses with the reduction of cardiac preload during exercise, which may become a unique method for rehabilitation in patients with cardiovascular diseases.
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Strength training with low loads in combination with vascular occlusion has been proposed as an alternative to heavy resistance exercise in the rehabilitation setting, especially when high forces acting upon the musculo-skeletal system are contraindicated. Several studies on low-to-moderate intensity resistance exercise combined with cuff occlusion have demonstrated increases in muscle strength and size that are comparable to those typically seen after conventional high-load strength training. However, the physiological mechanisms by which occlusion training induces increased muscle mass and strength are currently unclear, although several candidate stimuli have been proposed. Also, the long-term safety, practicality, and efficacy of this training method are still controversial. Furthermore, recent studies have demonstrated that in some instances, tourniquet cuffs may not be necessary for relative ischemia and significant training effects to occur with resistance exercise at low-to-moderate loads. The aims of the present review are to summarize current opinion and knowledge regarding the physiology of ischemic strength training and to discuss some of the training and health aspects of this type of exercise. In addition, suggestions for further research are given.
Article
The assessment of endothelial function as brachial artery flow-mediated vasodilatation is a widely used technique that determines the effect of risk factor intervention and may have the potential to predict the clinical benefit of antiatherogenic therapy. Previous studies suggest that flow-mediated dilation is greater using the upper-arm occlusion technique, but no data are available to compare intertester reliability between technicians. This study was undertaken to compare the amount of hyperemia between upper and lower occlusion techniques and to determine reproducibility between testers. Nineteen healthy adults, ages 25 to 50, were included in the study. Brachial artery vasodilatation was measured 1 and 3 minutes post cuff deflation and was compared with the baseline and expressed as a percent change. There was a tester effect in the percent change in diameter across all measurements. The results of this study reveal inconsistencies between testers when using a blood pressure cuff to induce hyperemia for the assessment of endothelial function through brachial artery flow-mediated vasodilation. However, upper arm as compared to lower arm blood pressure cuff occlusion results in significantly greater hyperemia and vasodilatation, even though there was a difference in measurements between testers.
Article
Purpose: To determine what factors should be accounted for when setting the blood flow restriction (BFR) cuff pressure for the upper and lower body. Methods: One hundred and seventy one participants visited the laboratory for one testing session. Arm circumference, muscle (MTH) and fat (FTH) thickness were measured on the upper arm. Next, brachial systolic (SBP) and diastolic (DBP) blood pressure measurements were taken in the supine position. Upper body arterial occlusion was then determined using a Doppler probe. Following this, thigh circumference and lower body arterial occlusion were determined. Models of hierarchical linear regression were used to determine the greatest predictor of arterial occlusion in the upper and lower body. Two models were employed in the upper body, a Field (arm size) and a Laboratory model (arm composition). Results: The Laboratory model explained 58 % of the variance in arterial occlusion with SBP (β = 0.512, part = 0.255), MTH (β = 0.363, part = 0.233), and FTH (β = 0.248, part = 0.213) contributing similarly to explained variance. The Field model explained 60 % of the variance in arterial occlusion with arm circumference explaining the greatest amount (β = 0.419, part = 0.314) compared to SBP (β = 0.394, part = 0.266) and DBP (β = 0.147, part = 0.125). For the lower body model the third block explained 49 % of the variance in arterial occlusion with thigh circumference (β = 0.579, part = 0.570) and SBP (β = 0.281, part = 0.231) being significant predictors. Conclusions: Our findings indicate that arm circumference and SBP should be taken into account when determining BFR cuff pressures. In addition, we confirmed our previous study that thigh circumference is the greatest predictor of arterial occlusion in the lower body.
