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This study examined the effects of heavy resistance training on physiological acute exercise-induced fatigue (5 x 10 RM leg press) changes after two loading protocols with the same relative intensity (%) (5 x 10 RM(Rel)) and the same absolute load (kg) (5 x 10 RM(Abs)) as in pretraining in men (n = 12). Exercise-induced neuromuscular (maximal strength and muscle power output), acute cytokine and hormonal adaptations (i.e., total and free testosterone, cortisol, growth hormone (GH), insulin-like growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), interleukin-1 receptor antagonist (IL-1ra), IL-1beta, IL-6, and IL-10 and metabolic responses (i.e., blood lactate) were measured before and after exercise. The resistance training induced similar acute responses in serum cortisol concentration but increased responses in anabolic hormones of FT and GH, as well as inflammation-responsive cytokine IL-6 and the anti-inflammatory cytokine IL-10, when the same relative load was used. This response was balanced by a higher release of pro-inflammatory cytokines IL-1beta and cytokine inhibitors (IL-1ra) when both the same relative and absolute load was used after training. This enhanced hormonal and cytokine response to strength exercise at a given relative exercise intensity after strength training occurred with greater accumulated fatigue and metabolic demand (i.e., blood lactate accumulation). The magnitude of metabolic demand or the fatigue experienced during the resistance exercise session influences the hormonal and cytokine response patterns. Similar relative intensities may elicit not only higher exercise-induced fatigue but also an increased acute hormonal and cytokine response during the initial phase of a resistance training period.
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Eur J Appl Physiol
DOI 10.1007/s00421-009-1139-x
123
ORIGINAL ARTICLE
Cytokine and hormone responses to resistance training
Mikel Izquierdo · Javier Ibañez · Jose A. L. Calbet · Ion Navarro-Amezqueta ·
Miriam González-Izal · Fernando Idoate · Keijo Häkkinen · William J. Kraemer ·
Mercedes Palacios-Sarrasqueta · Mar Almar · Esteban M. Gorostiaga
Accepted: 16 July 2009
© Springer-Verlag 2009
Abstract This study examined the eVects of heavy
resistance training on physiological acute exercise-induced
fatigue (5 £10 RM leg press) changes after two loading
protocols with the same relative intensity (%) (5 £
10 RMRel) and the same absolute load (kg) (5 £10 RMAbs)
as in pretraining in men (n= 12). Exercise-induced neuro-
muscular (maximal strength and muscle power output),
acute cytokine and hormonal adaptations (i.e., total and free
testosterone, cortisol, growth hormone (GH), insulin-like
growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3),
interleukin-1 receptor antagonist (IL-1ra), IL-1, IL-6, and
IL-10 and metabolic responses (i.e., blood lactate) were
measured before and after exercise. The resistance training
induced similar acute responses in serum cortisol concen-
tration but increased responses in anabolic hormones of FT
and GH, as well as inXammation-responsive cytokine IL-6
and the anti-inXammatory cytokine IL-10, when the same
relative load was used. This response was balanced by a
higher release of pro-inXammatory cytokines IL-1 and
cytokine inhibitors (IL-1ra) when both the same relative
and absolute load was used after training. This enhanced
hormonal and cytokine response to strength exercise at a
given relative exercise intensity after strength training
occurred with greater accumulated fatigue and metabolic
demand (i.e., blood lactate accumulation). The magnitude
of metabolic demand or the fatigue experienced during the
resistance exercise session inXuences the hormonal and
cytokine response patterns. Similar relative intensities may
elicit not only higher exercise-induced fatigue but also an
increased acute hormonal and cytokine response during the
initial phase of a resistance training period.
Keywords Serum hormones · Cytokines ·
Resistance training · Muscle power
M. Izquierdo (&) · J. Ibañez · I. Navarro-Amezqueta ·
M. González-Izal · E. M. Gorostiaga
Studies, Research and Sport Medicine Center,
Government of Navarra, C/Sangüesa 34,
31005 Pamplona, Navarra, Spain
e-mail: mikel.izquierdo@ceimd.org
J. A. L. Calbet
Department of Physical Education,
University of Las Palmas of Gran Canaria,
Las Palmas de Gran Canaria, Spain
F. Idoate
Departament of Radiology,
Clinic of San Miguel, Pamplona, Spain
K. Häkkinen
Department of Biology of Physical Activity,
University of Jyväskylä, Jyväskylä, Finland
W. J. Kraemer
Human Performance Laboratory, Department of Kinesiology,
University of Connecticut, Storrs, CT 06269-1110, USA
W. J. Kraemer
Human Performance Laboratory,
Department of Physiology and Neurobiology,
University of Connecticut, Storrs, CT 06269-1110, USA
M. Palacios-Sarrasqueta
Biochemistry Unit, Hospital of Navarre, Pamplona, Spain
M. Almar
Institute of Biomedicine, University of León, 24071 León, Spain
Eur J Appl Physiol
123
Introduction
Heavy resistance exercise protocols have been shown to
elicit signiWcant acute hormonal responses that are part of
an integrated system of signaling to a multitude of target
cells. Such complex interactions may be critical to the
support and mediation of physiological adaptations to
resistance training (Hakkinen et al. 1998; Kraemer and
Ratamess 2005; McCall et al. 1999; Staron et al. 1994).
Dramatic physiological changes in muscle have been dem-
onstrated in the Wrst several resistance training workouts. In
a study by Staron et al. (1994), it was demonstrated that
within four workouts myosin ATPase started to shift to the
Type IIa isoform. While changes in the muscle Wber charac-
teristics have been associated with the circulatory concen-
trations, how testosterone and cortisol help to mediate such
protein adaptations remains unclear. The direct interactions
in the circulation with immune cells and cytokine releases
might be a primary target of such hormones. Thus, new
insights into the physiological adjustments taking place
may be gained by the further elucidation of such relation-
ships and temporal changes in cytokine and immune regu-
lation with anabolic and catabolic hormones during a
resistance training program (Kraemer and Ratamess 2005;
Peake et al. 2005).
Resistance exercise may cause myoWbrillar disruption,
especially after a fatiguing task, and trigger an inXamma-
tory response. In fact, cytokines are increased in the circu-
lation in response to intense concentric and eccentric
muscle contractions. They are proposed to play a role in tis-
sue remodeling, especially in response to muscle damage
(Pedersen et al. 2001, 2003; Steensberg et al. 2000). While
the immune response to aerobic training and susceptibility
to upper respiratory tract infections has received great
attention (Pedersen et al. 2001, 2003), much less is known
about the acute changes in circulating cytokines induced by
a single resistance training session or following a number
of training sessions (Pedersen et al. 2001, 2003; Steensberg
et al. 2000).
Prior studies have demonstrated that acute resistance
exercise transiently elevates circulating concentrations of
anabolic/catabolic hormones (i.e., testosterone, growth hor-
mone (GH), cortisol), and cytokines including interleukin
(IL) IL-1, IL-6, IL-1, IL-1 receptor antagonist (IL-1ra)
and IL-10 (Evans et al. 1986; MacIntyre et al. 2001;
Takarada et al. 2000). The greatest testosterone and cortisol
responses are observed during large muscle-mass exercise
and high-volume sessions performed at moderate to high
intensity, using short resting intervals between sets
(Kraemer and Ratamess 2005). With the controversy of the
role of testosterone and cortisol in circulation, one of its
primary targets might be the modulating activities of
immune cells in circulation. In vitro evidence demonstrates
that testosterone may suppress the expression of the proin-
Xammatory cytokines TNF , IL-1ß, and IL-6 (D’Agostino
et al. 1999) and potentiate the expression of the antiinXam-
matory cytokine IL-10 (Bebo et al. 1999). Furthermore,
cytokine IL-6 release in response to exercise may also be
partly responsible for increases plasma cortisol in a similar
manner (Steensberg 2003). However, the extent to which
there is an interaction between the endocrine and cytokine
responses in trained and untrained individuals remains to be
elucidated.
It is a well-established principle of training that progres-
sive overload (e.g., increasing volume and intensity) is
necessary to increase muscular strength and that for
adaptations to occur, a stimulus exceeding a previous stim-
ulus needs to be applied during a resistance training pro-
gram (Gonzalez-Badillo et al. 2006; Izquierdo et al. 2006;
Kraemer and Ratamess 2005). Conceptually, this would
suggest that the stress-related overload in the context of a
short-term resistance training cycle may be progressively
increased in each training session (Gonzalez-Badillo et al.
2006; Izquierdo et al. 2006). However, the role played by
the absolute load and the relative load in the acute hormone
and cytokine response to resistance training remains to be
determined. Therefore, the purposes of the present study
were (1) to determine if the hormone and cytokine
responses to a standardized training session are augmented
after 7 weeks of heavy resistance training, (2) and to deter-
mine the role played by the relative load of the training ses-
sion in the hormone and cytokine responses. As a result, we
determined the total and free testosterone, cortisol, GH,
insulin-like growth factor-1 (IGF-1), and IGF binding
protein-3 (IGFBP-3), interleukin-1 receptor antagonist (IL-
1ra), IL-1 , IL-6, and IL-10 plasma responses and we
related them to neuromuscular and metabolic (i.e., blood
lactate) changes, after two loading protocols performed
with the same relative intensity (% of 1 RM) as well as the
same absolute load (kg) before and after training.
Methods
Experimental design
A longitudinal randomized research design was used during
the early phase of heavy resistance training (7 weeks) to
compare the neuromuscular and hormonal responses, and
their recovery proWles elicited by two loading protocols
with the same relative load (%) and the same absolute load
(kg) as in pretraining. The experimental design consisted of
three acute heavy-resistance exercise protocols (AHREP).
One of them was performed in pretraining (5 £10 RM leg
press) and the other two after the 7-week experimental
resistance training period. Baseline testing was completed
Eur J Appl Physiol
123
during the Wrst 3 weeks of the study preceding the start of
the training program. The two AHREP sessions performed
after training were randomized and separated by 7 days.
They were performed with the same relative load (%) (i.e.,
new 10 RM load) and the same absolute load (kg) as in pre-
training (see Fig. 1). The volunteers were familiarized with
the testing procedures about 2 weeks before the AHREP
session. After a thorough familiarization session, the sub-
jects participated in a control testing day 1 week before the
AHREP to determine one repetition maximum (1 RM),
maximal voluntary contraction (MVC), muscle power, and
the load corresponding to 10 RM (Fig. 1).
