The Effect of Breathing Pattern and Heel Strike Pattern on Peak Ground Reaction Force at Initial Contact During Walking

Background

During ambulation, the amount of force generated when the foot makes initial contact with the ground can be equivalent to two to three times one’s body weight (Coates, 2013). The forces are greater in running when compared to walking and are affected by the running kinematics, surface, speed, and angle of incline the individual is running on (Challis, 2001; Derrick, Caldwell, & Hamill, 2000; Hamill, Bates, Knutzen, & Sawhill, 1983; Mercer, Bezodis, Russell, Purdy, & DeLion, 2005; Mercer & Vance, 2002; Munro, Miller, & Fuglevand, 1987). It has also been reported that the forces and injury rates may be affected by the foot strike pattern of the individual. When a heel strike pattern is used at initial contact, this may be associated with increased peak ground reaction force (GRF) and result in higher injury rates (Milner, Ferber, Pollard, Hamill, & Davis, 2006; Pohl, Hamill, & Davis, 2009; Zadpoor & Nikooyan, 2011). Subsequently, the use of a non heel strike pattern has been popularized as a method of reducing peak GRF and lower extremity injury rates in running suggesting that this may be more optimal (Daoud et al., 2012; Lieberman et al., 2010; Willson, Ratcliff, Meardon, & Willy, 2015). Furthermore, during running, the greatest impact and stress may also occur when the foot strikes the ground and synchronization of breathing is present in which the exhalation phase occurs at the moment of initial heel contact (Bramble & Carrier, 1983). Since locomotion and respiration both rely on cyclic rhythms of the body, some form of patterning may be present in order to maximize efficiency and optimize performance (Bramble & Carrier, 1983) but the ideal pattern remains unclear from a performance or injury prevention perspective.