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Abstract

Primary objective of this study was to provide the insight into the effects of strength training on the testosterone (TE) level in men, as well as the mechanisms of anabolic effects of testosterone on human muscle apparatus, since it is known that one of the ways to increase muscle strength is through the increase of muscle mass (peripheral factor), and the basis of this process is the effect of TE. The collected data summarize the conclusions of a number of previous studies, out of which larger number of recently, and they relate to the effect of different methods of strength training (H - submaximal effort to failure, S - maximal effort, P - dynamic effort) with equally applied total volume of load, and the effect of different rest periods in strength training on the level of TE in men. The presented results confi rmed the claims that the H method is the most effective and reasonably called ‘the method for muscle hypertrophy’. When it comes to rest periods, the ones that last for about 90 seconds proved optimal because this period had most infl uence on the level of lactic acid and catecholamines in blood which are considered to be the key factors for the increased secretion of TE (this hormone was included in a group of stress hormones as well) However, according to many authors, further examinations in this fi eld are necessary in order to determine the causal link with greater certainty.
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Stanković A., et al., The Effect of Strength Training on the Testosterone... PHYSICAL CULTURE 2013; 67 (2): 157-166
Aleksandar Stanković
Marina Đorđević-Nikić
Filip Kukić, Miloš Petrović
Nenad Cvijanović 796.015.52:612.616.3
Nemanja Todorović Professional paper
University of Belgrade, Faculty of Sport and Physical Education, Belgrade, Serbia
THE EFFECT OF STRENGTH TRAINING
ON THE TESTOSTERONE LEVEL IN MEN
Abstract
Primary objective of this study was to provide the insight into the effects of strength training on the testosterone (TE) level in men, as
well as the mechanisms of anabolic effects of testosterone on human muscle apparatus, since it is known that one of the ways to increase
muscle strength is through the increase of muscle mass (peripheral factor), and the basis of this process is the effect of TE. The collected
data summarize the conclusions of a number of previous studies, out of which larger number of recently, and they relate to the effect of
different methods of strength training (H - submaximal effort to failure, S - maximal effort, P - dynamic effort) with equally applied total
volume of load, and the effect of different rest periods in strength training on the level of TE in men. The presented results con rmed the
claims that the H method is the most effective and reasonably called ‘the method for muscle hypertrophy’. When it comes to rest periods,
the ones that last for about 90 seconds proved optimal because this period had most in uence on the level of lactic acid and catecholamines
in blood which are considered to be the key factors for the increased secretion of TE (this hormone was included in a group of stress
hormones as well) However, according to many authors, further examinations in this eld are necessary in order to determine the causal
link with greater certainty.
Key words: MUSCLE MASS / TRAINING METHODS / HORMONES / STRENGTH TRAINING / REST PERIOD
Corespondence to: Aleksandar Stanković, University of Belgrade, Faculty of Sport and Physical Education,
Blagoja Parovica 156, Belgrade, Serbia; e-mail: aleksandars989@yahoo.com
INTRODUCTION
Strength, as anthropomotor ability, has a cer-
tain importance for the success in the performance
of sports activities and represents an important part
of sports preparation (Kukolj, 2003; Stefanović,
Jakovljević, & Janković, 2010; Zatsiorsky, & Kream-
er, 2009). In modern sport, it is almost inconceivable
to achieve excellent results without a signi cant
share of strength in most sport disciplines. Also, the
study of its principles of manifestation is important
for preserving and improving human health, so sci-
ence and practice of strength training reach far be-
yond the boundaries of sport.
Multiple studies in various elds of science
were focused precisely on strength training. So far
it is known that, in terms of physical changes on
an individual, strength training affects changes in
muscles that are associated with two components
(Kukolj, 2003 Mc Caulley, et al., 2008; Stefanović,
Jakovljević, & Janković, 2010; Zatsiorsky, & Krae-
mer, 2009): neural (adaptation of the central nervous
system) and muscular (the impact on the increase
in muscle mass). Depending on the approach to the
components of training load (intensity, scope of work,
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Stanković A., et al., The Effect of Strength Training on the Testosterone... PHYSICAL CULTURE 2013; 67 (2): 157-166
duration and type of rest periods, muscles operating
mode, etc.) different effects on these two components
are manifested. By choosing the appropriate method
of work one can get the greatest effects in the short-
est possible time, which is particularly important for
the success in modern sport and of great importance
for the effectiveness of training for recreational pur-
poses.
