Acute physiological responses to eccentric cycling: a systematic review and meta-analysis.

Area of Science:

• Exercise Physiology
• Sports Science
• Rehabilitation Medicine

Background:

• Eccentric cycling (ECCCYC) shows promise for exercise treatment in individuals with low exercise tolerance.
• Limited data exists on acute physiological responses to ECCCYC, hindering optimal exercise prescription.
• This study compares acute physiological responses between ECCCYC and concentric cycling (CONCYC).

Approach:

• A systematic literature search was conducted across PubMed, Embase, and ScienceDirect databases until November 2021.
• Studies measuring cardiorespiratory, metabolic, and perceptual responses to ECCCYC and CONCYC were included.
• Bayesian multilevel meta-analysis models were employed to compare physiological responses between the two cycling modalities.

Key Points:

• ECCCYC resulted in lower oxygen consumption (V̇O2), ventilation (V̇E), heart rate (HR), blood lactate ([BLa]), and rating of perceived exertion (RPE) compared to CONCYC at the same absolute power output.
• When matched for V̇O2, ECCCYC demonstrated greater cardiovascular strain, indicated by higher HR, cardiac output (Q), mean arterial pressure (MAP), plasma norepinephrine, and lower stroke volume (SV).

Conclusions:

• Prescribing ECCCYC based on CONCYC workloads appears safe and feasible for rehabilitation.
• Caution is advised when prescribing ECCCYC based on V̇O2 from CONCYC due to potential cardiovascular overload.
• Further research is needed to refine ECCCYC prescription guidelines, particularly for clinical populations.