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Your search keyword '"Pipinos, Iraklis I."' showing total 450 results
Start Over Author "Pipinos, Iraklis I." Publication Type Academic Journals
450 results on '"Pipinos, Iraklis I."'

6. Exercise Intolerance in Older Adults With Heart Failure With Preserved Ejection Fraction JACC State-of-the-Art Review

Author

Pandey, Ambarish, Shah, Sanjiv J, Butler, Javed, Kellogg, Dean L, Lewis, Gregory D, Forman, Daniel E, Mentz, Robert J, Borlaug, Barry A, Simon, Marc A, Chirinos, Julio A, Fielding, Roger A, Volpi, Elena, Molina, Anthony JA, Haykowsky, Mark J, Sam, Flora, Goodpaster, Bret H, Bertoni, Alain G, Justice, Jamie N, White, James P, Ding, Jingzhone, Hummel, Scott L, LeBrasseur, Nathan K, Taffet, George E, Pipinos, Iraklis I, and Kitzman, Dalane

Subjects
Aging, Heart Disease, Cardiovascular, Animals, Exercise Tolerance, Heart Failure, Diastolic, Humans, exercise intolerance, heart failure with preserved ejection fraction, senescence, skeletal muscle, aging, Cardiorespiratory Medicine and Haematology, Public Health and Health Services, Cardiovascular System & Hematology
Abstract

Exercise intolerance (EI) is the primary manifestation of chronic heart failure with preserved ejection fraction (HFpEF), the most common form of heart failure among older individuals. The recent recognition that HFpEF is likely a systemic, multiorgan disorder that shares characteristics with other common, difficult-to-treat, aging-related disorders suggests that novel insights may be gained from combining knowledge and concepts from aging and cardiovascular disease disciplines. This state-of-the-art review is based on the outcomes of a National Institute of Aging-sponsored working group meeting on aging and EI in HFpEF. We discuss aging-related and extracardiac contributors to EI in HFpEF and provide the rationale for a transdisciplinary, "gero-centric" approach to advance our understanding of EI in HFpEF and identify promising new therapeutic targets. We also provide a framework for prioritizing future research, including developing a uniform, comprehensive approach to phenotypic characterization of HFpEF, elucidating key geroscience targets for treatment, and conducting proof-of-concept trials to modify these targets.

Published
2021

16. Effects of Supervised Exercise Therapy on Muscle Function During Walking in Patients with Peripheral Artery Disease.

Author

Anderson, Cody P., Pipinos, Iraklis I., Johanning, Jason M., Myers, Sara A., and Rahman, Hafizur

Subjects
*EXERCISE physiology, *GROUND reaction forces (Biomechanics), *MUSCLE strength, *EXERCISE therapy, *SPORTS medicine, *WARMUP, *FLEXOR muscles, *KNEE
Abstract

Background: Although supervised exercise therapy (SET) is a primary treatment for peripheral artery disease (PAD), the current literature is limited regarding the mechanisms contributing to increased walking distances, including how lower extremity muscle function is altered after SET. This study aimed to investigate the effects of SET on lower extremity muscle function during walking in patients with PAD. Methods: Twelve patients with PAD participated in a 6-month SET program consisting of three weekly exercise sessions (a total of 72 sessions) and adhered to the American College of Sports Medicine's (ACSM) recommendations. Each session started with a 5 min warm-up of mild walking and static stretching of upper and lower body muscles, followed by 50 min of intermitted exercise on a treadmill, and then finished with 5 min of cool-down activities similar to the warm-up. Each patient walked across a 10 m pathway with reflective markers on their lower limbs twice: before (baseline) and after six months of participation in SET (post-exercise). Marker coordinates and ground reaction forces were recorded and imported to OpenSim software (version 4.0) for gait simulations. Muscle force, muscle power, and metabolic rate were estimated from OpenSim and compared between the baseline and post-exercise. Results: The mean plantar flexor force was not altered after SET. However, individuals' plantar flexor muscles demonstrated improvements in force production (lateral gastrocnemius: 75–80% of stance, Cohen's d = 0.20–0.43; medial gastrocnemius: 65–85% of stance, Cohen's d = 0.20–0.71; soleus: 90–95% of stance, Cohen's d = 0.20–0.26). Furthermore, plantar flexor power increased (80–95% of stance, Cohen's d = 0.20–0.39) and this was attributed to increased power in the lateral gastrocnemius (80–85% of stance, Cohen's d = 0.20–0.47), medial gastrocnemius (80–90% of stance, Cohen's d = 0.22–0.60), and soleus muscles (85–95% of stance, Cohen's d = 0.20–0.49). Similarly, other muscle groups (knee extensors, knee flexors, hip abductors, hip adductors, hip extensors, and hip flexors) also exhibited force and power increases after SET. Additionally, force and power variances were significantly decreased in several muscle groups (plantar flexors, knee extensors, hip abductors, hip external rotators, hip extensors, and hip flexors). Total metabolic rate also increased during the stance period where muscle force and power were elevated after SET (early stance: 5–25%, Cohen's d = 0.20–0.82; mid stance: 35–45%, Cohen's d = 0.20–0.47; late stance: 75–80%, Cohen's d = 0.20–0.36). Conclusions: Our results suggest that from a biomechanics perspective, muscle functions during walking are improved in patients with PAD after SET; however, the improvements were generally small and were not reflected by all muscle groups. [ABSTRACT FROM AUTHOR]