Immediately before each AHREP (pre-exercise) session
each subject’s 1 RM and MVC were determined. Muscle
power was assessed with the load corresponding to pre-
exercise 10 RM (i.e., control). After each AHREP, i.e., in
the fatigued state, the MVC and muscle power with the
load corresponding to 10 RM was performed immediately
post-exercise (post 0) (Fig. 1) (Izquierdo et al. 2009). Each
subject was required to have a 3-day food diary record for
the days prior to testing and repeat the same diet before
each main trial in order to minimize the variation in physio-
logical responses. In addition, subjects did not ingest any
food except water for 1 h prior to the experimental proce-
dures. In order to exclude any residual eVects of previous
exercise on the experimental treatment, the subjects were
also required to refrain from strenuous exercise and the
consumption alcohol, tobacco or caVeine 48 h before and
between the testing sessions.
Subjects
Twelve physically active healthy men volunteered to
participate in the study. The subjects’ mean (§SD) age,
height, body mass, and percentage of body fat were 33
(§4.4) years, 1.77 (§0.06) months, 72.4 (§6.9) kg and
9.2% (§2.5), respectively. In order to document the initial
physiologic changes we used subjects with no weight
training experience. This enabled the observation of the
acute physiologic changes that took place in a resistance
training program. Each subject gave his written informed
consent to participate after the risks involved in the study
were explained in detail. The experimental procedures were
approved by the Institutional Review Committee of the
Instituto Navarro del Deporte and were in accordance with
the Declaration of Helsinki. Before inclusion in the study,
all subjects were medically screened by a physician and
were seen to be free from any orthopedic, electrocardio-
graphic, endocrinal, or medical problems that would
contraindicate their participation or inXuence the results of
the investigation. None of them was taking exogenous
anabolic-androgenic steroids, drugs, medication, or dietary
supplements with potential eVects on physical performance.
Acute heavy resistance loading protocols
The experimental design comprised the examination of
resistance training-induced adaptations on the acute neuro-
muscular, hormonal, and cytokine responses with the same
absolute (kilogram) and relative load (% of 1 RM). Before
training, the AHREP consisted of Wve sets with the maxi-
mum load possible to achieve ten repetitions (10 RM) in
leg press with 120 s of rest between the sets. After training
each subject performed the two AHREP in random and bal-
anced order separated by 7 days: one with the same relative
load (5 £10 RMRel) and the other with the same absolute
load (5 £10Abs) as in pretraining testing. If the subject
failed to reach the tenth repetition during the 5 £10 RMRel,
Fig. 1 Acute heavy resistance
protocol design (a) and
longitudinal experimental
design (b)
Eur J Appl Physiol
123
the load was reduced and the exercise resumed allowing the
completion of ten repetitions on each set. This maneuver
was repeated as many times as necessary so that each
set always consisted of ten repetitions. For comparison pur-
poses, the 5 £10 RMAbs AHREP performed after the resis-
tance training period was carried out with the same absolute
loads used in pretraining testing.
A bilateral leg press exercise machine (i.e., leg press
action in a sitting position) (Technogym, Gambettola, Italy)
was used for all trials. The seat was individually adjusted to
minimize displacement between the lower back and the
backrest during muscular force exertion. Strong verbal
encouragement was given to all subjects to motivate them
to perform each test action as maximally and as rapidly as
possible.
Maximal strength and muscle power output
1 RM (i.e., the heaviest load that could be lifted only once
using the correct technique) was determined for the leg
press exercise (Technogym, Gambettola, Italy). The subject
was in a seated position so that the knee angle was 90º.
Three to four subsequent attempts were made to determine
1 RM. The rest between maximal attempts was always
2min.
Maximal isometric force was also measured on a modi-
Wed leg press exercise machine (Technogym, Gambettola,
Italy) at knee and hip angles of 90º and 45º, respectively.
The exercise machine incorporated several force transduc-
ers on a foot platform located below the subject’s feet. The
strain gauges recorded the applied force (N) to an accuracy
of 1 N at 1,000 HZ.
Muscle power output of the leg extensor muscles was
measured during the concentric phase of leg press using the
load corresponding to 10 RM. An optical encoder
(Computer Optical Products Inc, California, USA) was
attached to weight plates to record the position and direc-
tion of the displacement to an accuracy of 0.2 mm at
1,000 Hz. Customized software was used to calculate range
of motion, peak power output, and average velocity for
each repetition. Subjects were instructed to displace the
weights as fast as possible. Two testing trials were recorded
and the best trial was taken for further analysis. The test–
retest intraclass correlation coeYcients for all strength and
power variables were greater than 0.95 and the coeYcients
of variation (CV) ranged from 0.9 to 2.1%.
Muscle cross-sectional area (CSA) and anthropometry
The muscle CSA of the left quadriceps femoris (QF) was
assessed before and after the 7-week resistance training
period using magnetic resonance imaging (MRI) (SIE-
MENS Magnetom Impact Expert, 1 T). Once the subject
was positioned within the magnet, the thighs of both legs
were kept parallel to the MRI table, and the feet were
strapped together to prevent rotation. The length of the
femur (Lf), taken as the distance from the intercondilar
notch of the femur to the superior boundary of the femoral
head, was measured on a coronal plane. CSA computation
was carried out on the QF as a whole. Body mass and per-
cent body fat (estimated from the thickness of seven skin-
fold sites) were taken before and after each training period
(Jackson and Pollock 1978).
Resistance training program
A trained researcher supervised each workout session
carefully so that exercise prescriptions were correctly
administered during each training session (e.g., number
of repetitions, rest and velocity of movement). Compli-
ance with the study was 100% of the programmed
sessions.
Subjects trained two times per week for 7 weeks to
perform dynamic resistance exercises from 45 to 60 min
per session. A minimum of 2 days elapsed between two
consecutive training sessions. During the whole training
period, the core exercises were parallel-squat and bench
press in addition to supplementary strengthening exercises
for selected muscle groups (leg press, leg extension, shoul-
der press, lateral pull-down, abdominal crunch, trunk exten-
sion, and standing leg curl). The resistance training
consisted of a nonlinear undulating, multi-set, multi-exer-
cise, progressive program performed two times per week.
The daily workouts were alternated by varying the resis-
tance (intensity), and the volume (sets £repetitions £ load)
over the week. On Tuesday, the sets were performed at
12–15 RM with 2 min rest between sets. Finally, on Thursday
the sets were performed at the 10 RM intensity with 2 min
rest between sets. Three to Wve sets were performed during
the training program. The assigned training intensities were
gradually increased during the 7-week training period using
a repetition maximum approach.
Blood collection and analysis
The subjects visited the laboratory and rested for 30 min
before the Wrst blood collection. During the loading session,
blood samples were drawn from an antecubital forearm
vein using a 20-gauge needle and vacutainers® for the
determination of serum total an free testosterone, cortisol,
GH, insulin-like growth factor-1 (IGF-1), and IGF binding
protein-3 (IGFBP-3), interleukin-1 receptor antagonist (IL-
1ra), IL-1, IL-6, and IL-10 concentrations pre-exercise,
after the third set (mid-exercise), immediately after (post),
and after 15 min (post-15 min) and 45 min (post-45 min)
after the loadings. During the control day, i.e., without
Eur J Appl Physiol
123
exercise, two blood samples were also drawn within 30 min
at the same time of day when the loading protocols were
carried out. Blood samples were obtained at diVerent times
of the day from subjects but at the same time of day for
each subject in each loading protocol before and after the
experimental training period, to minimize the inXuence of
any diurnal variation.
Whole blood was centrifuged at 3,000 rpm (4°C) for
15 min and the resultant serum was then removed and
stored at ¡20°C until subsequent analysis. All samples
were assayed in duplicate and were decoded only after the
analyses were completed (i.e., blinded analysis procedure).
Circulating concentrations of total testosterone, cortisol,
GH, IGF-1, IGFBP-3, IL-1ra, IL-1, IL-6, and IL-10 were
determined using commercially available enzyme-linked
immunosorbent assay (ELISA) kits (DRG Diagnostics,
DRG Instruments GmbH, Marburg, Germany). Because no
signiWcant diVerences in plasma volume changes were
observed between the loading conditions before and after
training, hormonal concentrations were not corrected for
plasma volume changes (Dill and Costill 1974). Samples
were only thawed once before the analysis for all proce-
dures,
Capillary blood samples for the determination of blood
lactate concentrations were obtained from a hyperemized
earlobe pre-exercise, as well as after exercise to determine
the peak blood lactate concentration post exercise (i.e.,
post-exercise (post 0), and 3, 5, 10, 15 min into the recov-
ery period). Samples for whole blood lactate determination
(100 l) were deproteinized, placed in a preservative tube
(YSI 2315 Blood Lactate Preservative Kit), stored at 4°C,
and analyzed (YSI 1500) within 5 days of completing the
test. The blood lactate analyzer was calibrated after every
Wfth blood sample dose with three known controls (5, 15,
and 30 mmol l¡1).
Statistical analyses
The training-related eVects were assessed using a two-
way ANOVA with repeated measures (time £protocol).
When a signiWcant F value was achieved, Bonferroni
post hoc procedures were performed to locate the pair-
wise diVerences between the means. Statistical compari-
son during the control period (from week –3 to week 0)
was done by Student’s paired t test. Selected absolute
and relative changes (e.g., maximal strength, muscle
power output, acute cytokine and hormonal adaptations)
were analyzed via one-way analysis of variance. Statisti-
cal power calculations for this study ranged from 0.75 to
0.80. The P·0.05 criterion was used to establish statis-
tical signiWcance. Values are reported as mean values §
and standard deviations (SDs).
Results
Anthropometry and muscle CSA
After the 7-week training period, a signiWcant increase was
observed in body mass (from 72.4 §6.9 to 73.4 §6.2 kg,
P< 0.05), and quadriceps CSA (from 130.1 §10.6 to
135.7 §12.2 cm2, P< 0.001), whereas no signiWcant
changes were observed in body fat.
