Content uploaded by Liam P Kilduff
Author content
All content in this area was uploaded by Liam P Kilduff on May 01, 2016
Content may be subject to copyright.
EFFECT OF POSTACTIVATION POTENTIATION ON
SWIMMING STARTS IN INTERNATIONAL SPRINT
SWIMMERS
LIAM P. KILDUFF,
1
DAN J. CUNNINGHAM,
1
NICK J. OWEN,
1
DANIEL J. WEST,
1
RICHARD M. BRACKEN,
1
AND CHRISTIAN J. COOK
2
1
Sport and Exercise Science Research Center, Swansea University, Swansea, United Kingdom; and
2
UKsport, Bath University,
Bath, United Kingdom
A
BSTRACT
Kilduff, LP, Cunningham, DJ, Owen, NJ, West, DJ, Bracken, RM,
and Cook, CJ. Effect of postactivation potentiation on swim-
ming starts in international sprint swimmers. J Strength Cond
Res 25(9): 2418–2423, 2011—The aim of this study was
to investigate the effects of postactivation potentiation (PAP) on
swim start performance (time to 15 m) in a group of international
sprint swimmers. Nine international sprint swimmers (7 men
and 2 women) volunteered and gave informed consent for this
study, which was approved by the university ethics committee.
Initially, swimmers performed a countermovement jump (CMJ)
on a portable force platform (FP) at baseline and at the following
time points ;15 seconds, 4, 8, 12, and 16 minutes after a PAP
stimulus (1 set of 3 repetitions at 87% 1 repetition maximum
[RM]) to individually determine the recovery time required to
observe enhanced muscle performance. On 2 additional days,
swimmers performed a swim start to 15 m under 50-m freestyle
race conditions, which was preceded by either their in-
dividualized race specific warm-up or a PAP stimulus (1 set
of 3 repetitions at 87% 1RM). Both trials were recorded on 2
cameras operating at 50 Hz with camera 1 located at the start
and camera 2 at the 15-m mark. Peak vertical force (PVF) and
peak horizontal force (PHF) were measured during all swim
starts from a portable FP placed on top of the swim block. A
repeated measures analysis of variance revealed a significant
time effect with regard to power output (PO) (F = 20.963,
p , 0.01) and jump height (JH) (F = 14.634, p , 0.01) with
a paired comparison indicating a significant increase in PO and
JH after 8 minutes of recovery from the PAP stimulus. There was
a significant increase in both PHF and PVF after the PAP
stimulus compared to the swim-specific warm-up during the
swim start (PHF 770 6 228 vs. 814 6 263 N, p = 0.018;
PVF: 1,462 6 280 vs. 1,518 6 311 N, p = 0.038); however,
time to 15 m was the same when both starts were compared
(7.1 6 0.8 vs. 7.1 6 0.8 seconds, p = 0.447). The results from
this study indicate that muscle performance during a CMJ is
enhanced after a PAP stimulus providing adequate recovery
(;8 minutes) is given between the 2 activities. In addition, this
study demonstrated that swimmers performed equally well in
terms of time to 15 m when a PAP stimulus was compared to
their individualized race specific warm-up and indicates that
PAP may be a useful addition to a warm-up protocol before
races. However, more research is required to fully understand
the role PAP plays in swim performance.
KEY WORDS power development, elite athletes, time to 15 m
INTRODUCTION
A
t the international level, the swim start (as measured
by time to 15 m) has been reported to be a critical
component of overall swimming performance and
has been estimated to contribute up to 30% of the
total race in the 50-m sprints (18). In a recent study from our
laboratory, we reported a strong negative correlation between
lower body peak power (r = 20.85) and time to 15 m in
international sprint swimmers (20), which may indicate that
increasing lower body peak power will lead to an improve-
ment in swim start performance, a primary performance
outcome in sprint swimming. At present, there are a number of
methods purported to increase lower body power output (PO)
including athletes trying to develop power while working
against their body mass (e.g., plyometrics) and also while
working against external loads that equate to various
intensities of their 1 repetition maximum (1RM; e.g., 70–
80% for Olympic-style weightlifting movements) (15). Re-
cently, a training method that requires an athlete to work
against a heavy load (.80% 1RM) followed by a light load
(body mass) has been proposed to be an effective training
method for enhancing PO in athletes (e.g., [3,9]). This method
commonly referred to as contrast training is based on the
physiological condition, namely, postactivation potentiation
Address correspondence to Dr . Liam Patrick Kilduff, I.kilduff@swansea.ac.uk.
