Leg Exercise Assistive Paddling (LEAP): A Novel Therapy for Peripheral Artery Disease

Introduction: Peripheral artery disease (PAD) is an atherosclerotic disease that impairs circulatory function primarily in the lower extremities, for which treatment options are rather limited and ineffective. While exercise therapies improve vascular function and walking capacity in PAD, adherence is often low due to exercise-induced pain and high sedentarism. Passive limb movement (PLM) has been shown to enhance blood flow and may counteract the vascular decline associated with sedentary behaviors such as prolonged sitting (PS). Purpose: This study evaluates the effects of Leg Exercise Assistive Paddling (LEAP) therapy, a pain-free intervention, on vascular function in individuals with PAD during PS. Methods: In this vanguard phase, healthy control subjects (n=4, 75.3 ± 3.4 years old) underwent a randomized cross-over study with two 2.5-hour PS sessions: one with LEAP therapy (SIT+LEAP) and one without (SIT). LEAP therapy involved repeated passive lower-leg movement (90°–180° at 1 Hz) for 1 minute every 10 minutes. Pre- and post-sitting assessments included flow-mediated dilation (FMD) of brachial and popliteal arteries, central arterial stiffness (carotid-femoral, femoral-ankle), peripheral arterial stiffness (carotid-radial, carotid-ankle), femoral blood flow, and femoral shear rate. Results: Post-sitting brachial FMD was significantly reduced in SIT compared to SIT+LEAP (Δ -1.6 ± 0.40% vs. Δ 0.47 ± 0.31%, P ≤ 0.01), and popliteal FMD was also reduced in SIT compared to SIT+LEAP (Δ -1.8 ± 0.45% vs. Δ 0.34 ± 0.47%, P = 0.02). Femoral artery blood flow was significantly reduced in SIT compared to SIT+LEAP (pre: 492 ± 145 mL/min; post: 363 ± 124 mL/min vs. pre: 392 ± 56 mL/min; post: 384 ± 87 mL/min, P = 0.02). Femoral shear rate was also significantly reduced in SIT compared to SIT+LEAP (pre: 441 ± 51; post: 325 ± 17 vs. pre: 460 ± 44; post: 447 ± 77, P = 0.03). There were no significant differences observed in either peripheral or central measures of arterial stiffness. Conclusions: In this vanguard study, LEAP therapy has shown promise as a tolerable and effective intervention to attenuate vascular dysfunction in sedentary PAD patients. By eliciting a movement-induced hyperemia devoid of muscle contraction pain, LEAP therapy may address a key adherence barrier, providing a novel strategy for improving PAD management. This research was supported by the UNO Graduate Research and Creative Activity Grant and the National Institutes of Health (NIH) COBRE Pilot Award (1P20GM152301-01). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.