Content uploaded by Oleg Verbitsky
Author content
All content in this area was uploaded by Oleg Verbitsky on Aug 31, 2014
Content may be subject to copyright.
Concurrent activation potentiation enhances performance of swimming race start | 41
V. B. Issurin, O. Verbitsky
Concurrent activation potentiation enhances performance of swimming race start
CONCURRENT ACTIVATION POTENTIATION
ENHANCES PERFORMANCE OF SWIMMING
RACE START
V B. I O V
Wingate Institute for Physical Education and Sport, Netanya 42902, Israel
Technion, Institute of Technology, Haifa 32000, Israel
ABSTRACT
Concurrent activation potentiation (CAP) is recently developed method for
enhancing athletic performance in speed-strength exercises. is phenomenon
is based on the stimulatory e ect of the voluntary contraction of remote mus-
cles, which facilitates activation of prime movers and synergists for targeted
exercise. Physiological prerequisites for this ergogenic e ect are associated
with the integrative function of the cerebral motor cortex and increased excit-
ability of spinal motor neurons. e present study was aimed at evaluating the
ergogenic e ect producing by CAP treatment on the performance of the race
start in competitive swimming. e CAP modi ed start technique presupposed
the teeth clenching and voluntary contraction of abdominal muscles a er the
preliminary starting command. Eight elite and sub-elite swimmers executed
four crawl stroke starts: two CAP modi ed and two conventional trials with
objective registration of start reaction and time to complete a 15-m segment.
Statistical analysis included a repeated measures two-way ANOVA test and
size e ect. Both the p-value and d-value between experimental and control
sets were calculated. e average bene t of the CAP modi ed technique was
equal to 0.08 s, which includes an advantage in start reaction equal to 0.05 s.
As a result, application of the CAP modi ed technique to swimming race start
resulted in a signi cant ergogenic e ect, which was evaluated by start reaction
and performance time on the 15-m segment of distance.
Key words: concurrent activation potentiation, ergogenic e ect, swimming start,
split-unit design
Acta Kinesiologiae Universitatis Tartuensis, 2013. Vol. 19, pp. 41–47
http://dx.doi.org/10.12697/akut.2013.19.04
42 | V. B. Issurin, O. Verbitsky
INTRODUCTION
e stimulatory e ect of concurrent activation of remote muscles on the
targeted muscular performance has been known since the late 19th century,
when Hungarian physician Erno Jendrassik developed this original technique,
termed as the Jendrassik Manoeuver (JM). e JM technique proposes the
examination of tendon re ex in the lower limbs when the patient interlocks
his/her hands together, pulling them apart and clenching the teeth. Since then
the JM has been known as a procedure allowing for potentiating the tendon
re ex in neurologically impaired patients [16]. Correspondingly, the JM can
be considered as a classic example of the case when remote voluntary contrac-
tion (RVC) ampli es the motor output and neural excitability of other muscle
groups.
Earlier studies of the potentiation e ects of teeth clenching were performed
by Japanese researchers, who revealed that teeth clenching produces a signi -
cant potentiation e ect on shoulder adduction [15] and ankle plantar exion
[13]. e researchers investigated variations of H-re ex following RVC and
teeth clenching in a series of in-depth studies. H-re ex, which is evoked by
electricalstimulation of the sensory bers of the innervating nerve, serves as
the world-recognized indicator of the excitability of spinal motor neurons; its
variables characterize acute and chronic neuromuscular adaptation to maxi-
mal e ort and resistance training. It has been established that teeth clenching
increases the excitability of the soleus H-re ex (i), and the greater force level in
teeth clenching produces greater facilitation e ect on the soleus H-re ex (ii);
facilitation of H-re ex is associated with both the descending in uence from
the cerebral cortex and the a erent input from the oral-facial region (iii) [10,
11]. e similar facilitation of H-re ex induced by teeth clenching has been
found in the forearm muscles [14]. Hiroshi [7] reported that teeth clench-
ing before and during hand griping elicits a signi cant increase of maximal
force and rate of force development as compared with no clenching conditions.
Furthermore, a number of studies evaluated the potentiation e ect of RVC
combined with the performance of various speed-strength exercises, termed
Concurrent Activation Potentiation (CAP) [2]. us, a signi cant ergogenic
e ect of CAP has been found during the performance of the high jump, squat
jump, back squat, and knee exion and extension [3–5]. ese publications
reported gains of maximal force, rate force development, and jump height
that varied within 4.2–32.2% depending on the character of the variables and
experimental conditions.
e possible mechanisms underlying the CAP e ects were considered
with regards to two major theories a ributed to the integrative function of the
Concurrent activation potentiation enhances performance of swimming race start | 43
cerebral motor cortex and increased excitability of spinal motor neurons. e
rst one is focused on intercortical connections between di erent motor areas
of the brain, when activation of one part of the motor cortex that is induced by
RVC, such as teeth clenching, a ects the activation of neural centers located in
another part of the brain. ese centers descend a motor command to prime
movers, which initiates e orts for targeted exercise [2]. Another theory under-
lines the role of RVC in the increase of the excitability of spinal motor neurons.
is increased excitability is supported by extensive ndings of H-re ex investi-
gated during the administration of various RVCs, such as jaw clenching, JM,
etc. [6, 13]. e present study was aimed at evaluating the ergogenic e ect pro-
duced by the application of CAP to the movement technique of the swimming
competitive race start.
