Acute circulatory and femoral hemodynamic responses induced by standing core exercise at different rotational cadence: a crossover study

Background: Core exercise is often adopted as an adjunct in maintaining musculoskeletal health in rehabilitation; we previously showed that standing core rotational exercise improves femoral blood flow after training. This study aimed to investigate the effects of different rotational cadences on circulatory and hemodynamic responses after acute standing core exercise. Methods: Sixteen healthy male adults (22 ± 1 yrs) were randomly assigned to participate in two 30-min standing core exercises of fast (75 rpm, FC) and slow cadence (20 rpm, SC) sessions after completing an acute bout of seated knee extension exercise session (KE) (80% of 1 repetition maximum × 12 repetitions × 3 sets). Impedance cardiography-derived circulatory responses and femoral hemodynamics by ultrasound imaging were measured pre- and 30, and 60 min post-exercise. Results: KE acutely increased post-exercise cardiac output at 30 min (p = 0.008) and heart rate at 30 min (p = 0.04) and 60 min (p = 0.01), yet brachial blood pressure did not change. Systemic vascular resistance was significantly lower after FC and KE at 30 min (p = 0.008) and 60 (p = 0.04) min, respectively, compared with the baseline. In addition, KE acutely decreased post-exercise arterial stiffness (p = 0.05) at 30 min, increased femoral conductance (p = 0.03, p < 0.001), and blood flow (p = 0.009, p < 0.001) at 30 and 60 min. No significant changes were observed in absolute femoral blood flow after FC and SC, except that FC significantly increased relative femoral blood flow (p = 0.007) and conductance (p = 0.005). Post-exercise femoral diameter significantly increased in KE at 30 (p = 0.03) and 60 min (p = 0.01), but not in core exercise. Conclusion: Our results suggest that standing core exercise elicits circulatory and hemodynamic changes only when the rotational cadence is set at a faster cadence, which provides preliminary scientific evidence for its use in exercise programs.