Maximal bilateral isometric, 1 RM dynamic strength
and muscle power output
Maximal strength and muscle power output remained unal-
tered during the 3-week control period (from week ¡3 to
week 0). During the 7-week training period, signiWcant
increases of 10.8 §1.3% (P< 0.05) were recorded in max-
imal isometric force (from 1557 §211 to 1772.7 §304 N)
and 19.7 §4.7% in 1 RM (from 190.6 §30.2 to 237.9 §
38.8 kg).
After the 7-week training period, peak power output
with the same absolute load as in pretraining increased by
16.2 §12.8% (from 1163.2 §239.9 to 1414.4 §372.0 W,
P< 0.01), whereas no signiWcant changes were observed in
peak power output with the same relative load used in pre-
training (from 1163 §239 to 1159 §320 W).
Acute heavy 10 RM resistance loading
After the 7-week training period, the initial load of
the 5 £10Rel loading protocol was increased from
160.2 §26.3 to 198.9 §33.9 kg (P< 0.05). In pretrain-
ing, the load used during the 10 RM loading protocol
corresponded to 84.1 §4.8% of 1 RM (ranging from
75.1 to 90.5%) similar to that of 83.7 §4.8% of 1 RM
(ranging from 74.9 to 91.1%) used in posttraining. After
training, total work (sets £reps £load) performed with
the same relative load (5 £10Rel loading) was increased
by 15.5 §6.6% compared with that used in pretraining
(from 7515.7 §1040.1 to 8939.6 §1340.6 kg, P< 0.05).
After training, the load used during the 5 £10 RMAbs
represented 67.6 §5.7% of the posttraining 1 RM. Total
work (sets £reps £load) performed with the same
absolute load (5 £10 RMAbs loading) was similar in
pre and posttraining (7515.7 §1040.1 kg and 7521 §
1039.1 kg, respectively). After training, the relative
decrease (%) of the load during the 5 £10Rel protocol
was higher (P< 0.05) for the second, fourth, and Wfth
sets compared with that recorded in pretraining. For
comparison purposes, after training the absolute
decrease of the load during the 5 £10Abs loading proto-
col was matched to that recorded in pretraining.
Eur J Appl Physiol
123
Acute maximal isometric and muscle power output
responses to training
Maximal isometric force immediately after the 5 £10Rel
loading was decreased by 23.4 §11.7 and 34.2 §15.8%
(both P< 0.05), but with a signiWcantly greater exercise-
induced loss of MVC after training (pre vs. posttraining)
(Fig. 2a). Training attenuated the losses in MVC elicited by
the 5 £10Abs loading protocol (11.4%) compared to those
elicited by the 5 £10Rel loading protocol (Fig. 2a).
Peak power output decreased in a similar manner
(P< 0.05) immediately after the 5 £10Rel loading proto-
cols in both pretraining and posttraining (58.4 §14.5 and
62.3 §14.4%, respectively) (Fig. 2b). After training, sig-
niWcant decreases were observed in peak power output
immediately post-exercise in the 5 £10Abs loading
protocol (20.3%) (Fig. 2b). The 5 £10Abs loading protocol
elicited signiWcant lower reductions in peak power output
after training than both 5 £10Rel loading protocols.
Blood lactate concentrations
After training, post exercise peak blood lactate was signiW-
cantly greater in the 5 £10rel compared with that observed
in the 5 £10 pretraining protocol. The blood lactate
response was lower (P< 0.05) during the whole loading
period in the 5 £10Abs compared with the response
observed in the 5 £10Rel (Fig. 3).
Acute hormonal responses to training
Basal hormonal levels remained unaltered during the
3-week control period (from week ¡3 to week 0). There were
no signiWcant changes between the three control blood
Fi
g.
2Ab
so
l
ute an
d
re
l
at
i
ve
changes in maximal isometric
force (a) and peak power output
(b), pre and post loading before
at pretraining (5 £10 pretrain-
ing) and after 7 weeks of period-
ized strength training with both
the same relative (5 £10Rel) and
the same absolute load
(5 £10Abs) as pretraining. Filled
triangle signiWcant diVerence
(P< 0.05) compared to the
corresponding pre-exercise
value, for each protocol.
#P< 0.05 signiWcant diVerences
between 5 £10Abs post training
and the other two protocols.
§P< 0.05 signiWcant diVerences
between 5 £10 pretraining and
5£10Rel post-training
Eur J Appl Physiol
123
samples drawn within 30 min on the control day (i.e., with-
out exercise) at the same time at which each subject had
performed the two loading protocols before and after training.
Serum total and free testosterone concentrations
increased signiWcantly after the loading both before and
after the strength training period, but decreased to the pre-
exercise value at 45 min post-exercise. Acute exercise-
induced serum total testosterone responses to 5 £10Abs or
5£10Rel loading protocols were similar in pre and post-
training (Fig. 4a). After training, the mean acute free testos-
terone response was greater (P< 0.05, mid exercise and
post exercise) in 5 £10Rel compared with that observed in
the 5 £10Abs protocol and the 5 £10Rel at pretraining
(Fig. 4b).
Serum cortisol concentration increased signiWcantly 15
and 45 min after 5 £10Rel pretraining and 5 £10Rel post-
training (Fig. 5), the increment being similar in both condi-
tions. Acute cortisol responses were signiWcantly lower
during the whole loading and recovery period in 5 £10Abs
compared with the responses observed in both 5 £10Rel
loading protocols (pre and posttraining) (Fig. 5).
Serum GH concentration was signiWcantly increased
post-exercise as well as after 15 and 45 min during the
recovery period. This increase was similar during both rela-
tive loading sessions performed before (5 £10Re pretrain-
ing) and after the training period (5 £10Rel posttraining).
After training, no signiWcant changes were observed in any
Fig. 3 Blood lactate concentrations (Mmol L¡1) pre-exercise and
peak value at pretraining (5 £10 pretraining) and after 7 weeks o
f
periodized strength training with both the same relative (5 £10Rel) and
the same absolute load (5 £10Abs) as pretraining. Filled triangle
signiWcant diVerences (P< 0.05) from the corresponding pre-exercise
value. #SigniWcant diVerences (P< 0.05) with the other two protocols
Fig. 4 Serum total testosterone
(a) and free testosterone (b) con-
centrations before, pre-, mid-,
and post-exercise and during
recovery at pretraining (5 £10
pretraining) and after 7 weeks of
periodized streng th training with
both the same relative
(5 £10Rel) and the same abso-
lute load (5 £10Abs) as pretrain-
ing. Filled triangle signiWcant
diVerence (P< 0.05) compared
to the corresponding pre-exer-
cise value, for each protocol.
aSigniWcant diVerences
(P< 0.05) from the correspond-
ing post 0 value, for each proto-
col. bSigniWcant diVerences
(P< 0.05) from the correspond-
ing post 3 min value, for each
protocol. cSigniWcant diVerences
(P< 0.05) from the correspond-
ing post 5 min value, for each
protocol. #P< 0.05 signiWcant
diVerences between 5 £10Abs
post training and the other two
protocols
Eur J Appl Physiol
123
loading or recovery points of the loading session performed
with the same absolute load as in pretraining (5 £10Abs
protocol). After the training period, acute GH response was
signiWcantly greater in the 5 £10Rel protocol, compared
with those recorded during the 5 £10Rel pretraining (i.e.,
post exercise and post 15 min) and 5 £10Abs posttraining
loading sessions (i.e., post exercise, post 15 min and
45 min). Furthermore, the acute GH responses were signiW-
cantly lower after the 5 £10Abs protocol (i.e., post exercise,
15 and 45 min post-exercise) compared with the responses
observed during the 5 £10Rel loading sessions (pre and
posttraining) (Fig. 6).
No signiWcant changes were observed in the acute IGF-1
and IGFBP-3 responses at any point (P< 0.05, mid-exercise,
post-exercise, and 45 min after recovery) during the loading
or recovery period during both pretraining and posttraining
loading sessions (5 £10Abs or 5 £10Rel). No signiWcant
diVerences were observed in the acute IGF-1 and IGFBP-3
responses, regardless of whether 5 £10Abs or 5 £10Rel pro-
tocols were performed after the training period.
Cytokines
After the training period, the acute IL-1 response was sig-
niWcantly higher during the whole loading and recovery
period in both 5 £10Abs and 5 £10Rel protocols, compared
with the acute response recorded during the 5 £10 RM
protocol in pretraining.
Fig. 5 Serum cortisol concentration before, pre-, mid- and post-exer-
cise and during recovery at pretraining (5 £10 pretraining) and after
7 weeks of periodized strength training with both the same relative
(5 £10Rel) and the same absolute load (5 £10Abs) as pretraining.
Filled triangle signiWcant diVerence (P< 0.05) compared with the
corresponding pre-exercise value, for each protocol. aSigniWcant diVer-
ences (P< 0.05) from the corresponding post 0 value, for each proto-
col. bSigniWcant diVerences (P< 0.05) from the corresponding post
3 min value, for each protocol. #P< 0.05 signiWcant diVerences
between 5 £10Abs post training and the other two protocols
Fig. 6 Serum growth hormone concentration before, pre-, mid-, and
post-exercise and during recovery at pretraining (5 £10 pretraining)
and after 7 weeks of periodized strength training with both the same
relative (5 £10Rel) and the same absolute load (5 £10Abs) as pretrain-
ing. *SigniWcant diVerence (P< 0.05) compared to the corresponding
before value, for each protocol. Filled triangle signiWcant diVerence
(P< 0.05) compared to the corresponding pre-exercise value, for each
protocol. aSigniWcant diVerences (P< 0.05) from the corresponding
post 0 value, for each protocol. #P< 0.05 signiWcant diVerences
between 5 £10Abs post training and the other two protocols
Eur J Appl Physiol
123
IL-1ra concentrations signiWcantly increased at mid- and
post-exercise point, but decreased to the pre-exercise value
at 15 and 45 min after recovery during the 5 £10Rel pre-
training loading protocol. After training, no signiWcant
changes were observed IL-1 and IL-1ra (P< 0.05; for IL-
1ra at Post 0 min) concentrations in both relative loading
protocols (Fig. 7a, b).