25(9)/2418–2423
Journal of Strength and Conditioning Research
! 2011 National Strength and Conditioning Association
2418
Journa l of Str en gth and Con dit io nin g Res ea r ch
the
TM
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
(PAP), with PAP defined as an acute enhancement of muscle
function after a PAP stimulus (13).
The literature regarding an athlete’s ability to harness PAP
has been conflicting and can in part be explained by numerous
potential methodological differences in the various studies
(13). Recently, researchers have sought to investigate the
optimal conditions to observe an enhancement in muscle
performance after a PAP stimulus. For example, studies by
Kilduff et al. (16,17) and Bevan et al. (4) have investigated the
optimal recovery time to observe enhanced performance
after a PAP stimulus and have reported that on average
8-minute recovery is required between the PAP stimulus and
the subsequent explosive activity. However, both these
studies noted that individual differences existed between
each athlete’s optimal recovery time to harness the PAP
effect. Although researchers now have a better understanding
of the exact experimental design required to observe
enhanced performance with PAP during squat jumps and
ballistic bench throws (4,16,17), research still needs to be
carried out to see if PAP can be harnessed to enhance
performance in more functional activities such as the dive
start in swimming.
Therefore, in light of the above, the aims of this study were
firstly, to determine the optimal recovery time for maximal
benefits from a PAP stimulus in this group of swimmers and
secondly, because of the lack of research regarding PAP and
its effect on activities directly transferable to sport, to
investigate the effects of a PAP stimulus on time to 15 m in
international-level sprint swimmers compared to their
traditional swim-specific warm-up.
METHODS
Experimental Approach to the Problem
After familiarization, swimmers initially performed a counter-
movement jump (CMJ) on a portable force platform (FP) at
baseline and at the following time points ;15 seconds, 4, 8, 12,
and 16 minutes after a PAP stimulus (1 set of 3 repetitions at
87% 1RM) to individually determine the recovery time
required to observe enhanced muscle performance. On
2 additional days, swimmers performed a swim start to
15 m under 50-m freestyle race conditions, which was
preceded by either their individualized race-specific warm-up
or a PAP stimulus (1 set of 3 repetitions at 87% 1RM) to
compare the effectiveness of a PAP stimulus on time to 15 m.
Subjects
Nine international sprint swimmers (7 men and 2 women)
(Table 1), from whom written informed consent had been
obtained, volunteered to take part in this study, which was
approved by the university ethics committee. Swimmers were
recruited on the basis that they were members of the British
Sprint Development squad and they were engaged in a land-
based conditioning program for at least 2 years before the start
of the study. All swimmers in this study were within 5% of the
national record in their respective events. Swimmers trained
11 times a week in the pool and in addition completed 3 land
conditioning sessions a week also. Depending on the time of
year and overall goal of the land conditioning program,
swimmers performed incorporated traditional powerlifting,
Olympic lifting, and plyometrics into their program.
Experimental Procedures
Before the commencement of the main experimental trials,
swimmers visited the laboratory to become familiar with the
testing methods and to have their 3RM squat measured.
During this familiarization session, swimmers also practiced
performing the CMJ with the aim to maximize jump height
(JH). Forty-eight hours after the familiarization and strength
testing period, all swimmers performed the first testing
session, after an additional 48-hour recovery period swim-
mers completed the second and third testing sessions.
Swimmers reported to the laboratory on the morning of
testing after having refrained from alcohol, caffeine, and
strenuous exercise for the previous 48 hours. All testing was
conducted at the same time of the day after a standardized
meal and fluid intake. After the measurement of each subject’s
stature and body mass, swimmers underwent a standardized
warm-up, which comprised 5 minutes on a rowing ergometer,
followed by a series of dynamic stretches with an emphasis on
stretching the musculature associated with the squat and
CMJ. After the warm-up, swimmers completed a baseline
CMJ. After a recovery period, swimmers completed a PAP
stimulus (1 set of 3 repetitions at 87% 1RM) on the back squat.
Immediately after the PAP stimulus (within 15 seconds) and
every 4 minutes after the PAP stimulus up to 16 minutes
(4, 8, 12, and 16 minutes) the swimmers repeated the CMJ.
