Eur J Appl Physiol (2014) 114:715–724 DOI 10.1007/s00421-013-2808-3
Original Article
Vascular adaptations to low‑load resistance training with and without blood flow restriction Christopher A. Fahs · Lindy M. Rossow · Robert S. Thiebaud · Jeremy P. Loenneke · Daeyeol Kim · Takashi Abe · Travis W. Beck · Daniel L. Feeback · Debra A. Bemben · Michael G. Bemben
Received: 22 June 2013 / Accepted: 18 December 2013 / Published online: 31 December 2013 © Springer-Verlag Berlin Heidelberg 2013
Abstract Purpose To examine the effects of low-load knee extensor training to fatigue with and without blood flow restriction (BFR) on calf vascular conductance, calf venous compliance, and peripheral arterial stiffness in middle-aged individuals. Methods Eleven men (55 ± 8 years) and five post-menopausal women (57 ± 5 years) completed 6 weeks of unilateral knee extensor training with one limb exercising with BFR (BFR limb) and the contralateral limb exercising without BFR (free flow, FF limb). Before and after the training, femoral pulse wave velocity (PWV), calf blood flow (normalized as conductance), and calf venous compliance were measured in each limb. Results PWV increased following training in both limbs (main effect of time, p = 0.036; BFR limb 8.9 ± 0.8 vs.
9.5 ± 0.9 m/s, FF limb 9.0 ± 1.2 vs. 9.0 ± 1.1; Pre vs. Post). Calf blood flow increased (p = 0.026) in the FF limb (25.0 ± 7.0 vs. 31.8 ± 12.0 flow/mmHg; Pre vs. Post) but did not change (p = 0.831) in the BFR limb (29.1 ± 11.3 vs. 28.7 ± 11.5 flow/mmHg; Pre vs. Post). Calf venous compliance did not change in either limb following training. Conclusions These results suggest low-load BFR resistance training to fatigue elicits small increases in peripheral arterial stiffness without eliciting concomitant changes in venous compliance. In addition, unlike low-load knee extensor training without BFR, training with BFR did not enhance calf blood flow. Keywords Arterial stiffness · Calf blood flow · Venous compliance · Low-load resistance training
Communicated by William J. Kraemer. C. A. Fahs · L. M. Rossow Fitchburg State University, 160 Pearl Street, Fitchburg, MA 01420, USA L. M. Rossow e-mail: [email protected] C. A. Fahs (*) 155 North Street #111, Fitchburg, MA 01420, USA e-mail: [email protected] R. S. Thiebaud · J. P. Loenneke · D. Kim · T. W. Beck · D. L. Feeback · D. A. Bemben · M. G. Bemben The University of Oklahoma, 1401 Asp Ave #104, Norman, OK 73019, USA e-mail: Robert.S.Thiebaud‑[email protected] J. P. Loenneke e-mail: [email protected]
D. Kim e-mail: [email protected] T. W. Beck e-mail: [email protected] D. L. Feeback e-mail: Daniel.L.Feeback‑[email protected] D. A. Bemben e-mail: [email protected] M. G. Bemben e-mail: [email protected] T. Abe Indiana University, 1025 East 7th Street #104, Bloomington, IN 47405, USA e-mail: [email protected]
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Abbreviations ABI Ankle-brachial index AOP Arterial occlusion pressure BFR Blood flow restricted BMI Body mass index BP Blood pressure CBF Calf blood flow % CV Coefficient of variation MAP Mean arterial pressure MVO Maximum venous outflow 1RM One-repetition maximum PWV Pulse wave velocity SD Standard deviation SEM Standard error of measurement VVV Venous volume variation
Introduction Low-load (20–50 % one-repetition maximum, 1RM) resistance training with blood flow restriction (BFR) has been shown to enhance skeletal muscle size and function in a variety of populations (Clark et al. 2011; Gualano et al. 2010; Karabulut et al. 2010; Patterson and Ferguson 2010, 2011; Takarada et al. 2000, 2002; Loenneke et al. 2012b). In addition, evidence supports low-load resistance training to fatigue (without BFR) as an effective method for increasing muscle size and strength (Mitchell et al. 2012). Given that both low-load resistance training with and without BFR can improve skeletal muscle function, examination of the effects of both training regimens on other systems (e.g., cardiovascular system) could help determine which training regimen would be more optimal for overall health benefits. BFR resistance exercise