Serum IL-6 concentration signiWcantly increased at
45 min post-exercise in both pretraining and posttraining
5£10Rel protocols. After the training period, the acute IL-
6 response in the 5 £10Rel protocol in the 45-min recovery
period was signiWcantly greater compared with the acute
responses recorded during 5 £10 pretraining and posttrain-
ing 5 £10Abs loading conditions (Fig. 8a).
No signiWcant changes were observed in acute serum IL-
10 concentrations at any loading or recovery point of the
loading sessions performed in pretraining and posttraining
with the same absolute load (5 £10Abs protocol). After
training, acute serum IL-10 concentration signiWcantly
increased at mid- and post-exercise, as well as after 15 and
45 min during the recovery period in the 5 £10Rel proto-
col. After the training period, the acute IL-10 response in
the 5 £10Rel protocol was signiWcantly greater in mid- and
post-exercise as well as during the 15 and the 45 min recov-
ery period, compared with the acute responses recorded
during pretraining 5 £10 RM and posttraining 5 £10Abs
loading conditions (Fig. 8b).
Discussion
The mains Wndings of this study were that 7 weeks of heavy
resistance training induced (1) greater magnitude of acute
exercise-induced MVC loss than in pretraining, when exer-
cising with the same relative intensity, (2) similar acute
responses in serum cortisol concentration but increased free
testosterone and GH responses, to the same relative load,
(3) greater IL-6 (pro-inXammatory) and IL-10 (anti-inXam-
matory) responses after exercising with the same relative
load, as well as (4) greater release of pro-inXammatory
cytokines IL-1 and IL1-ra after exercising either at the
same relative or absolute load.
EVects on fatigue
The short-term resistance training period led to higher
accumulated fatigue and metabolic demand (i.e., blood lac-
tate accumulation) after multiple sets of dynamic fatiguing
contractions with the same relative load as in pretraining.
As has been previously reported (Izquierdo et al. 2009),
after a short-term strength training period, when the relative
intensity of the fatiguing dynamic protocol was kept the
same, the magnitude of exercise-induced loss of functional
capacity (power and MVC) was greater than that observed
before training, but lower fatigue occurred when the same
absolute load was used. Previous studies have demonstrated
Fig. 7 Interleukins IL-1 (a)
and IL-ra (b) serum concentra-
tions before, pre-, mid- and post-
exercise and during recovery at
pretraining (5 £10 pretraining)
and after 7 weeks of periodized
strength training with both the
same relativ e (5 £10Rel) and the
same absolute load (5 £10Abs)
as pretraining. *SigniWcant
diVerence (P< 0.05) compared
to the corresponding before
value, for each protocol. Filled
triangle signiWcant diVerence
(P< 0.05) compared to the cor-
responding pre-exercise value,
for each protocol. #P<0.05
signiWcant diVerences between
5£10Abs post training and the
other two protocols
Eur J Appl Physiol
123
similar decreases in maximal isometric strength in physi-
cally active and strength-trained male athletes (Ahtiainen
et al. 2003), when the relative intensity of the loading was
kept the same before and after a long-term strength training
period (21 weeks), whereas in other studies the magnitude
of exercise-induced loss in maximal strength or muscle
power was not reported (Hickson et al. 1994; Kraemer et al.
1998; Kraemer et al. 1999; McCall et al. 1999). Further-
more, as expected, resistance training resulted in a remark-
able increase in exercise performance (i.e., reduced
fatigability) as shown by the attenuation of the degree of
fatigue elicited by the same absolute load after training.
Hormonal responses
A limited number of studies have examined the eVects of
resistance training on acute exercise-induced hormonal
responses with the same relative and absolute intensity as in
pretraining. The increased free testosterone and GH
response to acute exercise with the same relative load after
progressive heavy resistance training is in accordance with
other studies (Craig et al. 1989; Kraemer et al. 1998). Craig
et al. (1989) reported that young men increased GH con-
centration up to Wvefold in response to an acute bout of
resistance exercise and this increased up to sixfold after
training, whereas the acute total testosterone response to a
single lifting session was the same before and after training.
Kraemer et al. (1998) reported that untrained men are able
to develop an acute exercise-induced increase in testoster-
one, but a similar GH response in pre and posttraining.
However, other studies did not Wnd any signiWcant changes
in the proWles of acute hormonal responses to resistance
exercise due to long-term strength training in adult men
(Ahtiainen et al. 2005; Hickson et al. 1994; Kraemer et al.
1999; McCall et al. 1999). Comparison of our results with
other studies is diYcult because the magnitude of exercise-
induced loss in maximal strength or muscle power has not
been reported systematically.
To the author’s knowledge only Ahtiainen et al. (2003)
reported similar exercise-induced decreases in maximal
isometric strength pre and posttraining after the 21-week
training period. This was accompanied by no signiWcant
diVerences in acute cortisol, total and free testosterone
responses between strength-trained and untrained men
between the loading sessions, but an attenuated acute GH
response in the male strength-athlete group. Resistance
training may also have led to an overall reduction (Kraemer
et al. 1999; Staron et al. 1994) or similar (Ahtiainen et al.
2003; Ahtiainen et al. 2005) cortisol responses to exercise
loading in men. In the present study, after the 7-week
strength training period, when the relative intensity of the
fatiguing dynamic protocol was kept the same, the acute
Fig. 8 Interleukins IL-6 (a) and
IL-10 (b) serum concentrations
before, pre-, mid- and post-exer-
cise and during recovery at pre-
training (5 £10 pretraining) and
after 7 weeks of periodized
strength training with both the
same relativ e (5 £10Rel) and the
same absolute load (5 £10Abs)
as pretraining. *SigniWcant
diVerence (P< 0.05) compared
with the corresponding before
value, for each protocol. Filled
triangle signiWcant diVerence
(P< 0.05) compared with the
corresponding pre-exercise val-
ue for each protocol. #P<0.05
signiWcant diVerences between
5£10Abs post training, and the
other two protocols
Eur J Appl Physiol
123
cortisol response to resistance exercise was similar to that
observed before training. These results may indicate that
diVerences in GH and testosterone responses to acute exer-
cise after training may not only be sensitive to the relative
intensity but also to other factors related to the higher abso-
lute intensity of the exercise after training, e.g., greater met-
abolic demand. It maybe that this metabolic demand plays a
primary role in these circulating hormonal concentrations.
A unique but expected Wnding of this study was fewer
signs of acute exercise-induced fatigue (i.e., reduced fatiga-
bility) in the protocol in posttraining with the same absolute
load as in pretraining, accompanied by an attenuated
release in the cortisol and GH response but interestingly
similar total and free testosterone acute responses after
training. This could be due to the decreased stress response
and/or decreased hormone production. A typical response
to resistance training is a reduction of the amount of muscle
mass needed to perform a given dynamic task, as demon-
strated using NMR and EMG measurements (Lewis et al.
1984; Ploutz et al. 1994). Thus, the same amount of
strength and power can be developed after training using
fewer muscle Wbers with lesser accumulation of fatigue.
These two eVects can only be explained by changes in neu-
ral activity combined with local muscular functional and
structural changes. Strength training leads to improvements
in neuromuscular eYciency (i.e., the relationship between
EMG and mechanical power output) (Behm and St-Pierre
1998), muscle mass (Aagaard et al. 2001; Hakkinen et al.
1985), selective hypertrophy of IIA muscle Wbers (Staron
et al. 1994) and enhanced muscle metabolism (i.e.,
increased activity of creatine kinase (CK), glycolytic
enzymes, e.g., phosphofructokinase (PFK), decreases in
lactate accumulation, and increases in muscle buVering
capacity) (Hellsten et al. 1996; McKenna et al. 1993; Mohr
et al. 2007; Sahlin and Henriksson 1984). Changes of this
nature could have occurred in our subjects as a result of
resistance training and hence contribute to the explanation
of reduced fatigability and attenuated acute hormonal
response to acute loading with the same absolute load as in
pretraining. This Wnding implies that it may be necessary to
adjust the load to achieve similar acute hormonal responses
after a short-term training period. Therefore, similar rela-
tive intensity may induce not only higher exercise-induced
fatigue but also increased acute hormonal responses during
the initial phase of the resistance training period.
Cytokine responses
Resistance exercise is known to cause myoWbrillar disrup-
tion, especially during eccentric muscle actions (Bruunsgaard
et al. 1997; Gibala et al. 2000). This disruption results in an
inXammatory response, modulated by cytokines (Pedersen
et al. 2001; Pedersen et al. 2003). Interleukin-6 (IL-6) is
locally produced by growing myoWbers and acts as an
essential regulator of satellite cell (muscle stem cell)-medi-
ated hypertrophic muscle growth (Hiscock et al. 2004; Kel-
ler et al. 2001; Penkowa et al. 2003; Serrano et al. 2008;
Vierck et al. 2000). Further, it appears that cytokines may
also play a role in the repair and remodeling process of
muscle (Pedersen et al. 2001, 2003; Steensberg et al. 2000).
Our study shows that greater exercise-induced levels of
IL-6 are only elicited in the training sessions in the initial
phase of heavy resistance training when the sessions are
carried out with the same relative loads. In accordance with
this, IL-6 was shown to be signiWcantly high for up to
48 hours after heavy total body eccentric resistance exer-
cise, together with closely matched delayed onset muscle
soreness (Smith et al. 2000; Suzuki et al. 2002). An earlier
isokinetic eccentric-only training study also reported
increases in IL-6 post exercise, but there were no signiWcant
diVerences between pre and posttraining levels (Croisier
et al. 1999). IL-6 was elevated for up to 1 day after pro-
longed eccentric leg extension exercise (300 repetitions),
and these elevations were signiWcantly correlated to
delayed onset muscle soreness (MacIntyre et al. 2001).
Even very light eccentric exercise (20% or 1 RM leg exten-
sion) coupled with circulatory occlusion resulted in
increased IL-6 response up to 3 h post exercise (Takarada
et al. 2000).
Furthermore, a higher release of pro-inXammatory cyto-
kine IL-1 in the 5 £10Abs or 5 £10Rel acute loading pro-
tocols was also reported after training in the present study.
Previous studies reported reduced (Smith et al. 2000) or
increased (Evans et al. 1986) levels of IL-1 associated
with muscle damage following eccentric exercise. The dis-
crepancies between these studies may partly result from
diVerences in the loading regimes studied, and to the fact
that IL-1 undergoes a rapid clearance rate and local accu-
mulation at the trauma site (i.e., in this case, muscle).
