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In-depth Notes on Eccentric Cycling Responses During HIIT Training

Original Research Overview

  • Title: The Acute Physiological Responses of Eccentric Cycling During the Recovery Periods of a High Intensity Concentric Cycling Interval Session.
  • Authors: Amelia J. Harrison, Catriona A. Burdon, Herbert Groeller, Gregory E. Peoples.
  • Published: 17 April 2020 in Frontiers in Physiology.
  • DOI: 10.3389/fphys.2020.00336

Introduction to HIIT and Eccentric Cycling

  • High Intensity Interval Training (HIIT): Involves intervals of high-intensity exercise interspersed with low-intensity recovery.
  • Eccentric Cycling: In this study, eccentric cycling was introduced during recovery phases to evaluate its effects on physiological responses.
  • The study explores cardiopulmonary, thermal, and psycho-physiological changes during recovery periods in HIIT sessions.

Study Design and Methodology

  • Participants: 12 males, average age 28 years, engaged in moderate to vigorous physical activity.
  • Trials Conducted: Two high-intensity interval cycling trials separated by 7-10 days:
    • CONR (Concentric Recovery): Participants cycled concentrically at 30% Peak Power Output (PPO) during recovery.
    • ECCR (Eccentric Recovery): Participants cycled eccentrically at 60% PPO during recovery.
  • Measurements: Various physiological parameters were recorded, including:
    • Oxygen consumption (VO2)
    • Heart rate (HR)
    • Rate of Perceived Exertion (RPE)
    • Skin and core temperatures
  • Statistical Analysis: Two-way repeated measures ANOVA, t-tests for comparisons between conditions.

Key Findings

  • Equal External Work: The workload during the high-intensity work intervals was equivalent for both trials, confirming that both methods provided similar intensity.
  • Recovery Periods:
    • Higher workload in ECCR (196 ± 3 W) compared to CONR (93 ± 3 W) but lower oxygen consumption in ECCR (1.20 L·min−1) compared to CONR (1.51 L·min−1).
    • No significant difference in heart rate between recovery types.
  • Muscle Oxygenation: Muscle tissue oxygenation decreased during high-intensity work but tended toward baseline faster during CONR recovery compared to ECCR.

Thermal Responses

  • Core and mean skin temperatures increased during both trials, with higher skin temperature observed during ECCR recovery (P < 0.05).
  • Participants in the ECCR trial reported more muscle soreness 24-48 hours post-exercise (P < 0.05).

Subjective Responses

  • Trial Preference: A majority (10 out of 12) preferred ECCR, rating it as more achievable (82.8 ± 11.4 mm) compared to CONR (79.4 ± 15.9 mm, P < 0.01).

Conclusions

  • The replacement of concentric cycling with eccentric cycling during HIIT recovery sessions maximizes external work without compromising cardiopulmonary and metabolic demands.
  • The study provides evidence that eccentric cycling can be a beneficial training modality for enhancing workout efficiency.

Implications for Future Research

  • Further exploration is warranted into the longer-term adaptations from ECCR to understand changes in muscle performance and recovery.
  • Consideration of how these findings could influence training protocols, especially in special populations and rehabilitation settings.

References

  • References included detailed studies on physiological adaptations, HIIT, muscle activation strategies, and the benefits of eccentric exercise methods. This research highlights the novel implementation of eccentric cycling and its potential application to improve training efficiency in both healthy and clinical populations.