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Effects of Low-Intensity Cycle Training with Restricted Leg Blood Flow on Thigh Muscle Volume and VO2MAX in Young Men

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Concurrent improvements in aerobic capacity and muscle hypertrophy in response to a single mode of training have not been reported. We examined the effects of low-intensity cycle exercise training with and without blood flow restriction (BFR) on muscle size and maximum oxygen uptake (VO2max). A group of 19 young men (mean age ± SD: 23.0 ± 1.7 years) were allocated randomly into either a BFR-training group (n=9, BFR-training) or a non-BFR control training group (n=10, CON-training), both of which trained 3 days/wk for 8 wk. Training intensity and duration were 40% of VO2max and 15 min for the BFR-training group and 40% of VO2max and 45 min for the CON-training group. MRI-measured thigh and quadriceps muscle cross-sectional area and muscle volume increased by 3.4-5.1% (P < 0.01) and isometric knee extension strength tended to increase by 7.7% (p < 0.10) in the BFR-training group. There was no change in muscle size (~0.6%) and strength (~1.4%) in the CON-training group. Significant improvements in VO2max (6.4%) and exercise time until exhaustion (15.4%) were observed in the BFR-training group (p < 0.05) but not in the CON-training group (-0.1 and 3. 9%, respectively). The results suggest that low-intensity, short-duration cycling exercise combined with BFR improves both muscle hypertrophy and aerobic capacity concurrently in young men. Key pointsConcurrent improvements in aerobic capacity and muscle hypertrophy in response to a single mode of training have not been reported.In the present study, low-intensity (40% of VO2max) cycle training with BFR can elicit concurrent improvement in muscle hypertrophy and aerobic capacity.
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©Journal of Sports Science and Medicine (2010) 9, 452-458
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Received: 25 April 2010 / Accepted: 07 June 2010 / Published (online): 01 September 2010
Effects of low-intensity cycle training with restricted leg blood flow on thigh
muscle volume and VO2max in young men
Takashi Abe 1, Satoshi Fujita 1, Toshiaki Nakajima 2, Mikako Sakamaki 1, Hayao Ozaki 1, Riki Oga-
sawara 1, Masato Sugaya 1, Maiko Kudo 3, Miwa Kurano 2, Tomohiro Yasuda 1, Yoshiaki Sato 2, Hiro-
shi Ohshima 4, Chiaki Mukai 4 and Naokata Ishii 3
1 Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Japan, 2 Graduate School of Medicine, Univer-
sity of Tokyo, Tokyo, Japan, 3 Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan, 4 Japan Aero-
space Exploration Agency, Tsukuba, Japan
Abstract
Concurrent improvements in aerobic capacity and muscle hyper-
trophy in response to a single mode of training have not been
reported. We examined the effects of low-intensity cycle exer-
cise training with and without blood flow restriction (BFR) on
muscle size and maximum oxygen uptake (VO2max). A group of
19 young men (mean age ± SD: 23.0 ± 1.7 years) were allocated
randomly into either a BFR-training group (n=9, BFR-training)
or a non-BFR control training group (n=10, CON-training), both
of which trained 3 days/wk for 8 wk. Training intensity and
duration were 40% of VO2max and 15 min for the BFR-training
group and 40% of VO2max and 45 min for the CON-training
group. MRI-measured thigh and quadriceps muscle cross-
sectional area and muscle volume increased by 3.4–5.1% (P <
0.01) and isometric knee extension strength tended to increase
by 7.7% (p < 0.10) in the BFR-training group. There was no
change in muscle size (~0.6%) and strength (~1.4%) in the
CON-training group. Significant improvements in VO2max
(6.4%) and exercise time until exhaustion (15.4%) were ob-
served in the BFR-training group (p < 0.05) but not in the CON-
training group (–0.1 and 3.9%, respectively). The results suggest
that low-intensity, short-duration cycling exercise combined
with BFR improves both muscle hypertrophy and aerobic capac-
ity concurrently in young men.
Key words: Muscle hypertrophy, Aerobic exercise, Occlusion,
Muscle strength.
Introduction
Skeletal muscle shows an enormous plasticity to adapt to
stimuli such as metabolic and/or contractile activities.
Based on the principle of specificity of exercise, resis-
tance exercise elicits specific muscular adaptations, with
little improvement in the physiologic adaptations experi-
enced with typical aerobic training (Hurley et al., 1984).
Conversely, aerobic training is thought to stimulate im-
provements in cardiovascular fitness, such as maximum
oxygen uptake (VO2max) and anaerobic threshold (Wenger
and Bell, 1986). Within muscle, opposite morphologic
and physiologic adaptive responses to the 2 types of train-
ing occur in myofibrillar protein content (Hoppeler, 1986;
Luthi et al., 1986), in mitochondria volume density (Hop-
peler, 1986; MacDougall et al., 1979), in capillary density
(Denis et al., 1986), in enzymes reflecting aerobic energy
production (Gollnick et al., 1973; Tesch et al., 1987), and
in the Akt/mTOR signaling pathway (Coffey and Hawley,
2007). In addition, some studies (Bell et al., 2000;
Kraemer et al., 1995) show interference in strength devel-
opment when aerobic training is added to resistance train-
ing. Thus, it would be advantageous to develop a training
method that can effectively and concurrently improve
both cardiovascular and muscular fitness within a single
mode of training.
