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Factors Modulating Post-Activation Potentiation and its Effect on Performance of Subsequent Explosive Activities

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Post-activation potentiation (PAP) is induced by a voluntary conditioning contraction (CC), performed typically at a maximal or near-maximal intensity, and has consistently been shown to increase both peak force and rate of force development during subsequent twitch contractions. The proposed mechanisms underlying PAP are associated with phosphorylation of myosin regulatory light chains, increased recruitment of higher order motor units, and a possible change in pennation angle. If PAP could be induced by a CC in humans, and utilized during a subsequent explosive activity (e.g. jump or sprint), it could potentially enhance mechanical power and thus performance and/or the training stimulus of that activity. However, the CC might also induce fatigue, and it is the balance between PAP and fatigue that will determine the net effect on performance of a subsequent explosive activity. The PAP-fatigue relationship is affected by several variables including CC volume and intensity, recovery period following the CC, type of CC, type of subsequent activity, and subject characteristics. These variables have not been standardized across past research, and as a result, evidence of the effects of CC on performance of subsequent explosive activities is equivocal. In order to better inform and direct future research on this topic, this article will highlight and discuss the key variables that may be responsible for the contrasting results observed in the current literature. Future research should aim to better understand the effect of different conditions on the interaction between PAP and fatigue, with an aim of establishing the specific application (if any) of PAP to sport.
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Factors Modulating Post-Activation
Potentiation and its Effect on Performance
of Subsequent Explosive Activities
Neale Anthony Tillin
1,2
and David Bishop
1,3
1 School of Human Movement and Exercise Science, the University of Western Australia, Crawley,
Western Australia, Australia
2 School of Sport and Exercise Science, Loughborough University, Loughborough, Leicestershire, UK
3 Facolta
`di Scienze Motorie, Universita
`degli Studi di Verona, Verona, Italy
Contents
Abstract................................................................................. 147
1. Post-Activation Potentiation (PAP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
2. Mechanisms of PAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
2.1 Phosphorylation of Regulatory Light Chains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
2.2 Increased Recruitment of Higher Order Motor Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
2.3 Changes in Pennation Angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
3. PAP and Mechanical Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
4. Acute Effects of PAP on Subsequent Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
4.1 PAP versus Fatigue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
4.2 Conditioning Contraction Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
4.3 Conditioning Contraction Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
4.4. Subject Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
4.4.1 Muscular Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
4.4.2 Fibre-Type Distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
4.4.3 Training Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
4.4.4 Power-Strength Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
4.5 Type of Subsequent Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
5. Conclusion ........................................................................... 163
Abstract Post-activation potentiation (PAP) is induced by a voluntary conditioning
contraction (CC), performed typically at a maximal or near-maximal in-
tensity, and has consistently been shown to increase both peak force and rate
of force development during subsequent twitch contractions. The proposed
mechanisms underlying PAP are associated with phosphorylation of myosin
regulatory light chains, increased recruitment of higher order motor units,
and a possible change in pennation angle. If PAP could be induced by a CC in
humans, and utilized during a subsequent explosive activity (e.g. jump or
sprint), it could potentially enhance mechanical power and thus performance
and/or the training stimulus of that activity. However, the CC might also
induce fatigue, and it is the balance between PAP and fatigue that will
REVIEW ARTICLE Sports Med 2009; 39 (2): 147-166
0112-1642/09/0002-0147/$49.95/0
ª2009 Adis Data Information BV. All rights reserved.
determine the net effect on performance of a subsequent explosive activity.
The PAP-fatigue relationship is affected by several variables including CC
volume and intensity, recovery period following the CC, type of CC, type of
subsequent activity, and subject characteristics. These variables have not
been standardized across past research, and as a result, evidence of the effects
of CC on performance of subsequent explosive activities is equivocal. In or-
der to better inform and direct future research on this topic, this article will
highlight and discuss the key variables that may be responsible for the con-
trasting results observed in the current literature. Future research should aim
to better understand the effect of different conditions on the interaction be-
tween PAP and fatigue, with an aim of establishing the specific application
(if any) of PAP to sport.
1. Post-Activation Potentiation (PAP)
Post-activation potentiation (PAP) or post-
tetanic potentiation (PTP) refers to the phenomena
by which muscular performance characteristics
are acutely enhanced as a result of their contrac-
tile history.
[1,2]
The difference between PAP and
PTP is defined by the nature of the conditioning
contraction. PTP is induced by an involuntary
tetanic contraction, and PAP is induced by a
voluntary contraction
[3,4]
performed typically
at a maximal or near-maximal intensity. For
simplicity, this article refers to all potentiation
responses as PAP, and refers to the activity res-
ponsible for inducing PAP as a conditioning
contraction (CC).
The presence of PAP in skeletal muscle has
been recorded by many studies in both mammals
and humans,
[5-17]
prompting a discussion
amongst recent review articles over the mechan-
isms of PAP
[1,3]
and its application to sports
performance.
[1-3,18]
If effectively utilized, PAP
could be implemented into a power-training
routine to enhance the training stimulus of a
plyometric exercise.
[2,18]
Inducing PAP prior to
competition might also prove better than con-
ventional warm-up techniques at enhancing per-
formance of explosive sports activities such as
jumping, throwing and sprinting.
[10]
Because of
inconsistencies within the literature, research re-
mains inconclusive on the possible benefits of
PAP to explosive sports performance and/or
training. The inconsistencies of past research
are most likely due to the complex interaction
of factors that influence acute performance fol-
lowing a CC.
[1-3,18]
This review discusses these
confounding factors in greater detail, with the
purpose of helping to inform and direct future
research efforts towards establishing the appli-
cation (if any) of PAP to performance/training of
explosive sports activities.
2. Mechanisms of PAP
It has been proposed that two principal me-
chanisms are responsible for PAP. One is the
phosphorylation of myosin regulatory light
chains (RLC),
[1,3,4,11,12,19,20]
and the other is an
increase in the recruitment of higher order motor
units.
[1,10,20]
There is also evidence to suggest that
changes in pennation angle may contribute to
PAP, and this possible mechanism is briefly in-
troduced in this article.
2.1 Phosphorylation of Regulatory Light
Chains
A myosin molecule is a hexamer composed of
two heavy chains (figure 1).
[21]
The amino-
termini of each heavy chain, classified as the
myosin head, contain two RLCs,
[9,21]
and each
RLC has a specific binding site for incorporation
of a phosphate molecule. RLC phosphorylation
is catalyzed by the enzyme myosin light chain ki-
nase, which is activated when Ca
2+
molecules,
released from the sarcoplasmic reticulum dur-
ing muscular contraction, bind to the calcium
regulatory protein calmodulin.
[1,5,13,21]
RLC
148 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
phosphorylation is thought to potentiate sub-
sequent contractions by altering the structure
of the myosin head and moving it away from
its thick filament backbone.
[1,21]
It has also
been shown that RLC phosphorylation renders
the actin-myosin interaction more sensitive to
myoplasmic Ca
2+
.
[13]
Consequently, RLC phos-
phorylation has its greatest effect at relatively
low concentrations of Ca
2+
, as is the case
during twitch or low-frequency tetanic
contractions.
[1,3,4,22,23]
An acute increase in RLC phosphorylation,
and a parallel potentiation of twitch tension fol-
lowing tetanic stimulation of specific efferent
neural fibres, has been reported by many studies
in skinned animal models
[5,7,9,13]
(figure 2). Re-
latively few studies have attempted to measure a
similar response in human skeletal muscle. Stuart
et al.
[8]
recorded a significantly elevated phos-
phate content of RLC in the vastus lateralis
muscle (p <0.01), and a significant potentiation of
twitch tension of the knee extensors, following
one 10-second isometric maximal voluntary con-
traction (MVC; p <0.05). There was also a posi-
tive but non-significant correlation between the
extent of twitch potentiation and the amount of
phosphate incorporated into individual RLC
units, and between potentiation and percentage
of type II muscle fibres (p >0.05).
Smith and Fry
[24]
also sampled muscle biopsies
at the vastus lateralis, and analysed dynamic
leg extension performance before and 7 minutes
after a 10-second isometric MVC. The authors
reported no significant change in RLC phos-
phorylation or leg extension performance for the
entire sample (p >0.05). The subjects were then
split into those who responded to the MVC with a
significant increase, and those who responded
with a significant decrease in RLC phosphoryla-
tion (p <0.05), but no significant differences in leg
extension performance were found between the
groups (p >0.05). Methodological factors and
differences in fibre-type distribution between an-
imals and humans may explain why an observed
increase in RLC phosphorylation following a
CC is not as consistent in humans as animals.
Nevertheless, the significance of RLC phosphory-
lation in human skeletal muscle remains unclear,
and Stuart et al.
[8]
suggest that other factors may
provide the major contribution to PAP.
2.2 Increased Recruitment of Higher Order
Motor Units
Research on animals has shown that an in-
duced tetanic isometric contraction (caused by
stimulating specific afferent neural fibres, which
in turn activate adjacent a-motoneurons via an
afferent neural volley; figure 3) elevates the
transmittance of excitation potentials across
synaptic junctions at the spinal cord. This ac-
commodating state can last for several minutes
following the tetanic contraction,
[10]
and as a
Myosin heavy chains
Actin binding site
RLC-2
ATP binding site
Fig. 1. One myosin molecule. Each myosin molecule is composed
of two myosin heavy chains. Regulatory light chain (RLC)-2 re-
presents a pair of RLCs positioned at the neck of a myosin head.
Each RLC can incorporate a phosphate molecule, altering the
structure of the myosin head. At each myosin head there is an actin
and adenosine triphosphate (ATP) binding site.
0
0.2
0.4
0.6
0 10 20 70 130 190 250
Time (sec)
mol phosphate/mol RLC
1.0
1.2
1.4
1.6
1.8
2.0
Twitch peak torque
potentiation (post/pre)
Phosphate content
Twitch potentiation
Tetanic
contraction
Fig. 2. The time-course of regulatory light chain (RLC) phosphor-
ylation and twitch peak torque potentiation, following a 10-second
pre-conditioning tetanus. Potentiation is represented as a ratio of the
post-maximal voluntary contraction (MVC) peak torque value to the
pre-MVC peak torque value (post/pre). These results indicate
a possible relationship between RLC phosphorylation and twitch
tension potentiation (reproduced from Moore and Stull,
[7]
with
permission).
Post-Activation Potentiation, Theory and Application 149
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
result there is an increase in post-synaptic po-
tentials, for the same pre-synaptic potential dur-
ing subsequent activity.
[25,26]
Luscher et al.
[26]
proposed a possible mechan-
ism underlying the elevated transmittance of ac-
tion potentials across synaptic junctions at the
spinal cord. For each parent neural fibre (i.e. Ia
fibre) numerous synapses project onto each
a-motoneuron. Activation of an a-motoneuron
works in an all-or-none fashion, whereby pre-
synaptic transmitter release must coincide with
the post-synaptic receptor sensibility. Transmit-
ter failure at various synaptic junctions is a
common occurrence during normal reflex or vo-
luntary responses, due to an autonomously pro-
tected activation reserve.
[26,27]
An induced tetanic
contraction is suggested to decrease the trans-
mitter failure during subsequent activity, via one
or a combination of several possible responses.