Previous research results (Ahtiainen, et al.,
2003, 2005; McCaulley, et al., 2008; Nikolić, 2003;
Rahimi, et al., 2010; Zatsiorsky, & Kraemer, 2009)
also gave support to the idea , that the leading role
in the basis of anabolic processes in muscles are so
called anabolic hormones, and that testosterone is
one of the most important representatives. Since it
is a dominant factor of the in uence on the increase
of muscle mass, testosterone plays an important role
when it comes to increasing muscle strength.
On the other hand, among the basic mecha-
nisms that promote increased secretion of testoster-
one in the body, physical activity plays an important
role. That was shown in many studies focused on the
effects of strength training on the work of endocrine
system, including many that were based solely on
the effect of strength training on testosterone levels
in men (Ahtiainen, et al., 2003; Baker, et al., 2006;
McCaulley, et al., 2009; Jakob, et al., 2010; Kraemer,
et al., 1999).
The aim this study was to show, on the basis
of previous studies, how certain methods of strength
training affect the level of testosterone in men, and
accordingly, to determine which methods would be
the most appropriate to obtain the desired effects,
which are the increase in muscle mass, and thus the
increase in strength. In addition, the goal would also
be obtaining insight to the mechanisms of the ana-
bolic effects of testosterone.
Testosterone
Testosterone (TE) is the predominant male sex
hormone produced in Leydig cells in testicles. In ad-
dition, androgens (testosterone, dihydrotestosterone
and androstenedione) - a group of hormones with
masculinising effects are also synthesized in the ad-
renal gland. Testosterone is secreted much more than
other hormones in the testicles and in the target tis-
sues it turns into its active form - dihydro-testoster-
one (5α DHT) (Guyton, & Hall, 2003; Majkić-Singh,
2006; Đorđevic-Nikić, 2004).
In male embryos testosterone is stimulated in
the seventh week of embryonic life, in Leydig cells.
These cells are found in the interstitium of testicles,
between seminal ducts and constitute about twenty
per cent of the mass of testicles of adult males and are
almost absent during childhood, when the testicles
barely secrete testosterone (until the age of about 10
years). During the rst months of life of male neo-
nates and in adult males the testicles secrete large
amounts of testosterone (Guyton, & Hall, 2003)
The level of TE in blood of adult males is con-
trolled by negative feedback, which is established by
the hypothalamus (gonadotropin-releasing hormone
Gn-RH), pituitary (luteinizing hormone - LH) and
testicles (Majkic-Singh, 2006). Gn-RH is secreted
intermittently, every 1 to 3 hours, for a few minutes,
and two parameters determine the strength of the hor-
monal stimuli: secretory cycle frequency and amount
of Gn-RH released in each cycle.
The amount of testosterone secreted is directly
proportional to the amount of LH released. In adult
males, testosterone is found in concentrations of 139-
312 nmol / L of blood, i.e., total daily amount of this
hormone secreted is approximately 8 mg (Guyton &
Hall, 2003).
Metabolism and physiological functions
of testosterone
When the testicles secrete testosterone, about
65% is bound to sex hormone-binding globulin
(SHBG) and 30% for albumin and circulates in plas-
ma for about 15 - 30 min, while 2-5% is free (Majkić-
Singh 2006; Lawrence, Bickerstaff, & Baker, 2010).
In target tissues testosterone turns into dihydrotes-
tosterone (5α DHT), and in this form it manifests
cellular effects. DHT binds to receptor protein in
the cytoplasm, and this complex then diffuses in the
nucleus where it activates DNA transcription process
(transcription of genetic information). Degradation
and inactivation of testosterone occurs in the liver.
Testosterone turns into androsterone and dehydro-
epiandrosterone (DHEA) and simultaneously is con-
jugated to glucuronide or sulfate and in this form it
leaves the body (Guyton, & Hall, 2003).
In general, testosterone is responsible for the
expression of male secondary sexual characteristics.
