Instructions to "push as hard as you can" improve average chest compression depth in dispatcher-assisted cardiopulmonary resuscitation. - Mirza M; Brown TB; Saini D; Pepper TL; Nandigam HK; Kaza N; Cofield SS; Mirza, Muzna; Brown, Todd B; Saini, Devashish; Pepper, Tracy L; Nandigam, Hari Krishna; et al. (Resuscitation, 2008)