Eccentric Cycling Exercise on Hemodynamic and Hemorheologic Properties

Effects of Eccentric and Concentric Cycling Exercise Regimens on Hemodynamic and Hemorheologic Properties in Sedentary Male

The effects of an eccentric endurance training on central and peripheral hemodynamic adaptations and erythrocyte rheology during maximal exercise remained to be unexplored. The current study examined the contribution of rheological functions and/or hemodynamic adaptation to changes in oxygen consumption (VO2) following the matched-power output eccentric (ECT) or concentric cycling training (CCT).

Method: A total of 39 sedentary males were randomly assigned into either CCT (n=13) or ECT (n=13) for 30 min a day, 5 days a week for 6 weeks at 60% of maximal workload or to a CTL (control group, n = 13). A graded exercise test (GXT) was performed before and after the intervention. Central and microvascular adaptations were evaluated using thoracic impedance and near-infrared spectroscopy (NIRS), respectively. Rheological characteristics was determined by an ektacytometer.

Endurance training is a well known strategy for improving fitness capacity. However, some populations are intolerance to complete the usual exercise training program, such as chronic heart or pulmonary disease or the elderly. Therefore, ECT is a candidate training strategy for those individuals.

Erythrocytes deformability is significantly related to the blood perfusion in microcirculation. The impaired erythrocyte-related rheology further lead to reduced aerobic capacity by our research team. Therefore, the lower energy consumed in ECT may avoid the oxidative stress. To now, less studies have demonstrated whether ECT influences peripheral hemodynamics by erythrocyte rheology and the blood flow from the central effect.

The investigators aimed to investigate the effects of CCT and ECT on oxygen consumption response explained by changes in local blood perfusion, blood cell rheology, or central function to attempt developing its application in rehabilitation.

Inclusion Criteria:

• in sedentary lifestyle, who were nonsmokers, nonusers of medications/vitamins, and free of any cardiopulmonary/hematological risks

Exclusion Criteria:

• regular exercise habits (i.e., exercise frequency once per week, duration >20 min).