Endurance Training Increases the Running Performance of Untrained Men without Changing the Mitochondrial Volume Density in the Gastrocnemius Muscle

Abstract

The activity and quantity of mitochondrial proteins and the mitochondrial volume density (MitoVD) are higher in trained muscles; however, the underlying mechanisms remain unclear. Our goal was to determine if 20 weeks’ endurance training simultaneously increases running performance, the amount and activity of mitochondrial proteins, and MitoVD in the gastrocnemius muscle in humans. Eight healthy, untrained young men completed a 20-week moderate-intensity running training program. The training increased the mean speed of a 1500 m run by 14.0% (p = 0.008) and the running speed at 85% of maximal heart rate by 9.6% (p = 0.008). In the gastrocnemius muscle, training significantly increased mitochondrial dynamics markers, i.e., peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) by 23%, mitochondrial transcription factor A (TFAM) by 29%, optic artrophy-1 (OPA1) by 31% and mitochondrial fission factor (MFF) by 44%, and voltage-dependent anion channel 1 (VDAC1) by 30%. Furthermore, training increased the amount and maximal activity of citrate synthase (CS) by 10% and 65%, respectively, and the amount and maximal activity of cytochrome c oxidase (COX) by 57% and 42%, respectively, but had no effect on the total MitoVD in the gastrocnemius muscle. We concluded that not MitoVD per se, but mitochondrial COX activity (reflecting oxidative phosphorylation activity), should be regarded as a biomarker of muscle adaptation to endurance training in beginner runners.

Metabolic flexibility in postmenopausal women: Hormone replacement therapy is associated with higher mitochondrial content, respiratory capacity, and lower total fat mass

“…Typically, elevated CS activity, thus mitochondrial content, correlates with increased VO 2 peak 45 . Notably, in our investigation, despite identifying a higher mitochondrial content in the HT group, no differences in VO 2 peak per FFM were observed between groups.…”

“…Typically, elevated CS activity, thus mitochondrial content, correlates with increased VO 2 peak. 45 Notably, in our investigation, despite identifying a higher mitochondrial content in the HT group, no differences in VO 2 peak per FFM were observed between groups. It is pertinent to acknowledge that VO 2 peak is predominantly dictated by central parameters, whereas peripheral adaptations, inclusive of augmented mitochondrial function or content, play a crucial role in mitigating peripheral fatigue.…”

Development of endurance in physical education lessons with the use of outdoor games

“…Endurance plays an essential role in optimizing vital activity, acts as an important component of physical health and, in turn, serves as a prerequisite for the development of special endurance 7,18,19 .…”

Advances in exercise to alleviate sarcopenia in older adults by improving mitochondrial dysfunction

“…Furthermore, resistance training for 10 weeks can also increase the levels of Mfn1, Mfn2, and Opa1 proteins in older people ( Mesquita et al, 2020 ). Aerobic exercise for 20 weeks can increase the levels of OPA1 and MFF in the gastrocnemius muscle of healthy adult males ( Zoladz et al, 2022 ). The use of HIIT and MICT for 12 weeks has been shown to reduce Drp1 and FIS1 levels and to increase the levels of Mfn1, Mfn2, and Opa1 to promote mitochondrial fusion ( Li B. et al, 2019 ).…”