Musculation des pectoraux : page 3.8

Michael Gundill fait une série de 100 reps au cable pour les pecs

17/02/2012 | Musculation des pectoraux

 

Michael Gundill fait des supersets pecs sur machines Nautilus

24/11/2011 | Musculation des pectoraux

 

Un peu de calculs pour nos amis qui aiment les pompes, pieds sur les meubles

24/09/2011 | Musculation des triceps et Musculation des pectoraux

 

KINETIC ANALYSIS OF SEVERAL VARIATIONS OF PUSH-UPS
WILLIAM P. EBBEN
J Strength Cond Res 25(10): 2891–2894, 2011

Push-ups are a common and practical
exercise that is used to enhance fitness, including upper body
strength or endurance. The kinetic characteristics of push-ups
and its variations are yet to be quantified. Kinetic quantification is
necessary to accurately evaluate the training load, and thus
the nature of the training stimulus, for these exercise variations.
This study assessed the peak vertical ground reaction forces
(GRFs) of push-up variations including the regular push-up and
those performed with flexed knee, feet elevated on a 30.48-cm
box, and a 60.96-cm box, and hands elevated on a 30.48-cm box
and a 60.96-cm box. Twenty-three recreationally fit individuals
(14 men, 9 women) performed each of the 6 push-up variations
in a randomized order. Peak GRF and peak GRF expressed as
a coefficient of subject body mass were obtained with a force
platform. Push-ups with the feet elevated produced a higher GRF
than all other push-up variations (p # 0.05). Push-ups with hands
elevated and push-ups from the flexed knee position produced
a lower GRF than all other push-up variations (p # 0.05). No
gender differences in response to these push-up variations were
found (p . 0.05). Additionally, subject height was not related
to the GRF for any of the push-up conditions (p . 0.05) other
than the condition where handswere elevated on a 60.96-cm box
(p # 0.05; r = 0.63). These data can be used to progress the
intensity of push-ups in a programand to quantify the training load
as a percentage of body mass.

INTRODUCTION
Push-ups are a commonly performed, easy to
execute, multijoint upper body exercise that do
not require expensive equipment. Thus, they can
be readily included in a fitness program. In fact,
push-ups have been recommended by a popular consumer
publication as one of the best practical upper body exercises
that can be used to enhance fitness (12). Push-ups are one of
a limited number of closed kinetic upper body exercises (2),
and there are many potential variations that can be used or
prescribed (15).
Push-ups have also been evaluated as an upper body
strength test (14) and are often included on standardized
fitness tests including those used for school children (13) and
military recruits (9). Training with traditional and plyometric
push-ups produces increased upper body strength and power
(17). Push-ups are also commonly used to evaluate muscular
endurance and can be modified to yield similar results
between men and women (11). Thus, push-ups are used, and
their quantification can be of value for programs designed for
youth, general fitness, and military recruits. Unfortunately,
the quantification of this exercise in a training program is
difficult compared to traditional resistance training exercises.
Resistance training exercises are often performed with
equipment such as a barbell and weight plates with clearly
labeled masses.These loads are often calculated, and exercises
are performed with a percentage of the exerciser’s maximum
ability. Determination of the intensity of a resistance training
stimulus allows for the progression of exercise intensity and
the calculation of training volume. The quantification of
push-ups intensity is more difficult.
Research quantifying push-ups and its variations is limited.
Studies have examined muscle activation of push-ups
typically examining variations in hand placement (4,6,8,16).
Other investigations have compared the traditional push-up
to a push-up using a manufactured product, or a specific
variation in exercise technique, using electromyography to
assess the differences (3,16). Only one study used ground
reaction forces (GRFs) to assess variations in push-ups
characterized by differences in hand position and a bent knee
condition. This study described the push-up as a percentage
of body weight and demonstrated differences in GRF
between variations of hand placement and between bent
knee and normal push-up conditions (8). However, many
variations of push-ups have not been studied such as
conditions that include elevated feet or hands. These
different types of push-ups can be readily prescribed in
fitness settings potentially offering variation to the program
and a range of low to higher intensity options.
Kinetic quantification of body mass exercises allows for the
estimated quantification of the training load and intensity,
which has been proposed to be important to calculate load
volume, metabolic demand, and work in a periodized program
(1).With free-weight exercises, this process is relatively
easy because load volume is based on the mass of the barbell
and weight plates. For exercises that include some portion of
body mass, determining this load is more complex.
The purpose of this study was to assess the peak GRF
associated with regular push-ups, and those performed with
flexed knee, feet elevated on a 30.48-cm box, feet elevated on a
60.96-cm box, hands elevated on a 30.48-cm box, and hands
elevated on a 60.96-cm box for the purpose of quantifying
the loads of these exercises for exercise intensity progression
and to allow for the calculation of exercise load and volume in
a program. This study also sought to assess if there were
gender-based differences in response to these push-up
variations and the relationship between subject height and
peak GRF.