Muscular blood flow restriction (BFR) during re-
sistance training has been shown to elicit similar muscle
hypertrophy as traditional high-intensity resistance train-
ing but much lower training intensity (Abe et al., 2005;
Takarada et al., 2002). An intensity as low as that associ-
ated with walking, when combined with BFR, can lead to
significant improvements in muscle strength and leg mus-
cle hypertrophy (Abe et al., 2006; 2010). Recently, our
laboratory demonstrated increased muscle activation
during low-load (20% of 1 repetition maximum [1 RM])
muscle contractions with BFR such that there was a
greater internal activation intensity of the muscle relative
to external load (Yasuda et al., 2008). In addition, signifi-
cantly greater oxygen uptake and heart rate (HR) are
observed during slow treadmill walking with BFR than
during walking without BFR (Abe et al., 2006). The nov-
elty of BFR appears to be the unique combination of
venous blood volume pooling and restricted arterial blood
inflow, which can result in a decreased stroke volume and
increased HR while maintaining cardiac output (Takano
et al., 2005). Consequently, increased HR at the same
systolic blood pressure (SBP) during exercise with BFR
may produce high mechanical stress on the heart, as indi-
cated by a greater rate-pressure product ([HR × SBP]/100)
(Nelson et al., 1974). Furthermore, the increased oxygen
uptake observed during BFR exercise may be the result of
increased arterial and mixed venous blood oxygen (a-v
O2) difference since cardiac output during exercise with
and without BFR is the same. We hypothesized that the
potential benefits of BFR exercise could include not only
an anabolic response by the muscular system (Abe et al.,
2006) but also improvements in cardiovascular fitness.
Thus, the purpose of the current study was to investigate
the effects of low-intensity exercise training combined
with BFR on muscle size and strength, as well as on
VO2max, in young male subjects.
Research article
Abe et al.
453
Methods
Subjects
Nineteen young men aged 20–26 yr volunteered to par-
ticipate in the study. Subjects were randomized into either
a BFR-training group (n = 9, BFR-training) or a non-BFR
control training group (n = 10, CON-training). The sub-
jects in this study were physically active, but none of the
subjects had participated in regular strength/resistance
and/or aerobic training (less than once a week) for a
minimum of 1 yr prior to the start of the study. Volunteers
who suffered from a chronic disease, such as hyperten-
sion, diabetes, an orthopedic disorder, deep venous
thrombosis, or peripheral vascular disease, were excluded
from the study. All subjects were informed of the meth-
ods, procedures, and risks, and signed an informed con-
sent document before participation. The study was con-
ducted according to the Declaration of Helsinki and was
approved by the institutional review board (IRB) of hu-
man research of Japan Aerospace Exploration Agency
(JAXA) and the Ethics Committee for Human Experi-
ments at the University of Tokyo, Japan.
Training protocol
Training was performed once a day, 3 days/wk, for 8 wk.
Following measurements of body weight and mid-thigh
girth, the subjects performed exercise on an electrically
braked bicycle ergometer (Aerobike 900U, Combi Corpo-
ration, Tokyo, Japan) at a predetermined 40% of VO2max
for 15 min in the BFR training group and at a predeter-
mined 40% of VO2max for 45 min in the CON-training
group. The exercise intensity and duration in each group
remained constant throughout the training period. Sub-
jects in the BFR-training group wore pressure belts
(Kaatsu-Master, Sato Sports Plaza, Tokyo, Japan) on both
legs during cycle exercise training. Prior to BFR training,
the subjects were seated on a chair, the belt air pressure
was set at 120 mmHg (the approximate SBP at heart level
for each subject) for 30 s, and the air pressure was re-
leased. The air pressure was increased by 20 mmHg, held
for 30 s, and then released for 10 s before the next occlu-
sive stimulation was performed. This process was re-
peated until a final occlusion pressure for each training
day was reached. On the first day of training, the final belt
pressure (training pressure) was 160 mmHg. As subjects
adapted to the occlusive stimulus during early phase of
the training, the training pressure was increased by 10
mmHg each week until a final belt pressure of 210 mmHg
was reached. A belt pressure of 160–210 mmHg was
selected for the restriction stimulus based on a review of
the data in young men (Abe et al., 2006). Blood flow to
the leg muscles was restricted for a total of ~18 min (3
min preparation time and 15 min bicycling time) during
each training session, with the belt pressure released im-
mediately upon completion of the session. During all
training sessions, HR was recorded at the 5th min and
15th min for the BFR-training group and CON-training
group, respectively. Ratings of perceived exertion (Borg
15 Point Scale) were also recorded at the end of training
session.
MRI-measured muscle cross-sectional area and vol-
ume
Multislice MRI images of the thigh were obtained using a
General Electric Signa 1.5-T scanner (Milwaukee, WI). A
T1-weighted, spin-echo, axial plane sequence was per-
formed with a 1,500-ms repetition time and a 17-ms echo
time (Figure 1). Subjects rested quietly in the magnet bore
in a supine position with their legs extended. The great
trochanter was used as the origin point, and continuous
Figure 1. Typical MRI images showing transverse sections of the mid-thigh taken before (pre) and after (post) 8 wk
of cycle training with BFR. The images show identical sections midway along the femur in the same subject (KK).
Pretraining
Posttraining
BFR training on muscle and VO2max
454
transverse images with 1.0-cm slice thickness (0-cm inter-
slice gap) were obtained from the great trochanter to the
lateral condyle of the femur for each subject. All MRI
data were transferred to a personal computer for analysis
using specially designed image analysis software (To-
moVision Inc., Montreal, Canada). For each slice, skeletal
muscle tissue cross-sectional area (CSA) was digitized,
and the muscle tissue volume (cm3) per slice was calcu-
lated by multiplying muscle tissue area (cm2) by slice
thickness (cm). Muscle volume of an individual muscle
was defined as the sum of the slices of muscle. We have
previously determined that the coefficient of variation
(CV) of this measurement was less than 1% (Abe et al.,
2003). This measurement, from the right side of the body,
was completed at baseline and 3 days after the final train-
ing (posttesting).
