If you use a shoulder - width grip you will use your outer and inner bicep heads almost equally, but the wider you go, the more your short / inner head starts to take more of the force. (fitnessandpower.com)
Built for competitive gamers, this fully modular headset allows you to quickly swap out the ear cups, inner head strap or outer headband in order to represent your team colors and find the perfect fit. (tomsguide.com)
For example, based on collective experience as well the rules of biomechanics, it's true that having your feet pointed straight ahead will train the inner and outer heads of your calves almost equally, turning the feet out will place more emphasis on the inner heads, and finally turning the feet in will shift the focus to the outer heads. (fitnessandpower.com)