These include an increase in the quantity of neuro-
transmitter released, an increase in the efficacy
of the neurotransmitter, or a reduction in axonal
branch-point failure along the afferent neural
fibres.
[28]
Hirst et al.
[27]
provided evidence to support a
decreased monosynaptic transmitter failure dur-
ing subsequent activity. They stimulated cat af-
ferent neural fibres, and observed a 54%increase
in excitatory post-synaptic potentials (EPSPs)
for the same pre-synaptic stimulus, following a
20-second tetanic isometric contraction. Larger
EPSPs represent greater depolarization of the
a-motoneuron membrane, which would increase
the likelihood of that a-motoneuron reaching the
threshold required to initiate an action potential,
and subsequently contract the muscle fibres of
that motor unit.
Luscher et al.
[26]
also measured EPSPs at cat
a-motoneurons, in response to electrical stimu-
lation. They found a significant positive correla-
tion between motoneuron input resistances and
EPSP amplitude, for a standard stimulus (r =0.77;
p<0.01; figure 4a), where input resistance was
associated with the size of the a-motoneuron
(with a smaller input resistance representing a
larger motoneuron). This suggests that mono-
synaptic transmitter failure is greater at larger
motoneurons (those responsible for activation
of higher order or fast-twitch motor units). Con-
versely, when a twitch was stimulated following a
10-second tetanic contraction, Luscher et al.
[26]
found a significant negative correlation between
EPSP potentiation and motoneuron input
resistance (r =-0.92; p <0.001; figure 4b). This
demonstrates that a tetanic contraction decreased
the transmitter failure occurring primarily
at larger motoneurons, which resulted in a
considerable PAP effect at these motoneurons.
If a CC could induce an increase in higher order
motoneuron recruitment in humans, this effect
might theoretically increase fast-twitch fibre
contribution to muscular contraction, and there-
fore enhance performance of a subsequent ex-
plosive activity.
[10]
Previous studies have measured the H-wave in
humans to investigate the effects of a CC on
motoneuron recruitment.
[10,29]
The H-wave
(H-reflex) is recorded at the muscle fibres using
electromyography, and is the result of an afferent
neural volley in response to single-pulse sub-
maximal stimulation of the relevant nerve bundle
(see figure 5 for more detail). An increase in
Spinal cord
Alpha motoneuron
to synergist
Alpha motoneuron
to antagonist
Antagonist
muscle
Synergist
muscle
Agonist muscle
Muscle spindle
Afferent neural
fibre (la)
Alpha motoneuron
to agonist
Alpha motoneuron
synapse
Fig. 3. The neural volleys of a Ia afferent fibre. An action potential
generated at the Ia afferent neural fibre travels to the spinal cord,
where it is transferred to the adjacent a-motoneuron of the agonist
muscle. The action potential then travels directly to the agonist
muscle, initiating the processes of muscular contraction.
150 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
H-wave following a CC may therefore represent
a decrease in transmitter failure at synaptic
junctions, and a subsequent increase in higher
order motoneuron recruitment. Gullich and
Schmidtbleicher
[10]
stimulated the tibial nerve
and measured changes in H-wave amplitude at
the gastrocnemius before and after five 5-second
isometric MVCs of the plantarflexors. They re-
ported a depression in H-wave amplitude 1 minute
after the MVCs (-24%;p<0.05), but a potentia-
tion of H-wave amplitude 513 minutes after the
MVCs (+20%;p<0.01). The H-wave, however,
was not normalized to maximal M-wave (M-wave
is the electrical counterpart of the activation of all
motor units in the pool
[30]
). Therefore, other
factors not relating to central activation, such as
increased activity of the Na
+
-K
+
pump at the
muscle fibres,
[12,14,28]
may be responsible for the
results that Gullich and Schmidtbleicher
[10]
ob-
served. Nevertheless, other studies have reported
a potentiation in normalized H-wave amplitude
310 minutes post eight sets of dynamic MVCs,
[29]
and 511 minutes post a 10-second isometric
MVC.
[31]
Collectively, these results suggest that
PAP increases H-wave amplitude in humans
(albeit after sufficient recovery), and this may be
the result of increased higher order motoneuron
recruitment at the spinal cord. Whether or not a
CC can enhance motoneuron recruitment and
performance during a subsequent voluntary con-
traction is yet to be determined.
The effect of isometric MVCs on subsequent
voluntary motoneuron recruitment has been as-
sessed using the interpolated twitch technique
(ITT). The ITT can facilitate measurement of
Spinal cord
Electrical
stimulation
1st response to the electrical
stimulation (M-wave)
2nd response to the electrical
stimulation (H-wave)
Afferent neural fibres
Efferent neural fibres
Muscle
Fig. 5. Elicitation of an M- and H-wave. Stimulation of a nerve with
a single submaximal electrical impulse evokes two electrical re-
sponses at the muscle. The first response (M-wave) is the result of
an action potential travelling directly down the efferent neural fibres
(a-motoneurons). The second response (H-wave) is the result of an
action potential travelling along the afferent neural fibres to the spinal
cord, where it is transmitted to adjacent efferent neural fibres, and
down to the muscle.
0
6
12
012345
Input resistance (MΩ)
% Increase in EPSP amplitude
Larger motoneurons Smaller motoneurons
012345
Input resistance (MΩ)
Larger motoneurons Smaller motoneurons
a
0
70
140
% Increase in EPSP amplitude
b
Fig. 4. (a) The relationship between input resistances of cat moto-
neurons, and amplitude of their excitatory post-synaptic potentials
(EPSP) in response to twitch stimulation of the adjacent afferent
neural fibres. (b) The relationship between input resistances of cat
motoneurons, and the percentage increase (potentiation) in EPSP
amplitude, in response to a twitch stimulation of the adjacent afferent
neural fibres, following a 10-second tetanus. Although EPSP ampli-
tude is greatest at smaller motoneurons (those with greater input
resistances), representing greater transmitter failure at larger moto-
neurons (a), potentiation is greatest at larger motoneurons (those
with smaller input resistances), demonstrating a decreased trans-
mitter failure at these motoneurons (b).
[22]
Post-Activation Potentiation, Theory and Application 151
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
motoneuron activation
[32]
by comparing maximal
twitch amplitude at rest with that evoked when
superimposed upon an MVC (for more detail of
the ITT please refer to Folland and Williams
[32]
and Shield and Zhou
[33]
). Using the ITT, Behm
et al.
[34]
reported a decrease in voluntary muscle
activation following 10-second MVCs (p <0.05).
These results are in contrast to the proposed
mechanism of PAP, but may demonstrate the
dominance of central fatigue observed through-
out this study (see section 4.2). Nevertheless, fu-
ture research should consider using the ITT to
investigate the mechanisms of PAP and their
contribution to subsequent performance.
2.3 Changes in Pennation Angle
The pennation angle of a muscle (the angle
formed by the fascicles and the inner apo-
neurosis) reflects the orientation of muscle fibres
in relation to connective tissue/tendon.
[35]
The
pennation angle will therefore affect force trans-
mission to the tendons and bones.
[35,36]
The sum
of the forces of all individual fibres being applied
to the relevant tendon during muscular contrac-
tion is reduced by a factor of cosy(where y=
pennation angle).
[36]
Consequently, smaller pen-
nation angles have a mechanical advantage with
respect to force transmission to the tendon.
[35,36]
Using ultrasonography, Mahlfeld et al.
[37]
mea-
sured resting pennation angle of the vastus la-
teralis before and after three 3-second isometric
MVCs. Pennation angle immediately after the
MVCs (15.7) had not changed from pre-MVC
values (16.2); however, 36 minutes after the
MVCs, the pennation angle had significantly de-
creased (14.4;p<0.05). This change would only
be equivalent to a 0.9%increase in force trans-
mission to the tendons, but it is possible that this
effect may contribute to PAP. Conditioning
contractions, however, are also likely to increase
connective tissue/tendon compliance,
[38]
and this
may counter any increase in force transmission
caused by a decrease in pennation angle. Never-
theless, the possibility that changes in muscle
architecture contribute to PAP warrants further
investigation.
3. PAP and Mechanical Power
Performance of explosive sports activities is
largely determined by mechanical power.
[10,39-43]
Mechanical power can be defined as the rate
at which force (F) is developed over a range
of motion (d), in a specific period of time (t)
[P =F·d/t], or as force multiplied by velocity (v)
[P =F·v].
[39,40,43]
Accordingly, increasing the
level of force at a given velocity will increase
mechanical power, and this has been demon-
strated in skinned rat/mouse models.
[16,17,22]
Similarly, decreasing the time over which a speci-
fic force is applied, without altering the distance
over which that force is applied, will increase
velocity, and consequently mechanical power.
PAP could, therefore, increase force and/or
velocity of the muscle contraction, which would
enhance mechanical power and the associated
sport performance.
To date, there is little evidence that PAP can
increase maximal force. This is consistent with
the observation that increased sensitivity of the
myosin-actin interaction to Ca
2+
has little or no
effect in conditions of Ca
2+
saturation, such as
those caused by higher stimulation frequencies
(>20 Hz for tetanic, or 200 Hz for voluntary
contractions).
[9,22]
Stuart et al.
[8]
also found that a
10-second isometric MVC of the knee extensors
was unable to increase maximum unloaded velo-
city of subsequent dynamic contractions. Al-
though PAP appears to have little effect at the
extremes of the force-velocity curve (figure 6), it
has been shown to increase rate of force devel-
opment (RFD) of tetanic contractions elicited at
any frequency.
[9]
An increase in RFD causes a
less concave force-velocity curve (figure 6), re-
sulting in a greater velocity for a specific force, or
vice versa.
[3,44]
Therefore, PAP may enhance the
performance of activities that require sub-
maximal force and velocity production.
[3,11]
Typically, athletes participating in explosive
sports activities will not produce maximal force
because the mass they are attempting to move is
often relatively small (e.g. body mass), but they
must still overcome that mass so will not achieve
maximal unloaded velocity either.
[40]
Conse-
quently, PAP could benefit the performance
152 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
of explosive sports activities by increasing RFD
and thus mechanical power.
[3,11]
There is consensus over the existence of PAP,
but if it is to be effectively utilized in performance
and/or training, research must first confirm that
PAP can be induced by an isometric or dynamic
voluntary contraction, and then show that its
benefits can be realized during a subsequent ex-
plosive sports activity. Unfortunately, measure-
ment of both PAP and its effect on performance
of a subsequent explosive sports activity in
humans is inconsistent. Furthermore, little is
known about the degree to which the proposed
mechanisms underlying PAP may play a role in
inducing an elevated neuromuscular response.
4. Acute Effects of PAP on Subsequent
Activity
The performance of explosive sports activities
relies predominantly on the activation of large
muscle groups (e.g. ankle, knee, hip and/or arm
and ab/adductors). Therefore, studies assessing
the effect of PAP on smaller muscle groups have
been excluded from the following sections. Fur-
thermore, it has been shown
[45,46]
and is widely
accepted that contractions of maximal or near
maximal intensity (>80%of dynamic or iso-
metric MVC) optimize PAP.