Maximum isometric strength
Maximum voluntary isometric strength of the knee exten-
sors and flexors was determined using a Biodex System 3
dynamometer (Shirley, NY). Subjects were carefully
familiarized with the testing procedures of voluntary force
production of the thigh muscles during several attempts of
submaximal and maximal muscular contractions ~1 wk
prior to baseline testing. The subjects were seated on a
chair with their hip joint angle positioned at 85˚. The
center of rotation of the knee joint was visually aligned
with the axis of the lever arm of the dynamometer, and
the ankle of the right leg was firmly attached to the lever
arm of the dynamometer with a strap. After a warm-up
consisting of submaximal contractions, the subjects were
instructed to perform maximal isometric (MVC) knee
extension at a knee joint angle of 75˚ and maximal iso-
metric knee flexion at a knee joint angle of 60˚. A knee
joint angle of 0˚ corresponded to full extension of the
knee (Abe et al., 2000). If MVC strength for the first two
trials were varied by >5%, up to an additional MVC was
performed. The coefficient of variation for this test in our
laboratory was 7%. The test was assessed at baseline and
3 days after the final training session (posttesting).
Maximum oxygen uptake
Graded exercise tests on an electrically braked bicycle
ergometer (Aerobike 75XL-II, Combi Corporation, To-
kyo, Japan) were performed in a laboratory where room-
temperature was stabilized at 20–22°C. At the baseline
test, seat height was noted and reproduced for posttraining
testing. The exercise test was started at an initial workload
of 50 W, which was increased by 15 W every minute until
volitional exhaustion. (If the workload reached 200 W, the
rate of increase was 10 W every minute.) During the test,
HR was continuously monitored (HR monitor, Minato
Medical Science Co., Ltd., Osaka, Japan). Ventilation was
also monitored, and oxygen and carbon dioxide concen-
trations in the expired air were continuously measured to
calculate of oxygen uptake (O2), carbon dioxide output
(CO2), and the respiratory gas exchange ratio (RER;
CO2/O2) by a calibrated breath-by-breath system (Aero
monitor AE300S, Minato Medical Science Co., Ltd.,
Osaka, Japan). The following criteria were used to estab-
lish that maximum effort had been achieved: VO2max
appeared as a plateau in VO2 despite an increase in work-
load (increased VO2 within 150 ml min-1), maximum
heart rate within ± 11 beats·min-1 of the age-predicted
maximum (220 minus age), and a maximum respiratory
exchange ratio above 1.15. Exercise time to exhaustion
was also recorded for each subject (Ozaki et al., 2010).
Statistical analyses
StatView, version 4.5, was used to compute the data, and
the results are expressed as means and standard deviations
(SDs) for all variables. Statistical analyses were per-
formed by a 2-way analysis of variance (ANOVA) with
repeated measures (Group [BFR-training and CON-
training] × Time [pre- and posttesting]) to evaluate train-
ing effects for all dependent variables. When appropriate,
post hoc paired t tests were used to assess within-group
changes. All baseline characteristics and percentage
changes in anthropometric variables, skeletal muscle
volume and CSA, muscular strength, and aerobic capacity
were compared between groups with a 1-way ANOVA.
Statistical significance was set at p < 0.05.
Results
At baseline, there were no differences between the two
groups for standing height, body weight, body mass index
(BMI), and mid-thigh girth (Table 1). The subjects in both
training groups completed all training and testing ses-
sions, and no training-related injuries were sustained.
There were no significant changes in body weight and
BMI for either group following the training program;
Table 1. Changes in anthropometric variables and thigh muscle cross-sectional area and muscle volume. Values are mean(SD).
BFR-Training Group CON-Training Group
Pre Post % Pre Post %
Anthropometric variables
Height, m 1.72 (.07) 1.71 (.04)
Weight, kg 61.1 (8.4) 62.0 (9.0) 1.4 61.7 (6.3) 61.4 (6.1) –.4
BMI, kg·m-2 21.2 (2.5) 21.5 (2.5) 1.4 21.0 (2.4) 20.9 (2.3) –.4
Thigh girth, cm 49.7 (3.1) 50.5 (3.0)a 1.7b 50.0 (3.9) 49.7 (3.6) –.6
Muscle cross-sectional area, cm2
Thigh at 50% 142.3 (8.7) 147.1 (9.2)c 3.4d 144.0 (17.6) 144.1 (15.0) .1
Quadriceps at 50% 69.5 (5.4) 72.6 (5.3)c 4.6b 70.7 (7.3) 71.0 (6.5) .6
Muscle volume, cm3
Thigh 3508 (283) 3641 (320)c 3.8b 3696 (447) 3689 (418) –.1
Quadriceps 1575 (153) 1655 (132)c 5.1b 1730 (190) 1731 (180) –.1
BMI, body mass index. Significant differences between BFR-training and CON-training: d p < 0.05, b p < 0.01. Significant differences
between pre- and posttraining: a p < 0.05, c p < 0.01.
Abe et al.
455
Table 2. Changes in isometric knee extension and flexion strength and specific tension. Values are mean (SD).
BFR-Training Group CON-Training Group
Pre Post % Pre Post %
Isometric muscle strength, Nm
Knee extension 194 (80) 209 (73) 7.7a 216 (47) 219 (45) 1.4
Knee flexion 77 (26) 79 (27) 3.3 87 (23) 84 (16) –3.4
Specific tension, Nm/cm2
Knee extension/qCSA 2.79 (1.08) 2.86 (.90) 2.5 3.05 (0.51) 3.09 (0.54) 1.3
qCSA, quadriceps muscle cross-sectional area (at 50%). Significant differences between BFR-training and CON-training: a p < 0.10.
however, mid-thigh girth increased (p < 0.05) in the BFR-
training group but not in the CON-training group (Table
1).