Furthermore, in early studies such as this one, assay did not
diVerentiate between IL-1 and IL-1 (Evans et al. 1986).
However, the concomitant greater increase of IL-1ra in
response to resistance exercise (either at the same absolute
or relative intensity) could have blunted the biological
activities of IL-1 and IL-1 (Pedersen et al. 2001). IL-1ra
is up-regulated among others by IL-6 (Pedersen et al. 2001,
2003).
The present study also shows that short-term resistance
training only enhances the responsiveness of IL-10 to a
resistance exercise session when exercising at the same rel-
ative load. Previous studies have shown that IL-10 is
increased by catecholamines and in vivo IL-6 (Peake et al.
2005). IL-10 is increased after an acute bout of eccentric
elbow Xexor exercise; interestingly, this response is accen-
tuated when the same eccentric exercise is repeated 4 weeks
later (Hirose et al. 2004). The latter could contribute to an
Eur J Appl Physiol
123
attenuated inXammatory response to eccentric exercise and
explain the known protective eVect of a single session of
eccentric exercise on muscle structure and function. It
remains to be determined why and how the IL-10 and IL-6
responses to a resistance exercise session performed at the
same relative exercise intensity are accentuated after resis-
tance training. The interactions with circulating anabolic
and catabolic hormones may provide one distinct area of
research, linking these circulatory elements in an endo-
crine-immune cytokine cybernetic relationship. Our data
reXect such a pattern of interactions.
In summary, the present resistance training program
induced similar acute responses in serum cortisol concen-
tration but increased responses in anabolic hormones of
FT and GH, as well as inXammation responsive cytokine
IL-6 and the anti-inXammatory cytokine IL-10, when the
same relative load was used. This response was balanced
by a higher release of pro-inXammatory cytokines IL-1,
cytokine inhibitors (IL-1ra) when both the same relative
and absolute load was used after training. This enhanced
hormonal and cytokine response to resistance exercise at a
given relative exercise intensity after resistance training
occurred with greater accumulated fatigue and metabolic
demand (i.e., blood lactate accumulation). The magnitude
of metabolic demand or the fatigue experienced during
the resistance exercise session inXuences the hormonal
and cytokine response patterns. Similar relative intensi-
ties may elicit not only higher exercise-induced fatigue
but also an increased acute hormonal and cytokine
response during the initial phase of the resistance training
period.
Acknowledgments This study was supported by the Ministry of
Education (National Plan of R&D + i 2004-2007. Key Action “Sport
and Physical Activity” DEP2006-56076)
ConXict of interest statement The authors declare that they have no
conXict of interest relevant to the content of this manuscript.
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... HPA axis stimulation by regular resistance exercise is generally characterized by reduced resting cortisol concentrations [117]. The cortisol response to a single bout of resistance exercise is attenuated following a period of resistance training in already trained individuals [118], especially when post-training measurements are made when exercising against the same absolute load [119]. In contrast with the traditional iso-inertial loading (i.e. ...
... On the contrary others have failed to corroborate these results in similar patients [136]. In healthy individuals 7 weeks of heavy resistance training resulted in increased IL-6 responses to resistance exercise, coupled with a concomitant increase of IL-1β [119]. However, a muscle biopsy study in young and old men showed that a single bout of resistance exercise (repeated sets of isokinetic knee extension/flexion) was followed by greater IL-6 concentrations in skeletal muscle in the older men, while repetition of this exercise (3 times a week) over 12 weeks led to attenuation of this response [51]. ...
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... This is the first report on the effects of simultaneous VCG (including VC) and iron intake on liver function. VC improves liver function in patients with fatty liver, and VC reportedly has an antioxidant effect in that organ 26,27) . Furthermore, in animal studies, VCG has been reported to accelerate the recovery of hepatectomised rats better than VC. ...
... Vitamin C has a strong antioxidant effect and suppresses intracellular inflammation 26) . Therefore, VC should supress increases in hepcidin in athletes, although this was not observed by Díaz et al. 33) and a consensus is lacking. ...
... Finally, no studies addressed the impact of resistance or mixed (e.g., aerobic and resistance) exercise interventions on oncological outcomes to ICIs. Resistance exercise is known to influence immune function e.g., through modulation of hormone and cytokine responses (including promoting the release of IL-6 and IL-15 myokines which are associated with trafficking of T-cells and NK-cells to the TIME) [51][52][53][54][55]. Therefore, the role of resistance training as an adjunctive therapy for ICIs holds promise, but this requires elucidation in future research. ...
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The impact of using exercise as a non-pharmacological intervention in patients with cancer receiving immune checkpoint inhibitors (ICIs) is not well known. Our objective was to determine the extent of, and identify gaps within, available literature addressing the effect of exercise on (a) oncological outcomes and (b) quality of life (QoL) in patients with cancer receiving ICIs, and c) the underlying biological mechanisms for such effects. We conducted searches across EMBASE, APA PsycInfo and Ovid MEDLINE(R). Studies were eligible if they addressed at least one aspect of the objective and were available in the English language. Results were synthesised using a narrative approach and subsequently discussed with multidisciplinary stakeholders. As of the final search on 5 April 2022, 11 eligible studies were identified, of which 8 were preclinical and 3 were clinical. Clinical studies only focused on QoL-related outcomes. When studies were grouped by whether they addressed oncological outcomes (n = 7), QoL (n = 5) or biological mechanisms (n = 7), they were found to be heterogeneous in methodology and findings. Additional evidence, particularly in the clinical setting, is required before robust recommendations about whether, and how, to include exercise alongside ICI treatment can be made.
... High-intensity exercise has been demonstrated to generate significant alterations in brain metabolism [13,19], resulting in higher levels of neurochemicals [16,19,20] that are hypothesized to negatively affect cognitive functioning. A decline in performance following high-intensity exercise has also been observed in other studies [14,21]. ...
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Background: The purpose of the present study was to compare the influence of an acute bout of high-intensity functional training (HIFT) with an acute bout of moderate-intensity continuous training (MICT) on measures of cognitive function. Methods: Sixty-nine young adults (Mean ± SD: age = 21.01 ± 2.79 yrs; body mass = 69.65 ± 6.62 kg; height = 1.74 ± 0.05 m; Body Mass Index = 22.8 ± 1.41) gave informed consent and were randomly divided into three groups. The HIFT group, with 27 participants, performed a high-intensity (>85% Max. HR) circuit of functional exercises for 30 min. The MICT group, with 28 participants, performed moderate-intensity (70-80% Max. HR) continuous training on a cyclo-ergometer. The control group did not perform any activity. The Stroop Test, Word Recall and N-Back Test were completed to assess during the familiarization period, immediately before and immediately after the training's bouts. Results: The repeated measures ANOVA did not show significant mean differences for any group. However, the T-Test for the paired samples demonstrated very significant differences in the Stroop Test, in terms of fastest response time (FRT; mean difference (MD) = -1.14, p < 0.01, d = 0.9), mean response time (MRT; MD = -2.16, p < 0.01, d = 0.66) and the number of correct answers (NCA; MD = 1.08, p < 0.05, d = 0.5) in the HIFT group and in the MICT group (FRT; MD = -1.79, p < 0.01, d = 0.9), (MRT; MD = -3.07, p < 0.01, d = 0.9) (NCA; MD = 1.54, p < 0.05, d = 0.5). Conclusions: There were no differences in the control group. HIFT and MICT may elicit specific influences on cognitive function, mainly in executive function and selective attention.
... Following power loadings, serum cortisol concentration has been found to continue to decrease along the expected circadian rhythmic pattern (McCaulley et al. 2009;Walker et al. 2010). Therefore, it seems that a robust cortisol response to resistance training only occurs when there is a high training volume, likely due to high energy requirements (Simmons et al. 1989), with maximal loads (Izquierdo et al. 2009) leading to some appreciable muscle damage. As the present study's loading protocols led to performing ~4-8 repetitions per set and inter-set rest intervals were 3 minutes, there may not have been sufficient metabolic nor psycho-physiological stress to induce acute responses. ...
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New findings: What is the central question of this study? Do males and females differ in fatiguability during dynamic loadings, and what are the acute neuromuscular and hormonal responses to 20% versus 40% velocity-loss resistance loadings? How does an 8-week velocity-loss resistance training period modify acute neuromuscular and hormonal responses in males and females? What is the main finding and its importance? Utilizing resistance training methods that regulate the within-set fatigue limit, males appeared to be more susceptible to fatigue than females before the training period. This between-sex difference was diminished after training. The predominant mechanisms of fatigue from 20% and 40% velocity-based resistance training appears to be within the musculature. Abstract: Scientific examination of velocity-based resistance training (VBRT) has increased recently, but how males and females respond to different VBRT protocols or how these acute responses are modified after a period of training is unknown. Habitually resistance-trained males and females followed either a 20% or 40% velocity-loss program for 8 weeks. Acute squat loading tests (5 sets, 70% 1-RM load, 3 minutes rest) were performed before and after the training period. Tests of maximum neuromuscular performance and blood sampling were conducted prior to, within 10 minutes of completion (POST) and 24 hours after each acute loading test. Testing included countermovement jump, resting femoral nerve electrical stimulation, and bilateral isometric leg press. Blood samples were analysed for whole-blood lactate, serum testosterone, cortisol, growth hormone and creatine kinase concentrations. Countermovement jump height, maximum isometric bilateral leg press force, and force from 10 Hz doublet decreased in all groups at POST after 20% and 40% velocity-loss. Only males showed reduced force from 100 Hz doublet and voluntary force over 100 ms at POST before training. 40% velocity-loss led to increased blood lactate and growth hormone responses before training in both males and females. After training, more systematic and equivalent responses in force over 100 ms, force from 100 Hz doublet and blood lactate were observed regardless of sex/VBRT protocol. Overall, acute responses were greater from 40% VBRT and males were more susceptible to acute loss in force production capacity before the training period. These VBRT protocol- and sex-related differences were diminished after training. This article is protected by copyright. All rights reserved.