This phase of the experiment was carried out to determine the
recovery period required to observe enhanced CMJ perfor-
mance after a PAP stimulus and also to determine individual
variation in terms of optimal recovery. To ensure that any
effect observed during this experiment was because of the
PAP stimulus the 9 swimmers completed 5 CMJs after
a standardized warm-up with a 4-minute recovery between
each one. This was carried out to ensure that during the main
experimental trial there was no warm-up effect or fatigue
effect from the subsequent CM J. A repeated measures 1-way
analysis of variance (ANOVA) revealed no significant time
effect over the duration of the study (ES = 0.78, p = 0.759).
TABLE 1. Physical characteristics of subjects at
baseline (n = 9).
Variables Mean 6 SD
Mass (kg) 77.9 6 11.2
Stature (cm) 179.2 6 13.8
Age (y) 22 6 2
1RM squat (kg) 127.1 6 18.0
VOLUME 25 | NUMBER 9 | SEPTEMBER 2011 | 2419
Journa l of Str en gth and Con dit ion ing Resear c h
the
TM
|
www .nsca-jscr .org
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
On 2 additional days (each separated by 48 hours’ recovery),
swimmers performed a dive start to 15 m (under 50-m freestyle
race conditions), which was preceded by either their in-
dividualized race-specific warm-up (Table 2) or a PAP stimulus
(1 set of 3 repetitions at 87% 1RM) in a randomized fashion.
Measurements
Strength Testing. Before the start of the strength testing session,
all swimmers underwent a standardized warm-up, which
comprised light intensity rowing for 5 minutes, followed by
a series of dynamic movements with an emphasis on warming
the musculature associated with the squat. Swimmers then
performed 3 warm-up sets of 8 repetitions at 50% 1RM,
4 repetitions at 70% 1RM and finally 2 repetitions at 80% of
their 1RM, which was approximately from their training log.
After the final warm-up set, swimmers attempted 3 repetitions of
a set load (3RM) and if successful, the lifting weight was
increased until the subject could not lift the weight through the
full range of motion. All swimmers had been previously exposed
to 3RM testing for the squat. A 5-minute rest was imposed
between all attempts to allowswimmersadequatetimeto
repleni sh energy stores. T he 3RM was determine d after 2–3
attempts in all swimmers. After determination of each subject’s
3RM, their 1RM was estimated using the tables provided in
Baechle and Earle (2). T he squat movement was carried out as
per the International Powerlifting Federat ion rules (14).
Countermovement Jump. For the measurement of lower body
power, swimmers completed CMJ on a portable FP. To isolate
the lower limbs, subject’s stood with arms akimbo (1,11).
After an initial stationary phase of at least 2 seconds, in the
upright position, for the determination of body weight, the
subject’s performed a CMJ, dipping to a self-selected depth
and then exploding upwards in an attempt to gain maximum
height. Subject’s landed back on the FP and their arms were
kept akimbo throughout the movement. Subject’s completed
6 CMJs at the following times: baseline, immediately after
PAP stimulus (;15 seconds) and then every 4 minutes up to
and including 16 minutes. The PAP stimulus consisted of 1 set
of 3 repetitions at 87% of the swimmers estimated 1RM on the
squat. A Kistler portable FP with built-in charge amplifier
(type 92866AA, Kistler Instruments Ltd., Farnborough,
United Kingdom) was used for data collection of the ground
reaction force (GRF) time history of the CMJ. A sample rate
of 1,000 Hz was used for all jumps and the platform’s
calibration was confirmed pre and posttesting.
Countermovement Jump Data Analysis. The vertical compo-
nent of the GRF as the subject performed the CMJ was used in
conjunction with the subject’s body weight to determine the
instantaneous velocity and displacement of the subject’s
center of gravity (CG) (11). Instantaneous power was
determined using the following standard relationship:
Power ðWÞ¼vertical GRF ðNÞ 3
vertical velocity of CG ðm$s
%1
Þ:
To determine the velocity of the subject’s CG, numerical
integration was performed using Simpson’s rule with intervals
equal to the sample width. Before the calculation of the strip
area, the subject’s body weight (as measured in the stationary
phase) was subtracted from the GRF values. The area of the
strip, of width equal to the sample rate, then represented the
impulse for that time interval. Using the relationship that
impulse equals change in momentum, the strip area was then
divided by the subject’s mass to produce a value for the
change in velocity for the CG (it was assumed that the
swimmers’ mass remained constant throughout the jump).