is typically performed using a pneumatic cuff applied to the proximal portion of the exercising limb. The inflated cuff restricts venous return and reduces arterial inflow altering central and peripheral hemodynamics (Takano et al. 2005) and increases metabolic stress (Suga et al. 2009) during exercise. These alterations in shear and metabolic stress during BFR exercise may affect both conduit and resistance vessel adaptations (Green et al. 2011) and lead to different vascular adaptions compared to training without BFR. In fact, unilateral resistance training has been shown to enhance post-occlusive calf blood flow (Patterson and Ferguson 2010, 2011) and increase brachial artery diameter (Hunt et al. 2012) to a greater extent in a limb trained under BFR compared to the contralateral control limb trained with an equal volume of non-BFR exercise. Limb venous compliance may also be affected by BFR exercise due to the increased hydrostatic forces in the veins during BFR. Compared to nonBFR treadmill walking 4 weeks of BFR treadmill walking
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Eur J Appl Physiol (2014) 114:715–724
increases calf venous compliance (CVC) in older individuals (Iida et al. 2011). Currently, it is unclear if a higher volume of low-load resistance training (i.e., performed to fatigue) may elicit similar vascular adaptations as that from low-load BFR resistance training. Most previous work has investigated the vascular effects of low-load BFR resistance training in younger individuals (Clark et al. 2011; Patterson and Ferguson 2010; Hunt et al. 2012; Credeur et al. 2009; Evans et al. 2010). The effect of BFR training on vascular function in middle-aged or older individuals is not as well studied (Patterson and Ferguson 2011). The effects of BFR training on vascular function are important to investigate as decrements in arterial and venous function are apparent with age (Mitchell et al. 2004; Proctor et al. 2005; Monahan et al. 2001). Furthermore, most studies have examined the vascular effects of BFR calf or forearm resistance training (Credeur et al. 2009; Evans et al. 2010; Hunt et al. 2012; Patterson and Ferguson 2010, 2011). Less is known about the vascular effects of large muscle group training with BFR. Therefore, the purpose of this study was to examine the vascular adaptations to low-load knee extensor resistance training performed to fatigue with and without BFR. These two training modalities were chosen as low-load resistance training to fatigue both with (Takarada et al. 2004) and without BFR (Mitchell et al. 2012) have been shown to increase muscle size and strength. We chose to use a within-subject mixed limb experimental design since vascular adaptations to exercise training appear to be affected primary by regional (e.g. shear, transmural, and/or metabolic stress) rather than systemic factors. Furthermore, this study design is similar to previous investigations (Credeur et al. 2009; Evans et al. 2010; Hunt et al. 2012; Patterson and Ferguson 2010, 2011) on vascular adaption to training with and without BFR. We hypothesized that, compared to training without BFR, low-load resistance training with BFR would increase calf vascular conductance and venous compliance whereas arterial stiffness would decrease following training both with and without BFR.
Methods Participants Fourteen men and eight post-menopausal women aged 40–64 years volunteered to participate in this study. Appropriate standards for human experimentation were followed, all participants provided written informed consent to participate, and this study was approved by the University of Oklahoma Health Science Center Institutional Review Board. Participants did not smoke, did not have any orthopedic problems preventing strength testing or training,
Eur J Appl Physiol (2014) 114:715–724
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Table 1 Participant characteristics
Age (years) Height (m) Body mass (kg) BMI (kg/m2) Left ABI Right ABI Aerobic activity (h/week) Thyroid medication (no.) Cholesterol medication (no.) Blood pressure medication (no.)