... Acute resistance exercise causes a temporary stress condition, which activates the hypothalamic-pituitaryadrenal (HPA) axis eventually leading to elevated cortisol levels (Becker et al., 2021;Izquierdo et al., 2009). Cortisol and catecholamines bind to special receptors on the surface of immune cells in the organ reservoirs and vascular walls, causing reduction in adhesion molecule expression, which eventually leads to leukocytosis (Gleeson et al., 2013). ...
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Little is known how acute exercise‐induced inflammation and metabolic stress affect immune cell bioenergetics and the portion of its components. Therefore, we investigated acute effects of eccentric‐only (E), concentric‐only (C) and combined eccentric‐concentric resistance exercise (E + C) bouts on cellular respiration of peripheral blood mononuclear cells (PBMCs). Twelve strength‐trained young men performed bench press resistance exercises in randomized order. Venous blood samples were drawn at pre‐, 5 min post‐ and 24 h post‐exercise. Several PBMC respiration states were measured using high‐resolution respirometry. Levels of leukocytes, interleukin 6 (IL‐6), C‐reactive protein (CRP), creatine kinase (CK), blood lactate and maximum voluntary isometric force were measured from the same time points. Effects of blood lactate and pH change on bioenergetics of PBMCs were investigated ex vivo. PBMC routine respiration (p = 0.017), free routine capacity (p = 0.025) and ET‐capacity (p = 0.038) decreased immediately after E + C. E responded in opposite manner 5 min post‐exercise compared to E + C (p = 0.013) and C (p = 0.032) in routine respiration, and to E + C in free routine activity (p = 0.013). E + C > C > E was observed for increased lactate levels and decreased isometric force that correlated with routine respiration (R = −0.369, p = 0.035; R = 0.352, p = 0.048). Lactate and pH change did not affect bioenergetics of PBMCs. Acute resistance exercise affected cellular respiration of PBMCs, with training volume and the amount of metabolic stress appear influential. Results suggest that acute inflammation response does not contribute to changes seen in cellular respiration, but the level of peripheral muscle fatigue and metabolic stress could be explaining factors. Resistance exercise with different workloads have distinct effect on cellular respiration of PBMCs. Training volume and amount of metabolic stress are influential.
... Circulating cytokines are dysregulated at rest with increased age [3], which could result in varying responses to acute resistance exercise with age. Some variations in cytokine and hormone response to acute resistance exercise based on training status have been examined [46,50], but it is unknown if these are consistent with BFR-RE. ...
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Purpose The purpose of this study was to examine the response of myokines to blood-flow restricted resistance-exercise (BFR-RE) in younger and older males before and after completing a 12-week resistance-training program. Methods There were 8 younger (24.8 ± 3.9 yrs) and 7 older (68.3 ± 5.0 yrs) untrained male participants completed this study. Anthropometric and maximal strength (1RM) measurements were collected before and after a 12-week, supervised, progressive full-body resistance-training program. As well, an acute bout of full-body BFR-RE was performed with venipuncture blood samples collected before and immediately following the BFR-RE, followed by sampling at 3, 6, 24 and 48 h. Results The 12-week training program stimulated a 32.2% increase in average strength and 30% increase in strength per kg of fat free mass. The response of particular myokines to the acute bout of BFR-RE was influenced training status (IL-4, untrained = 78.1 ± 133.2 pg/mL vs. trained = 59.8 ± 121.6 pg/mL, P = 0.019; IL-7, untrained = 3.46 ± 1.8 pg/mL vs. trained = 2.66 ± 1.3 pg/mL, P = 0.047) or both training and age (irisin, P = 0.04; leukemia inhibitory factor, P < 0.001). As well, changes in strength per kg of fat free mass were correlated with area under the curve for IL-4 ( r = 0.537; P = 0.039), IL-6 ( r = 0. 525; P = 0.044) and LIF ( r = − 0.548; P = 0.035) in the untrained condition. Conclusion This study identified that both age and training status influence the myokine response to an acute bout of BFR-RE with the release of IL-4, IL-6 and LIF in the untrained state being associated with changes in strength per kg of fat free mass.
... In athletic training, resistance exercise (RE) effects are derived by controlling the loading, sets, repetitions, rest duration, and movement velocity of exercise, these stimulations result in physiological response and adaptation (Spiering et al., 2008). Heavy RE protocols that consist of high loads (<10 repetition maximum, RM), high volume (6 or more sets of 10 repetitions per exercise), short inter-set rests, and use of major muscle groups, are frequently used to induce muscle hypertrophy and improve strength in athletes (Tesch, 1988;Izquierdo et al., 2009). However, excess mechanical force during heavy RE protocols could injure muscle sarcomere, resulting in exercise-induced muscle damage (EIMD). ...