[4]
Therefore, studies
assessing the effects of low-intensity contractions
on subsequent performance have also been
excluded from the following sections. Table I
summarizes the studies that have investigated
the effects of a voluntary CC on subsequent
voluntary activity in humans.
In agreement with the results produced by
studies conducted on skinned mammalian
models, research has consistently reported an
enhanced twitch response following a CC in
humans. Hamada et al.
[12]
elicited a twitch reflex
at the femoral nerve prior to, 5 seconds after, and
then every 30 seconds for 300 seconds after a
10-second isometric MVC of the knee extensors.
Twitch P
t
(peak torque) was significantly in-
creased 5 seconds after the isometric MVC
(+71%;p<0.01); however, by 30 and 60 seconds
after the isometric MVC, twitch P
t
potentiation
had decreased to +44%and +31%, respectively
(p <0.01). Potentiation continued to decrease at a
more gradual rate for the remainder of the re-
covery period, but was still +12%300 seconds
after the isometric MVC (p <0.01). Similar find-
ings have been reported in other studies,
[6,11,59]
demonstrating that peak PAP is achieved im-
mediately after a CC, but instantly begins to de-
crease. The decrease in PAP is rapid for the first
minute, but then becomes more gradual resem-
bling an exponential function (figure 7).
Although an isometric MVC has been found
to consistently enhance subsequent twitch ten-
sion, evidence to show that PAP can be effectively
utilized to enhance the performance of sub-
sequent voluntary contractions is not as convin-
cing. Gossen and Sale
[11]
assessed movement
mechanics of both twitch and submaximal vo-
luntary contractions following a 10-second iso-
metric MVC. While the MVC enhanced twitch P
t
(p <0.01), knee extension peak velocity follow-
ing the MVC was significantly lower than knee
extension peak velocity executed in a control
condition (326.7 vs 341.6/sec; p <0.03). These
results suggest that although the 10-second MVC
induced PAP, it also induced fatigue, and that
the latter was more dominant during the volun-
tary contractions. It has been proposed, there-
fore, that it is the balance between PAP and
fatigue that determines whether the subsequent
0
100
0 100
Percentage of maximum force
Percentage of maximum unloaded velocity
Increased RFD
Fig. 6. The relationship between force and velocity. The dotted line
represents a less concave force-velocity curve due to an increase
in rate of force development (RFD) [reproduced from Sale,
[3]
with
permission].
Post-Activation Potentiation, Theory and Application 153
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
Table I. A summary of studies that have investigated the effects of a pre-conditioning contraction on a subsequent activity
Study Subjects Pre-conditioning contraction
(condition)
Volume Rest interval Performance test Performance changes
Batista et al.
[47]
10 UT M Isovelocity MVC, knee
extension
10 (30 sec RI) 4 min
6min
8min
10 min
Isovelocity knee
extensions at all rest
intervals
6%P
t
*at each rest
interval
Behm et al.
[34]
9 UT M Isometric MVC, knee
extension
1·10 sec
2·10 sec
(1 min RI)
3·10 sec
(1 min RI)
1, 5, 10, 15 min
for all volumes
Isometric MVC knee
extensions at all rest
intervals
2
2
10-min post: 8.9%P
f
*
15-min post: 7.5%P
f
*
Chatzopoulos et al.
[48]
15 UT M Back-squat 10 ·1rep90%
1 RM (3 min RI)
3min
5min
30-m sprint
30-m sprint
2
3%010-m sprint time*,
2%030-m sprint time*
Chiu et al.
[20]
24; 7 RT, 17 UT
(12 M, 12 F)
Back-squat 90%1RM·5 (2 min RI) 5 min
6min
7min
5min
6min
7min
CMJ: 30%1RM
50%1RM 70%1RM
SJ:
30%1RM
50%1RM
70%1RM
RT: 13%, UT: 14%.
RT >UT*
RT: 13%, UT: 14%.
RT >UT*
RT: 13%, UT: 14%.
RT =UT
RT: 13%, UT: 14%.
RT >UT*
RT: 13%, UT: 14%.
RT =UT
RT: 13%, UT: 14%.
RT =UT
Ebben et al.
[49]
10 RT M Dynamic bench-press 35RM 05 sec Medicine ball BPT 2GRF
French et al.
[50]
14 RT (10 M,
4F)
Isometric MVC, knee
extension
3 sec ·3 (3 min RI)
5 sec ·3 (3 min RI)
05 sec CMJ
DJ
5 sec C-sprint
Isovelocity KE CMJ DJ
5 sec C-sprint isovelocity
KE
2
5.0%*(4.9%GRF*)
26.1%P
t
*2
2
2
3.0%P
t
*
Gilbert et al.
[51]
7 RT M Back-squat 100%1RM·5 (5 min RI) 2 min
10 min
15 min
20 min
30 min
Isometric MVC at all rest
intervals
5.8%RFD
5.8%RFD
10.0%RFD
13.0%RFD*
2
Gossen and Sale
[11]
10 UT (6 M,
4F)
Isometric MVC, knee
extension
10 sec 20 sec
40 sec
Dynamic KE
Dynamic KE
2
2
Continued next page
154 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
Table I. Contd
Study Subjects Pre-conditioning contraction
(condition)
Volume Rest interval Performance test Performance changes
Gourgoulis et al.
[15]
20 M (11 RT,
9 UT)
Back-squats 2 reps of: 20%,40%,
60%,80%, and 90%1RM
(5 min RI)
05 sec CMJ 2.4%RT +UT*
RT: 4.0%
UT: 0.4%
Gullich and
Schmidtbleicher
[10]
Study 1: 34 RT
(22 M, 12 F)
Study 2: 8 RT
Isometric MVC, leg press
Isometric MVC, plantarflexion
3·5 sec (5 min RI)
5·5 (1 min RI)
3 min, then every
20 sec. 8 jumps
measured
1 min, then every 2nd
min for 13 min
CMJ and DJ
Isometric MVC,
plantarflexion
3.3%CMJ*.DJ*
13%RFD 1 min post*.
RFD 3 min post. 19%
RFD 513 min post*
Hanson et al.
[52]
30 UT (24 M,
6F)
Back-squats 4 reps of 80%1RM 5 min CMJ 2
Jenson and Ebben
[53]
21 RT (11 M,
10 F)
Back-squats 5RM 10 sec
1min
2min
3min
4min
CMJ
CMJ
CMJ
CMJ
CMJ
413%*
2
2
2
2
Kilduff et al.
[54]
23 RT M Dynamic back-squats
Dynamic bench-press
1·3RM
1·3RM
15 sec
4min
8min
12 min
16 min
20 min
15 sec
4min
8min
12 min
16 min
20 min
CMJ
CMJ
CMJ
CMJ
CMJ
CMJ
Barbell BPT
Barbell BPT
Barbell BPT
Barbell BPT
Barbell BPT
Barbell BPT
2.9%P
p
*
2
6.8%P
p
*
8.0%P
p
*
2
2
4.7%P
p
*
2
2.8%P
p
*
5.3%P
p
*
0.8%P
p
*
Magnus et al.
[55]
10 UT M Back-squats 90%1RM 3 min CMJ 2
Rahimi
[45]
12 RT M Back-squats 2·4 reps of 80%
1 RM (2 min RI)
4 min 40-m sprint 3%040 m sprint time*
Rixon et al.
[56]
30 UT (15 M,
15 F)
Dynamic back-squats
Isometric MVC back-squats
3RM
3·3 sec (2 min RI)
3min
3min
CMJ
CMJ
2.9%JH *,8.7%P
p
*
2JH, 8.0%P
p
*
Robbins and
Docherty
[57]
16 UT M Isometric MVC back-squats 3 ·7 sec (8 min
between each set)
4 min CMJ after each set of
isometric MVC
2
Young et al.
[58]
10 UT M Back-squats 5RM 4 min LCMJ 2.8%*
BPT =bench press throw; CMJ =counter movement jump; C-sprint =cycle sprint; DJ =drop jump; F=females; GRF =ground reaction force; JH =jump height; KE =knee extensions;
LCMJ =loaded counter movement jump; M=males; MVC =maximum voluntary contractions; P
f
=peak force; P
p
=peak power; P
t
=peak torque; RFD =rate of force development;
RI =rest interval; RM =repetition maximum; RT =resistance/athletically trained; SJ =squat jump; UT =un/recreationally trained; indicates increase; indicates decrease;
2indicates no differences; *p<0.05.
Post-Activation Potentiation, Theory and Application 155
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
contractile response is enhanced, diminished or
unchanged.
[2]
4.1 PAP versus Fatigue
The balance between PAP and fatigue and its
effect on subsequent explosive contractions has
been observed by several studies. Immediately
after a CC, Gullich and Schmidtbleicher
[10]
and
Gilbert et al.
[51]
reported a decrease or no change
in isometric RFD, but following a sufficient re-
covery (4.512.5 minutes
[10]
and 15 minutes
[51]
)
isometric RFD was significantly increased
(+1024%;p<0.05). The same pattern of no
change/decrease followed by an increase in
counter-movement jump (CMJ) peak power
(+78%;p<0.05)
[54]
and 30-m sprint perfor-
mance (23%;p<0.05)
[48]
812 minutes and
5 minutes, respectively, following a CC have also
been reported. Collectively, these results suggest
that although twitch studies have reported max-
imal PAP immediately after a CC (described in
section 4; see figure 7), fatigue is also present
early on. Furthermore, fatigue seems more
dominant in the early stages of recovery and,
consequently, performance of subsequent volun-
tary activity is diminished or unchanged. How-
ever, fatigue subsides at a faster rate than PAP,
and potentiation of performance can be realized
at some point during the recovery period. Figure 8
illustrates the PAP-fatigue relationship and
shows how the net affect on subsequent volun-
tary contractions might be very different to the
effect of a MVC on subsequent twitch contrac-
tions (represented in figure 7).
There is also evidence that a recovery period
may not be required to benefit from PAP, or that
even with a recovery period performance of
a subsequent voluntary activity may remain
unchanged/diminished. French et al.
[50]
did not
utilize a recovery period, but still observed a sig-
nificant increase in both drop jump (DJ) height
and isovelocity knee extension P
t
(+5.0%and
+6.1%, respectively; p <0.05), immediately after
three sets of 3-second isometric MVC knee ex-
tensions. Likewise, Gourgoulis et al.,
[15]
reported
a significant increase in CMJ height (+2.4%;
p<0.05) immediately after two back-squats per-
formed with 90%of one repetition maximum
(1RM). Conversely, Chiu et al.
[20]
were unable to
detect a significant improvement in peak power
of three CMJs or three loaded squat jumps (SJ)
[p >0.05], even though they were performed after
a recovery period of 5, 6 and 7 minutes, respec-
tively, following five sets of one back-squat, with
90%1RM. The three CMJs (5, 6 and 7 minutes
post-activation), were executed with different
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
0 30 60 90 120 150 180 210 240 270 300
Time immediately after a 10-sec isometric MVC (sec)
Twitch peak torque potentiation (post/pre)
Fig. 7. The time-course of twitch peak torque potentiation im-
mediately after a 10-second isometric maximal voluntary contraction
(MVC).