Muscle CSA increased (p < 0.01) by 3.4% for the
thigh and 4.6% for the quadriceps in the BFR-training
group. Thigh and quadriceps muscle volumes increased (p
< 0.01) by 3.8 and 5.1%, respectively, for the BFR-
training group. Neither muscle CSA nor volume changed
for the CON-training group (Table 1).
Maximal isometric knee extension strength tended
to increase (p < 0.10) in the BFR-training group (7.7%)
but not in the CON-training group (1.4%). There was no
change in isometric knee flexion strength for either group
(Table 2). Relative isometric knee extension strength per
unit quadriceps muscle CSA was similar at pre- and post-
training in both groups.
During training sessions, heart rate (HR) ranged
between 129 and 149 beats/min (50–65% heart rate re-
serve [HRR], mean 59%) for BFR-training subjects and
between 105 and 141beats/min (37–46% HRR, mean
42%) for CON-training subjects. The ratings of perceived
exertion were higher (p < 0.01) in the BFR-training group
than in the CON-training group at the end of training
session (10.5 ± 1.4 and 13.6 ± 1.3, respectively). There
was no change in maximum HR attained during graded
exercise test for either group. Absolute and relative
VO2max increased in the BFR-training group (p < 0.05) but
did not change in the CON-training group. Increase in
exercise time until exhaustion was observed in the BFR-
training group (15.4%, p < 0.01) but not in the CON-
training group (Figure 2).
Discussion
This study demonstrated that a single mode of low-
intensity (40% of VO2max), short-duration (15 min) exer-
cise training with BFR can elicit improvements in muscle
volume in healthy young subjects. Aerobic capacity also
improved concurrently following the training. Previously,
concurrent improvements in muscular strength and aero-
bic capacity by a single mode of exercise have been
achieved after high-intensity and long-duration exercise
training (Hass et al., 2001; Tabata et al., 1990). However,
none of the studies demonstrated significant muscular
Figure 2. Changes in absolute and relative V
O2max and exercise time. Significant differences between pre- and post-
training: a p < 0.05, b p < 0.01.
HRmax (bpm)
0
50
100
150
200
250
Exercise time (min)
0
5
10
15
20
VO2max (l/min)
0
1
2
3
4
VO2max (ml/kg/min)
0
20
40
60
Pre
Post
b
a
a
BFR-
training
CON-
training
BFR-
training
CON-
training
BFR training on muscle and VO2max
456
hypertrophy, which suggests that the increased strength
was due mainly to neural adaptations. Thus, high-
intensity, long-duration exercise training rarely produces
significant muscle hypertrophy in young and middle-aged
adults. Additionally, it is reported that maximal knee
extension strength was reduced and the thigh muscle
cross-sectional area was unchanged following 4 weeks of
cycle training under conditions of local leg ischaemia,
although VO2max increased with this training (Nygren et
al., 2000; Sundberg, 1994). However, there are few pub-
lished studies documenting concurrent improvements in
VO2max and muscle hypertrophy after aerobic training in
older and failed subjects (Harber et al., 2009; Schwartz et
al., 1991).
Previous studies (Bell et al., 2000; Kraemer et al.,
1995) have shown that combining aerobic training with
resistance exercise negatively affected resistance train-
ing–induced muscular hypertrophy. For instance, Bell et
al. (2000) reported that type I and type II muscle fiber
CSA increased (27% and 28%, respectively) following 12
weeks of high-intensity resistance training (HI-RT), but
the magnitude of increases in fiber CSA in the concurrent
resistance and aerobic training group was less than one-
half of that occurring with resistance training alone (10%
and 14%, respectively). In the present study, the increases
in thigh and quadriceps muscle CSA (4.1% and 5.1%,
respectively) and muscle volume (3.2% and 5.3%, respec-
tively) were similar to the increments observed in previ-
ous HI-RT studies (Jones and Rutherford, 1987; Wilkin-
son et al., 2006), but lower than a short (5-wk) period of
HI-RT studies (Seynnes et al., 2007; Tesch et al., 2004).
Although the differences in mode, intensity, and volume
of exercise might have caused the variability in the train-
ing-induced muscle hypertrophy, it is clear that the mag-
nitude of hypertrophic potential associated with BFR
cycle training is comparable with that associated with HI-
RT.
Our previous study (Abe et al., 2006) demon-
strated that slow walk training combined with BFR not
only produced thigh muscle hypertrophy but also in-
creased isometric and dynamic strength of the knee exten-
sor. McCarthy et al. (1995) reported that cycle exercise
training alone did not significantly change isokinetic or
isometric strength, a finding that is consistent with our
CON-training group results. On the other hand, an aver-
age 7.7% change in knee extension strength was observed
when cycle training was combined with BFR. However,
there were large individual variations in strength adapta-
tion in response to cycle training with BFR, which re-
sulted in a nonsignificant increase in isometric knee ex-
tension strength. The specific tension of the knee extensor
muscle did not change significantly between pre- and
posttraining using BFR resistance training (Takarada et
al., 2002) and BFR walk training (Abe et al., 2006); nor
did it change in the present study. Therefore, a main con-
tributor of increased muscle strength after BFR training is
the increase in muscle CSA, which surpasses the neural
adaptation, such as fiber recruitment patterns.
