Ty Armstrong’s research while affiliated with Wayne State College and other places

... Barnett et al. 14 demonstrated greater overall excitation of the pectoral muscle during conventional BP. According to Egger 21 , an incline bench angle activates the clavicular part of the pectoral muscle more, while decline bench press increases excitation of the sternocostal part of the muscle, as noted by Glass and Armstrong 22 and Coratella et al. 23 . However, Jagessar et al. 24 arrived at a different conclusion. ...

Reference:

Neuromuscular Repatterning of the Pectoralis Major During the Bench Press Exercise Following a 10-week Targeted Resistance Training Intervention

... The decline bench press exercise (DBPE) is a variation of the traditional flat bench press exercise performed on a declined bench. This variation has been shown to have greater activation of the sternocostal head of the pectoralis major when compared to an incline bench press (Coratella et al., 2020;Glass & Armstrong, 1997;Lauver et al., 2016) and less activation of the anterior deltoid when compared to a flat bench press (Coratella et al., 2020;Lauver et al., 2016;Saeterbakken et al., 2017). Since athletes use different variations of the bench press exercise to train the upper body pushing muscles, which help to improve performance (Saeterbakken et al., 2017), it is important to study this variation, specially because, to the authors knowledge, no research to date has investigated the load-velocity or load-power relationship in this exercise. ...

Reference:

Sex-related differences in the load-velocity and load-power relationships of the decline bench press exercise