[12]
Potentiation is represented as a ratio of the post-MVC
peak torque value to the pre-MVC peak torque value (post/pre).
0
1
2
Potentiation (post/pre)
Window
1 Window 2
Condition volume Recovery time
Peak PAP
Peak fatigue
Performance
Fig. 8. A model of the hypothetical relationship between post-
activation potentiation (PAP) and fatigue following a pre-conditioning
contraction protocol (condition).
[3]
When the condition volume is low,
PAP is more dominant than fatigue, and a potentiation in subsequent
explosive performance (post/pre) can be realized immediately (win-
dow 1). As the condition volume increases, fatigue becomes domi-
nant, negatively affecting subsequent performance. Following the
condition, fatigue dissipates at a faster rate than PAP, and a po-
tentiation of subsequent explosive performance can be realized at
some point during the recovery period (window 2).
156 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
loads (30%,50%and 70%of 1RM, respectively),
which may have affected peak power output, and
makes it difficult to compare differences in perfor-
mance over the time-course. However, these re-
sults were supported by those of Mangus et al.,
[55]
who reported no change in CMJ height 3 minutes
after one back-squat with 90%1RM. Finally,
Behm et al.
[34]
observed no change in isometric
peak force immediately after three 10-second MVCs;
however, after a 10- to 15-minute recovery period,
maximal force had decreased (79%;p<0.05).
These contradictory findings suggest that the
PAP-fatigue relationship and its effects on sub-
sequent voluntary activity are multi-faceted.
In summary, it has been suggested that fol-
lowing a CC an optimal recovery time is required
to diminish fatigue and realize PAP; however,
evidence is inconsistent in support of this theory.
There are a number of possible explanations for
the contrasting results produced by the afore-
mentioned studies. The relationship between
PAP and fatigue, and the overall effect of con-
tractile history on subsequent performance, is
influenced by a combination of factors.
[2]
These
include: volume of the CC (e.g. sets, repetitions
and rest interval between numerous sets); in-
tensity of the CC (although there is consensus
that maximal-intensity contractions optimize
PAP), the type of CC performed (e.g. dynamic or
isometric); subject characteristics (e.g. muscular
strength, fibre-type distribution, training status
or power-strength ratio), and the type of activity
performed after the CC.
[1,2]
Figure 9 illustrates
the interaction of these complex factors and the
following sections discuss them in more detail.
4.2 Conditioning Contraction Volume
The effect of the CC volume on the interaction
between PAP and fatigue is highlighted by one
particular study. Hamada et al.
[14]
used a fati-
guing protocol of 16 5-second isometric MVC
knee extensions, with each MVC separated by
a 3-second rest interval. A twitch response was
stimulated at the femoral nerve pre-MVCs, bet-
ween each MVC, 1 minute after the MVCs, and
then every second minute after the MVCs, for
13 minutes. Twitch P
t
gradually augmented over
the first three MVCs, peaking at a 127%increase
from baseline values (p <0.05). This demon-
strates that PAP was more dominant than fati-
gue, after the first three MVCs when the MVC
volume was small. For the remainder of the fati-
gue protocol, however, twitch P
t
progressively
decreased, and by the sixteenth MVC measured
32%below baseline-values (p <0.05). This de-
monstrates that as the volume of MVCs con-
tinued to increase, so did the dominance of
fatigue. Following the fatigue protocol twitch P
t
gradually increased, and exceeded baseline values
after 30120 seconds of recovery (+32%;p<0.05).
This demonstrates that fatigue dissipated at a
faster rate than PAP and, consequently, there was
a potentiation in twitch P
t
during the recovery
Condition
intensity
Condition
volume Performance
Condition
type:
• Dynamic
• Isometric
Mechanisms of PAP:
• RLC phosphorylation
higher order
motor-unit
recruitment
pennation angle
Mechanisms of fatigue:
• Central
• Peripheral
Subject characteristics:
• Muscular strength
• Fibre type distribution
• Training level
• Strength-power ratio
Recovery
time
Type of
explosive
activity
Fig. 9. The complex factors influencing performance of a voluntary explosive activity following a conditioning contraction (condition). Con-
dition intensity, volume and type will affect individuals differently, depending on their subject characteristics. Collectively, these factors will
influence the extent to which the mechanisms of post-activation potentiation (PAP) and fatigue are affected. The interaction between the
mechanisms of PAP and fatigue will determine whether subsequent performance is potentiated, and the recovery period required to realize
potentiation. Regardless of the previous interactions, however, the response of some explosive activities to the condition may be different to
the response of other explosive activities. RLC =regulatory light chain.
Post-Activation Potentiation, Theory and Application 157
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
period. An adaptation of these results is presented
in figure 10. These findings were supported in
another study.
[6]
They recorded twitch tension
in the dorsiflexors before and immediately
after five isometric dorsiflexion MVC protocols,
where each protocol differed in MVC dura-
tion (volume). Accordingly, each protocol in-
duced a different level of PAP, with a 10-second
isometric MVC eliciting the greatest potentia-
tion (twitch P
t
: after a 1-second MVC =+43%;
after a 3-second MVC =+130%; after a 10-second
MVC =+142%; after a 30-second MVC =+65%;
after a 60-second MVC =+14%). Again, the
important question is whether or not a similar
effect will occur during performance of voluntary
explosive activities?
French et al.
[50]
assessed the effect of different
CC volumes on performance of subsequent vo-
luntary explosive activities. They measured a
significant increase in isovelocity knee-extension
P
t
immediately after three 3-second isometric
MVCs (+6.1%;p<0.05), but reported a sig-
nificant decrease in isokinetic knee-extension P
t
immediately after three 5-second isometric
MVCs (3%;p<0.05). In contrast, Behm et al.
[34]
measured isometric MVC peak force after one,
two and three sets of 10-second isometric MVCs,
and the only effect reported was an 89%
decrease in peak force 1015 minutes after three
sets of MVCs. As discussed in section 3, PAP is not
expected to enhance isometric peak force (which
represents maximal force), so Behm et al.
[34]
may
have observed potentiation had they measured
voluntary RFD or dynamic performance. Ad-
ditionally, the smallest CC volume used by Behm
et al.
[34]
(10-second isometric MVC) is arguably
larger than the smallest CC volume used by
French et al.
[50]
(three 3-second isometric MVCs
separated by 3 minutes), and may therefore have
induced a greater degree of fatigue. Furthermore,
due to the various other measurements taken
by Behm et al.
[34]
during the recovery period
(including high-frequency tetanic contractions,
twitches, 30%isometric MVC and ITT), fatigue
may have continued to accumulate, thus reducing
any opportunity to realize PAP.
The results of the four aforementioned stu-
dies
[6,14,34,50]
demonstrate the influence of CC
volume on the PAP-fatigue relationship. They
also present the possibility that PAP develops
quicker than fatigue and may therefore be uti-
lized immediately after a relatively low CC vo-
lume (window 1 in figure 8). In contrast, as the
CC volume increases so does fatigue and its
dominance in the PAP-fatigue relationship, and
therefore a recovery period may be required be-
fore PAP is realized (window 2 in figure 8). The
specific recovery period required for different
CC volumes is yet to be determined and it is dif-
ficult to compare the results of individual studies
because methodologies have not been standar-
dized. If future research intends to infer the ideal
warm-up and/or training protocol for optimizing
PAP, CC volume and recovery between the
CC and subsequent activity should be assessed
together.
4.3 Conditioning Contraction Type
Although, to varying degrees, any type of
contraction is likely to activate the mechanisms of
PAP,
[4]
the degree of potentiation achieved is
likely to be related to contraction type. Conse-
quently, the use of different types of CC has
probably contributed to the inconsistent results
that have already been discussed. As past research
40
20
0
20
40
60
80
100
120
140
Change in twitch torque (%)
Fatigue
protocol Recovery period
Time (min)
02 7
Fig. 10. The time-course of knee extensor twitch torque during a
fatigue protocol and throughout a subsequent 5-minute recovery
period. The fatigue protocol consisted of 16 5-second MVCs sepa-
rated by 3 seconds of recovery. A twitch contraction was recorded
pre-fatigue protocol, between each MVC, 5 seconds post-fatigue
protocol, and then every 30 seconds throughout the recovery period.
Twitch torque is given as percentages of pre-fatigue values.
[14]
158 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
has typically used either isometric or dynamic CC,
this article will only discuss the differences be-
tween these two types of contractions.
Several studies have investigated the effects of
isometric MVCs on subsequent explosive activity,
and whilst two reported an increase,
[10,50]
others
reported no change in performance.
[11,34,57]
Past
studies have also used dynamic maximal/near
maximal voluntary contractions to induce PAP,
and again, some recorded potentiation of a
subsequent explosive activity
[15,45-48,54,58]
and
others did not.
[20,49,52,53,55]
These conflicting re-
sults (see table I for results) present no clear re-
lationship between contraction type (isometric vs
dynamic) and PAP-response, and only one study
(to our knowledge) has directly compared iso-
metric and dynamic CC with respect to their
effects on performance of a subsequent explosive
activity.
[56]
This study reported that while a
significant increase in CMJ height (2.9%;p<0.01)
and peak power (8.7%;p<0.001) was observed
3 minutes after three 3-second isometric MVC
back-squats, no change in CMJ height (p >0.05)
but a significant increase in CMJ peak power
(8.0%;p<0.001) was measured 3 minutes after a
3RM dynamic back-squat set. The authors con-
cluded that their isometric condition induced a
greater PAP-response than their dynamic condi-
tion. The two conditions, however, were not
matched with respect to volume or frequency, and
as a result, it is difficult to make a direct com-
parison between their effects.
Theoretically, different types of contraction
would have different effects on neuromuscular
fatigue.
[60,61]
Babault et al.
[60]
assessed neuro-
muscular fatigue during a dynamic contraction
fatiguing protocol and an isometric contraction
fatiguing protocol, where the two protocols were
matched in terms of P
t
decrement. The authors
reported that early fatigue during the dynamic
protocol was preferentially peripheral in origin
(peripheral fatigue defined as a decrease in force
generating capacity due to action potential fail-
ure, excitation-contraction coupling failure, or
impairment of cross-bridge cycling in the pre-
sence of unchanged or increased neural drive
[61]
),
while central fatigue (defined as a reduction in
neural drive to muscle
[61]
) developed towards the
end of the dynamic fatiguing protocol. The iso-
metric protocol, however, produced the opposite
profile, whereby fatigue was firstly central and
then peripheral in origin.
Babault et al.
[60]
proposed that the difference
in fatigue development between isometric and
concentric contractions might be associated with
muscle metabolite accumulation, which is sug-
gested to activate and/or sensitize groups of small
diameter (III and IV) afferent neural fibres.
[60,62,63]
This would in turn cause central fatigue by in-
hibiting a-motoneuron activation, and/or redu-
cing the supraspinal descending drive,
[60,63]
and/or
decreasing motoneuron firing rate.
[64]
The inter-
mittent nature of dynamic contractions may fa-
vour blood flow, subsequently aiding the removal
of metabolic by-products. Accordingly, metabo-
lite accumulation would be greater during iso-
metric contractions, resulting in greater central
fatigue. Conversely, lactate accumulation has been
reported to alleviate peripheral fatigue.