Our results showed that BFR cycle training pro-
duced a 6.4% increase (p < 0.05) in absolute VO2max and a
15.4% increase (p < 0.01) in exercise time until exhaus-
tion. The magnitude of change in VO2max (percentage
increase in VO2max divided by total training sessions) in
the BFR-training group (0.25%) is similar to that reported
in some studies (0.25%–0.26%) (Gaesser and Rich, 1984;
Wilmore et al., 1980), but lower than that reported in
another study (0.60%) (McCarthy et al., 1995). Studies
(Gaesser and Rich, 1984; Wenger and Bell, 1986) have
demonstrated that the magnitude of change in VO2max
increases as exercise intensity increases from 50% to
100% of VO2max. The minimum stimulus necessary to
evoke change is ~50% of VO2max, although 1 study
(Gaesser and Rich, 1984) reported the increase in VO2max
after cycle training to be 45% of VO2max. If exercise in-
tensity is low, longer-duration efforts (>35 min) can be
more effective than shorter-duration efforts at higher
intensity (Wenger and Bell, 1986). During low-intensity
exercise with BFR, stroke volume (SV) decreased and HR
increased without changes in cardiac output (Ozaki et al.,
2010; Takano et al., 2005). In the present study, exercise
intensity and duration were set at 40% of VO2max and 15
min in the BFR-training group. During the training ses-
sions, however, the exercise intensity estimated from
maximum HRR was 59% on average, which is within the
effective exercise intensity for improvements in VO2max.
The exercise training–induced increase in VO2max
is known to be due to central cardiovascular and/or pe-
ripheral metabolic adaptations, and the VO2max is the
product of cardiac output and arterial and mixed venous
blood oxygen (a-v O2) difference at maximal exercise
workload. However, there is a lack of studies investigat-
ing the cardiovascular hemodynamic and muscle meta-
bolic responses to BFR exercise training (Ozaki et al.,
2010). Although the BFR method is different, Sundberg
(1994) found an increase in VO2max by utilizing supine
one-legged cycle training with 50 mmHg chamber pres-
sure (reduced leg blood flow by 16%) for 4 weeks (4
sessions/wk). In that study, muscle enzyme of oxidative
metabolism and capillary density are increased in the
ischaemically-trained leg, but cardiovascular adaptations
to the ischaemic exercise training were not reported. Re-
cently, a study reported that increases in VO2max and sub-
maximal exercise SV were observed after 2 weeks of
twice–daily, 6 days/wk BFR walk training, while resting
SV remain unchanged (Park et al., 2010). Therefore, the
increase in VO2max by BFR training may be due to adapta-
tions in muscle oxidative capacity (a-v O2 difference) and
SV. In addition, increase in lower body muscle mass may
be associated with improvements in VO2max in the BFR
training group.
Few studies have attempted to elucidate the cellu-
lar and molecular mechanisms of adaptation in skeletal
muscle as well as the cardiorespiratory system in response
to low-intensity BFR exercise (Manini and Clark, 2009).
Our previous studies demonstrated that a single bout of
20% of 1-RM intensity knee extension exercise with BFR
increased both vastus lateralis muscle protein synthesis
and the Akt/mTOR signaling pathway in young (Fujita et
al., 2007) and old (Fry et al., 2010) men, although the rate
of muscle protein breakdown was not measured. These
anabolic responses may contribute significantly to BFR
training–induced muscle hypertrophy. However, there
Abe et al.
457
have not been any studies assessing the changes in mito-
chondrial and capillary density and muscle enzymes re-
flecting aerobic energy production, as well as cardiac
function in response to BFR exercise training. Further
research is needed to clarify the mechanisms of the BFR
training–induced concurrent improvement in both types of
physical fitness.
Conclusion
In conclusion, low-intensity (40% VO2max) cycle training
of short duration (15 min) combined with blood flow
restriction can produce a significant increase in thigh
muscle volume and aerobic capacity in young men.
Acknowledgements
The authors thank the students who participated in this study. We also
greatly appreciate the assistance of the JAXA staffs. This study is finan-
cially supported in part by JAXA.
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Key points
Concurrent improvements in aerobic capacity and
muscle hypertrophy in response to a single mode of
training have not been reported.
In the present study, low-intensity (40% of VO2max)
cycle training with BFR can elicit concurrent im-
provement in muscle hypertrophy and aerobic ca-
pacity.