This change in velocity was then added to the CG’s previous
velocity to produce a new velocity at a time equal to that
particular interval’s end time. This process was continued
throughout the jump. Because this method can only
determine the change in velocity, it was necessary to know
the CG’s velocity at some point in time. For this purpose, the
velocity of the CG was taken to be zero before the initiation of
the jump (during the period of body weight measurement)
and specifically at the point identified as the start of the jump.
The start point was defined as the time when the subject’s GRF
exceeded the mean 6 5 SDsfromthevaluesobtainedinthe
second (of the stationary body weight measuring phase)
immediately before the command to jump, in a fashion similar
to Vanrenterghem et al. (19). Integration started from this point.
Vertical displacement was determined by a second in-
tegration. The instantaneous velocity time history was
numerically integrated (in the same way as described above)
from the start point of the jump. The height (vertical
displacement) of the C G at the start point of the jump was
defined as zero. Jump height was then defined as the
difference in the vertical displacement of the CG, between
take off (toes leave the force plate) and maximum vertical
displacement achieved.
Test–retest reliabilities (intraclass correlation [ICC]) for PO
and maximum JH were 0.979 and 0.976, respectively.
Time to 15 m. On 2 separate test days, swimmers performed
a dive start to 15 m under 50-m freestyle race conditions,
which was preceded by either their race specific warm-up or
a PAP stimulus (1 set of 3 repetitions at 87% 1R M). In each
trial, the subject was requested to mount the block. When in
TABLE 2. Example of individualized warm-up.
300-m Easy freestyle swim
6 3 100-m Freestyle (3 pull @ 100 s,
3 kick at 110 s)
10 3 50-m Freestyle swim (25 m fast/25 m easy,
50-m lowest stroke count, 50-m build up,
2 3 50 at 200-m race pace) (repeat)
100 m Loosen
2420
Journa l of Str en gth and Con dit io nin g Res ea r ch
the
TM
PAP and Swim Starts
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
position, the subject was given verbal command !take your
mark," and shortly after the starting signal was sounded. The
subject performed the start and a maximal freestyle sprint to
a distance further than the 15-m mark. All starts were
performed from a standard poolside mounted starting block
under simulated race conditions with a portable FP mounted
on the block to record both peak vertical force (PVF) and
peak horizontal force (PHF). In addition, both starts were
recorded by 2 cameras mounted on poolside. Test–retest
reliability (ICC) for time to 15 m was 0.987.
Data Collection for Swim Starts. Each trial was recorded with
2 digital video cameras (Sony D CR-PC120E, Sony Manufactur-
ing Co UK Ltd, Wales, United Kingdom), operating at a sampling
rate of 50 Hz. The shutter speed was not manually adjustable;
however, the camera was placed in a modality (Sports Mode)
that maximized the shutter speed within the limits of the cameras
being used (1 /4,0 00 seconds), consequently minimizing any
distortion within the movement of the swimmers. The 2 cameras
were mounted on tripods, positioned on the poolside
perpendicular to lane 5 and were set to record continuously
throughout the experimental part of the trials. Camera 1 was
placed at 15 m and was used to determine the sprint time over
this distance only . The second camera was mounted on a tripod
positioned 15 m from the end of the pool, and initially focused on
the starting system to view the light emitted from the starting
signal. T he starting system simultaneously emitted an audible
signal and a strobe flash; this was used to synchronize the starting
signal with the video image. After the start, camera 1 was
immediately panned to focus on a marked point on the opposite
side of the pool at the 15-m mark (to record the moment the
swimmers head reached the 15-m mark). Simultaneously,
camera 2 was static with its optical axis horizontal, and
approximately 1 m in front of the vertical plane of the leading
edge of the starting block and 1 m above the surface of the water .
The subject was visible throughout the start, up to the point of
entry . The start system was visible in the background of the
image, allowing the strobe light to be used for synchronizing the
timing system. All starts were performed from lane 5, using the
camera’s maximum zone facility .
Data Analysis for Swim Starts. Start time (t
S
): Time from the
starting signal to the first frame in which the swimmers head
reaches the 15-m mark. Start time was measured directly by
viewing each trial frame by frame.
