NEUROMUSCULAR ACTIVITY DURING BENCH PRESS EXERCISE PERFORMED WITH AND WITHOUT THE PREEXHAUSTION METHOD
ALLAN BRENNECKE,1 THIAGO M. GUIMARA˜ ES,1,2 RICARDO LEONE,1 MAURO CADARCI,2
The purpose of the present study was to
investigate the effects of exercise order on the tonic and phasic
characteristics of upper-body muscle activity during bench
press exercise in trained subjects. The preexhaustion method
involves working a muscle or a muscle group combining a
single-joint exercise immediately followed by a multi-joint exercise
(e.g., flying exercise followed by bench press exercise).
Twelve subjects performed 1 set of bench press exercises with
and without the preexhaustion method following 2 protocols
(P1—flying before bench press; P2—bench press). Both exercises
were performed at a load of 10 repetition maximum
(10RM). Electromyography (EMG) sampled at 1 kHz was
recorded from the pectoralis major (PM), anterior deltoid (DA),
and triceps brachii (TB). Kinematic data (60 Hz) were synchronized
to define upward and downward phases of exercise.
No significant (p . 0.05) changes were seen in tonic control of
PM and DA muscles between P1 and P2. However, TB tonic
aspect of neurophysiologic behavior of motor units was significantly
higher (p , 0.05) during P1. Moreover, phasic control of
PM, DA, and TB muscles were not affected (p . 0.05). The
kinematic pattern of movement changed as a result of muscular
weakness in P1. Angular velocity of the right shoulder performed
during the upward phase of the bench press exercise
was significantly slower (p , 0.05) during P1. Our results
suggest that the strategies set by the central nervous system to
provide the performance required by the exercise are held
constant throughout the exercise, but the tonic aspects of the
central drive are increased so as to adapt to the progressive
occurrence of the neuromuscular fatigue. Changes in tonic
control as a result of the muscular weakness and fatigue can
cause changes in movement techniques. These changes may
be related to limited ability to control mechanical loads and
mechanical energy transmission to joints and passive structures.
INTRODUCTION
An important strategy for strength training is the
exercise order. Inadequate sequence of exercises
may impair the athlete’s capacity to control
intensity and volume in each exercise during
a training session (43–45,49). Several training methods that
change exercise order are applied in strength training.
Training sessions usually start with multi-joint exercises
involving large-muscle groups (1,46). However, other methods
show different exercise sequences, such as the preexhaustion
method. The preexhaustion method involves exercising
the same muscle or muscle group to the point of muscular
failure using a single-joint exercise immediately before
a multi-joint exercise (12,13,17,18,20,31,41,49). This method
for upper-body strength training using the flying exercise just
before the bench press exercise is widely recommended in
popular strength training literature (12,13,17,18,31). The high
intensities and temporal patterns of activation for pectoralis
major and anterior deltoid muscles during flying exercise
(19,39,40) and bench press exercise (6,10,16,23,27,32–34)
support the application of such a combination of exercises.
In nonscientific weight training literature, the rationale for
the preexhaustion method utilization probably lies in increase
of motor unit (MU) recruitment during fatigue, resulting in
greater muscle activation for subsequent multi-joint exercise
(12,13,18,31). But the evidence is contradictory regarding the
practical application of this method, both related to training
and rehabilitation (4,5,21,43,49). Augustsson et al. (5)
observed a decrease in electromyography (EMG) amplitude
of the quadriceps muscle during leg press exercise with
Journal of Strength and Conditioning Research
2009 National Strength and Conditioning Association
VOLUME 23 | NUMBER 7 | OCTOBER 2009 | 1933