AUTHORS BIOGRAPHY
Takashi ABE
Employment
Professor, University of Tokyo, Graduate School of Frontier
Sciences, Japan
Degree
PhD
Research interest
Exercise physiology and sports performance, training science
E-mail: abe@k.u-tokyo.ac.jp
Satoshi FUJITA
Employment
University of Tokyo, Graduate School of Frontier Sciences,
Japan
Degree
PhD
Toshiaki NAKAJIMA
Employment
University of Tokyo, Graduate School of Midicine, Japan
Degree
MD, PhD
Mikako SAKAMAKI
Employment
University of Tokyo, Graduate School of Frontier Sciences,
Japan
Degree
PhD
Hayao OZAKI
Employment
University of Tokyo, Graduate School of Frontier Sciences,
Japan
Degree
MSc
Research interest
Exercise physiology, sport and training science
Riki OGASAWARA
Employment
University of Tokyo, Graduate School of Frontier Sciences,
Japan
Degree
MSc
Masato SUGAYA
Employment
University of Tokyo, Graduate School of Frontier Sciences,
Japan
Degree
MSc
Maiko KUDO
Employment
University of Tokyo, Graduate School of Arts and Sciences,
Japan
Degree
MSc
Miwa KURANO
Employment
University of Tokyo, Graduate School of Medicine, Japan
Degree
MSc
Tomohiro YASUDA
Employment
University of Tokyo, Graduate School of Frontier Sciences,
Japan
Degree
PhD
Research interest
Exercise physiology, sport science
Hiroshi OHSHIMA
Employment
Japan Aerospace Exploration Agency, Japan
Degree
MD, PhD
Chiaki MUKAI
Employment
Japan Aerospace Exploration Agency, Japan
Degree
MD, PhD
Naokata ISHII
Employment
Professor, University of Tokyo, Graduate School of Arts and
Sciences, Japan
Degree
PhD
Takashi Abe, PhD
Graduate School of Frontier Sciences, University of Tokyo, 5-1-
5 Kashiwanoha, Kashiwa, Chiba, Japan 227-8563
... Meanwhile, changes induced by low-intensity aerobic training combined with BFR (LABFR) have been investigated in recent studies, with the results showing the advantages of BFR training as a single mode of training based on the simultaneous increase in aerobic fitness and muscular strength, in addition to the increased maximum oxygen uptake (VO2max), delayed onset of blood lactate accumulation, and enhanced economy of motion [10,11]. For these reasons, LABFR has been applied to individuals with a low level of training or a handicap in certain training, such as those recovering from an injury or those seeking assistive training to add new stimuli to aerobic training, and the reported effects were positive in inducing a variety of physiological changes [12][13][14]. In fact, Abe et al. [15] reported that, although the intensity of slow-walk training with BFR was set to a low level, secretion of growth hormone after acute exercise was increased and, after three weeks, the thigh muscle cross-sectional area and volume were increased by 4-7%. ...
... The results indicated a higher level of increase in muscle mass and thigh circumference in the LABFR group compared to the control group, which agrees with the results of a number of previous studies. Abe et al. [13] and Kim et al. [14] had reported a positive effect of LABFR on the cross-sectional area and volume of thigh and quadriceps muscles. In Abe et al. [13], when young adults who did not regularly participate in aerobic training performed LABFR for eight weeks, the cross-sectional area and volume of the thigh and quadriceps muscles showed a significant increase compared to the control group. ...
... Abe et al. [13] and Kim et al. [14] had reported a positive effect of LABFR on the cross-sectional area and volume of thigh and quadriceps muscles. In Abe et al. [13], when young adults who did not regularly participate in aerobic training performed LABFR for eight weeks, the cross-sectional area and volume of the thigh and quadriceps muscles showed a significant increase compared to the control group. In Kim et al. [14], healthy undergraduates performed LABFR for six weeks, as a result of which the leg muscle mass significantly increased, and the knee flexion muscle strength increased to a similar level as in vigorous-intensity cycling. ...
Article
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This study investigated the effect of low-intensity aerobic training combined with blood flow restriction (LABFR) on body composition, physical fitness, and vascular functions in recreational runners. The participants were 30 healthy male recreational runners, randomized between the LABFR (n = 15) and control (n = 15) groups. The LABFR group performed five sets of a repeated pattern of 2 min running at 40% VO2max and 1 min passive rest, while wearing the occlusion cuff belts on the proximal end of the thigh. The frequency was three times a week for the period of eight weeks. The control group performed the identical running protocol without wearing the occlusion cuff belts. At the end of the training, the participants’ body composition (fat mass, body fat, muscle mass, and right and left thigh circumference), physical fitness (power and VO2max), and vascular responses (flow-mediated dilation (FMD), brachial ankle pulse wave velocity (baPWV), ankle brachial index (ABI), systolic blood pressure (SBP) and diastolic blood pressure (DBP)) were measured. The results showed a significant time × group interaction effect on muscle mass (F = 53.242, p = 0.001, ηp2 = 0.664) and right thigh circumference (F = 4.544, p = 0.042, ηp2 = 0.144), but no significant variation in any other factors, including fat mass, body fat, left thigh circumference, FMD, baPWV, ABI, SBP, and DBP (p > 0.05). Overall, our results suggested that eight-week LABFR exerted a positive effect on the body composition, especially muscle mass and thigh circumference, of recreational runners.
... After reading the titles and abstract, 23 studies were excluded. After the exclusion of 14 records for inappropriate research design (acute studies), of 7 records for the characteristics of the occlusion (pre or post exercise) and of 1 record for inappropriate BFR method, 17 studies [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] were included in the qualitative synthesis. Twelve [33][34][35][36][37][38][39][40][41][42][43][44] of the 17 studies examined were included in the quantitative synthesis. ...
... After the exclusion of 14 records for inappropriate research design (acute studies), of 7 records for the characteristics of the occlusion (pre or post exercise) and of 1 record for inappropriate BFR method, 17 studies [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] were included in the qualitative synthesis. Twelve [33][34][35][36][37][38][39][40][41][42][43][44] of the 17 studies examined were included in the quantitative synthesis. Figure 1 represents the selection process of the study. ...
... The change in AC of the non-BFR groups in the seven other studies ranged from − 4.21% to + 2.69%. [33,35,36,39,[41][42][43]. Finally, the one study in which the BFR group did not exceed a 3.4% improvement in AC (a high-intensity study) did observe a decrease in AC that was less than the non-BFR group (− 2.17% versus − 4.21%, respectively) [36]. ...