[65]
This
might account for the slower development of per-
ipheral fatigue during isometric contractions
when compared with dynamic contractions.
[60]
If isometric and dynamic contractions can in-
duce different fatigue responses, then it is fair to
assume that they might also have different effects
on the mechanisms of PAP. For example, the ec-
centric motion of dynamic contractions (but not
isometric contractions) increases muscle spindle
firing, activating group Ia neural fibres.
[63]
In
turn, this might enhance the afferent neural volley
at the spinal cord. Consequently, decreased trans-
mission failure from Ia neural fibres to adjacent
a-motor units, resulting in increased higher order
motor unit activation during subsequent activity,
might be greater after dynamic contractions. On
the other hand, isometric contractions activate a
greater number of motor units than dynamic
contractions.
[66]
Consequently, more muscle fi-
bres might be involved during an isometric
contraction, and this might result in a greater
percentage of RLC phosphorylation, and greater
changes in muscle architecture.
In summary, preliminary evidence suggests
that isometric CCs may induce greater central
fatigue, but are more likely to activate the per-
ipheral mechanisms of PAP. In contrast, dynamic
Post-Activation Potentiation, Theory and Application 159
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
CCs may induce greater peripheral fatigue, but are
possibly more likely to activate the central me-
chanisms of PAP (table II). The manner in which
these mechanisms interact has not yet been de-
termined, but it is fair to assume that isometric and
dynamic contractions will have different effects on
subsequent explosive activities. The differences
between isometric and dynamic contractions will
also influence the volume and recovery period re-
quired to potentiate subsequent explosive activity.
Future research should investigate the effects of
contraction type on the mechanisms of PAP and
fatigue, whilst standardizing CC volume and re-
covery period. It is also not known whether a CC
of any type is more beneficial than conventional
warm-up methods,
[18]
and although one study
suggested that it is,
[46]
their results were specific to
the individuals and protocols assessed. Future re-
search should compare the potentiating effects of
CC to conventional warm-up techniques.
4.4. Subject Characteristics
The subject characteristics that have been
suggested to affect an individual’s PAP-fatigue
response include muscular strength, fibre-type
distribution, training level and power-strength
ratio. These factors are discussed in more detail in
the following sections.
4.4.1 Muscular Strength
There is evidence to suggest that an in-
dividual’s muscular strength might partly de-
termine their PAP response following a CC.
Gourgoulis et al.
[15]
observed a 4%increase in
CMJ height (p <0.05) following five sets of back-
squats in those subjects able to squat a load of
>160 kg. Conversely, those subjects unable to
squat loads of >160 kg, only recorded a 0.4%in-
crease in CMJ height (p >0.05). Similarly, Kilduff
et al.
[54]
reported a correlation between muscular
strength (absolute and relative) and CMJ peak
power potentiation 12 minutes after a 3RM
back-squat set (r =0.63; p <0.01). A possible
explanation for these findings might be asso-
ciated with subject fibre-type distribution. The
positive linear relationship between muscular
strength and percentage of type II muscle fibres
is well documented (r =0.50.93; p <0.05),
[67-69]
and type II muscle fibres display the greatest
increase in RLC phosphorylation following a
CC.
[7]
Furthermore, subjects with a higher per-
centage of type II muscle fibres would pre-
sumably have a greater number of higher order
motor units in reserve, which could be activated
via decreased transmitter failure, following a CC.
The combined effect of a greater RLC phos-
phorylation and a greater increase in higher-
order motor unit recruitment would theoretically
predispose individuals with a higher percentage
of type II muscle fibres to a greater PAP re-
sponse. Consequently, it could be speculated that
the stronger subjects in the two studies discussed
above
[15,54]
had a higher percentage of fast-twitch
muscle fibres, and thus achieved a greater PAP
response.
4.4.2 Fibre-Type Distribution
Hamada et al.
[14]
provided evidence to support
a relationship between fibre-type distribution and
PAP. They separated their subjects into two
groups: one with predominantly fast-twitch (type
II) muscle fibres (T-II; n =4), and a second, with
predominantly slow-twitch (type I) muscle fibres
(T-I; n =4). They reported a greater P
t
response in
the T-II group during a 3-second isometric MVC
(250.0 vs 171.0 N m; p <0.01). Furthermore, in
response to a fatigue protocol of 16 5-second
isometric MVCs of the knee extensors, the T-II
group showed significantly greater twitch tension
potentiation during the early stages of the fatigue
protocol (+127%vs +40%increase in P
t
after the
third MVC; p <0.05). However, the T-II group
also had a greater decrease in both twitch P
t
and
MVC P
t
during the later stages of the fatigue
protocol (p <0.05). Therefore, although subjects
Table II. An illustration of the hypothetical effects of isometric and
dynamic conditioning contractions on the central and peripheral
mechanisms of post-activation potentiation (PAP) and fatigue
Type of
conditioning
contraction
The mechanisms of
PAP predominantly
induced
The mechanisms of
fatigue predominantly
induced
Isometric Peripheral Central
Dynamic Central Peripheral
160 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
with a greater percentage of type II muscle fibres
elicited a greater PAP response, they also elicited
a greater fatigue response following a high-
volume CC protocol.
There are a number of possible reasons
why Hamada et al.
[14]
observed a greater fatigue
response in the T-II group. As stated, Hamada
et al.
[14]
reported a greater P
t
production in the T-II
group during the early stages of the fatigue pro-
tocol. Therefore, according to the force-fatigue
relationship,
[70]
a greater fatigue response in the
T-II group would be expected. Additionally, a
negative correlation has been reported between
initial glycolytic rate and fatigue during inter-
mittent exercise.
[71]
The specific task employed by
Hamada et al.
[14]
(16 5-second isometric MVCs,
with 3 seconds of rest between MVCs) would rely
predominantly on a high anaerobic adenosine
triphosphate (ATP) turnover rate, especially in
subjects with a higher percentage of type II mus-
cle fibres.
[72,73]
Therefore, although subjects with
a higher percentage of type II muscle fibres are
expected to produce a larger MVC P
t
, due to a
higher initial anaerobic ATP turnover rate, they
are also likely to show greater P
t
decrements, due
to a greater utilization of anaerobic energy stores
and the production of metabolites associated
with fatigue.
[74,75]
4.4.3 Training Level
An individual’s training level may also influ-
ence PAP and fatigue responses following a CC.
Chiu et al.
[20]
separated a sample of 24 subjects
into athletes who were training and participating
in a sport at national and/or international level
(RT; n =7), and those who participated in re-
creational resistance training (UT; n =17). Five
sets of one back-squat with 90%1RM and 57
minutes of subsequent recovery induced a 13%
increase in CMJ and SJ height in the RT group.
In contrast, the UT group reacted to the same
condition with a 14%decrease in CMJ and SJ
height. Chiu et al.
[20]
suggested that those subjects
training at higher levels of resistance would de-
velop fatigue resistance as an adaptation of their
intensive training regimens, and were more likely
to realize PAP. Chiu et al.,
[20]
however, did not
measure fibre-type distribution, so it is possible
that a greater percentage of fast-twitch muscle
fibres in the RT group also contributed to the
effects observed in this study.
4.4.4 Power-Strength Ratio
There is also evidence to suggest that a sub-
ject’s power-strength ratio will influence their
PAP response to a CC. Schneiker et al.
[76]
re-
ported a significant negative correlation between
power-strength ratio and potentiation of peak
power during loaded CMJ, executed 24 minutes
after one set of 6RM back-squats (r
2
=0.65;
p<0.05). Furthermore, when the sample of
strength-trained subjects were separated into
those with a power-strength ratio of <19 W/kg
(group 1) and those with a power-strength ratio
of >19 W/kg (group 2), group 1 had a significant
negative correlation between power-strength
ratio and peak power potentiation (r
2
=0.91;
p<0.05). In contrast, group 2 showed no re-
lationship between power-strength ratio and
peak power potentiation (p >0.05). These results
suggest that those subjects less able to effectively
convert their strength into power are more likely
to benefit from PAP than those that can. In ad-
dition, it appears that there may be a power-
strength ratio threshold above which subjects do
not benefit from PAP.
In summary, several subject characteristics
have been suggested to affect an individual’s
PAP-fatigue response, and this may partly ex-
plain the inconsistencies of past research. Evi-
dence suggests that individuals most likely to
benefit from PAP include those with a greater
muscular strength, a larger percentage of type
two fibres (although fatigue may also be greater
in these individuals), a higher level of resistance
training, and a smaller power-strength ratio.
Further research, however, is required to validate
these findings as well as determine the possible
effects of other subject characteristics such as
muscle and/or lever lengths. For coaches con-
sidering the implementation of CC prior to ex-
plosive activities (in training or performance), it
may be pertinent to first assess each athlete’s sus-
ceptibility to PAP during the off-season period.
Post-Activation Potentiation, Theory and Application 161
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
4.5 Type of Subsequent Activity
An additional explanation for the inconsistent
results of past research is the different types of
subsequent explosive activities used to determine
the acute effects of PAP. The types of subsequent
explosive activities employed by previous studies
have included isometric MVCs,
[10,34,51]
isolated
dynamic contractions (e.g. isovelocity knee
extensions),
[11,47,50]
and compound ballistic
activities (e.g. CMJ and DJ).
[10,15,46,49,52-58]
It is
possible that a specific CC will not have the same
effect on different explosive activities.
With regard to differences between isometric
and dynamic explosive contractions, previous
studies have reported moderate to strong corre-
lations between isometric and dynamic RFD
(r =0.650.75),
[77]
and moderate to strong corre-
lations between isometric and dynamic peak
force (r =0.660.77).
[77,78]
These results indicate a
clear relationship between tests measuring isometric
and dynamic strength and power. There are,
however, a number of differences in the neural
and mechanical processes involved in isometric
and dynamic activities. For example, the motor
unit recruitment and rate coding for an isometric
contraction will probably be regulated by the size
principle,
[79]
whereby motor units are recruited in
a hierarchical order of small, followed by higher
order units. On the other hand, dynamic con-
tractions might display a specific pattern of mo-
tor unit recruitment relevant to joint angle and
position through the range of motion.
[80]
Ad-
ditionally, the eccentric movement involved in
dynamic contractions, but not isometric con-
tractions, would result in a greater afferent
(group Ia neural fibres) input from muscle
spindles.
[61,81]
As a result, the a-motoneuron ac-
tivation responses for isometric and dynamic
contractions would be different.
[82]
Furthermore,
utilization of elastic strain energy (stretch-
shortening cycle), stored in the muscles during an
eccentric contraction, provides a significant con-
tribution to overall performance of dynamic
movements.
[83-85]
The stretch-shortening cycle,
however, is not utilized during an isometric con-
traction and, consequently, isometric contrac-
tions may not reflect the muscles capabilities for
dynamic situations.
[82]
Finally, PAP is greatest
whilst the muscle is shortening
[86]
and extends to
higher stimulation frequencies in concentric
when compared with isometric contractions.
[22]
This suggests that PAP may have a performance-
enhancing effect beyond what would be expected
based on isometric contractions.
It is also likely that whilst a specific CC might
enhance performance of a particular dynamic
activity, it might decrease or have no effect on the
performance of a different dynamic activity.