In addition, the functions of testosterone are (Guyton,
& Hall, 2003; Majkić-Singh, 2006; Nikolić, 2003;
Ugarković, 2004; Đorđević-Nikić, 2004):
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Stanković A., et al., The Effect of Strength Training on the Testosterone... PHYSICAL CULTURE 2013; 67 (2): 157-166
Daily and life biorhythms of testosterone
and other factors that in uence its secretion
Daily biorhythms of testosterone are de ned
by periods and duration of Gn-RH pulses, through
LH.
Chrat 1 shows life biorhythm of testoster-
one secretion in men, from birth until the old age.
(Guyton, & Hall, 2003). The period from the onset
of puberty until the age of 20 (18 to 22) is charac-
terized by steep increase in the amount of testoster-
one secreted per day, which reaches its maximum at
that time. Thus, in the age of 13 the secreted volume
amounts to approximately 1,500 μg/day and at the
age of 20 about 7,500 μg/day (up to 8mg/day).
Chart 1. Life biorhythm of testosterone secretion
in men, from birth until the old age
(Guyton, & Hall 2003)
After reaching its peak at the age of 20 (and
retaining the maximum daily secreted amount, up to
the age of 25), the amount of secreted testosterone
decreases with age, but retains high values until the
age of 45 (about 6,500 μg /day), i.e. until the age of
60 (approximately 5,000 μg/day, with large individu-
al differences) (Guyton, & Hall, 2003).
In addition to normal daily life and biorhythms
of testosterone, there are several factors that in uence
its increased output (Guyton, & Hall, 2003; Nikolić,
2003; Ugarković, 2004):
Physical stress - hard physical work,
The states of fasting and semi fasting
Psychological factors - sexual desire
Sleep and rest.
functions during embryonic development of
male foetus,
the effect on protein synthesis and muscle
development
the effect on bone growth and retention of
calcium and non-osseous minerals,
the effect on the deposition of glycogen in
the muscles,
the effect on the formation of red blood cells,
the effect on electrolytes and water balance.
The in uence of this hormone on strength
training is primarily related to the control of protein
synthesis and muscle development as well as bone
growth and retention of calcium and non-osseous
minerals.
The effect of testosterone on protein synthesis
and muscle development
It is thought that the primary mechanism of ac-
tion of testosterone is the stimulation of protein syn-
thesis in cells of different tissues. Increased produc-
tion of RNA, which occurs as a result of testosterone
on the level of DNA, leads to an increase in muscle
proteins. It is believed that testosterone stimulates the
production of proteins in general (Ahtiainen, et al.,
2011), but to a greater extent does so in target organs
that are associated with secondary sexual characteris-
tics (Guyton, & Hall, 2003 Majkic-Singh, 2006).
Apart from the anabolic, it is believed that tes-
tosterone has anti-catabolic function, blocking the
glucocorticoid receptor, which prevents the binding
of cortisol (Jakob, et al., 2010).
After the great increase in amounts of testos-
terone in circulation, the bones become signi cant-
ly thicker, and the deposit of calcium salts is much
higher. This way testosterone increases the amount
of bone matrix and causes the deposition of calcium.
In addition, testosterone has a speci c effect on the
pelvis. It narrows the pelvic outlet, extends it, caus-
ing a funnel appearance and signi cantly increases
the strength of the entire pelvis in relation to its ca-
pacity (Guyton, & Hall, 2003). It is believed that
during adolescence, 2/3 of height growth of young
men is conditioned by the in uence of testosterone
(Đorđević-Nikić, M., 1995).
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Stanković A., et al., The Effect of Strength Training on the Testosterone... PHYSICAL CULTURE 2013; 67 (2): 157-166
When it comes to physical activity, the degree
of acute hormonal responses to training depends on
(Zatsiorsky, & Kreamer, 2009):
• The quantities of activated muscle mass
- when small muscle groups are involved
in the exercise, despite high intensity
and volume of work, there will not be a
signi cant increase in testosterone levels in
blood compared to rest state (Zatsiorsky, &
Kreamer, 2009; Jakob, et al., 2010),
The amount of work - higher overall volume
and intensity of work have greater in uence
on the change in the level of testosterone,
Total duration of rest period between sets
and exercises - the impact of rest periods
on the recovery from the previous exercise
/ series: the level of lactic acid in blood,
the heart rate per minute and the impact on
global and local muscle fatigue (the level of
experienced physical stress).
