|Lighter weight = relatively larger contribution of the pecs ≠ greater gains|
By combining IEMG and camera techniques in a multimodular measuring system SMART, the scientists were also able to record the muscle activity and track the exact path of the barbell in the twenty healthy, male recreational weight trainers with at least 1 year of lifting experience (the mean +/- SD = 3.3 +/- 1.6 years) who were recruited for their study.
|Figure 1: As you can see in the relative difference between pectoralis and anterior deltoid activity (negative value = anterior deltoids do the main work) the magic happens during the early phase of the|
|Relative increase in load (%) = increase of EMG activity of pecs, delts, triceps and lats compared to lifting only the 12-RM (70% of 1RM).|
In other words: If you go from your 12RM (that's ~70% of your 1RM) the relative load on the pecs on the descending and ascending phase of the bench press increases 62% and 82% less, respectively, than the load on your triceps.
- Król, Henryk, and Artur Golas. "Effect Of Barbell Weight On The Structure Of The Flat Bench Press." The Journal of Strength & Conditioning Research (2017).