Men n = 11
Women n = 5
Total n = 16
55 (8) 1.80 (0.06) 87.1 (14.3) 26.7 (4.1) 1.1 (0.1) 1.1 (0.1) 2.3 (2.0)
57 (5) 1.63 (0.05)* 69.1 (12.2)* 25.9 (4.4) 1.1 (0.1) 1.2 (0.1) 2.1 (2.7)
55 (7) 1.75 (0.10) 81.5 (15.8) 26.5 (4.1) 1.1 (0.1) 1.1 (0.1) 2.3 (2.1)
0
1
1
2
1
3
2
1
3
Data presented as mean (SD) BMI body mass index, ABI ankle-brachial index * p
Original Article
Vascular adaptations to low‑load resistance training with and without blood flow restriction Christopher A. Fahs · Lindy M. Rossow · Robert S. Thiebaud · Jeremy P. Loenneke · Daeyeol Kim · Takashi Abe · Travis W. Beck · Daniel L. Feeback · Debra A. Bemben · Michael G. Bemben
Received: 22 June 2013 / Accepted: 18 December 2013 / Published online: 31 December 2013 © Springer-Verlag Berlin Heidelberg 2013
Abstract Purpose To examine the effects of low-load knee extensor training to fatigue with and without blood flow restriction (BFR) on calf vascular conductance, calf venous compliance, and peripheral arterial stiffness in middle-aged individuals. Methods Eleven men (55 ± 8 years) and five post-menopausal women (57 ± 5 years) completed 6 weeks of unilateral knee extensor training with one limb exercising with BFR (BFR limb) and the contralateral limb exercising without BFR (free flow, FF limb). Before and after the training, femoral pulse wave velocity (PWV), calf blood flow (normalized as conductance), and calf venous compliance were measured in each limb. Results PWV increased following training in both limbs (main effect of time, p = 0.036; BFR limb 8.9 ± 0.8 vs.
9.5 ± 0.9 m/s, FF limb 9.0 ± 1.2 vs. 9.0 ± 1.1; Pre vs. Post). Calf blood flow increased (p = 0.026) in the FF limb (25.0 ± 7.0 vs. 31.8 ± 12.0 flow/mmHg; Pre vs. Post) but did not change (p = 0.831) in the BFR limb (29.1 ± 11.3 vs. 28.7 ± 11.5 flow/mmHg; Pre vs. Post). Calf venous compliance did not change in either limb following training. Conclusions These results suggest low-load BFR resistance training to fatigue elicits small increases in peripheral arterial stiffness without eliciting concomitant changes in venous compliance. In addition, unlike low-load knee extensor training without BFR, training with BFR did not enhance calf blood flow. Keywords Arterial stiffness · Calf blood flow · Venous compliance · Low-load resistance training
Communicated by William J. Kraemer. C. A. Fahs · L. M. Rossow Fitchburg State University, 160 Pearl Street, Fitchburg, MA 01420, USA L. M. Rossow e-mail: [email protected] C. A. Fahs (*) 155 North Street #111, Fitchburg, MA 01420, USA e-mail: [email protected] R. S. Thiebaud · J. P. Loenneke · D. Kim · T. W. Beck · D. L. Feeback · D. A. Bemben · M. G. Bemben The University of Oklahoma, 1401 Asp Ave #104, Norman, OK 73019, USA e-mail: Robert.S.Thiebaud‑[email protected] J. P. Loenneke e-mail: [email protected]
D. Kim e-mail: [email protected] T. W. Beck e-mail: [email protected] D. L. Feeback e-mail: Daniel.L.Feeback‑[email protected] D. A. Bemben e-mail: [email protected] M. G. Bemben e-mail: [email protected] T. Abe Indiana University, 1025 East 7th Street #104, Bloomington, IN 47405, USA e-mail: [email protected]
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Abbreviations ABI Ankle-brachial index AOP Arterial occlusion pressure BFR Blood flow restricted BMI Body mass index BP Blood pressure CBF Calf blood flow % CV Coefficient of variation MAP Mean arterial pressure MVO Maximum venous outflow 1RM One-repetition maximum PWV Pulse wave velocity SD Standard deviation SEM Standard error of measurement VVV Venous volume variation
Introduction Low-load (20–50 % one-repetition maximum, 1RM) resistance training with blood flow restriction (BFR) has been shown to enhance skeletal muscle size and function in a variety of populations (Clark et al. 2011; Gualano et al. 2010; Karabulut et al. 2010; Patterson and Ferguson 2010, 2011; Takarada et al. 2000, 2002; Loenneke et al. 2012b). In addition, evidence supports low-load resistance training to fatigue (without BFR) as an effective method for increasing muscle size and strength (Mitchell et al. 2012). Given that both low-load resistance training with and without BFR can improve skeletal muscle function, examination of the effects of both training regimens on other systems (e.g., cardiovascular system) could help determine which training regimen would be more optimal for overall health benefits. BFR