The effect of core exercises on transdiaphragmatic pressure.

Abdominal exercises, such as sit ups and leg lifts, are used to enhance strength of the core muscles. An overlooked aspect of abdominal exercises is the compression the abdomen, leading to increased diaphragmatic work. We hypothesized that core exercises would produce a variety of transdiaphragmatic pressures. We also sought to determine if some of the easy exercises would produce pressures sufficient for a training stimulus to the diaphragm. We evaluated the effect of 13 different abdominal exercises, ranging in difficulty, on transdiaphragmatic pressure (Pdi), an index of diaphragmatic activity. Six healthy subjects, aged 22 to 53, participated. Each subject was instrumented with two balloon-tipped catheters to obtain gastric and esophageal pressures, from which Pdi was calculated. Prior to initiating the exercises, each subject performed a maximal inspiratory pressure (MIP) maneuver. Resting Pdi was also measured. The exercises were performed from least to most difficult, with five repetitions each. There was a significant difference between the exercises and the MIP Pdi, as well as between the exercises and resting Pdi (p < 0.001). The exercises stratified into three Pdi levels. Seven of the exercises yielded Pdi ≥ 50% of the Pdi during the MIP maneuver, which may provide a training stimulus to the diaphragm if used as a regular exercise. The Pdi measurements also provide insight into diaphragm recruitment during different core exercises, and may aid in the design of exercises to improve diaphragm strength and endurance. Key pointsPlease provide 3-5 bullet points of the study.The study examined the effect of different core exercises of varying difficulty on activation of the diaphragm.We found that the exercises yielded different pressures, some of which were greater than 50% of the pressures generated during a maximal inspiratory maneuver.The difficulty of the exercise was not always correlated with the magnitude of the pressure.Some of these exercises should be easy enough for subjects in rehabilitation programs to perform and still generate high enough pressures to help strengthen the diaphragm.