French et al.
[50]
analysed isovelocity knee exten-
sion, CMJ, DJ and 5-second cycle sprint perfor-
mance before and immediately after three
3-second MVC knee extensions. They reported
significant improvements in DJ height, DJ RFD
and knee extension P
t
(+5.0%,+9.5%and +6.1%,
respectively; p <0.05) after the MVCs, but found
no significant effect in any of the other activities
(p >0.05). French et al.
[50]
used time-motion
analysis to explain their results. They reported
that the DJ and knee extension MVC had a
muscle activation period of £0.25 seconds. In
contrast, the CMJ and 5-second cycle sprint had
a muscle activation period of 0.25 seconds. Ex-
plosive muscle actions have previously been
defined as those that have an activation period
of £0.25 seconds.
[77]
French et al.
[50]
therefore
concluded that PAP was only effective in tasks
defined as explosive muscle actions. The conclu-
sions of French et al.,
[50]
however, should be
interpreted with caution. Some studies have re-
corded a potentiation effect in CMJ performance,
as well as other activities that otherwise might not
fall under the above definition of explosive mus-
cle action.
[10,15,46,51,54,56,58]
In addition, French
et al.
[50]
only measured exercise performance im-
mediately after the CC, and a rest interval may
have been needed for a potentiation effect to be
realised. Finally, the CC exercise was an isola-
tion exercise targeting the knee extensors alone.
The DJ may load the knee extensors to a greater
extent than the CMJ and 5-second cycle sprint,
which would explain the increase in DJ
height/RFD. The CMJ and 5-second cycle sprint,
however, may rely on the contribution of various
other large muscle groups, which due to the
kinematics of the CC, had not been potentiated.
162 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
These results therefore highlight the importance
of closely matching the kinematics of the CC to
those of the subsequent explosive activity. By
doing so, an individual is more likely to activate
the higher order motor units, phosphorylate the
RLC and change the architecture of those muscle
fibres specifically associated with the subsequent
activity.
The aim of recent research has been to estab-
lish the application of PAP to specific explosive
sports activities. Explosive sports activities are
dynamic in nature so, for the reasons discussed
above, isometric responses to a CC should not be
used to infer effects of the same CC on sub-
sequent sports activities. If researchers are in-
vestigating the application of PAP to a training
scenario, the reported effects of a CC on sub-
sequent ballistic activities (e.g. CMJ and DJ) may
be useful, as ballistic exercises are used in power-
training programmes. On the other hand, whilst
PAP may sometimes be effective in enhancing
performance of a ballistic exercise, it may not
have the same ergogenic effect on performance of
a specific explosive sports activity (e.g. sprinting,
long jump). If PAP is to be utilized in competi-
tion, research must first determine its effects
beyond those reported for ballistic training ex-
ercises. Two recent studies have shown that PAP
can enhance performance of a specific explosive
sports activity, reporting a decrease in sprint time
(-3%over 10 m,
[48]
-2%over 30 m,
[48]
and -3%
over 40 m;
[45]
p<0.05) 45 minutes after the
execution of near maximal (>80%1RM) back-
squats. Nevertheless, further research is required
to establish the application of PAP to many dif-
ferent explosive sports activities. Furthermore,
even if PAP is consistently shown to enhance
performance of different explosive sports activ-
ities, several practical implications would need to
be addressed to effectively apply PAP to a com-
petitive scenario (such as the need for possible
equipment in the warm-up area and the require-
ment to compete within the optimal recovery
period following activation). As a result of these
impracticalities, the application of PAP to
performance has been challenged,
[18]
but with
reported increases in performance by >3%,
further investigation is warranted.
5. Conclusion
It may be possible to effectively utilize PAP to
enhance mechanical power and therefore perfor-
mance and/or the training stimulus of an explo-
sive sports activity. Evidence over the practical
application of PAP to explosive activities is,
however, inconclusive. The inconsistent results of
past research appear to be due to the complex
interaction of several factors that determine the
degree to which the different mechanisms of PAP
and fatigue are affected. Greater CC volumes and
intensities are expected to induce greater levels of
both PAP and fatigue. However, the rates at
which PAP and fatigue develop and dissipate
may differ, resulting in two windows of oppor-
tunity to potentiate performance; immediately
after a low-volume CC, or after a specific re-
covery period following a high-volume CC. The
type of CC may also have different effects on the
mechanisms of PAP and fatigue. For example,
isometric MVCs may induce central fatigue, but
peripheral PAP, whilst dynamic MVCs may in-
duce the opposite response. The interaction of
these different mechanisms would, in turn, de-
termine the optimal CC volume and recovery
time required to potentiate (if at all) subsequent
performance. Regardless of the above factors, an
individual training at a higher level, with a greater
muscular strength, a greater fast-twitch fibre
distribution and a lower power-strength ratio
may be more likely to benefit from PAP than an
individual without these characteristics. When
interpreting results, consideration should also be
given to the specific application of PAP in sport.
If the intention is to utilize PAP in competition,
only the results of studies reporting the effects of
a CC on performance of a specific explosive
sports activity should be considered. Although
standardization of these various factors provides
future research with an extremely arduous task,
the results of studies showing 210%increases in
performance suggests further investigation of
PAP may be worthwhile. It may be pertinent,
however, for research to first establish how the
mechanisms of PAP and fatigue interact under
different conditions before applying PAP to
sport.
Post-Activation Potentiation, Theory and Application 163
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)
Acknowledgements
No sources of funding were used in the preparation of this
review and the authors have no conflicts of interest that are
directly relevant to the contents of the review.
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Correspondence: Mr Neale A. Tillin, School of Sport and
Exercise Science, Loughborough University, Ashby Road,
Loughborough, Leicestershire, LE11 3TU, UK.
E-mail: N.A.Tillin@lboro.ac.uk
166 Tillin & Bishop
ª2009 Adis Data Information BV. All rights reserved. Sports Med 2009; 39 (2)

Supplementary resource (1)

... Las investigaciones (Tillin y Bishop, 2009) han propuesto dos mecanismos fundamentales para la PAP: 1) la fosforilación de las cadenas livianas reguladoras de la miosina y 2) el mayor reclutamiento de unidades motoras de alto umbral. Otros investigadores proponen como tercer mecanismo posible, el ángulo de peneación muscular (Malhfeld, Franke y Awiszus, 2004;Kubo, Kanehisa, Kawakami, Fukunaga, 2001). ...
... Ese estado potenciado permanece un período de tiempo determinado, durante el cual el deportista puede obtener beneficios en su rendimiento. Es importante destacar que diversas variables afectan la respuesta PAP, éstas son: a) características del ejercicio potenciador (tipo, mecánica, intensidad y volumen); b) semejanzas mecánicas entre el ejercicio potenciador y el potenciado; c) características del participante (nivel de rendimiento, edad, sexo, morfología muscular y tipo de fibras prevalentes); d) período de pausa entre el ejercicio potenciador y el potenciado (Tillin y Bishop, 2009;Robbins 2005;Ebben, 2002). ...
... Relación PAP y fatiga(Tillin y Bishop, 2009). ...
Thesis
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El acondicionamiento previo en un entrenamiento y competición deportiva es la estrategia utilizada por los deportistas y entrenadores para optimizar el rendimiento. Las rutinas suelen basarse en conocimiento empírico y en la influencia de modelos que surgen de las prácticas de los equipos de élite. El presente Trabajo Final de Grado diferencia el conjunto de actividades incluidas al inicio de cada sesión de entrenamiento o competición deportiva para el rendimiento inmediato. Asimismo, esta revisión bibliográfica propone su análisis identificando los efectos principales, 1) dependiente del incremento de la temperatura (por ejemplo, disminución de la rigidez muscular, incremento de la tasa de conducción del estímulo nervioso, aumento del aporte de energía oxidativa y no oxidativa, etc.), y 2) independiente del incremento de la temperatura (por ejemplo, efectos de la acidemia, aumento del consumo de oxígeno e incremento de la post activación fisiológica). En consecuencia, precisar la relación con el rendimiento deportivo en general, y finalmente proponer un modelo de acondicionamiento previo para el Taekwondo Olímpico. Deporte que se encuentra en el listado de las artes marciales más practicadas del mundo, contando con más de 60.000 deportistas en la modalidad de combate, y caracterizado fisiológicamente por la realización de esfuerzos rápidos y explosivos, con acciones que incluyen numerosos golpes, bloqueos, saltos y desplazamientos.
... Many studies showed improvements in sprint performance using resistance exercises [11], resistance running [9] and plyometrics [14] as conditioning stimuli in a PAP protocol. The response to a PAP protocol depends on methodological factors, including the type and the intensity of muscle contraction, the length of the rest period, the training background of the participants and their physiological characteristics [15][16][17]. Finally, previous researchers highlighted the importance of mechanical similarity between conditioning stimuli and subsequent activity [18]. ...
... The individual sled load used in this study was sufficient to activate the responsible mechanisms for the PAP phenomenon. A possible mechanism for the enhancement of sprint performance is the increase of neural activation and recruitment of higher-order motor units [16,39]. Due to the absence of electromyography in the current study, it can only be assumed that heavy sled towing caused the activation of type II muscle fibers specific to sprinting, which resulted in higher force and power production. ...
... Due to the absence of electromyography in the current study, it can only be assumed that heavy sled towing caused the activation of type II muscle fibers specific to sprinting, which resulted in higher force and power production. Another potential explanation for improved performance is the phosphorylation of myosin regulatory light chains that increases the sensitivity of the actin-myosin complex to calcium (Ca 2+ ), leading to an increased rate of binding of myosin cross-bridges to the actin [16]. The present results showed that there were no significant changes in the mechanical properties F 0 , v 0 , P max , S Fv , RF max and D rf after performing resisted sprints. ...
Article
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The aim of this study was to investigate the effects of heavy sled towing using a load corresponding to a 50% reduction of the individual theoretical maximal velocity (ranged 57–73% body mass) on subsequent 30 m sprint performance, velocity, mechanical variables (theoretical maximal horizontal force, theoretical maximal horizontal velocity, maximal mechanical power output, slope of the linear force–velocity relationship, maximal ratio of horizontal to total force and decrease in the ratio of horizontal to total force) and kinematics (step length and rate, contact and flight time). Twelve (n = 5 males and n = 7 females) junior running sprinters performed an exercise under two intervention conditions in random order. The experimental condition (EXP) consisted of two repetitions of 20 m resisted sprints, while in the control condition (CON), an active recovery was performed. Before (baseline) and after (post) the interventions, the 30 m sprint tests were analyzed. Participants showed faster 30 m sprint times following sled towing (p = 0.005). Running velocity was significantly higher in EXP at 5–10 m (p = 0.032), 10–15 m (p = 0.006), 15–20 m (p = 0.004), 20–25 m (p = 0.015) and 25–30 m (p = 0.014). No significant changes in sprint mechanical variables and kinematics were observed. Heavy sled towing appeared to be an effective post-activation potentiation stimulus to acutely enhance sprint acceleration performance with no effect on the athlete’s running technique.