resistance exercise is typically performed using a pneumatic cuff applied to the proximal portion of the exercising limb. The inflated cuff restricts venous return and reduces arterial inflow altering central and peripheral hemodynamics (Takano et al. 2005) and increases metabolic stress (Suga et al. 2009) during exercise. These alterations in shear and metabolic stress during BFR exercise may affect both conduit and resistance vessel adaptations (Green et al. 2011) and lead to different vascular adaptions compared to training without BFR. In fact, unilateral resistance training has been shown to enhance post-occlusive calf blood flow (Patterson and Ferguson 2010, 2011) and increase brachial artery diameter (Hunt et al. 2012) to a greater extent in a limb trained under BFR compared to the contralateral control limb trained with an equal volume of non-BFR exercise. Limb venous compliance may also be affected by BFR exercise due to the increased hydrostatic forces in the veins during BFR. Compared to nonBFR treadmill walking 4 weeks of BFR treadmill walking
13
Eur J Appl Physiol (2014) 114:715–724
increases calf venous compliance (CVC) in older individuals (Iida et al. 2011). Currently, it is unclear if a higher volume of low-load resistance training (i.e., performed to fatigue) may elicit similar vascular adaptations as that from low-load BFR resistance training. Most previous work has investigated the vascular effects of low-load BFR resistance training in younger individuals (Clark et al. 2011; Patterson and Ferguson 2010; Hunt et al. 2012; Credeur et al. 2009; Evans et al. 2010). The effect of BFR training on vascular function in middle-aged or older individuals is not as well studied (Patterson and Ferguson 2011). The effects of BFR training on vascular function are important to investigate as decrements in arterial and venous function are apparent with age (Mitchell et al. 2004; Proctor et al. 2005; Monahan et al. 2001). Furthermore, most studies have examined the vascular effects of BFR calf or forearm resistance training (Credeur et al. 2009; Evans et al. 2010; Hunt et al. 2012; Patterson and Ferguson 2010, 2011). Less is known about the vascular effects of large muscle group training with BFR. Therefore, the purpose of this study was to examine the vascular adaptations to low-load knee extensor resistance training performed to fatigue with and without BFR. These two training modalities were chosen as low-load resistance training to fatigue both with (Takarada et al. 2004) and without BFR (Mitchell et al. 2012) have been shown to increase muscle size and strength. We chose to use a within-subject mixed limb experimental design since vascular adaptations to exercise training appear to be affected primary by regional (e.g. shear, transmural, and/or metabolic stress) rather than systemic factors. Furthermore, this study design is similar to previous investigations (Credeur et al. 2009; Evans et al. 2010; Hunt et al. 2012; Patterson and Ferguson 2010, 2011) on vascular adaption to training with and without BFR. We hypothesized that, compared to training without BFR, low-load resistance training with BFR would increase calf vascular conductance and venous compliance whereas arterial stiffness would decrease following training both with and without BFR.
Methods Participants Fourteen men and eight post-menopausal women aged 40–64 years volunteered to participate in this study. Appropriate standards for human experimentation were followed, all participants provided written informed consent to participate, and this study was approved by the University of Oklahoma Health Science Center Institutional Review Board. Participants did not smoke, did not have any orthopedic problems preventing strength testing or training,
Eur J Appl Physiol (2014) 114:715–724
717
Table 1 Participant characteristics
Age (years) Height (m) Body mass (kg) BMI (kg/m2) Left ABI Right ABI Aerobic activity (h/week) Thyroid medication (no.) Cholesterol medication (no.) Blood pressure medication (no.)
Men n = 11
Women n = 5
Total n = 16
55 (8) 1.80 (0.06) 87.1 (14.3) 26.7 (4.1) 1.1 (0.1) 1.1 (0.1) 2.3 (2.0)
57 (5) 1.63 (0.05)* 69.1 (12.2)* 25.9 (4.4) 1.1 (0.1) 1.2 (0.1) 2.1 (2.7)
55 (7) 1.75 (0.10) 81.5 (15.8) 26.5 (4.1) 1.1 (0.1) 1.1 (0.1) 2.3 (2.1)
0
1
1
2
1
3
2
1
3
Data presented as mean (SD) BMI body mass index, ABI ankle-brachial index * p