Strength training
Strength as motor ability is de ned as the abil-
ity of man to overcome external resistance or to con-
front it with muscular effort or muscle force – mus-
cles, that is muscle groups generate a speci c force
which is in various motion actions manifested as
strength (Stefanović, Jakovljević, & Janković, 2010).
Since strength training is a complex concept, it
is necessary to decompose it to speci c parts, which
vary according to the components of the load and the
impact on mechanisms of expression of this ability
(neural / muscle), i.e., work methods.
According to Zatsiorsky & Kraemer (2009),
strength training can be classi ed according to the
method of achieving maximal voluntary muscular ef-
fort. There are three basic ways to achieve maximal
muscular effort:
1. By lifting maximal resistance - the method of
maximal effort,
2. By lifting submaximal resistance to failure;
when the muscles in the last repetition develop
maximal strength which is possible in a state
of fatigue, i.e. the method of repetitive effort,
3. By lifting (ejecting) resistance as fast as
possible - the method of dynamic effort.
In addition, the same authors suggest that sub-
maximal workload can also be lifted with medium
number of repetitions (not until failure) as an addi-
tional training method - the method of submaximal
effort.
The method of maximal effort is considered to
be the most effective for improving intra / intermus-
cular coordination and is commonly used to maxi-
mize the effects of strength training. The usage of this
method recruits the largest number of motor units
with best discharge frequency. Disadvantages of this
method are the risk of injury and worse conditions for
muscle hypertrophy (Zatsiorsky, & Kraemer, 2009).
This method is usually implemented through
a load of 1-3, or 3-5 repetitions per series to muscles
failure, with the load intensity of 90-100% of 1RM
(One Repetitium Maximum - the ability to overcome
the maximum external load under dynamic condi-
tions one time to muscle failure for a given load),
with 6-10 series and the duration of rest between se-
ries and exercises of 3-5 minutes (Stefanović, et al.,
2010; Zatsiorsky, & Kraemer, 2009).
Repetition method is considered to be the most
ef cient when it comes to the effect on muscle hy-
pertrophy (Ahtiainen et al., 2003; Baker et al., 2006;
Hakkinen et al., 1998; Jakob et al., 2010; McCaul-
ley et al., 2009; Stefanović, Jakovljević, & Janković,
2010; Zatsiorsky & Kraemer, 2009). This method is
not much different from the method of submaximal
effort, only in the number of repetitions to failure
compared to the submaximal. Stimulation of muscle
hypertrophy is similar in both methods. The differ-
ence is in the amount of mechanical work generated
on the training in favour of the rst. However, it can
be compensated by the duration of rest between se-
ries and exercises (Zatsiorsky, & Kraemer, 2009).
There are some variations in the approach
to load components in this method as well, but the
choice that McCaulley et al. (2009) used in their re-
search is the most widely used: The number of repeti-
tions to muscle failure in the series is 10, the intensity
of the load is 75%, the number of sets per exercise is
11, and the rest period between sets 90 seconds.
The method of dynamic effort – is most ef-
fective when aimed at improving the level of force
development in the muscle (Zatsiorsky, & Kraemer,
2009). This method is often implemented without
external loads, or with small external load (30% of
the weight of the practitioner) in jumping exercises,
but also with high load (70-90% 1RM) when used in
Clean and Jerk exercises .
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The effect of different methods of strength
training on testosterone levels in men
A small number of previous studies dealt
with comparing the effects of different methods of
strength training on the level of TE (McCaulley, et
al., 2009), although it is known that its presence in
the body is one of the most important conditions for
muscle growth and strength training has the biggest
in uence on its secretion (McCaulley, et al., 2009;
Linnamo, et al., 2005).
The study of McCaulley et al. (2009) led to
information about the different in uence of the three
methods of strength training (the method of maximal
effort - S, repetition method - H, the method of dy-
namic effort - P) on hormonal response to load, for:
TE, SHBG (sex hormone-binding globulin) and cor-
tisol. Blood samples were taken 20 minutes before
exercise, at rest (PRE), immediately after completion
of training (OP) and one hour after exercise (60P)
and 24 and 48 hours after exercise. The test was per-
formed on 10 young men, average age of 22 years (±
1.9 years) with previous experience in weight train-
ing of at least two years.