Calculation of Peak Vertical and Horizontal Forces. Data were
collected via an F P, which was mounted to a standard starting
block such that the platform was elevated by 10" (Figure 1).
F
z#
can be resolved into vertical and horizontal components,
F
z1
and F
x1,
respectively. F
x#
can be resolved into vertical and
horizontal components, F
z2
and F
x2
, respectively. The 2 vertical
components (F
z1
and F
z2
) and the 2 horizontal components
(F
x1
and F
x2
) are then added to given the total vertical and
horizontal components, F
z
and F
x
, respectively, giving
F
z
¼ F
z
0
sin 80 þ ð%F
x
0
sin 10Þ;
F
x
¼ F
z
0
cos 80 þ F
x
0
cos 10:
Statistical Analyses
After a test for the normality of distribution, data were expressed
as the mean 6 SD.Statisticalanalysiswascarriedoutusinga
repeated measures 1-way ANOVA to determine whether PO,
Figure 1. Diagram of force platform positioned on a 10" incline on the
starting block. Forces measured by the inclined force platform are F
z#
,
orthogonal to the plane of the force platform, and F
x#
, in line with the plane
of the force platform and the direction of diving.
Figure 2. Power output (A) and jump height (B) during countermovement
jumps before and after a postactivation potentiation (PAP) stimulus.
†Indicates significant decrease compared to baseline. *Indicates
significant increase compared to all other time points.
VOLUME 25 | NUMBER 9 | SEPTEMBER 2011 | 2421
Journa l of Str en gth and Con dit ion ing Resear c h
the
TM
|
www .nsca-jscr .org
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
maximum JH, and peak rate of force development (PRFD)
changed throughout the testing session. When significant F
values were observed (p # 0.05), paired comparisons were used
in conjun ction with Holm’s Bonferroni method for control of
type 1 error to determine significant differences. Differences
between time to 15 m performed after the race specific warm-
up or the PAP stimulus was assessed using a paired t-test. The
level of significance was set at p # 0.05 in this study, and all
statistics were performed using SPSS 13.1 (SPSS Inc., Chicago,
IL, USA).
RESULTS
Power Output
ArepeatedmeasuresANOVArevealedasignificanttimeeffect
over the duratio n of the study (F =14.634,p , 0.05) with follow-
up paired comparisons indicating a significant decrease in PO in
the CMJ performed ;15 seconds after the PAP stimulus
compared to the baseline CMJ (Figure 2A). After 4 minutes of
recovery, PO returned to a similar value to baseline with no
significant differ ence between these 2 values (Baseline: 4,024 6
974 vs. 4 minutes: 4,038 6 982 W, p . 0.05). All swimmers in this
study produced their peak power output after 8 minutes of
recovery from the preload stimulus, and this PO was significantly
higher than the POs at all other time points (Figure 2A).
Jump Height
The repeated measures ANOVA revealed a significant time
effect on JH (F = 20.963, p , 0.001). Maximum JH during the
CMJ was observed after 8 minutes of recovery from the PAP
stimulus, and this was significantly higher when compared to
JH recorded at baseline (34.1 6 4.7 vs. 35.7 6 5.6 cm, p , 0.01).
In addition, the height jumped at the 8-minute time point was
significantly higher than the JH at any other time point
throughout the study (Figure 2B). When the players performed
the CMJ immediately (;15 seconds) after the PAP stimulus,
their JH was significantly reduced compared to their baseline
jump (34.1 6 4.7 vs. 32.3 6 4.8 cm, p , 0.01) (Figure 2B).
Swim Start Performance
There was no significant difference between swim start
performance preceded by the PAP stimulus compared to the
dive start preceded by the swim-specific warm-up with regard
to time to 15 m (Figure 3C). There was a significant increase
in both PVF and PHF after the PAP stimulus warm-up
compared to the swim-specific warm-up (PVF: 1,462 6 280
vs. 1,518 6 311 N, p = 0.038; PHF: 770 6 228 vs. 814 6 263
N, p = 0.018) (Figure 3A and B).
DISCUSSION
The results of this study demonstrate that PAP can be
harnessed to enhance PO during a CMJ in a group of
international sprint swimmers providing adequate recovery
(;8 minutes) is given between the PAP stimulus and
subsequent explosive activity (Figure 2). In addition, the
PAP stimulus used in this study produced a similar dive start
time (as measured by time to 15 m) compared to the
swimmers traditional race-specific warm-up (Figure 3)
indicating a potential role for PAP during sprint swimming.