Article
Full-text available
Background and purpose Numerous research studies have shown the effects of Blood Flow Restriction (BFR) training on muscle strength and hypertrophy, but there is still no comprehensive analysis of the effects on aerobic capacity. The purpose of this study was to conduct a systematic review with meta-analysis to evaluate the qualitative and quantitative results of BFR training on aerobic capacity. Methods PRISMA guidelines were used to carry out the systematic review and meta-analysis. Five electronic databases were searched up to October 2020: PubMed, Web of Science, EBSCO, Scopus and Cochrane/Embase. Data selected for primary analysis consisted of post-intervention changes in VO2 values (VO2max, VO2peak). Case reports, acute studies and review studies were excluded. The protocol was registered on PROSPERO (CRD42020214919). Results After the elimination of duplicates, 62 records were screened. Among these, 17 studies were included in the systematic review. Twelve of these were involved in the meta-analysis. Discussion BFR training compared with exercise under normal blood flow conditions could positively influences both aerobic capacity and athletic performance. Differences in young and older subjects were discussed. BFR showed to be a promising and beneficial training to elicit improvements in aerobic capacity (measured in VO2) and performances. Level of evidence 1a.
... This provides appropriate superficial pressure for the mechanisms responsible for the positive effects of BFRT [16], including muscle cell swelling, muscle fiber recruitment, systemic hormones (specifically growth hormone, GH), and protein synthesis (MPS) [16,17]. In addition to strength training, benefit was found in BFR aerobic training as well, which is considered to be the concurrent channel of strength and endurance training [18]. ...
... For the BFR groups, the performance showed significant higher jump height when compared with baseline: BFR-30-30 (baseline: 50. 18 In terms of the average power output, a repeated measures ANOVA revealed a significant time effect over the duration of this study (F = 4.946, p = 0.009, η 2 p = 0.31), for the specific time points, significant changings were observed in five of the seven groups: CON (Figure 3). ...
Article
Full-text available
(1) Background: To explore the influence on post-activation potentiation (PAP) when combining different degrees of blood flow restriction (BFR) with multi-levels of resistance training intensity of activation. (2) Purpose: To provide competitive athletes with a more efficient and feasible warm-up program. (3) Study Design: The same batch of subjects performed the vertical jump test of the warm-up procedure under different conditions, one traditional and six BFR procedures. (4) Methods: Participants performed seven counter movement jump (CMJ) tests in random order, including 90% one repetition maximum (1RM) without BFR (CON), and three levels of BFR (30%, 50%, 70%) combined with (30% and 50% 1RM) (BFR-30-30, BFR-30-50, BFR-50-30, BFR-50-50, BFR-70-30 and BFR-70-50). Jump height (H), mean power output (P), peak vertical ground reaction force (vGRF), and the mean rate of force development (RFD) were recorded and measured. (5) Results: Significantly increasing results were observed in: jump height: CON (8 min), BFR-30-30 (0, 4 min), BFR-30-50 (4, 8 min), BFR-50-30 (8 min), BFR-50-50 (4, 8 min), BFR-70-30 (8 min), (p < 0.05); and power output: CON (8 min), BFR-30-30 (0, 4 min), BFR-30-50 (4 min), BFR-50-30 (8 min), BFR-50-50 (4, 8 min) (p < 0.05); vGRF: CON (8 min), BFR-30-30 (0, 4 min), BFR-30-50 (4, 8 min), BFR-50-30 (4 min), BFR-50-50 (4, 8 min) (p < 0.05); RFD: CON (8 min), BFR-30-30 (0, 4 min), BFR-30-50 (4 min), BFR-50-30 (4 min), BFR-50-50 (4 min) (p < 0.05). (5) Conclusions: low to moderate degrees of BFR procedures produced a similar PAP to traditional activation. Additionally, BFR-30-30, BFR-30-50, and BFR-50-50 were longer at PAP duration in comparison with CON.
... In addition, training resulted in 17%, 21% and 9% increases in the isokinetic knee extensor and flexor strength, and isokinetic knee extensor endurance, respectively for RIT-BFR group. We speculated that the BFR training increased muscle hypertrophy and muscle oxidative (arteriovenous oxygen difference) and glycolytic capacity, which resulted in greater adaptations in muscular fitness 10,14,30,32 ; this, in turn, may improve RPmax in endurance athletes. In contrast to our findings, those of Paton et al. indicated that running training (83% V O 2 max, [running at 8 intervals of 30 s each, 30-s rest interval] × 3 sets, 150-s rest interval) combined with BFR did not significantly increase RPmax after 8 training sessions (2 days per week for 4 weeks) in general population 33 . ...
... We suggested that RIT-BFR may be a practical training strategy for promoting isokinetic knee extensor strength at high-and low-speed muscle actions as well as increasing isokinetic knee flexor strength at high-speed muscle contraction in male runners. Similar studies have indicated that compared with cycling or walking alone, low-intensity cycling (40% V O 2 max) or walking (45% HRR) training combined with BFR increased knee extensor strength or flexor strength more substantially in young and older adults after 24-40 training sessions 10,32,34 . By contrast, in contrast to walking alone, walking training (40% V O 2 max) combined with BFR did not increase isokinetic (60°/s) knee extensor and flexor strength after 24 training sessions in basketball players 14 . ...
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Full-text available
We investigated the effects of 8 weeks (3 days per week) of running interval training (RIT) combined with blood flow restriction (RIT-BFR) on the maximal running performance (RPmax), isokinetic muscle strength, and muscle endurance in athletes. Twenty endurance-trained male runners were pair-matched and randomly assigned to the RIT-BFR and RIT groups. The RIT-BFR group performed RIT (50% heart rate reserve, 5 sets of 3 min each, and 1-min rest interval) with inflatable cuffs (1.3× resting systolic blood pressure), and the RIT group performed the same RIT without inflatable cuffs. RPmax, isokinetic muscle strength, and muscle endurance were assessed at pre-, mid-, and post-training. Compared with the RIT group, the RIT-BFR group exhibited a significantly (p < 0.05) greater increase in RPmax, isokinetic knee extensor and flexor strength, and knee extensor endurance after 24 training sessions. These results suggested that RIT-BFR may be a feasible training strategy for improving muscular fitness and endurance running performance in distance runners.
