Ikirangantego cya Discovery-R Ikomeza igituza gikomeza pectoralis yo hepfo binyuze mumigambi yo guhuza imbere mugihe ukora pectoralis major, triceps, na deltoid imbere.Inzira nziza ya biomehanike ituma imyitozo irushaho kuba nziza kandi ikora neza.Imbaraga zingana ziyongera, inkunga yo guhugura ukuboko kumwe, byombi tubikesha imyitozo itandukanye itangwa nintwaro yigenga.