However, future research is required to assess if adding PAP
to the swimmers traditional race warm-up produces
additional benefits compared to the either along.
The initial aim of this study was to determine the optimal
recovery period between the PAP stimulus and the subsequent
explosive activity for enhancing performance during the
explosive activity. Previous studies have used recovery periods
ranging from 0 to 18.5 minutes (3,6,7,8,10,21) with no uniform
agreement to date on the optimal time required. The majority
of the studies have used recovery periods of approximately
4minutespresumablytoallowforPCrresynthesisafterthe
preload stimulus (e.g., [3,6,8,21]). In previous studies from our
laboratory, we demonstrated that ;8-minute recovery was
required between the PAP stimulus and the subsequent
explosive activity for both the upper and lower body
(4,16,17) and this is a similar finding to this study. The results
of this study help clarify the recovery period needed to achieve
maximal increases in CMJ performance in well-trained athletes.
The second key finding from this study was that a P AP warm-
up comprising of 1 set of 3 repetitions on the squat exercise lead
Figure 3. Peak horizontal force (A), peak vertical force (B) and time to 15
m after a swim-specific warm-up and a postactivation potentiation (PAP)
stimulus. *Indicates significant difference between the swim specific
warm-up and the PAP stimulus. Open circles indicate female swimmers,
closed circles indicate male swimmers.
2422
Journa l of Str en gth and Con dit io nin g Res ea r ch
the
TM
PAP and Swim Starts
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
to a similar dive start time compared to the swimmers traditional
swim specific warm-up. Based on a recent review by Bishop (5),
it can be speculated that the mechanism behind the 2 warm-up
protocols would be different, with any improvements in dive
start performance being related to temperature associa ted effects
such as increased oxygen delivery to the muscles and increased
nerve conduction rate. Although the mechanism for the PAP-
mediated effect have 2 primary theories have to date: (a) the
preload stimulus acts to enhance motor-unit excitability,
possibly affecting a number of processes such as increased
motor-unit recruitment, increased motor-unit synchronization,
decreased presynaptic inhibition or greater central input to the
motor neuron; and (b) enhanced phosphorylation of the myosin
light chain (MLC), where the preload causes an increase in
sarcoplasmic Ca
2+
,whichactivatesMLCkinasewhichinturn
increases actin–myosin cross bridging (13).
The results from this study provide the basis for further
examination of the effectiveness of PAP strategies for
enhancing time to 15 m in international swimmers. Future
studies should examine the combination of the swimmers
traditional swim specific warm-up and a PAP stimulus, also
because of the constraints of getting swimmers to lift heavy
weights ;8 minutes before they start their event other high
velocity low force activities (e.g., plyometrics) should be
examined to see if they can induce a similar PAP effect.. Some
evidence for this exists from Hilfiker et al. (12) who
demonstrated the effectiveness of adding a set of drop jumps
into a warm-up for explosive force development and found
a consistent tendency for improved PO.
In conclusion, this study demonstrated the international
sprint swimmers observed improvements in lower body
power after a PAP stimulus when adequate recovery was
given between the PAP stimulus and the sprint and that this
PAP improvement was able to be harnessed in a more
functional performance measure as time to 15 m as demon-
strated by the similar performance time compared to their
traditional swim warm-up.
PRACTICAL APPLICATIONS
The current findings indicate that time to 15-m performance
was similar when swimmers performance their individualized
race warm-up compared to a much lower volume PAP warm-
up. This study further highlights the need for individual
determination of the optimal recovery time required for
enhanced performance after a PAP stimulus. These findings
point toward a potential role for the inclusion of a PAP stimulus
into swimmers’ warm-ups which may lead to a improvement of
time to 15-m performance. In addition, PAP may also be
a useful training tool on sessions dedicated to improving time to
15 m; however, further investigations are required on this topic.
REFERENCES
1. Aragon-Vargas, LF and Gross, MM. Kinesiological factors in vertical
jump performance: differences among individuals. J Appl Biomech
13: 24–44, 1997.
2. Baechle, TR and Earle, RW. Resistance training and spotting
techniques. In: Essentials of Strength Training and Conditioning.
Beachle, TR and Earle, RW, eds. Champaign, IL: 2000. pp. 410–411.