The effect of different methods was performed
using the exercise “parallel back squat”. Pre-test was
performed by using the same technique of lifting,
to the angle between the thigh and lower leg of 90°,
through 1RM, and by the test of maximal isometric
force in the squatting position, 24 hours and 48 hours
after completion of one-day training program. The
control group was introduced in order to better con-
trol the internal validity of the protocol. The total vol-
ume of work performed in the training, using all three
methods was equal (p = 0.99).
The method of maximal effort (S) was realized
in the following way: number of sets - 11, number of
repetitions per set - 3, duration of rest period between
sets - 5 min., intensity of load - 90% of 1RM. The fol-
lowing changes in hormonal response are shown on
the charts 2 and 3. It is shown that:
Acute hormonal response of the observed
hormones (for this study the data were taken
for TE and SHBG) on the training load of
this type exists but it is moderate,
Training with the maximal effort does not
seem essential for the provoking of high
hormonal response - low ef ciency on
muscle hypertrophy,
Long rest periods between series, in the
application of this method of training,
seem to reduce the amount of the hormonal
response to the load,
• The amount of lactic acid, which increased
after the application of these methods
seems to be in a certain relation to the
growth monitored hormonal responses (the
relationship is more signi cant for SHBG).
Chart 2. The effect of the S method on SHBG:
immediately after completion of training there was
an increase of 14.38% (taken and modi ed from
McCaulley, et. al., 2009, 699)
Chart 3. The effect of the S method on TE:
immediately after completion of training there was
an increase of 19.6% (taken and modi ed from
McCaulley, et. al., 2009, 699)
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Stanković A., et al., The Effect of Strength Training on the Testosterone... PHYSICAL CULTURE 2013; 67 (2): 157-166
The repetition method (H) was realized in the
following way: number of sets - 4, number of repeti-
tions per set - 10, duration of rest period between sets
– 90 sec., intensity of load - 75% of 1RM. The results
of the hormonal response are shown in charts 4 and
5. The application of this method, as it is assumed,
and in accordance with previous studies (Kraemer, et
al., 1987, 1990) gave the best results, considering the
levels of hormones. A signi cant increase in SHBG
and TE was found immediately after exercise. The
authors suggest that a signi cant increase in lactic
acid caused increased secretion of catecholamines
which are considered key mechanisms responsible
for the increased secretion of TE (McCaulley, et al.,
2009). Changing the ratio of the load components
caused the advantage in some areas – by small reduc-
tion in intensity (15% compared to the S method),
and a signi cant increase in the number of repetitions
(7 per series) and drastically shortening the rest pe-
riod (5 minutes to 90 minutes - 1.5 seconds), we get
a lot more physical work per unit time, which is more
stressful for the organism (greater heart beat and
higher level of lactates in blood).
Chart 4. The effect of the H method on SHBG:
immediately after completion of training there was
an increase of 29.05% (taken and modi ed from
McCaulley et. al., 2009, 699)
Chart 5. The effect of the H method on TE:
immediately after completion of training there was
an increase of 32.3% (taken and modi ed from
McCaulley, et. al., 2009, 699)
The differences in concentration of the ob-
served hormones, which are approximately one-third
compared to rest state, in favour of the H method,
show a signi cant effect of strength training on the
acute response of testosterone, regardless of the to-
tal volume of exercise and support the application of
the method of submaximal effort, when the goal is
to increase muscle mass, and therefore the strength
in men.
The method of dynamic effort (P) was realized
in the following way: exercise - squat jump; number
of sets - 8, number of repetitions per set - 6, dura-
tion of rest period between sets – 3 min. The follow-
ing changes in hormonal response are shown on the
charts 6 and 7. The application of the method of dy-
namic effort in strength training provokes a moderate
response of testosterone and SHBG, but this amount
is insuf cient to produce anabolic effects in muscle
tissue. What could justify the application of this
method when the desired effects are increasing mus-
cle mass is its dominant in uence on the inclusion of
the largest and most explosive motor units, which are
most vulnerable to hypertrophy, and then this train-
ing method can be used as an auxiliary method. (Mc-
Caulley, et al., 2009).
