I was told that the positioning of the clavicular head meant that the muscle was activated best when the arms are flared, almost 90° to the body. I'm just wodnering if this is true?

1 Answer 1


If EMG activation is an outcome you care about, maybe.

The full text is paywalled (thanks Elsevier), but figure 4 of “Force direction and arm position affect contribution of clavicular and sternal parts of pectoralis major muscle during muscle strength testing” indicates that the highest ratio EMG amplitude between the clavicular and sternal heads of the pectoralis major occur when the arms are in the transverse plane and you’re doing incline or decline bench press. However, this study observed greater clavicular head activation with the arms at 45 degrees to the transverse plane when doing a flat bench press. So to directly answer the question, “maybe?”.

But is EMG activation really something you care about? No research to date has reliably indicated a strong relationship between EMG activations and the outcomes most people actually care about, hypertrophy and strength.

  • You're right, I have no interest in EMG results. I'm just interested in whether it has an significant affect on hypertrophy and strength increase in the upper cheat.
    – Ethan
    Commented Jan 23 at 0:15
  • I will have to dig around, I thought I saw something a while ago that suggested the best angle was around 60-70 degrees (Counting next to the body as zero and at right angles to body as 90), but I have no idea where I read that.]
    – JohnP
    Commented Jan 23 at 20:10
  • @JohnP Even then, we ought avoid the mistake of allowing group-level averages dictate individual practice. We can use study results like this to generate hypotheses for our own training, but from there we ought be individualizing our training to what works for us.
    – Thomas Markov
    Commented Jan 23 at 21:21
  • @ThomasMarkov - Correct and true. Read, educate yourself and figure out what applies for your own training. Good point.
    – JohnP
    Commented Jan 23 at 22:17
  • @Ethan it seems to be a less important detail compared to pressing angle, for example.
    – Luciano
    Commented Jan 24 at 11:08

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