Article
IntroductionAn unresolved question in resistance training combined with blood flow restriction (BFR) is what percentage of estimated arterial occlusion pressure provides the most robust acute muscular response.Methods Forty participants were assigned to Experiments 1, 2, or 3. Each experiment completed exercise protocols differing by pressure, exercise load, and/or volume. Torque was measured pre- and postexercise, and muscle activation was measured pre- and during each set.ResultsPressure and load did not affect torque greatly. Muscle activation increased in all conditions (P < 0.05) and was higher with 30% 1RM compared with 20% 1RM. Pressure appeared to increase muscle activation from 40% to 50% arterial occlusion [66% vs. 87% maximal voluntary contraction (30% 1RM)] but was not further increased with higher pressure.Conclusion Different levels of BFR may alter the acute muscular response to a degree, although higher pressures do not appear to augment these changes. Muscle Nerve 51:713-721, 2015
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The purpose of this study was to determine the muscular adaptations to low-load resistance training performed to fatigue with and without blood flow restriction (BFR). Middle-aged (42–62 years) men (n = 12) and women (n = 6) completed 18 sessions of unilateral knee extensor resistance training to volitional fatigue over 6 weeks. One limb trained under BFR, and the contralateral limb trained without BFR [free flow (FF)]. Before and after the training, measures of anterior and lateral quadriceps muscle thickness (MTh), strength, power and endurance were assessed on each limb. The total exercise training volume was significantly greater for the FF limb compared with the BFR limb (P<0·001). Anterior quadriceps thickness and muscle function increased following the training in each limb with no differences between limbs. Lateral quadriceps MTh increased significantly more (P<0·05) in the limb trained under BFR (BFR: 3·50 ± 0·61 to 3·67 ± 0·62 cm; FF: 3·49 ± 0·73 to 3·56 ± 0·70 cm). Low-load resistance training to volitional fatigue both with and without BFR is viable options for improving muscle function in middle-aged individuals. However, BFR enhanced the hypertrophic effect of low-load training and reduced the volume of exercise needed to elicit increases in muscle function.
Article
Complications of the pneumatic tourniquet used during limb surgery result from excessive direct pressure. Traditional recommendations suggests parameters for maximum pressure and time limits rather than the minimal effective pressure to achieve a bloodless field. A clinical study was undertaken to evaluate the pneumatic tourniquet setting required for adequate haemostasis in the upper limb. The correlations between several possible influencing parameters (age, sex, arm fat thickness, extremity length, systolic, diastolic, and mean blood pressures) and the minimal pneumatic tourniquet pressure at which the peripheral pulse reappeared were studied in 50 patients undergoing surgery, using a Doppler stethoscope. The average Doppler Opening Pressure was 168.5 +/- 42.7 mmHg and the only significant clinical variable was the mean blood pressure. From these results an equation was derived to predict the minimal effective tourniquet pressure. The mean calculated tourniquet pressure was 202.3 +/- 34.2 mmHg, well below the 250 to 300 mmHg previously recommended. The technique consisted of inflating the tourniquet to a pressure of 300 mmHg, then reducing it to the calculated value. A bloodless field was maintained in all patients.
Article
The between-day repeatability of simultaneous measures of brachial artery diameter (D) (echo Doppler) and mean blood velocity (MBV) (pulsed Doppler) was tested during rest and exercise. On 3 separate days, six volunteers performed one trial of 1-min rest followed by a step increase in dynamic handgrip exercise for 4 min which required the lifting and lowering of a 4.4-kg weight (approximately 8-12% MVC) in a 1s/2s (work/rest) cadence. Measures for MBV and D were collected continuously on a beat-by-beat basis during the transition from rest to end exercise. The mean rest values over one min, and single data points at 30, 60, 120, and 240 s of exercise were extracted from the time series data. At all exercise time points, MBV was greater than rest (P < 0.05), but these levels were not different across test days. Arterial D at all exercise time points ranged from 3.8 +/- 0.1 mm to 4.1 +/- 0.1 mm (mean +/- SEM) and did not differ from rest (3.9 +/- 0.1 mm) (P > 0.05), nor did D differ between days. The mean between-day coefficient of variation for D was 4.08 +/- 0.7% at rest and ranged from 2.90 +/- 0.4% to 3.96 +/- 0.5% during exercise. The coefficient of variation for MBV was 13.2 +/- 2.6% at rest and reached 20.2 +/- 3.1% during the final min of exercise; the exercise variability was reduced to 14.9 +/- 2.4% by averaging MBV over 3 s (the duration of a contraction/relaxation duty cycle) (P < 0.05) with no further advantage of averaging over ten 60-s sample periods. The data indicate that, for the six subjects tested, Doppler ultrasound measures of arterial MBV and diameter during both rest and exercise were reproducible across different test days and can be used as a reliable, noninvasive means of testing hypotheses pertaining to blood flow control.
Article
Previous studies have shown that low-intensity resistance training with restricted muscular venous blood flow (Kaatsu) causes muscle hypertrophy and strength gain. To investigate the effects of daily physical activity combined with Kaatsu, we examined the acute and chronic effects of walk training with and without Kaatsu on MRI-measured muscle size and maximum dynamic (one repetition maximum) and isometric strength, along with blood hormonal parameters. Nine men performed Kaatsu-walk training, and nine men performed walk training alone (control-walk). Training was conducted two times a day, 6 days/wk, for 3 wk using five sets of 2-min bouts (treadmill speed at 50 m/min), with a 1-min rest between bouts. Mean oxygen uptake during Kaatsu-walk and control-walk exercise was 19.5 (SD 3.6) and 17.2 % (SD 3.1) of treadmill-determined maximum oxygen uptake, respectively. Serum growth hormone was elevated (P < 0.01) after acute Kaatsu-walk exercise but not in control-walk exercise. MRI-measured thigh muscle cross-sectional area and muscle volume increased by 4-7%, and one repetition maximum and maximum isometric strength increased by 8-10% in the Kaatsu-walk group. There was no change in muscle size and dynamic and isometric strength in the control-walk group. Indicators of muscle damage (creatine kinase and myoglobin) and resting anabolic hormones did not change in both groups. The results suggest that the combination of leg muscle blood flow restriction with slow-walk training induces muscle hypertrophy and strength gain, despite the minimal level of exercise intensity. Kaatsu-walk training may be a potentially useful method for promoting muscle hypertrophy, covering a wide range of the population, including the frail and elderly.