... The differing definitions and citations used has led to confusion amongst researchers. Accordingly, this confusion, and subsequent discrepancies in terminology, are reflected in a large number of acute studies (i.e., time-course of potentiation in one session following conditioning contractions) and reviews on the topic [27,[41][42][43][44][45][46][47][70][71][72][73], hence the importance to clarify. ...
... Yet, trained/stronger athletes can better cope with training loads and overall training volume [97], and may require, a varied training stimuli, thus CPX training could be inferred as an advanced technique that may be appropriate after the athlete has developed the pre-requisite training history and levels of strength. Based on the available evidence [42,70,72], to prescribe CNT, the athletes should have adequately familiarised with resistance training, and a pre-requisite level of strength (kg/kg) of ~ 2.0 in the back squat exercise, and ≥ 1.35 in the bench press regardless of sex [42]. However, perhaps the loads, volume and rest periods will differ, and the largest acute effects will ultimately be seen in those with greater strength levels and also dependent on the exercise performed. ...
Article
The primary aim of this narrative review was to outline the historical genesis of resistance training strategies that incorporate high-load, low-velocity exercises and low-load, high-velocity exercises in the same training session allowing for different "exercise sequences" to be simultaneously implemented. Discrepancies between scientific works and the terminology used within contemporary sport science publications are identified. Upon review of the literature, we propose "complex training" to be considered an umbrella term with 4 different implementations, generally used to indicate a method in which movement velocity or load is altered between sets and/or exercises within the same session with the aim of improving slow and fast force expression. We propose the following terminology for said implementations: contrast training-exercise sequence with alternating high-load and low-load (higher-velocity) exercises in a set-by-set fashion within the same session (corresponding with 'intra-contrast pairs' and 'intra-contrast rest'); descending training-several sets of high-load (e.g., back squat) exercises completed before the execution of several sets of low-load, higher-velocity (e.g., vertical jump) exercises within the same session; ascending training-several sets of low-load, higher-velocity exercises completed before several sets of high-load exercises within the same session; and French contrast training-subset of contrast training in which a series of exercises are performed in sequence within a single session: heavy compound exercise, plyometric exercise, light-to-moderate load compound exercise that maximizes movement speed (i.e., external power), and a plyometric exercise (often assisted). Finally, practical applications and training considerations are presented.
... When considering the recovery period following heavy resistance CE, performance is initially impaired, potentiation is then realised, peaks and decreases in an inverted U-shaped fashion (6,52,56). However, when considering a lighter CE, that of a WV, the same level of agreement is yet to be reached with the reporting of equivocal results. ...
... From studies where a heavy resistance CE has been used during a warm-up, performance is consistently compromised immediately after the CE (6,26,52). However, speculation exists regarding the rest duration required following a lighter mode of CE. ...
Article
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This investigation examined the effects of a warm-up containing weighted vest (WV) sprints on subsequent 20-metre sprint time relative to a control (C) condition in youth soccer players (n=12, mean ± SD age 16 ± 0.60 years, height 175.17 ± 5.92 cm and body mass 61.85 ± 5.88 kg). The main experimental trials consisted of three WV conditions at 10, 20 and 30% of body mass (WV10, WV20 and WV30) and C. Participants were required to complete one 20-metre sprint with each of WV conditions or without additional mass as part of C prior to a 20-metre sprint at 4-, 8- and 12-minutes. A two-way repeated measures ANOVA revealed no significant difference between any of the conditions and rest periods (p = >0.05). The between condition effect sizes for 20-metre sprint times were moderate at 4- and 12-minutes post WV10 (d = -0.86 and -1.15, respectively) and 12-minutes post WV20 (d = -0.84) and WV30 (d = -0.80). Moderate effect sizes were also observed at 4-minutes post WV10 (d = -1.04) and WV20 (d = -0.67) for 10-metre sprint times. These findings demonstrate that WV loading has no significant effect on 20-metre sprint time in youth soccer players. However, there is an opportunity for S&C coaches to implement WV warm-ups of no more than 30% body mass to improve 20-metre sprint times.
... Meanwhile, it has been proved that the relationship between VL and the percentage of completion repetitions is not affected by exercise level [26] and strength growth [27]. However, these two factors can impact the PAP effect [28]. Therefore, the conclusion of this experiment may be applicable for other athlete populations. ...
... However, PAP effect is a highly personalized phenomenon, the optimal interval time may be influenced by individual factors (e.g. fast muscle fiber ratio, strength level) [28]. Therefore, in practical application, coaches need to conduct further research on individuals if they want to know the optimal interval time for athletes accurately, but considering the convenience and universality of practical use, the best PAP effect can be obtained by The study also had some limitations which should be noted. ...
Article
The aim of this study was to determine the optimal velocity loss (VL) threshold that maximises the post activation potentiation (PAP) stimulus for achieving larger and more consistent performance gains in track and field athletes. Twenty-two athletes from athletics participated in four back squat PAP tests with four different VL threshold (5%, 10%, 15% and 20% VL) at an intensity of 85% 1RM. Countermovement jump (CMJ) height, power, and momentum were assessed before, and 10s, 4, 8, 12, 16 minutes after the PAP condition. Repetitions of the squat in all the PAP conditions were also recorded. Only the 5% VL condition produced significant improvements in height (ES=0.73, P=0.038), peak power output (ES=0.73, P=0.038) and momentum (ES=0.72, P=0.041) of CMJ, and these changes appeared 8 minutes after the condition. The total number of repetitions during the 5% VL condition was significantly lower than that observed in the 15% (P=0.003) and 20% VL (P<0.001) trials. The results from this study indicate that 5%VL during the 2 sets preconditioning squat at 85%1RM was optimal for eliciting PAP in a CMJ exercise, and resulted in significant increases at the 8-min recovery period. The same squat condition also had the least number of repetitions. However, considering the efficiency in practice, athletes can also choose the rest time of 4-min, which can also achieve similar results.
... The exact mechanisms underlying the PAPE effect are still unknown. However, the existing literature is consistently indicating that this phenomenon is related to local physiological responses (Hodgson et al., 2005;Tillin and Bishop, 2009; Results are mean ± SD (95% confidence intervals); *significant increase in comparison to baseline; # significant increase in comparison to the corresponding set in the CTRL condition; BA, baseline; PAP-A, post-activation and accessory exercise condition; PAP, post-activation condition; CTRL, control condition. PAP-A 4.3 ± 1.3 (3.6-5.1) ...
Article
Full-text available
This study aimed to determine whether the intra-complex active recovery within the strength-power potentiating complex will impact the upper-body post-activation performance enhancement effect and how the magnitude of this effect will change across the upper-body complex training session. Thirteen resistance-trained males [the age, body mass, height, experience in resistance training, and one-repetition maximum (1RM) in bench press were 27 ± 4 years; 92.3 ± 15.4 kg; 182 ± 6 cm; 6.4 ± 2.4 years, and 118 ± 29 kg, respectively) participated in this study. Each participant completed a baseline bench press throw performance assessment at 30% 1RM. Next, five strength-power potentiating complexes consisting of a bench press at 80% 1RM were tested until the average barbell velocity decreased by 10% as a conditioning activity, and 6 min later, a re-test of bench press throw was carried out. During one experimental session during the rest interval inside the complex, they performed swiss ball leg curls, while between the complexes, a plank exercise (PAP-A) was performed. During the second experimental session, participants performed no exercises within the strength-power potentiating complexes and between them (PAP). Under control conditions, participants ran the same protocol (as the PAP condition) without the conditioning activity (CTRL). Friedman's test showed significant differences in peak (test = 90.634; p < 0.0001; Kendall's W = 0.410) and average (test = 74.172; p < 0.0001; Kendall's W = 0.336) barbell velocities during bench press throw. Pairwise comparisons indicated that the peak and average barbell velocities significantly increased in the fourth set [p = 0.022, effect size (ES) = 0.76 and p = 0.013, ES = 0.69, respectively], and the average barbell velocity was also increased in the second set (p = 0.018, ES = 0.77) in comparison to the baseline value during the PAPA condition. Moreover, the peak barbell velocity was increased in the second (p = 0.008, ES = 0.72) and third (p = 0.019, ES = 0.76) sets compared to the baseline value during the PAP condition. This study showed that bodyweight lower-body exercise as an intra-complex active recovery did not impair the upper-body post-activation performance enhancement effect across the complex training session.
... However, single bouts of exercise also have the potential to produce a positive transient performance response (130,132). Research has shown that low-volume exercise stimuli may acutely enhance neuromuscular performance (132,145). This is generally referred to as postactivation performance enhancement (PAPE). ...
... Initially, some authors suggested that the acute physiological effects linked to post-activation potentiation (PAP) (e.g., improvement of the sensitivity of the Ca 2+ released by the sarcoplasmic reticulum due to phosphorylation of the regulatory light chain of myosin) caused by a precedent conditioning activity is the cause of improved performance in high-speed strength or power exercises during a session (Sale, 2002). The repetition of contrast training configurations can achieve a long-term improvement in the performance of activities such as jumping, throwing, or all those that depend on high values of rate of force development (Sale, 2002;Tillin and Bishop, 2009). However, other authors have exposed their concerns about PAP causing an improvement in force production after conditioning activity because the specific physiological mechanism of PAP is based on the contractile response after a conditioning activity that could or not contribute to the posterior performance enhancement (Cuenca-Fernandez et al., 2017;Boullosa et al., 2020). ...
Article
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To investigate the effects of implementing low-load blood flow restriction exercises (LL-BFRE) instead of high-load exercises (HL-RE) in a contrast training program on high-level young athletes’ strength and power performance. Fifteen high-level pre-pubescent trampoline gymnasts (national level, Tanner Stage Ⅱ, intermediate experience in strength training) were divided into two groups to complete the same structure of a ten-week contrast strength training program differing only in the configuration of the first resistance exercise of the contrast sequence. The LL-BFRE group (n=7, four girls, 13.94 ± 0.42 y) performed the first resistance exercise of the contrast with LL-BFRE (20% to 30% 1RM, perceived pressure of 7 on a scale from 0 to 10). The HL-RE group (n=8, four girls, 13.83 ± 0.46y) trained the first resistance exercise of the contrast sequence with moderate-to-high load (60% to 85% 1RM). Before and after the training period, isometric mid-thigh pull (IMTP), squat jump (SJ), countermovement jump (CMJ), and drop-jump (DJ) were performed to evaluate the effect of the intervention on strength and power capacities as primary outcomes. Changes in participants’ anthropometric measures, muscle mass, left and right thigh girth, IMTP relative to bodyweight (IMTP-R), eccentric utilization ratio (EUR), and reactive strength index (RSI) were assessed as secondary outcomes. There was no significant interaction (p >0.05) between group x time in any power and strength outcome, although SJ and EUR showed a trend to significant interaction (p=0.06 and p=0.065, respectively). There was an overall effect of time (p <0.05) in all power and strength variables (CMJ, SJ, EUR, DJ, RSI, IMTP, and IMTP-R). There was a significant interaction in muscle mass (MM) (β = 0.57 kg, 95% CI = [0.15; 0.98], t13 = 2.67, p = 0.019), revealing that participants in LL-BFRE increased their muscle mass (6.6 ±3.1%) compared to HL-RE (3.6 ±2.0%). Anthropometric variables did not present any group or interaction effect, however, there was a time effect (p <0.05). Implementing LL-BFRE in place of HL-RE as a conditioning activity in a contrast training sequence might be equally effective in improving lower-body strength and power in preadolescent trampoline gymnasts.