3. Baker, D. Acute effects of alternating heavy and light resistances on
power output during upper-body complex power training. J Strength
Cond Res 17: 493–497, 2003.
4. Bevan, HR, Owen, NJ, Cunningham, DJ, Kingsley, MIC, and
Kilduff, LP. Complex training in professional rugby players:
Influence of recovery time on upper body power output. J Strength
Cond Res 23: 1780–1785, 2009.
5. Bishop, D. Warm-up I: Potential mechanisms and the effects of
passive warm-up on exercise performance. Sports Medicine 33:
439–454, 2 003.
6. Brandenburg, JP. The acute effects of prior dynamic resistance exercise
using different loads on subsequent upper-body explosive performance
in resistance-trained men. J Strength Cond Res 19: 427–432, 2005.
7. Chiu, LZE, Fry, AC, Weiss, LW, Schilling, BK, Brown, LE, and
Smith, SL. Postactivation potentiation response in athletic and
recreationally trained individuals. J Strength Cond Res 17: 671–677, 2003.
8. tdDuthie, G, Young, WB, and Aitken, DA. The acute effects of heavy
loads on jump squat performance: An evaluation of the complex and
contrast methods of power development. J Strength Cond Res 16:
530–538, 2 002.
9. Gosseen, ER and Sale, DG. Effect of postactiv ation potentiation
on dynamic knee extension performance. Eur J Appl Physiol 83:
524–530, 2000.
10. Gourgoulis, V, Aggeloussis, N, Kasimatis, P, Mavromatic, G, and
Garas, A. Effect of a submaximal half-squat warm-up program on
vertical jumping ability. J Strength Cond Res 17: 342–344, 2003.
11. Hatze, H. Validity and reliability of methods for testing vertical
jumping performance. J Appl Biomech 14: 127–140, 1998.
12. Hilfiker, R, Hubner, K, Lorenz, T, and Marti, B. Effects of drop jumps
added to the warm-up of elite sport athletes with a high capacity for
explosive force development. J Strength Cond Res 21: 550–555, 2007.
13. Hodgson, M, Dochery, D, and Robbins, D. Post-activation
potentiation. Sports Medicine 35: 585–595, 20 05.
14. International Powerlifting Federation. Technical Rules Book of
International Powerlifting Federation. Retrieved fromhttp://
www.powerlifting-ipf.com/IPF_rulebook.pdf, 2002.
15. Kilduff, LP, Bevan, H, Owen, N, Kingsley, MIC, Bunce, P,
Bennett, M, and Cunningham, D. Optimal loading for peak power
output during the hang power clean in professional rugby players.
Int J Sports Physiol Perform 2: 260–269, 2007.
16. Kilduff, LP, Bevan, HR, Kingsley, MIC, Owen, NJ, Bennett, MA,
Hore, AM, Maw JR, and Cunningham, DJ. Postactivation poten-
tiation in professional rugby players: Optimal recovery. J Strength
Cond Res 21: 1134–1138, 2007.
17. Kilduff, LP, Owen, N, Bevan, H, Bennett, M, Kingsley, MIC, and
Cunningham, D. Influence of recovery time on post-activation
potentiation in professional rugby players. J Sports Sci 26: 795–8 02,
2008.
18. Mason, B and Cossor, J. What can we learn from competition
analysis at the 1999 Pan Pacific swimming championships?
In: Proceeding of XVII International Symposium on Biomechanics
in Sports. Sanders, R and Hong, Y, eds. Hong Kong: Chinese
University Press, 2000. pp. 75–82.
19. Vanrentergem, J, DeClercq, D, and Van Cleven, P. Necessary
precautions in measuring correct vertical jumping height by means
of force plate measurement. Ergonomics 44: 814–818, 2001.
20. West, DJ, Owen, NJ, Cunningham, DJ, Cook, C, and Kilduff, LP.
Strength and power predictors of swimming starts in international
sprint swimmers. J. Strength Cond. Res, in press.
21. Young, WB, Jenner, A, and Griffiths, K. Acute enhancement of
power performance from heavy load squats. J Strength Cond Res
12: 82–84, 1998.
VOLUME 25 | NUMBER 9 | SEPTEMBER 2011 | 2423
Journa l of Str en gth and Con dit ion ing Resear c h
the
TM
|
www .nsca-jscr .org
Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.