Article
Resistance training at low loads with blood flow restriction (BFR) (also known as Kaatsu) has been shown to stimulate increases in muscle size and strength. It is unclear how occlusion pressure, exercise intensity, and occlusion duration interact, or which combination of these factors results in the most potent muscle stimulus. To determine the effect of eight BFR protocols on muscle fatigue (decrement in maximal voluntary contraction (MVC) after the performance of exercise), and to compare the decrement in MVC with the currently recommended resistance exercise intensity (~80% MVC). During five test sessions, 21 subjects (14 males and 7 females, 27.7 +/- 4.9 yr) completed nine protocols, each consisting of three sets of knee extensions (KE) to failure. One protocol was high-load (HL) exercise (80% MVC) with no BFR, and the other eight were BFR at varying levels of contraction intensity (20 or 40% MVC), occlusion pressure (partial (~160 mm Hg) or complete (~300 mm Hg)), and occlusion duration (off during the rest between sets or continuously applied). To evaluate each protocol, MVC were performed before and after exercise, and the decrement in force was calculated. Three sets of KE at 20% MVC with continuous partial occlusion (20%(ConPar)) resulted in a greater decrement in MVC compared with HL (31 vs 19%, P = 0.001). None of the other BFR protocols were different from the HL protocol, nor were they different from 20%(ConPar) (P > 0.05). All BFR protocols elicited at least as much fatigue as HL, even though lower loads were used. The 20%(ConPar) protocol was the only one that elicited significantly more fatigue than HL. Future research should evaluate protocol training effectiveness and overall safety of BFR exercise.
Article
This study investigated whether muscle hypertrophy-promoting effects are cross-transferred in resistance training with blood flow restriction, which has been shown to evoke strong endocrine activation. Fifteen untrained men were randomly assigned into the occlusive training group (OCC, N = 8) and the normal training group (NOR, N = 7). Both groups performed the same unilateral arm exercise (arm curl) at 50% of one-repetition maximum (1RM) without occlusion (three sets, 10 repetitions). Either the dominant or nondominant arm was randomly chosen to be trained (OCC-T, NOR-T) or to serve as a control (OCC-C, NOR-C). After the arm exercise, OCC performed leg exercise with blood flow restriction (30% of 1RM, three sets, 15-30 repetitions), whereas NOR performed the same leg exercise without occlusion. The training session was performed twice a week for 10 wk. In a separate set of experiments, acute changes in blood hormone concentrations were measured after the same leg exercises with (N = 5) and without (N = 5) occlusion. Cross-sectional area (CSA) and isometric torque of elbow flexor muscles increased significantly in OCC-T, whereas no significant changes were observed in OCC-C, NOR-T, and NOR-C. CSA and isometric torque of thigh muscles increased significantly in OCC, whereas no significant changes were observed in NOR. Noradrenaline concentration showed a significantly larger increase after leg exercise with occlusion than after exercises without occlusion, though growth hormone and testosterone concentrations did not show significant differences between these two types of exercises. The results indicate that low-intensity resistance training increases muscular size and strength when combined with resistance exercise with blood flow restriction for other muscle groups. It was suggested that any circulating factor(s) was involved in this remote effect of exercise on muscular size.
  • P Armitage
  • T Colton
Armitage P, Colton T. Encyclopedia of Biostatistics (2005), vol. 8, 2nd edn. John Wiley & Sons, Chichester, UK.
Effects of exercise load and blood-flow restriction on skeletal muscle function
  • P Armitage
  • Colton T Encyclopedia
  • Biostatistics
Armitage P, Colton T. Encyclopedia of Biostatistics (2005), vol. 8, 2nd edn. John Wiley & Sons, Chichester, UK. Cook SB, Clark BC, Ploutz-Snyder LL. Effects of exercise load and blood-flow restriction on skeletal muscle function. Med Sci Sports Exerc (2007); 10: 1708-1713.
  • Armitage