Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: A brief review

Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA.
Clinical Physiology and Functional Imaging (Impact Factor: 1.44). 07/2012; 32(4):247-52. DOI: 10.1111/j.1475-097X.2012.01126.x
Source: PubMed


Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise.

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    • " and ( d ) occlusion pressure and / or exercise intensity modulation did not affect the muscle strength response between BFRT protocols and produced likely lower muscle strength gains than RT80 . It has been speculated that higher occlusion pressure and / or higher exercise intensity protocols may be able to enhance the anabolic response to BFRT ( Abe et al . 2012 ; Loenneke et al . 2014a , b ; Suga et al . 2010 ; Sugaya et al . 2011 ; Takarada et al . 2000 ; Yasuda et al . 2008 ) . This assumption is based on acute findings that increases in occlusion pressure and / or exercise intensity are capable of enhancing metabolic stress and , consequently , motor - unit recruitment ( Loenneke et al . 20"
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    ABSTRACT: We compared the effects of different protocols of blood-flow restriction training (BFRT) with different occlusion pressures and/or exercise intensities on muscle mass and strength. We also compared BFRT protocols with conventional high-intensity resistance training (RT). Twenty-six subjects had each leg allocated to two of five protocols. BFRT protocols were performed at either 20 or 40 % 1-RM with either 40 or 80 % occlusion pressure: BFRT20/40, BFRT20/80, BFRT40/40, and BFRT40/80. Conventional RT was performed at 80 % 1-RM (RT80) without blood-flow restriction. Maximum dynamic strength (1-RM) and quadriceps cross-sectional area (CSA) were assessed at baseline and after 12 weeks. Regarding muscle mass, increasing occlusion pressure was effective only at very low intensity (BFRT20/40 0.78 % vs. BFRT20/80 3.22 %). No additional increase was observed at higher intensities (BFRT40/40 4.45 % vs. BFRT40/80 5.30 %), with no difference between the latter protocols and RT80 (5.90 %). Exercise intensity played a role in CSA when comparing groups with similar occlusion pressure. Muscle strength was similarly increased among BFRT groups (~12.10 %) but to a lesser extent than RT80 (21.60 %). In conclusion, BFRT protocols benefit from higher occlusion pressure (80 %) when exercising at very low intensities. Conversely, occlusion pressure seems secondary to exercise intensity in more intense (40 % 1-RM) BFRT protocols. Finally, when considering muscle strength, BFRT protocols seem less effective than high-intensity RT.
    Arbeitsphysiologie 09/2015; 115(12). DOI:10.1007/s00421-015-3253-2 · 2.19 Impact Factor
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    • "Con el precedente de que el entrenamiento de fuerza con restricción del flujo sanguíneo en régimen concéntrico provoca un incremento mayor en la circunferencia de la extremidad ejercitada con respecto al mismo ejercicio en un régimen excéntrico (Umbell, Hoffman, Dearth, Cheboun, y Manini, 2009), Yasuda, Loenneke, Thiebaud, y Abe (2012) quisieron comprobar las respuestas tras 6 semanas de entrenamiento con restricción del flujo sanguíneo mediante un trabajo exclusivamente concéntrico o excéntrico en un grupo de hombres que no habían realizado entrenamiento contra resistencias con anterioridad. Tras dicha intervención se observaron mejoras significativamente superiores en los valores de fuerza máxima isométrica (8,6%) y el área de sección transversal del brazo (12%) y del volumen muscular (11,7%) en el brazo que se ejercitó concéntricamente con respecto al que se ejercitó excéntricamente. "
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    ABSTRACT: El entrenamiento de fuerza orientado a aumentar la masa muscular se ha convertido en un objetivo común en programas de entrenamiento tanto en deportistas de alto rendimiento como en personas que realizan programas de actividad física con objetivo de mejorar su salud o calidad de vida. Generalmente, el trabajo de fuerza orientado hacia la hipertrofia muscular se ha asociado con la utilización de altas cargas de trabajo (70-85% de 1 RM). Actualmente, se ha propuesto que el entrenamiento de fuerza con cargas de tan solo el 20% de 1 RM realizadas en condiciones de restricción del flujo sanguíneo podría provocar incrementos en los niveles de fuerza y masa muscular similares a los observados al ejercitarse con cargas altas. Dado que ciertos colectivos podrían beneficiarse del empleo de bajas cargas en sus programas de entrenamiento orientados a incrementar la masa muscular, el objetivo del presente trabajo de revisión bibliográfica ha sido el de revisar en la literatura las evidencias que existen en torno a la efectividad del entrenamiento con restricción del flujo sanguíneo a la hora de provocar hipertrofia muscular.
    RICYDE. Revista internacional de ciencias del deporte 09/2015; 10(38):367-382. DOI:10.5232/ricyde2014.03806
    • "Studies using dual energy X-ray absorptiometry (DXA), which estimates the lean tissue mass of the entire lower limb, however, produced mixed results as to the efficacy of daily ambulatory activity on muscle hypertrophy. Whereas, Abe et al. (2012) recently examined the correlation between the time spent for ambulatory activities at moderate -vigorous intensities (> 3 METs) and the muscle thickness using B-mode ultrasound, which allowed evaluation of individual lower limb muscle groups. They found a positive correlation between the time spent on moderate -vigorous ambulatory activities and muscle thickness for the tibialis anterior and triceps surae, suggesting that increased daily locomotor activities may prevent age-related loss of muscle mass in the lower leg muscles 51) . "
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    ABSTRACT: This paper reviews the existing literature about muscle hypertrophy resulting from various types of training to document the significance of mechanical and metabolic stresses, and to challenge the conventional ideas of achieving hypertrophy that exclusively rely on highload resistance training. Low-load resistance training can induce comparable hypertrophy to that of high-load resistance training when each bout or set is performed until lifting failure. This is attributable to the greater exercise volume and metabolic stress achieved with low-load exercise at lifting failure, which, however, results in a prolonged exercise bout. Endurance exercises (walking and cycling) at moderate intensity are also capable of eliciting muscle hypertrophy, but at much slower rates (months rather than weeks) in limited muscle or age groups. Blood flow restriction (BFR) in working muscles, however, accelerates the development of metabolic fatigue, alleviating the time consuming issue associated with low-load or endurance training. These alternative training methods, however, cannot completely replace conventional high-load resistance training, which provides superior strength gain as well as performance improvement even for trained individuals. The alternative approaches, therefore, may be considered for those who are less enthusiastic or under certain medical conditions, or who have limited or no access to proper equipment. However, people should be aware that low-load resistance training or endurance training entails substantial effort and/or discomfort at lifting failure or with BFR. Understanding the advantages and disadvantages of each method will help in assigning the most suitable training program for each client’s goals and needs.
    Tairyoku kagaku. Japanese journal of physical fitness and sports medicine 02/2015; 4(1):43-51. DOI:10.7600/jpfsm.4.43 · 0.08 Impact Factor
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