MATERIALS AND METHODS
Subjects
Eight elite and sub-elite male swimmers took part in the study (mean±standard
deviation [SD]: age: 19.1±2.13 yrs, height: 179.2±3.2 cm, body mass:
74.3±3.4kg, training experience 8.9±1.3 yrs). All subjects were su ciently
familiar with the CAP modi ed start, using this technique in practice and
competitions during at least two months. All subjects were informed of the
purpose and study design of the present research.
Procedures
e experimental model of the CAP modi ed swimming start has been elabo-
rated upon based on the outcomes of previous studies [3–5], and taking into
account our experience in start technique investigation in Olympic swimmers
[9]. e technique protocol included teeth clenching and voluntary contrac-
tion of abdominal muscles, which were initiated immediately a er the preli-
minary starting command (“take your marks”). e time interval between the
preliminary command and the starting signal varied between 0.9–1.2 s. is
time course completely corresponds to the three-phasic character of the poten-
tiation process: initial teeth clenching and abdominal contraction embraces
the 1
st
phase, whereas the takeo was corresponded to the 2
nd
phase, where
intensity of the potentiation impact reaches maximum [1]. e subjects were
required to stop the teeth clenching immediately a er takeo , while abdominal
contraction was maintained according to a habitual coordinative pa ern.
44 | V. B. Issurin, O. Verbitsky
e data were collected during the competitive period. Two VHS video
cameras operating at a nominal rate of 50 Hz were positioned perpendicular to
the axis of the swimmers’ movement. One camera was placed opposite the start
block at 5 m from the swimmers’ location; the second one was installed at the
side of the pool and served for measuring time on the mark 15 m. e starting
command was produced in accordance with the competition’s rules, and a LED
signal was transmi ed to the videosystem. e videotape data were analyzed
with the Ariel Performance Analysis System (Ariel Dynamics Inc., CA, USA);
start reaction (SR) was indicated as the time from start signal to takeo ; start
e ciency (SE) was assessed with the time to complete the segment 15 m.
Experimental design
e subjects randomly performed four trials with the crawl stroke, using either
the conventional or the CAP modi ed technique, with the rest interval about
8min. Eight swimmers were de ned as experimental units, while 32 individual
measurements, which were performed on eight swimmers, were de ned as
subunits, correlated the evaluations. A type of start was de ned as a repeated
treatment design, which was applied to the experimental units. Repeated e orts
(trials) within each type of start, de ned as a repeated treatment design, were
applied to the subunits, correlated observations. Start reaction and start e -
ciency were de ned as a response variable structure. e experimental design
structure can be de ned as a 2x2 factorial within-subject repeated experiment
with a completely randomized split-unit design structure [8].
Statistical analysis
In the present study we used a repeated measures two-way ANOVA test with
Greenhouse-Geisser epsilon adjustment. E ect size was evaluated by the
Cohen’s d-test for dependent variables. We reported d-test value as a measure of
e ect size, which generally considered 0.20 as a small e ect, 0.50 as a medium
e ect, 0.80 as a large e ect, and 1.30 a very large e ect. e descriptive statis-
tics were presented by average di erence between two sets in s. e statistical
signi cance was established at p<0.05.
RESULTS
As shown in Table 1, the di erence between the experimental and the control
sets reached signi cance for start reaction time (F
1,7
=20.70, p=0.0029) and for
Concurrent activation potentiation enhances performance of swimming race start | 45
start e ciency (F
1,7
=11.137, p=0.0125). e start reaction time was shorter
in the experimental set as compared with a control set; average di erence
= 0.05 s, e ect size, d=1.59. e start e ciency was higher in experimental set
as compared with a control set; average di erence 0.08 s, e ect size, d=1.01.
Table 1. The effect of start type on the start reaction and start efficiency Repeated
Measures two-way ANOVA test
Source of Variance df Start reaction Start efficiency
Fp F p
Factor A, Control vs. Experiment sets 1 20.070 0.0029 11.137 0.0125
Residual 7
Factor B, Trial I vs. Trial II, 1 1.346 0.2840 0.806 0.3990
Residual 7
A x B interaction 1 2.944 0.1299 0.023 0.8835
Residual 7
Number of total observations 31
Note: The statistical significance is established at p< 0.05.