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PurposeThe purpose of this study was to investigate the effects of acute repeated hypoxia–hyperoxia preconditioning on resistance exercise (RE)-induced muscle damage in male athletes.Methods Eleven young male athletes participated in this randomized double-blind counter-balanced crossover study, and were divided into Normoxia (N) and Hypoxia–Hyperoxia (HH) trials. Subjects of the respective trials were supplied with normoxic (FiO2 = 0.21), or alternating hypoxic/hyperoxic air (FiO2 = 0.10/0.99, 5 min each) for 60 min. Thirty minutes after preconditioning, subjects performed acute bouts of RE consisting of bench press, deadlift, and squats. Each exercise included 6 sets of 10 repetitions at 75% one-repetition maximum (1RM) with 2 min rest between sets. After a 2-week washout period, subjects changed trials and completed the same study procedure after the alternate preconditioning. Muscle soreness, maximal voluntary contraction (MVC), and circulating biochemical markers were tested before preconditioning (baseline) and during recovery at 0, 24, and 48 h after exercise.ResultsAcute RE significantly increased levels of muscle soreness, creatine kinase (CK) and myoglobin (Mb), and decreased levels of peak knee extension torque in the N trial. Muscle soreness, CK, and Mb levels of the HH trial were significantly lower than that of the N trial after exercise. Interestingly, interleukin-6 (IL-6) levels of the HH trial increased significantly 0 h after exercise compared to baseline and were significantly higher than that of the N trial 0 and 24 h after exercise. However, no significant differences of thiobarbituric acid reactive substances (TBARS), cortisol, testosterone, peak torque, and average power levels were found between N and HH trials during recovery.Conclusion Our data suggest that pre-exercise treatment of alternating hypoxic/hyperoxic air could attenuate muscle damage and pain after acute RE, but has no effect on muscle strength recovery in young male athletes.
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1  ، ‫ﺟﻌﻔﺮي‬ ‫اﻓﺸﺎر‬ 2 ، ‫زاد‬ ‫اﺣﻤﺪي‬ ‫ﺳﺠﺎد‬ 3 ، ‫ﻧﯿﮑﻮﺧﺼﻠﺖ‬ ‫دﺑﺎغ‬ ‫ﺳﻌﯿﺪ‬ 4 1 ‫ﺗﺒﺮﯾﺰ‬ ‫داﻧﺸﮕﺎه‬ ‫ورزش‬ ‫ﻓﯿﺰﯾﻮﻟﻮژي‬ ‫دﮐﺘﺮي‬ ‫داﻧﺸﺠﻮي‬. 2 ‫ﺗﺒﺮﯾﺰ‬ ‫داﻧﺸﮕﺎه‬ ‫ورزﺷﯽ‬ ‫ﻓﯿﺰﯾﻮﻟﻮژي‬ ‫داﻧﺸﯿﺎر‬. 3 ‫ﺗﻬﺮان‬ ‫ﺑﻬﺸﺘﯽ‬ ‫ﺷﻬﯿﺪ‬ ‫داﻧﺸﮕﺎه‬ ‫ورزﺷﯽ‬ ‫ﻓﯿﺰﯾﻮﻟﻮژي‬ ‫داﻧﺸﯿﺎر‬. 4 ‫ﺗﺒﺮﯾﺰ‬ ‫داﻧﺸﮕﺎه‬ ‫ورزﺷﯽ‬ ‫ﻓﯿﺰﯾﻮﻟﻮژي‬ ‫داﻧﺸﯿﺎر‬. ‫ﺗﺎر‬ ‫ﯾ‬ ‫در‬ ‫ﺦ‬ ‫ﯾ‬ ‫ﻣﻘﺎﻟﻪ:‬ ‫ﺎﻓﺖ‬ 7 / 4 / 95 ‫ﺗﺎر‬ ‫ﯾ‬ ‫ﭘﺬ‬ ‫ﺦ‬ ‫ﯾ‬ ‫ﻣﻘﺎﻟﻪ:‬ ‫ﺮش‬ 22 / 5 / 95 ‫ﭼﮑ‬ ‫ﯿ‬ ‫ﺪه‬ ‫ﻫﺪف‬ : ‫ﺗﻨﺎﻗﺾ‬ ‫ﺑﻪ‬ ‫ﺗﻮﺟﻪ‬ ‫ﺑﺎ‬ ‫ﺗﻤﺮ‬ ‫اﺛﺮات‬ ‫ﺑﻪ‬ ‫ﻣﺮﺑﻮط‬ ‫ﻫﺎي‬ ‫ﯾ‬ ‫ﺑﯿﻤﺎري‬ ‫ﺑﺎ‬ ‫ﻣﺮﺗﺒﻂ‬ ‫ﻫﻤﻮرﺋﻮﻟﻮژﯾﮑﯽ‬ ‫ﭘﺎراﻣﺘﺮﻫﺎي‬ ‫ﺑﺮ‬ ‫ﻣﻘﺎوﻣﺘﯽ‬ ‫ﻨﺎت‬ ‫ﻗﻠﺒﯽ‬ ‫ﻫﺎي‬-‫ﻋﺮوﻗﯽ،‬ ‫ﺗﻌﯿﯿﻦ‬ ‫ﻫﺪف‬ ‫ﺑﺎ‬ ‫ﺣﺎﺿﺮ‬ ‫ﺗﺤﻘﯿﻖ‬ ‫ﺗﺄﺛﯿﺮ‬ 12 ‫ﻫﻔﺘﻪ‬ ‫ﺗﻤﺮ‬ ‫ﯾ‬ ‫ﻦ‬ ‫ﻣﻘﺎوﻣﺘ‬ ‫ﯽ‬ ‫ﻣﺨﺘﻠﻒ‬ ‫ﻣﺮدان‬ ‫در‬ ‫ﻫﻤﻮرﺋﻮﻟﻮژﯾﮑﯽ‬ ‫ﻋﻮاﻣﻞ‬ ‫ﺑﺮ‬ ‫ﺑﯿﺸﯿﻨﻪ(‬ ‫ﻗﺪرﺗﯽ‬ ‫و‬ ‫)ﻫﺎﯾﭙﺮﺗﺮوﻓﯽ‬ ‫ﺷﺪ.‬ ‫اﻧﺠﺎم‬ ‫ﺳﺎﻟﻢ‬ ‫ﻏﯿﺮﻓﻌﺎل‬ ‫روش‬ ‫ﺷﻨﺎﺳﯽ‬ : 39 ‫ﻣﺮد‬ ‫داﻧﺸﺠﻮي‬ 20-18) ‫ﮐﻨﺘﺮل‬ ‫ﮔﺮوه‬ ‫ﺳﻪ‬ ‫ﺑﻪ‬ ‫ﺗﺼﺎدﻓﯽ‬ ‫ﻃﻮر‬ ‫ﺑﻪ‬ ‫ﻓﻌﺎل‬ ‫ﻏﯿﺮ‬ ‫ﺳﺎﻟﻢ‬ ‫ﺳﺎﻟﻪ‬ 12 n= ،() ‫ﻫﺎﯾﭙﺮﺗﺮوﻓﯽ‬ ‫ﻣﻘﺎوﻣﺘﯽ‬ ‫ﺗﻤﺮﯾﻦ‬ 14 n=) ‫ﺑﯿﺸﯿﻨﻪ‬ ‫ﻗﺪرﺗﯽ‬ ‫و‬ (13 n= ‫ﮔﺮوه‬ ‫ﺷﺪﻧﺪ.‬ ‫ﺗﻘﺴﯿﻢ‬ (‫ﺗﻤﺮ‬ ‫ﻫﺎي‬ ‫ﯾ‬ ‫ﺑﻪ‬ ‫ﻦ‬ ‫ﻣﺪت‬ 12 ‫ﺗﻤﺮ‬ ‫در‬ ‫ﻫﻔﺘﻪ‬ ‫ﯾ‬ ‫ﻣﻘﺎوﻣﺘﯽ‬ ‫ﻨﺎت‬) 3 ‫ﺟﻠﺴﻪ/ﻫﻔﺘﻪ،‬ 6 ‫ا‬ ‫ﯾ‬ ‫ا‬ ‫ﻫﺮ‬ ‫در‬ ‫و‬ ‫ﺴﺘﮕﺎه/ﺟﻠﺴﻪ‬ ‫ﯾ‬ ‫ﺴﺘﮕﺎه‬ 3 ‫ﺗﻤﺮ‬ ‫داﺷﺘﻨﺪ.‬ ‫ﺷﺮﮐﺖ‬ ‫ﻧﻮﺑﺖ(‬ ‫ﯾ‬ ‫ﺑ‬ ‫ﻗﺪرﺗﯽ‬ ‫و‬ ‫ﻫﺎﯾﭙﺮﺗﺮوﻓﯽ‬ ‫ﻣﻘﺎوﻣﺘﯽ‬ ‫ﻨﺎت‬ ‫ﯿ‬ ‫ﺸ‬ ‫ﯿ‬ ‫ﺗﺮﺗ‬ ‫ﺑﻪ‬ ‫ﻨﻪ‬ ‫ﯿ‬ ‫ﺐ‬ ‫ﺑﺎﺷﺪت‬ 70-65 ‫و‬ % 85-80 ‫ﻧﻤﻮﻧﻪ‬ ‫ﺷﺪ.‬ ‫اﻧﺠﺎم‬ ‫ﺑﯿﺸﯿﻨﻪ،‬ ‫ﺗﮑﺮار‬ ‫ﯾﮏ‬ % ‫و‬ ‫ﻗﺒﻞ‬ ‫ﺧﻮﻧﯽ‬ ‫ﻫﺎي‬ 48 ‫ﺷﺪﻧﺪ‬ ‫ﮔﺮﻓﺘﻪ‬ ‫ﺗﻤﺮﯾﻦ‬ ‫دوره‬ ‫از‬ ‫ﭘﺲ‬ ‫ﺳﺎﻋﺖ‬ ‫ﺑﺮاي‬ ‫و‬ ‫اﻧﺪازه‬ ‫ﮔﯿﺮي‬ ‫داده‬ ‫ﺷﺪﻧﺪ.‬ ‫آﻧﺎﻟﯿﺰ‬ ‫ﻫﻤﻮرﺋﻮﻟﻮژﯾﮑﯽ‬ ‫ﻣﺘﻐﯿﺮﻫﺎي‬ ‫ﺑﺮرﺳﯽ‬ ‫ﻣﺴﺘﻘﻞ‬ ‫ﯾﮑﻄﺮﻓﻪ‬ ‫وارﯾﺎﻧﺲ‬ ‫ﺗﺤﻠﯿﻞ‬ ‫از‬ ‫اﺳﺘﻔﺎده‬ ‫ﺑﺎ‬ ‫ﻫﻤﻮرﺋﻮﻟﻮژﯾﮑﯽ‬ ‫ﻋﻮاﻣﻞ‬ ‫ﻫﺎي‬ ‫ﺷﺪﻧﺪ.‬ ‫ﻧﺘﺎﯾﺞ‬ : ‫ﭘﺮوﺗﺌﯿﻦ‬ ‫ﺗﺠﻤﻊ‬ ‫و‬ ‫ﭘﻼﺳﻤﺎ‬ ‫وﯾﺴﮑﻮزﯾﺘﻪ‬ ‫ﺗﺎم،‬ ‫ﮔﻠﺒﻮل‬ ‫ﭘﺬﯾﺮي‬ ‫ﻣﺘﻌﺎﻗﺐ‬ ‫ﻗﺮﻣﺰ‬ ‫ﻫﺎي‬ 12 ‫ﻫﺎ‬ ‫ﻣﻘﺎوﻣﺘﯽ‬ ‫ﺗﻤﺮﯾﻦ‬ ‫ﻫﻔﺘﻪ‬ ‫ﯾ‬ ‫ﻗﺪرﺗﯽ‬ ‫و‬ ‫ﭙﺮﺗﺮوﻓﯽ‬ ‫ﺑ‬ ‫ﯿ‬ ‫ﺸ‬ ‫ﯿ‬ ‫ﻣﻌﻨﯽ‬ ‫ﻃﻮر‬ ‫ﺑﻪ‬ ‫ﻨﻪ‬ ‫ﮐﺎﻫﺶ‬ ‫دار‬ ‫ﯾ‬ ‫ﺎﻓﺘﻨﺪ‬) 05 / 0 < P ‫ﺗﻐﯿﯿﺮﺷﮑﻞ‬ ‫ﻃﺮﻓﯽ،‬ ‫از‬ .(‫ﮔﻠﺒﻮل‬ ‫ﭘﺬﯾﺮي‬ ‫ﻃﻮر‬ ‫ﺑﻪ‬ ‫ﻣﻘﺎوﻣﺘﯽ‬ ‫ﺗﻤﺮﯾﻦ‬ ‫ﮔﺮوه‬ ‫دو‬ ‫ﻫﺮ‬ ‫در‬ ‫ﻗﺮﻣﺰ‬ ‫ﻫﺎي‬ ‫ﻣﻌﻨﯽ‬ ‫ﭘ‬ ‫اﻓﺰاﯾﺶ‬ ‫دار‬ ‫ﯿ‬) ‫ﮐﺮد‬ ‫ﺪا‬ 05 / 0 < P ‫ﺑﻪ‬ ‫ﺑﯿﺸﯿﻨﻪ‬ ‫ﻗﺪرﺗﯽ‬ ‫ﮔﺮوه‬ ‫ﺑﻪ‬ ‫ﻧﺴﺒﺖ‬ ‫ﻫﺎﯾﭙﺮﺗﺮوﻓﯽ‬ ‫ﮔﺮوه‬ ‫در‬ ‫ﭘﻼﺳﻤﺎ‬ ‫وﯾﺴﮑﻮزﯾﺘﻪ‬ ‫داﻣﻨﻪ‬ ‫اﻓﺖ‬ ‫ﺣﺎل،‬ ‫ﻫﺮ‬ ‫ﺑﻪ‬ .(‫ﻣﻌﻨﯽ‬ ‫ﻃﻮر‬ ‫ﺑ‬ ‫دار‬ ‫ﯿ‬ ‫ﺑ‬ ‫ﺸﺘﺮ‬) ‫ﻮد‬ 05 / 0 < P ‫ﻣﻌﻨﯽ‬ ‫اﻓﺖ‬ ‫ﻋﻼوه،‬ ‫ﺑﻪ‬ .() ‫ﺷﺪ‬ ‫ﻣﺸﺎﻫﺪه‬ ‫ﻫﺎﯾﭙﺮﺗﺮوﻓﯽ‬ ‫ﮔﺮوه‬ ‫در‬ ‫ﺗﻨﻬﺎ‬ ‫ﺧﻮن‬ ‫وﯾﺴﮑﻮزﯾﺘﻪ‬ ‫دار‬ 05 / 0 < P .(‫ﻧﺘﯿﺠﻪ‬ ‫ﮔﯿﺮي‬ : Abstract Purpose: Based on controversies about the effects of resistance training on hemorheological parameters associated with cardiovascular disease, this study was carried out to determine the effect of 12 weeks of resistance training (hypertrophy and maximal strength) on hemorheological parameters in healthy inactive men. Methods: Thirty nine collegiate men (18-20 years) were randomly divided into three groups: control (n =12), hypertrophy (n =13) and strength (n =13) training groups. Training groups participated in 12 weeks of resistance training (3 sessions / week, 6 stations / session and 3 times per station). Hypertrophy and maximal strength resistance training were performed at 65-70% and 80-85% of one repetition maximum, respectively. Blood samples were taken before and 48 hours after the training period and were analyzed for measuring the hemorheological variables. Hemorheological data were analyzed by using the independent one-way ANOVA. Results: The significant reductions in total protein, plasma viscosity and aggregation of red blood cells in inactive men were found after 12 weeks of hypertrophy and maximal resistance training (P <0.05). Whereas, the deformability of red blood cells increased significantly in both resistance training groups (P<0.05). The reductions in the plasma viscosity was significantly higher in the hypertrophy training group than the strength training group (P <0.05). Moreover, a significant reduction in blood viscosity was only observed in the hypertrophy group (P <0.05). Conclusion: Based on the findings of the present study it could be concluded that both hypertrophy and strength resistance training affect on rheological characteristics of red blood cells similarly, though, the hypertrophy resistance training results in more improvements in blood and plasma viscosity and eventually blood fluidity. Therefore, healthy inactive men can participate in resistance training to achieve benefits from these training without any concern and adverse changes in hemorheological parameters associated with thrombosis.