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Stanković A., et al., The Effect of Strength Training on the Testosterone... PHYSICAL CULTURE 2013; 67 (2): 157-166
Chart 6. The acute effect of the P training method
on the changes in the level of SHBG in blood; the
difference of 7.41% for SHBG testify that there
is no signi cant impact of using this method on
the response of the monitored hormone (taken and
modi ed from McCaulley, et al., 2009)
.
Chart 7. The acute effect of the P training method
on the changes in the level of TE in blood; the
difference of 10.7% for TE testify that there is
no signi cant impact of using this method on the
response of the monitored hormone (taken and
modi ed from McCaulley, et al., 2009)
The effect of different rest periods duration
in strength training on the levels
of testosterone
Many studies (Ahtiainen, et al, 2003; Ahtianen,
et al, 2005; McCaulley, et al, 2009; Stefanović,
Jakovljević, & Jankovič, 2010; Zaciorsky, & Krae-
mer, 2009; Linnamo, et al., 2005) favour the fact that
the training method with submaximal effort to muscle
failure, in which the load is overcome approximately
10 times to failure (8-12), the intensity of the load is
70-80% of 1RM, the number of series ranging from
6-8 (with great individual variation of the number of
series per training) and rest between series lasting be-
tween 60-120 seconds, has the greatest in uence on
the secretion of anabolic hormones, and therefore the
increase in muscle mass.
Since using H method of strength training
causes a signi cant fatigue because of muscle ex-
haustion due to peripheral factors (inability to follow
up on account of muscular components, leading to
protein catabolism, which in the recovery period is an
incentive for protein synthesis (Zaciorsky, & Krae-
mer, 2009)). The response on the tremendous physi-
cal stress of the body leads to increased secretion of
testosterone (and other anabolic hormones), which in
the recovery period signi cantly affects protein syn-
thesis in stimulated muscles (Stefanović, Jakovljević,
& Janković, 2010), with an adequate intake of amino
acids (Zasiorsky, & Kraemer, 2009).
According to McCaulley et al. (2009), this
dose-response” relationship was con rmed by a sig-
ni cant correlation (p <0.01) between the amount of
lactic acid in OP and the percentage difference in the
levels of SHBG, compared to rest state. Considering
the impact of all the methods on the level of lactic
acid in relation to rest state, we got the following
data:
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Chart 8. The effect of the three methods of strength
training (H, S and P) to the level of lactic acid in
blood; the measured values relate to the period
immediately before (PRE), immediately after (OP)
and 60 minutes after (60P) the end of exercise
with the particular method of training. (taken and
modi ed from McCaulley, et al., 2009, 699)
The obtained results suggest an important ef-
fect of the rest period as a factor that indirectly af-
fects the level of overall stress on the body (along
with the intensity of the load), because the same au-
thors state that the total magnitude of the load is less
important parameter for the monitored hormonal re-
sponse, compared with the intensity and duration of
the rest period.
According to Rahimi and colleagues (2010):
“...the rest periods between series of resistance train-
ing are of particular importance, and are de ned as
the period between the completion of one series of
training and beginning of the second, in which an in-
dividual reaches a state of physiological readiness of
the body to start a new activity. The length of rest
between series affects the metabolism, cardiovascu-
lar function, hormonal response, and the number of
repetitions in the next series.” (Rahimi, et al., 2010;
p. 1851)
Differences in the length of rest periods be-
tween series indirectly affect, based on the volume
of lactic acid and heart rate (Ahtiainen, et al. 2005;
McCaulley, et al., 2009; Rahimi, et al., 2010), and
the fatigue of the central nervous system and, “quick”
muscle bres (Stefanović, Jakovljević, & Janković,
2010; Zatsiorsky & Kraemer, 2009), announcing the
stress of the body, thus provoking stronger hormonal
response. In this respect, considering their duration
as a central detail of strength training, one can search
for the optimal duration of rest periods, while keep-
ing the number of repetitions from 8-12 to failure of
muscles, so that the external load varies from series
to series, depending on the ability of subjects (Ahti-
ainen et al., 2005; Rahimi et al., 2010).