... Therefore, a linear mixed effects model was conducted with Q tw as the dependent variable, H 2 PO 4 − × trial interaction as fixed effects dependent variables, and random effects for subject (intercept). To assure a similar level of muscle potentiation for all fatigue related variables included in the analysis, the first, or first two, neuromuscular function measurements were omitted (due to incomplete potentiation; Kufel et al., 2002;Tillin & Bishop, 2009). The data from this maximal Q tw to the initial measurement in which Q tw reached a nadir (<3% point-to-point change relative to maximal Q tw ; range fifth to eleventh measurement) were used for the linear mixed effects models to focus on when fatigue is occurring and to minimize the data along the plateau from leveraging the regression analyses. ...
Article
Key points: We investigated the relationship between intramuscular metabolites and neuromuscular function in humans performing 2 maximal, intermittent, knee-extension trials interspersed with 5min of rest. Concomitant measurements of intramuscular hydrogen (H+ ) and inorganic phosphate (Pi) concentrations, and quadriceps twitch-force (Qtw ) and voluntary activation (VA), were made throughout each trial using 31 P-MRS and electrical femoral nerve stimulations. While [Pi] fully recovered prior to the onset of the second trial, [H+ ] did not. Qtw was strongly related to both [H+ ] and [Pi] across both trials. However, the relationship between Qtw and [H+ ] shifted leftward from the first to the second trial, while the relationship between Qtw and [Pi] remained unaltered. VA was related to [H+ ], but not [Pi], across both trials. These in-vivo findings support the hypotheses of intramuscular Pi as a primary cause of peripheral fatigue, and muscle acidosis, likely acting on group III/IV muscle afferents, as a contributor to central fatigue. Abstract: Intramuscular hydrogen ion (H+ ) and inorganic phosphate (Pi) concentrations were dissociated during exercise to challenge their relationships with peripheral and central fatigue in vivo. Ten recreationally active, healthy men (27±5 years; 180±4 cm; 76±10 kg) performed two consecutive intermittent isometric single-leg knee-extensor trials (60 maximal voluntary contractions; 3s-contraction, 2s-relaxation) interspersed with 5 min of rest. Phosphorus magnetic resonance spectroscopy (31 P-MRS) was used to continuously quantify intramuscular [H+ ] and [Pi] during both trials. Using electrical femoral nerve stimulation, quadriceps twitch force (Qtw ) and voluntary activation (VA) were quantified at rest and throughout both trials. Decreases in Qtw and VA from baseline were used to determine peripheral and central fatigue, respectively. Qtw was strongly related to both [H+ ] (β Coefficient: -0.9, P < 0.0001) and [Pi] (-1.1, P < 0.0001) across trials. There was an effect of trial on the relationship between Qtw and [H+ ] (-0.5, P < 0.0001), but not Qtw and [Pi] (0.0, P = 0.976). This suggests that, unlike the unaltered association with [Pi], a given level of peripheral fatigue was associated with a different [H+ ] in trial 1 vs trial 2. VA was related to [H+ ] (-0.3, P < 0.0001), but not [Pi] (-0.2, P = 0.243), across trials and there was no effect of trial (-0.1, P = 0.483). Taken together, these results support intramuscular Pi as a primary cause of peripheral fatigue, and muscle acidosis, likely acting on group III/IV muscle afferents in the interstitial space, as a contributor to central fatigue during exercise. Abstract figure legend Schematic diagram illustrating the experimental design and major findings. This article is protected by copyright. All rights reserved.
... 20 Tillin ve Bishop, pliometrik uyaran içeren aksiyonların ağır direnç egzersizi ile benzer mekanizmaya sahip olduğunu belirtmiştir. 29 Çalışmamızda, DS performansının yorgunluk sonrası ne oranda değişim gösterdiğini tespit etmek amacıyla 30 sn boyunca (maksimal) tekrarlı olarak gerçekleştirilen CMS metodu tercih edilmiştir. Dolayısıyla hem CMS tekniğinin alt ekstremite özelinde oluşturduğu akut yorgunluk, hem de 30 sn süresince maksi- mal eforla gerçekleştiren sıçrama hareketinin anaerobik mekanizmayı yoğun olarak kullanması, organizmanın zorlayıcı bir durum ile karşılaştığını göstermektedir. ...
Article
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Amaç: Adölesan basketbolcularda akut nöromusküler yorgunluk (NY) durumunun “drop” sıçrama (DS) performansına etkisinin incelenmesi dikkate değer görünmektedir. Sunulan çalışmanın amacı; adölesan basketbolcularda tekrarlı “counter movement” sıçrama (CMS) modelli oluşturulan NY’nin DS performansına etkisinin incelenmesidir. Gereç ve Yöntemler: Çalışmaya 18 basketbolcu ve 18 sedanter olmak üzere toplam 36 adölesan erkek gönüllü olarak katılmıştır. Katılımcılara 30 saniyelik tekrarlı CMS (TCMS-30) modelli NY öncesi ve hemen sonrası olmak üzere DS testleri uygulanmıştır. DS ve TCMS-30 protokolleri kuvvet platformu kullanılarak gerçekleştirilmiştir. Verilerin analizinde grup farklılıkları (TCMS-30) için bağımsız örneklemler için t-testi; yorgunluk protokolü öncesi ve sonrası (grup içi ve gruplar arası) DS performansındaki değişimin belirlenmesinde ise karışık ölçümlerde ANOVA analizleri kullanılmıştır. Bulgular: Grup içi DS ön ve sontest değerlerinde farklılık tespit edilmiştir (p<0,05). Bu farklılığın özellikle sedanter gruba ait parametrelerde olduğu belirlenmiştir. Gruplar arası DS son-test karşılaştırmasında basketbolcu grup lehine eğilim olduğu gözlenmiştir. Akut yorgunluk için uygulanan TCMS-30 performansında ise gruplar arası istatistiki farklılık görülmemiştir (p>0,05). Sonuç: Adölesan basketbolculara uygulanan yorgunluk protokolü sonrası DS performansında negatif yönde bir eğilim olsa da bu eğilimin istatistiki olarak önemsiz olduğu ortaya koyulmuştur. Çalışma sonuçları, gelişim çağında ve düzenli egzersiz yapan bireylerde organizmanın zorlayıcı bir egzersize karşı daha hazır olduğunu işaret etmektedir.
Article
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The response of muscle to volitional or electrically induced stimuli is affected by its contractile history. Fatigue is the most obvious effect of contractile history reflected by the inability of a muscle to generate an expected level of force. However, fatigue can coexist with post-activation potentiation (PAP), which serves to improve muscular performance, especially in endurance exercise and activities involving speed and power. The measured response of muscular performance following some form of contractile activity is the net balance between processes that cause fatigue and the simultaneous processes that result in potentiation. Optimal performance occurs when fatigue has subsided but the potentiated effect still exists. PAP has been demonstrated using electrically induced twitch contractions and attributed to phosphorylation of myosin regulatory light chains, which makes actin and myosin more sensitive to Ca2+. The potentiated state has also been attributed to an increase in α-motoneuron excitability as reflected by changes in the H-reflex. However, the significance of PAP to functional performance has not been well established. A number of recent studies have applied the principles of PAP to short-term motor performance as well as using it as a rationale for producing long-term neuromuscular changes through complex training. Complex training is a training strategy that involves the execution of a heavy resistance exercise (HRE) prior to performing an explosive movement with similar biomechanical characteristics, referred to as a complex pair. The complex pair is then repeated for a number of sets and postulated that over time will produce long-term changes in the ability of a muscle to generate power. The results of these studies are equivocal at this time and, in fact, no training studies have actually been undertaken. The discrepancies among the results of the various studies is due in part to differences in methodology and design, with particular reference to the mode and intensity of the HRE, the length of the rest interval within and between the complex pairs, the type of explosive activity, the training history of the participants, and the nature of the dependent variables. In addition, few of the applied studies have actually included measures of twitch response or H-reflex to determine if the muscles of interest are potentiated. There is clearly more research required in order to clarify the functional significance of PAP and, in particular, the efficacy of complex training in producing long-term neuromuscular adaptations.
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PQ] © by IAAF 11:4:67-81,1996 % ^ /n numerous sports and sport events performance is, to a great extent, determined by the level of speed-strength. An optimal preparation (worm-up) is necessary to achieve the highest possible realization of speed-strength in training and competition. Some top international athletes ore said to have produced the highest speed and speed-strength performances immediately after having performed a few Maximal Voluntary Contractions (MVCs). However, os yet no target-oriented and systematic studies of MVCs. as an element of warm-up programmes, have been conducted. Therefore the focus of the following study is on the following questions: (1) To what extent can the short-term potentia-tion of speed-strength induced by MVCs be considered us a general effect? (2) Can effects of post-tetanic potentiation be triggered in human beings by MVCs? (3) To what extent Is there a connection between possible short-term increases in speed-strength and neuronal effects of post-tetanic potentiation? The results of two complex training experiments show that MVCs carried out during the warm-up can really lead to a considerable increase In speed-strength performances of the lower extremities in alt athletics sprint and jumping events and of the upper extremities in the shot put and the throws, m ^ Dr Arne Gütlich was. from 1992 to 1996.
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High-resistance strength training (HRST) is one of the most widely practiced forms of physical activity, which is used to enhance athletic performance, augment musculo-skeletal health and alter body aesthetics. Chronic exposure to this type of activity produces marked increases in muscular strength, which are attributed to a range of neurological and morphological adaptations. This review assesses the evidence for these adaptations, their interplay and contribution to enhanced strength and the methodologies employed. The primary morphological adaptations involve an increase in the cross-sectional area of the whole muscle and individual muscle fibres, which is due to an increase in myofibrillar size and number. Satellite cells are activated in the very early stages of training; their proliferation and later fusion with existing fibres appears to be intimately involved in the hypertrophy response. Other possible morphological adaptations include hyperplasia, changes in fibre type, muscle architecture, myofilament density and the structure of connective tissue and tendons. Indirect evidence for neurological adaptations, which encompasses learning and coordination, comes from the specificity of the training adaptation, transfer of unilateral training to the contralateral limb and imagined contractions. The apparent rise in whole-muscle specific tension has been primarily used as evidence for neurological adaptations; however, morphological factors (e.g. preferential hypertrophy of type 2 fibres, increased angle of fibre pennation, increase in radiological density) are also likely to contribute to this phenomenon. Changes in inter-muscular coordination appear critical. Adaptations in agonist muscle activation, as assessed by electromyography, tetanic stimulation and the twitch interpolation technique, suggest small, but significant increases. Enhanced firing frequency and spinal reflexes most likely explain this improvement, although there is contrary evidence suggesting no change in cortical or corticospinal excitability. The gains in strength with HRST are undoubtedly due to a wide combination of neurological and morphological factors. Whilst the neurological factors may make their greatest contribution during the early stages of a training programme, hypertrophic processes also commence at the onset of training.