Published
2024
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21. Ground Reaction Forces and Joint Moments Predict Metabolic Cost in Physical Performance: Harnessing the Power of Artificial Neural Networks.

Author

Mohammadzadeh Gonabadi, Arash, Fallahtafti, Farahnaz, Antonellis, Prokopios, Pipinos, Iraklis I., and Myers, Sara A.

Subjects
GROUND reaction forces (Biomechanics), ASSISTIVE technology, PHYSICAL mobility, TORQUE, SPORTS sciences, ARTIFICIAL neural networks, TIME series analysis
Abstract

Understanding metabolic cost through biomechanical data, including ground reaction forces (GRFs) and joint moments, is vital for health, sports, and rehabilitation. The long stabilization time (2–5 min) of indirect calorimetry poses challenges in prolonged tests. This study investigated using artificial neural networks (ANNs) to predict metabolic costs from the GRF and joint moment time series. Data from 20 participants collected over 270 walking trials, including the GRF and joint moments, formed a detailed dataset. Two ANN models were crafted, netGRF for the GRF and netMoment for joint moments, and both underwent training, validation, and testing to validate their predictive accuracy for metabolic cost. NetGRF (six hidden layers, two input delays) showed significant correlations: 0.963 (training), 0.927 (validation), 0.883 (testing), p < 0.001. NetMoment (three hidden layers, one input delay) had correlations of 0.920 (training), 0.956 (validation), 0.874 (testing), p < 0.001. The models' low mean squared errors reflect their precision. Using Partial Dependence Plots, we demonstrated how gait cycle phases affect metabolic cost predictions, pinpointing key phases. Our findings show that the GRF and joint moments data can accurately predict metabolic costs via ANN models, with netGRF being notably consistent. This emphasizes ANNs' role in biomechanics as a crucial method for estimating metabolic costs, impacting sports science, rehabilitation, assistive technology development, and fostering personalized advancements. [ABSTRACT FROM AUTHOR]

Published
2024
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22. Design and Evaluation of a Bilateral Semi-Rigid Exoskeleton to Assist Hip Motion.

Author

Mohammadzadeh Gonabadi, Arash, Antonellis, Prokopios, Dzewaltowski, Alex C., Myers, Sara A., Pipinos, Iraklis I., and Malcolm, Philippe

Subjects
ROBOTIC exoskeletons, COST control, WALKING speed, FREEDOM of movement, CENTER of mass
Abstract

This study focused on designing and evaluating a bilateral semi-rigid hip exoskeleton. The exoskeleton assisted the hip joint, capitalizing on its proximity to the body's center of mass. Unlike its rigid counterparts, the semi-rigid design permitted greater freedom of movement. A temporal force-tracking controller allowed us to prescribe torque profiles during walking. We ensured high accuracy by tuning control parameters and series elasticity. The evaluation involved experiments with ten participants across ten force profile conditions with different end-timings and peak magnitudes. Our findings revealed a trend of greater reductions in metabolic cost with assistance provided at later timings in stride and at greater magnitudes. Compared to walking with the exoskeleton powered off, the largest reduction in metabolic cost was 9.1%. This was achieved when providing assistance using an end-timing at 44.6% of the stride cycle and a peak magnitude of 0.11 Nm kg−1. None of the tested conditions reduced the metabolic cost compared to walking without the exoskeleton, highlighting the necessity for further enhancements, such as a lighter and more form-fitting design. The optimal end-timing aligns with findings from other soft hip exosuit devices, indicating a comparable interaction with this prototype to that observed in entirely soft exosuit prototypes. [ABSTRACT FROM AUTHOR]

Published
2024
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