When the rest periods between series are short
- 60 seconds, the concentration of TE in blood in the
rst few series is high, but because of the great fa-
tigue of the organism in the next series it is not pos-
sible to achieve high intensity exercise, so the total
volume of load lifted in training is reduced, with the
reduced ability to maintain intensity, leading to lower
hormonal response. Thus, the level of this hormone
in the blood immediately after exercise is lower than
immediately before the training activity, and 30 min-
utes after the end of training it is slightly above the
pre-exercise values, but still not in a signi cant in-
crease. Although very short breaks between series
in strength training do not support an increased se-
cretion of testosterone, they lead to a signi cant in-
crease in growth hormone levels in blood, and can
be applied for the purpose of muscles hypertrophy
(Rahimi, et al., 2010).
With rest periods of 90 seconds, a number of
previous studies (Ahtiainen, et al., 2005; Hakkinen,
et al., 1998; Hakkinen, et al., 2000; McCaulley, et
al., 2009; Rahimi, et al., 2010) led to the information
of higher concentration of TE in blood immediately
after, and certain time after the end of exercise, in
relation to the rest periods that last shorter or longer
than this period.
Rest periods of 120 seconds between series,
in overcoming resistance 10 times to failure, signi -
cantly affect the increase in demonstrated strength in
training (more work per unit of time) compared to
very short rest periods (up to 15%). Also, compared
with the rest periods of 90 seconds, the total amount
of work is somewhat smaller (Rahimi, et al., 2010).
The reactions of the endocrine system (especially
anabolic hormones) showed higher levels of the hor-
mone immediately after training, and 30 minutes af-
ter training, then in case of training with very short
breaks between series, but no signi cant difference in
relation to training in which the rest period between
series was 90 seconds.
In long rest periods - 3 to 5 minutes, there were
no signi cant differences in the level of TE compared
165
Stanković A., et al., The Effect of Strength Training on the Testosterone... PHYSICAL CULTURE 2013; 67 (2): 157-166
to the rest periods of 90 - 120 seconds. Some studies
(Kraemer, et al., 1999; Rahimi, et al., 2010), found
the differences in the level of TE after comparing rest
periods of 60 seconds and 3 minutes, in favour of
short ones, which supports the use of series of short
duration with the aim of anabolic processes in mus-
cles. Long rest periods may have more signi cant
impact on increasing the intensity of a series, which
would have a positive impact primarily on the CNS.
CONCLUSION
Undoubtedly, anabolic hormones have the
main role in the grounds of anabolic processes in
muscle. One of the most important hormones is tes-
tosterone. Also, it is well known that the strength
training affects the increased secretion of testoster-
one. Considering analyzed researches, following
conclusions may be drawn:
Systematic, organized physical training
increases testosterone levels in blood, and
the most effective is strength training.
High-intensity exercise (70-80%), which is
accompanied by fatigue and exhaustion of
muscles, on peripheral (primarily) and the
central level, leads to a signi cant increase in
the level of TE. Duration of the rest periods,
which is directly related to the recovery
and muscle exhaustion, must be optimal.
The highest level of hormones is recorded
when the rest periods are about 90 seconds,
or a combination of short and moderate rest
periods (60 and 90 seconds);
Different methods of strength training make
a different impact on the level of TE in men,
and among them the method of submaximal
effort to failure manifests the strongest
effects, and it is reasonably characterized as
the method for muscle hypertrophy;
After strength training, the level of TE stays
increased for the next 30 minutes (Jakob,
et al., 2010, McCaulley, et al., 2009). After
this period, the value of hormones decreases
to the values that are equal to or slightly
lower than at rest before training. The period
immediately after training is particularly
useful for improving the anabolic effects of
TE and through consumption of adequate
nutrients (proteins and amino acids
through food or supplements) (Stefanović,
Jakovljević, & Janković, 2010; Zatsiorsky,
& Kraemer, 2009; Đorđević-Nikić, 2004).
• The greatest in uence of H method on the
level of TE in men is probably related to
the signi cantly increased amount of lactic
acid and catecholamines (McCaulley et al.,
2009), however, further studies are needed
to con rm this statement.
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