Sentences with phrase «pectoralis major»

Poster: Muscle activity pattern in Olympic lifting: latissimus dorsi and pectoralis major — an EMG study

While the anterior deltoid has only the fourth largest peak moment arm length during shoulder flexion, the clavicular pectoralis major and posterior and anterior subscapularis have maximum moment arms lengths at moderate (71 degrees) and small (2.5 degrees) shoulder positions respectively.

The pectoralis major is the big superficial chest muscle that goes from your ribs and sternum all the way out to the shoulder.

They are the pectoralis major and the pectoralis minor.

Ackland et al. (2008) showed that the pectoralis major (clavicular head) displayed a peak moment arm length of 30.2 mm at 120 degrees of shoulder flexion (arms above head) and a minimum moment arm length at 2.5 degrees (length = +3.1 mm) of shoulder scapular plane flexion.

As you can see from the chart below, the clavicular head of the pectoralis major displays the largest shoulder flexion muscle moment arm out of all parts of the pectoralis major, with a peak moment arm length of 53.7 mm at 71 degrees of shoulder flexion (arms just below parallel with the ground).

The pectoralis major is a heavily pennated muscle.

They reported the pectoralis major displayed a much greater proportion of type II muscle fibers than type I muscle fibers (65 % type II and 35 % type I).

In contrast, the inferior part of the sternocostal head of the pectoralis major provides a large shoulder scapular plane extensor muscle moment arm length.

Using a reverse (supinated) grip could increase the involvement of the clavicular part of the pectoralis major.

Ackland et al. (2008) showed that the pectoralis major (clavicular head) displayed a peak moment arm length at 120 degrees of shoulder abduction (length = +11.2 mm), and a minimum moment arm length at 2.5 degrees of shoulder abduction (length = -3.0 mm).

Assessing four different bench angles, Barnett et al. (1995) found greater pectoralis major sternocostal muscle activity when using an incline bench of 0 (i.e. flat) and -18 degrees (i.e. decline) than with an incline of 40 and 90 degrees, with a narrow grip.

Specifically, the barbell bench press performed on a Swiss ball displays either similar (Goodman et al. 2008) or inferior (Saeterbakken & Fimland, 2013) pectoralis major EMG amplitudes, compared to performing the bench press on a stable bench.

In contrast, the bench press produces superior pectoralis major EMG amplitude compared to the standing cable press, probably because this exercise seems to have an upper ceiling in force output of 41 % of total body mass.

The purpose of this section is to describe the muscle architecture of the pectoralis major muscle.

There is limited data regarding the physiological cross section of the pectoralis major.

Keuchle et al (1997) reported that the pectoralis major as a whole displayed an average moment arm length of 41.0 mm and a minimum moment arm length of approximately 20.0 mm.

In contrast, the pectoralis major overall has a small extension moment arm length, making it a weak contributor to movement in the opposite direction, along with the latissimus dorsi.

Assessing the effect of grip width, Lehman et al. (2005) found no difference in pectoralis major clavicular head muscle activity between narrow, middle and wide grip conditions.

Assessing the effect of load, Pinto et al. (2013) found increases in pectoralis major muscle activity with increasing relative loads from 60, 70, 80 to 90 % of 1RM when performing the free - weight bench press.

The reverse grip bench press produces (non-significantly) greater EMG amplitudes in the clavicular pectoralis major compared to the traditional pronated grip variation.

So the clavicular head of the pectoralis major seems only to assist in shoulder abduction and then mainly only above 40 degrees, peaking at 120 degrees (arms above the head), as is shown in the following chart below.

The majority of the data reports no difference between push ups with hands on stable or unstable surfaces (Lehman et al. 2006, Marshall and Marshall 2006), though in contrast, Sandhu et al. (2008) reported greater pectoralis major activation during the swiss ball push up compared to the stable push up with the hands at the same height.

Wider grips increase pectoralis major sternocostal head activity.