DISCUSSION
e study outcomes give strong evidence of the signi cant ergogenic e ect
of the CAP application, which was shown both for the start reaction and start
e ciency evaluated by time on 15 m. It can be expected that possible e ects of
CAP treatment may be the increased rate force development in takeo followed
by increased horizontal velocity and ight distance, which may be the major
contributors of higher start e ciency. e study revealed one more factor of
the ergogenic e ect – shortening reaction time. To our knowledge, this is the
rst evidence that CAP may produce more rapid motor reaction. It is worth
noting that the time course of swimming start provides a very small chance
for shortening motor reaction, although this possibility was realized in a study
where the Grab start was replaced by Track technique [9].
e observations during competitions give additional support for the
occurrence of an ergogenic e ect during implementation of the CAP modi-
ed swim start technique. e monitoring of start reaction is a routine practice
of o cial competitions, where the “Omega” electronic time system presents
on-line data and protocols. In our observations, several swimmers employing
the CAP start enhanced their reaction time by 0.12–0.16 s as compared with
their habitual data. Of course, these extraordinary gains exceed the range that
46 | V. B. Issurin, O. Verbitsky
can be expected following neurophysiological and biomechanical prerequisites.
However, factors such as cognitive input, bene cial mental concentration, and
a more favorable emotional state can also be taken into account as contributors
to these motor e ects. To date, the swimmers who practiced a CAP modi ed
start have utilized it in European Championships in the event 50 m backstroke
and earned bronze (2011) and gold (2012) medals.
In conclusion, unlike previously conducted studies [e.g., 3–5, 7, 12, 15],
the targeted technical component in the present research was not a separate
exercise, but rather a relatively short part of the entire athletic performance.
erefore, this study is one of the rst a empts to implement CAP treatment
into athletic performance that is regulated by o cial competition protocol. e
study outcomes evidence that this implementation is of distinct value and per-
spective for competitive practice and further research projects in other sports.
REFERENCES
1.
Delwade PJ, Toulouse P. (1981) Facilitation of monosynaptic reflexes by
voluntary contraction in remote parts of the body. Mechanisms involved in the
Jendrassik maneuver. Brain, 104 (Pt 4), 701–709
2.
Ebben WP. (2006) A brief review of concurrent activation potentiation: eoreti-
cal and practical constructs. J Strength Cond Res, 20 (4), 985–991
3.
Ebben WP, Flanagan EP, Jenssen RL. (2008) Jaw clenching results in concurrent
activation potentiation during the countermovement jump. J Strength Cond Res,
22 (6), 1850–54
4.
Ebben WP, Kaufmann CE, Fauth ML. (2010) Kinetic analysis of concurrent
activation potentiation during back squats and jump squats. J Strength Cond
Res, 24 (6), 1515–19
5. Ebben WP, Petushek EJ, Fauth ML. (2010) EMG analysis of concurrent activa-
tion potentiation. Med Sci Sports Exerc, 42 (3), 556–62
6.
Gregory JE, Wood SA, Proske U. (2001) An investigation into mechanisms of
re ex reinforcement by the Jendrassik maneuver. Exp Brain Res, 138 (3), 366–74
7.
Hiroshi C. (2003) Relation between teeth clenching and grip force production
characteristics. Kokubyo Gakkal Zasshi, 70 (2), 82–88
8.
Hurlbert SH. (2013) Pseudofactorialism, response structures and collective
responsibility. Austral Ecology 38: 6, 646–663
9.
Issurin VB, Verbitsky O. (2003) Track start vs. Grab start: evidence of the Sydney
Olympic games. In: Chatard J-K. (Ed.). Biomechanics and Medicine in Swim-
ming IX. Saint-Etienne University, France, pp. 213–218
10. Miyahara T. (1991) Modulation of soleus H-re ex by teeth clenching. Kokubyo
Gakkal Zasshi, 58 (4), 670–686
Concurrent activation potentiation enhances performance of swimming race start | 47
11.
Miyahara T, Haqiya N, Ohyama T. (1996) Modulation of human soleus H-re ex
in association with voluntary clenching of the teeth. J Neurophysiol, 76 (3),
2033–41
12.
Sasaki Y, Ueno T, Taniquchi H, Ohyama T. (1998) E ect of teeth clenching on
isometric and isokinetic strength of ankle plantar exion. J Med Dent Sci, 45
(1), 29–37
13.
Takada Y, Miyahara T, Tanaka T, Ohyama T, Nakamura Y. (2000) Modulation
of H-re ex of pretibial muscles and reciprocal inhibition of soleus muscle during
voluntary teeth clenching in humans. J Neurophysiol, 83, 2063–2070
14.
Takahashi T, Ueno T, Ohyama T. (2003) Modulation of H-re ex in the fore-
arm during voluntary teeth clenching in humans. Eur J Appl Physiol, 90 (5–6),
651–53
15.
Ueno T. (1995) Study on relationship between teeth clenching in intercuspal
position and isometric movement of upper limbs. Kokubyo Gakkal Zasshi, 62
(2), 212–253
16.
Zehr EP, Stein RB. (1999) Interaction of the Jendrassik maneuver with segmental
pre-synaptic inhibition. Exp Brain Res, 124, 474–480
Correspondence to:
Vladimir B. Issurin,
Wingate Institute of Physical Education and Sport
Netanya 42902
Phone: 972-528470347
Fax: 972 -8639536
e-mail: v.issurin@gmail.com