... Aerobic training can improve aerobic fitness and arterial function, but it is insufficient to improve muscle mass and strength to counteract the loss of muscle strength that accompanies advancing age (29). However, BFR with an external pressure cuff applied to the upper legs can be combined with aerobic exercise training, such as low-intensity walking or cycling (∼20-40% of maximal oxygen consumption). ...
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Sarcopenia is a geriatric syndrome that is characterized by a progressive and generalized skeletal muscle disorder and can be associated with many comorbidities, including obesity, diabetes, and fracture. Its definitions, given by the AWGS and EWGSOP, are widely used. Sarcopenia is measured by muscle strength, muscle quantity or mass and physical performance. Currently, the importance and urgency of sarcopenia have grown. The application of blood flow restriction (BFR) training has received increased attention in managing sarcopenia. BFR is accomplished using a pneumatic cuff on the proximal aspect of the exercising limb. Two main methods of exercise, aerobic exercise and resistance exercise, have been applied with BFR in treating sarcopenia. Both methods can increase muscle mass and muscle strength to a certain extent. Intricate mechanisms are involved during BFRT. Currently, the presented mechanisms mainly include responses in the blood vessels and related hormones, such as growth factors, tissue hypoxia-related factors and recruitment of muscle fiber as well as muscle satellite cells. These mechanisms contribute to the positive balance of skeletal muscle synthesis, which in turn mitigates sarcopenia. As a more suited and more effective way of treating sarcopenia and its comorbidities, BFRT can serve as an alternative to traditional exercise for people who have marked physical limitations or even show superior outcomes under low loads. However, the possibility of causing stress or muscle damage must be considered. Cuff size, pressure, training load and other variables can affect the outcome of sarcopenia, which must also be considered. Thoroughly studying these factors can help to better determine an ideal BFRT scheme and better manage sarcopenia and its associated comorbidities. As a well-tolerated and novel form of exercise, BFRT offers more potential in treating sarcopenia and involves deeper insights into the function and regulation of skeletal muscle.
... When compared to non-restricted walking, blood flow restriction combined with walk training improves muscle size and muscle strength in elderly adults [7], and anaerobic power, cardiorespiratory fitness, and minute ventilation in athletes [54]. Additionally, in physically active men, a training protocol combining blood flow restriction with 15 min of cycling at light intensity increased cardiorespiratory fitness after 8 weeks compared to 45 min of cycling at the same intensity without blood flow restriction [55]. However, in recreationally active males, vigorous cycling for 20 min three times a week over 6 weeks did not differ in cardiorespiratory fitness when compared to light cycling with blood flow restriction or a non-exercise control [56]. ...
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Blood flow restriction is growing in popularity as a tool for increasing muscular size and strength. Currently, guidelines exist for using blood flow restriction alone and in combination with endurance and resistance exercise. However, only about 1.3% of practitioners familiar with blood flow restriction applications have utilized it for vascular changes, suggesting many of the guidelines are based on skeletal muscle outcomes. Thus, this narrative review is intended to explore the literature available in which blood flow restriction, or a similar application, assess the changes in vascular structure or function. Based on the literature, there is a knowledge gap in how applying blood flow restriction with relative pressures may alter the vasculature when applied alone, with endurance exercise, and with resistance exercise. In many instances, the application of blood flow restriction was not in accordance with the current guidelines, making it difficult to draw definitive conclusions as to how the vascular system would be affected. Additionally, several studies report no change in vascular structure or function, but few studies look at variables for both outcomes. By examining outcomes for both structure and function, investigators would be able to generate recommendations for the use of blood flow restriction to improve vascular structure and/or function in the future.
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The utilization of blood flow restriction has garnished considerable attention due to its widespread application and benefits that include strength enhancement, muscle hypertrophy, and increased level of function for specific populations. Blood flow restriction induces a hypoxic environment within a muscle group, initiating a metabolic cascade that stimulates muscle protein synthesis, altered gene regulation of muscle satellite cells, and increased muscle fiber recruitment, ultimately resulting in improved strength and endurance. When using blood flow restriction, consideration of the individual patient, occlusion pressure, cuff width, and cuff size are paramount. Blood flow restriction has been proven to be a consistently safe and effective tool for augmenting rehabilitative regimens for the upper and lower extremity.
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Thirty-five healthy men were matched and randomly assigned to one of four training groups that performed high-intensity strength and endurance training (C; n = 9), upper body only high-intensity strength and endurance training (UC; n = 9), high-intensity endurance training (E; n = 8), or high-intensity strength training (ST; n = 9). The C and ST groups significantly increased one-repetition maximum strength for all exercises (P < 0.05). Only the C, UC, and E groups demonstrated significant increases in treadmill maximal oxygen consumption. The ST group showed significant increases in power output. Hormonal responses to treadmill exercise demonstrated a differential response to the different training programs, indicating that the underlying physiological milieu differed with the training program. Significant changes in muscle fiber areas were as follows: types I, IIa, and IIc increased in the ST group; types I and IIc decreased in the E group; type IIa increased in the C group; and there were no changes in the UC group. Significant shifts in percentage from type IIb to type IIa were observed in all training groups, with the greatest shift in the groups in which resistance trained the thigh musculature. This investigation indicates that the combination of strength and endurance training results in an attenuation of the performance improvements and physiological adaptations typical of single-mode training.
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