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Background: Autologous conditioned serum (ACS) is a commonly administered intra-articular treatment for the management of osteoarthritis in athletic horses. Objectives: To investigate the influence of exercise on the concentration of cytokines in a non-commercial method of ACS production. Study design: Non-randomised cross over design. Methods: Whole blood was obtained from 8 healthy Standardbred horses immediately prior to, 1 hour and 24 hours following a single bout of exhaustive exercise. Blood was processed using a non-commercial method of ACS production. Fluorescent microsphere immunoassay (FMIA) analysis was performed to quantify Interleukin 1 receptor antagonist (IL-1Ra), Interleukin-10 (IL-10), Interleukin 1β (IL-1β) and tumour necrosis factor α (TNF-α) concentrations at each time point. Mixed effect repeated measures analysis of variance (ANOVA) was used to compare the pre-exercise and post-exercise cytokine concentrations. Significance was set at P < 0.05. Results: A reduced concentration of IL-1Ra (median 584.4, IQR 81.9 - 5098 pg/mL, P = 0.004) and an increased concentration of TNF-α (11.92, 9.28 - 39.75 pg/mL, P = 0.05) at 1 hour post-exercise was observed when compared to baseline values (IL-Ra 7349, 1272 - 10760 pg/mL; TNF TNF-α 11.16, 8.36 - 32.74 pg/mL). No difference in cytokine concentrations of IL-10 or IL-1β were found between any of the time points. Main limitations: The large biological variability and small sample size represents limitations of this study. Conclusions: These results suggest that a single bout of intense exercise can reduce the concentration of the anti-inflammatory cytokine IL-1Ra and increase the concentration of the pro-inflammatory cytokine TNF-α, reducing the 'anti-inflammatory' cytokine composition of ACS. Our findings suggest that collection of blood for ACS production should be performed no sooner than 24 hours following a single episode of intense exercise.
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Cited By (since 1996): 68 Export Date: 10 April 2012 Source: Scopus
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Increases in force, electromyography, reflex potentiation, muscle action potential amplitude and protein synthesis occur with strength training. Training-induced increases in the efficiency of the neuromuscular system and capacity of the muscle to generate force result in an improved ability to cope with a submaximal load. There is also some evidence of improved fatigue resistance with maximal contractions which could be attributed to a prolongation of membrane excitation or decreased antagonist activity with training. On the other hand, although a variety of factors including strength are diminished with disuse, a number of studies have demonstrated no significant difference in the rate of fatigue with maximal contractions (fatigue index) between trained, untrained and disused muscle. Equivalent control and disuse fatigue indexes in some studies might be attributed to decreased muscle activation resulting in a comparison of maximal (control) and submaximal (disuse) efforts. Furthermore, increases in the duration of muscle membrane electrical propagation with disuse may increase the quantity of Ca++ released, augmenting force production. In addition, the smaller volume of disused muscle may allow a more efficient diffusion of oxygen and energy substrates in comparison with a hypertrophied muscle.
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Acute and long-term hormonal and neuromuscular adaptations to hypertrophic strength training were studied in 13 recreationally strength-trained men. The experimental design comprised a 6-month hypertrophic strength-training period including 2 separate 3-month training periods with the crossover design, a training protocol of short rest (SR, 2 minutes) as compared with long rest (LR, 5 minutes) between the sets. Basal hormonal concentrations of serum total testosterone (T), free testosterone (FT), and cortisol (C), maximal isometric strength of the leg extensors, right leg 1 repetition maximum (1RM), dietary analysis, and muscle cross-sectional area (CSA) of the quadriceps femoris by magnetic resonance imaging (MRI) were measured at months 0, 3, and 6. The 2 hypertrophic training protocols used in training for the leg extensors (leg presses and squats with 10RM sets) were also examined in the laboratory conditions at months 0, 3, and 6. The exercise protocols were similar with regard to the total volume of work (loads 3 sets 3 reps), but differed with regard to the intensity and the length of rest between the sets (higher intensity and longer rest of 5 minutes vs. somewhat lower intensity but shorter rest of 2 minutes). Before and immediately after the protocols, maximal isometric force and electro-myographic (EMG) activity of the leg extensors were measured and blood samples were drawn for determination of serum T, FT, C, and growth hormone (GH) concentrations and blood lactate. Both protocols before the experimental training period (month 0) led to large acute increases (p < 0.05-0.001) in serum T, FT, C < and GH concentrations, as well as to large acute decreases (p < 0.05-0.001) in maximal isometric force and EMG activity. However, no significant differences were observed between the protocols. Significant increases of 7% in maximal isometric force, 16% in the right leg 1RM, and 4% in the muscle CSA of the quadriceps femoris were observed during the 6-month strength-training period. However, both 3-month training periods performed with either the longer or the shorter rest periods between the sets resulted in similar gains in muscle mass and strength. No statistically significant changes were observed in basal hormone concentrations or in the profiles of acute hormonal responses during the entire 6-month experimental training period. The present study indicated that, within typical hypertrophic strength-training protocols used in the present study, the length of the recovery times between the sets (2 vs. 5 minutes) did not have an influence on the magnitude of acute hormonal and neuromuscular responses or long-term training adaptations in muscle strength and mass in previously strength-trained men.
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To address the question of whether the increased plasma concentration of interleukin 6 (IL-6) following strenuous muscular work could be related to exercise-induced muscle damage, 5 moderately active male volunteers underwent two isokinetic exercise sessions in the eccentric mode, separated by a period of 3 weeks during which the subjects underwent five training sessions. Before training, exercise was followed by severe muscle pain (delayed-onset muscle soreness; DOMS), and by significant increases in plasma IL-6 level and serum myoglobin concentration (SMb) (P < 0.001). After training, postexercise DOMS and SMb values were significantly lower than those measured before training. There was no significant difference between plasma IL-6 levels measured at the same time points before and after training. We conclude that the hypothetical relationship between exercise-induced muscle damage and increased postexercise levels of circulating IL-6 is not substantiated by the present results. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 208–212, 1999
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The purpose of this study was to examine the time-course and relationships of technetium-99m (99mTc) neutrophils in muscle, interleukin-6 (IL-6), myosin heavy chain fragments (MHC), eccentric torque, and delayed onset muscle soreness (DOMS) following eccentric exercise in humans. Twelve male subjects completed a pre-test DOMS questionnaire, performed a strength test and had 100 ml blood withdrawn for analysis of plasma IL-6 and MHC content. The neutrophils were separated, labelled with 99mTc, and re-infused into the subjects immediately before the exercise. Following 300 eccentric repetitions of the right quadriceps muscles on an isokinetic dynamometer, the subjects had 10 ml of blood withdrawn and repeated the eccentric torque exercise tests and DOMS questionnaire at 0, 2, 4, 6, 20, 24, 48, 72 h, and 6 and 9 days. Bilateral images of the quadriceps muscles were taken at 2, 4, and 6 h. Computer analysis of regions of interest was used to determine the average count per pixel. The 99mTc neutrophils and IL-6 increased up to 6 h post-exercise (P < 0.05). The neutrophils were greater in the exercised muscle than the non-exercised muscle (P < 0.01). The DOMS was increased from 0 to 48 h, eccentric torque decreased from 2 to 24 h, and MHC peaked at 72 h post-exercise (P < 0.001). Significant relationships were found between IL-6 at 2 h and DOMS at 24 h post-exercise (r=0.68) and assessment of the magnitude of change between IL-6 and MHC (r=0.66). These findings suggest a relationship between damage to the contractile proteins and inflammation, and that DOMS is associated with inflammation but not with muscle damage.
This investigation examined hormonal adaptations to acute resistance exercise and determined whether training adaptations are observed within an 8-week period in untrained men and women. The protocol consisted of a 1-week pre-conditioning orientation phase followed by 8 weeks of heavy resistance training. Three lower-limb exercises for the quadriceps femoris muscle group (squat, leg press, knee extension) were performed twice a week (Monday and Friday) with every other Wednesday used for maximal dynamic 1 RM strength testing. Blood samples were obtained pre-exercise (Pre-Ex), immediately post-exercise (IP), and 5 min post-exercise (5-P) during the first week of training (T-1), after 6 weeks (T-2) and 8 weeks (T-3) of training to determine blood concentrations of whole-blood lactate (LAC), serum total testosterone (TT), sex-hormone binding globulin (SHBG), cortisol (CORT) and growth hormone (GH). Serum TT concentrations were significantly (P ≤ 0.05) higher for men at all time points measured. Men did not demonstrate an increase due to exercise until T-2. An increase in pre-exercise concentrations of TT were observed both for men and women at T-2 and T-3. No differences were observed for CORT between men and women; increases in CORT above pre-exercise values were observed for men at all training phases and at T-2 and T-3 for women. A reduction in CORT concentrations at rest was observed both in men and women at T-3. Women demonstrated higher pre-exercise GH values than men at all training phases; no changes with training were observed for GH concentrations. Exercise-induced increases in GH above pre-exercise values were observed at all phases of training. Women demonstrated higher serum concentrations of SHBG at all time points. No exercise-induced increases were observed in men over the training period but women increased SHBG with exercise at T-3. SHBG concentrations in women were also significantly higher at T-2 and T-3 when compared to T-1 values. Increases in LAC concentrations due to exercise were observed both for men and women for all training phases but no significant differences were observed with training. These data illustrate that untrained individuals may exhibit early-phase endocrine adaptations during a resistance training program. These hormonal adaptations may influence and help to mediate other adaptations in the nervous system and muscle fibers, which have been shown to be very responsive in the early phase of strength adaptations with resistance training.