Bench press angle affects pectoralis major muscle activity.

Using a wide or narrow grip width causes differences in the shoulder abduction angle, which are probably what leads to the stress being placed on different parts of the pectoralis major muscle.

Therefore, it seems that despite their popularity, unstable surfaces are likely not suitable for training the pectoralis major.

Depending on the part of the muscle and the joint range of motion, the pectoralis major can act as either a scapular shoulder flexor or as a scapular shoulder extensor (Keuchle et al. 1997; Ackland et al. 2008).

Steeper bench angles (28 — 56 degrees) produce greater pectoralis major clavicular head activity.

Assessing the effect of bench press technique, Jagessar (thesis) found no difference in pectoralis major muscle activity between an «elbows out» (90 degree abduction) and a «tucked powerlifting - style elbows» (70 degrees abduction) shoulder position.

Together the two pectoralis major muscles cover the whole of the chest.

Bench press posture seems to have little effect on the pectoralis major EMG amplitude, although the literature is very limited at present.

Similarly, Jagessar (thesis) reported no difference in pectoralis major muscle activity between a neutral and retracted scapular position, and between arched, neutral and flat lower back positioning.

These figures indicate that the pectoralis major (clavicular head) functions as a primary shoulder flexor between 25 and 120 degrees of shoulder flexion, with its greatest contribution to shoulder flexion occurring towards 120 degrees (arms above the head).

The flat and decline variations of the bench press appear best for developing the sternocostal head of the pectoralis major.

Several studies have directly compared the EMG activity of the pectoralis major across a range of resistance exercises.

And given that the pectoralis major EMG amplitude during the stable push up measures approximately 21 to 34 %, the muscle activation during these unstable push up variations is still below the level that would be considered optimal.

Yasuda et al. (2011) recorded cross-sections of the pectoralis major using magnetic resonance imaging (MRI) scans from three groups of 10 healthy recreationally active male subjects prior to a resistance training program.

The pectoralis major muscle originates on the middle third of the clavicle, the length of the sternum, and from the cartilage between the first six ribs.

Since the other prime movers (including the triceps brachii) did not display such close relationships with increasing bench press strength, these findings demonstrate that the bench press is an ideal exercise for increasing the size of the pectoralis major muscles, particularly when a wide grip variation is used.

Bench press angle, grip width and load all affect pectoralis major muscle activity (both sternocostal and clavicular heads) and anterior deltoid muscle activity in varying ways.

Several studies have compared the barbell bench press to isolation exercises, including the pec deck, flat dumbbell fly and the bent forward cable fly (Welsch et al., 2005; Schanke, 2012; Rocha - Junior et al. 2007) and most of these have found no differences in pectoralis major muscle activity between exercises.

Multi-joint exercises that target the pectoralis major activate the muscle to levels sufficient to provide a good training stimulus.

Strangely, even though larger muscles tend to be more pennate than smaller ones, the smaller clavicular head of the pectoralis major appears to be more highly pennated than the much larger sternocostal head.

Changing the posture used to perform the push up by either elevating the feet (Lehman et al. 2006, Escamilla et al. (2009) or hands (Sandhu et al. 2008) does not appear to effect pectoralis major EMG amplitude.

Although overall the pectoralis major may have a small shoulder flexion moment arm, this obscures the fact that the different heads have very different moment arm lengths.

Thus, the pectoralis major provides a primary function in internal shoulder axial rotation independently of joint position (Keuchle et al. 2000).

However, no variation produced greater pectoralis major EMG amplitude than any other variation.

In practice, large levels of pectoralis major EMG amplitude can be achieved by a number of traditional multi-joint shoulder horizontal adduction and elbow extension exercises.

They reported that the pectoralis major displayed greater muscle activity during the sticking and post-sticking region when performing the counter-movement bench press compared with the concentric - only condition, while the pre-sticking region muscle activity was not different between phases.