RESULTS
Results revealed a significant main effect for push-up condition
for peakGRFexpressed as a body weight coefficient (p #
0.001, h2
p = 0.94, d = 1.00), with no interaction between
push-up condition and gender for this variable (p . 0.05).
There was also a significant main effect for peak GRF
(p # 0.001, h2
p = 0.76, d = 1.00) with no interaction between
condition and gender for this variable (p . 0.05). Results of
pairwise comparisons of peak GRF expressed as a body
weight coefficient, and peak GRF, are presented in Tables 1
and 2, respectively.
Subject height was not correlated to peakGRFexpressed as
a body weight coefficient (p . 0.05) for all push-up variations
except for the hands elevated 60.96-cm variation (p = 0.001;
r = 0.63). Trial-to-trial reliability of the peak GRF expressed
as a body weight coefficient was moderately to highly reliable
(7) as demonstrated by single and average measures ICC
values in a range from 0.64 to 0.84 with no significant
differences between trials (p . 0.05). Trial-to-trial reliability
of the mean peak GRF was highly reliable (7) as demonstrated
by single and average measures ICC values in the
range from 0.97 to 0.99 with no significant differences
between trials (p . 0.05).

DISCUSSION
This is the first study to assess push-up variations that include
different levels of feet and hand elevation, and bent knee
and normal positions. A variety of differences were found
between most of these conditions. Results of this study can be
used to guide the progression of overload, by incorporating
the push-up variations with higher GRF throughout a program.
Progression of overload is believed to be important for
exercise program design (5). This study also allows the
quantification of training load, as an estimated coefficient of
body mass, because quantifying training load is an important
component of program design (1).
The results of this study demonstrated a GRF of
approximately 64 and 49% of body weight in the regular
and bent knee push-up conditions, respectively. These
findings were slightly different from the values previously
found, which were 66 and 53%, for the regular and flexed knee
push-up variations, respectively (8). Previous research showed
that changes in hand placement produce a GRF in a range
from 52.9 to 72.9% of body mass (8). In this study, push-up
conditions that included hand elevation of 60.96 cm
produced a GRF as low as 41% of body mass and as high
as 74% of body mass when the feet were elevated 60.96 cm.
Thus, it is possible to progress push-ups from low intensity
with hands elevated, to high intensity via feet elevation.
These results show that exercise intensity can increase up to
33% from progressing from the lowest intensity to highest
intensity push-up variations. No previous study has assessed
variations of hand and feet elevation during the push-up.
Previous research has commonly used electromyography to
assess hand placement including wide and narrow grip
(4,6,8), anterior and posterior hand position (6,8), or one-arm
push-ups (6). These studies demonstrate varied results with
respect to muscle activation. The flexed knee push-up option
has been used as a gender modification for women in some
studies (11). In this study, this variation represented 49% of
body mass, compared to the regular push-up condition
which produced 64% of body mass. Results indicate that the
kinetic characteristics of these push-up variations do not
differ between men and women. Similarly, subject height was
not correlated with GRF, except for the condition in which
the hands were elevated to 60.96 cm. Thus, other than this
latter exception, these data apply similarly for both men and
women and regardless of subject height.

PRACTICAL APPLICATIONS
Practitioners in fitness settings should use the body weight
coefficient data presented in this study to understand the
progression of push-up intensity from lower to higher
intensity push-up variations. These data can also be used to
quantify the approximate load as a percentage of body mass
for the purpose of quantifying load and volume in a resistance
training program to enhance upper body fitness.

Michael Gundill fait des dips d’un bras à la machine

12/09/2011 | Musculation des triceps et Musculation des pectoraux

 

Michael Gundill fait du vis-à-vis pour les pectoraux

08/09/2011 | Musculation des pectoraux

 

Michael Gundill fait de la presse Nautilus pour les pectoraux

29/07/2011 | Musculation des pectoraux

 

Michael Gundill parle de sa machine Nautilus à pectoraux

27/07/2011 | Musculation des pectoraux et Machines de musculation

 

Page 3 sur 7 pages  <  1 2 3 4 5 >  Last »