To establish whether McKenzie lumbar flexion and extension mobility exercises performed in lying affect central as well as systemic hemodynamics: A crossover experimental study

ObjectiveExamine systemic and central hemodynamic responses following McKenzie lumbar flexion and extension mobility exercises performed in lying (FIL and EIL).DesignCrossover experimental study.SettingClinical laboratory.ParticipantsHealthy male volunteers (n = 25) (mean(SD) age: 28(3) years; range 21 to 34).InterventionsBased on alternating assignment of either FIL or EIL to participants, three sets of the first exercise (10, 15, 20 repetitions) were performed with 5-minute rest between sets; after 15-minute rest, the protocol was repeated for the other exercise.Main outcome measuresSystemic hemodynamic parameters included heart rate (HR), and systolic and diastolic blood pressures (SBP, DBP). Central hemodynamic parameters included abdominal aortic diameter (AD), peak systolic velocity (PSV/AD), end diastolic velocity (EDV/AD) and resistive index (RI). Measures recorded after each exercise set.ResultsFIL RPP at baseline was 9.1 (1.4), after 20 repetitions 18.3 (2.5), mean difference 8.9 (95% confidence interval (CI) 7.9 to 9.8) compared to EIL at baseline 9.1 (1.5), after 20 repetitions 13.0 (3.1), mean difference 4.1 (95% CI 3.3 to 5.0). FIL RI at baseline was 0.78 (0.03), after 20 repetitions 0.87 (0.03), mean difference 0.08 (95% CI 0.06 to 0.10) compared to EIL at baseline 0.78 (0.03), after 20 repetitions 0.83 (0.03), mean difference 0.05 (95% CI 0.04 to 0.07).ConclusionsAlthough 10 repetitions of FIL and EIL may be regarded as safe, our findings support screening patients with lifestyle risk factors, and cautioning about adhering to recommended repetition number given associated increased work of the heart. The extent of AD mechanical perturbation remains unclear.