Georgios Mavropalias, Edith Cowan UniversityFollow
Leslie Calapre, Edith Cowan UniversityFollow
Michael Morici, Edith Cowan UniversityFollow
Wayne C. K. Poon, Edith Cowan UniversityFollow
Oliver R. Barley, Edith Cowan UniversityFollow
Elin Gray, Edith Cowan UniversityFollow
Anthony J. Blazevich, Edith Cowan UniversityFollow
Kazunori Nosaka, Edith Cowan UniversityFollow
European Journal of Applied Physiology
School of Medical and Health Sciences / Exercise Medicine Research Institute
Cancer Council Western Australia
Edith Cowan University
Australian Government Research Training Program
We examined changes in plasma creatine kinase (CK) activity, hydroxyproline and cell-free DNA (cfDNA) concentrations in relation to changes in maximum voluntary isometric contraction (MVIC) torque and delayed-onset muscle soreness (DOMS) following a session of volume-matched higher- (HI) versus lower-intensity (LI) eccentric cycling exercise.
Healthy young men performed either 5 × 1-min HI at 20% of peak power output (n = 11) or 5 × 4-min LI eccentric cycling at 5% of peak power output (n = 9). Changes in knee extensor MVIC torque, DOMS, plasma CK activity, and hydroxyproline and cfDNA concentrations before, immediately after, and 24–72 h post-exercise were compared between groups.
Plasma CK activity increased post-exercise (141 ± 73.5%) and MVIC torque decreased from immediately (13.3 ± 7.8%) to 48 h (6.7 ± 13.5%) post-exercise (P < 0.05), without significant differences between groups. DOMS was greater after HI (peak: 4.5 ± 3.0 on a 10-point scale) than LI (1.2 ± 1.0). Hydroxyproline concentration increased 40–53% at 24–72 h after both LI and HI (P < 0.05). cfDNA concentration increased immediately after HI only (2.3 ± 0.9-fold, P < 0.001), with a significant difference between groups (P = 0.002). Lack of detectable methylated HOXD4 indicated that the cfDNA was not derived from skeletal muscle. No significant correlations were evident between the magnitude of change in the measures, but the cfDNA increase immediately post-exercise was correlated with the maximal change in heart rate during exercise (r = 0.513, P = 0.025).
Changes in plasma hydroxyproline and cfDNA concentrations were not associated with muscle fiber damage, but the increased hydroxyproline in both groups suggests increased collagen turnover. cfDNA may be a useful metabolic-intensity exercise marker.
Mavropalias, G. (2020). Muscle damage and adaptations induced by eccentric cycling in relation to extracellular matrix. https://ro.ecu.edu.au/theses/2336