Mitochondrial Efficiency: A Strength Athlete’s Missing Link

by Joseph Giandonato, PhD, MBA, CSCS

Analogous to the four seasons and FBS program coaching regimes, fitness trends come and go. Around a decade ago, legions of upper middle-class suburbanites, many of whom Gen-Xers and older millennials exiting their prime with musculoskeletal integrity akin to the eroding undercarriage of a twenty-year-old Chevy Silverado that’s endured harsh midwestern winters accompanied by endless barrages of rock salt, immersed themselves in a cocktail of WODs and gimmicky mobility modalities.

Instead of developing a bedrock of tried-and-true fitness qualities such as strength, flexibility, and work capacity inclusive of both anaerobic and aerobic bases, many disillusioned souls with broken bodies migrated to enchantingly challenging, but arbitrarily hatched, training sessions and band aid convalescents, such as dynamic figure four stretches and hip airplanes, seemingly plucked from thin air. It should be noted that developing mobility, particularly in the presence of strength to centrate or stabilize joints and body segments, is critical to optimizing musculoskeletal health and performance, however, often these pursuits are poorly executed.

Let’s not hold decades-old training transgressions against once well-intentioned iron enthusiasts but rather elucidate a non-gimmicky element on which recovery is predicated and is required for sustained success as a strength athlete. Enter mitochondrial efficiency.

Mitochondrial efficiency refers to how effectively mitochondria can convert nutrients, including byproducts, into usable energy known as ATP, or short for adenosine triphosphate, a high-energy phosphate group that is composed of an adenine base and three phosphate molecules attached to ribose. In other words, mitochondrial efficiency is the ability to achieve and maintain cellular homeostasis, or balance, amid metabolic demands. Optimal mitochondrial efficiency enables the body to stay calm, cool, and collected during chaos like a prime Black Mamba slithering through zone defenses and double teams deep in the Western Conference playoffs.

The body has a scant amount of ATP available on hand to facilitate immediate and immense energetic outputs such as stress hormone-mediate “fight or flight” responses. ATP is also produced in varying amounts and at varying rates by three distinct energy systems — phosphagen, glycolytic, and oxidative — within the body. ATP supply from the phosphagen energy system is the quickest, but the smallest, whereas its formation via the oxidative system is like a slow molasses drip, but the greatest of the systems. ATP production from glycolysis falls somewhere in the middle and it is here that improvements in mitochondrial function is realized.

During glycolysis, lactate is produced. Lactate diffuses to the mitochondria and oxidized to pyruvate where it is converted to acetyl-CoA which enters the Krebs Cycle and re-emerges as usable ATP. For this to occur, the mitochondria must be able to handle a significant amount of lactate and shuttle it to its reticulum where the process of oxidation to pyruvate is initiated. 

Trained individuals and those with greater mitochondrial density, which is observed among those engaging in regular aerobic exercise, have a greater capacity to clear and convert lactate into usable energy, which in turn will enhance intrasession recoverability.

Though training twice a day was shown to improve mitochondrial efficiency (Ghiarone et al., 2019), additional daily training sessions are not required. Instead, simply aiming for more training density by tightening up rest periods during accessory work and incorporating more aerobic exercise or non-exercise physical activity (NEPA) through walking and various forms of active and staggered commuting during the week will contribute to optimizing mitochondrial functioning.

Here are some measures that can be put into immediate practice:

1. Begin timing sessions or at the very least, time blocks of accessory work or portions of your session that are explicitly aimed at improving muscular endurance or hypertrophy. Strive to increase density, or the amount of work done in a fixed period of time, incrementally. Reduced rest periods are not recommended when using circa maximal loads or velocities or attempting biomechanically complex movements such as Olympic lifts and their variants.
2. Perform a battery of drills, corrective, and activation exercises in rapid succession to begin your session. For example, a dynamic warm-up of specific or non-specific movements can be performed from a stationary position or linearly or laterally, if space affords. An example warm up would be: jumping rope or performing line hops then progressing to linear ladder drills before progressing to movements performed through greater excursions such as Spiderman, lunge matrices, and bear crawls, then moving into high knees and skip variations prior to short sprint starts and directed barbell work that is part of a specific warm-up. The key here is to keep your heart rate up the entire time and ideally around 70% of your heart rate or higher, which will help you transition into more intense training.
3. Engage in aerobic exercise and NEPA that falls within Zone 2, or 60-70% of your maximum heart rate, which has been shown to confer improvements in mitochondrial performance (Meixner et al., 2025). Gradually increase the frequency, duration, and intensity of your cardio sessions. Take full advantage of great weather and do something active outdoors. Have a shopping errand? Walk to the store or refrain from fighting for the closest parking spot and briskly walk from your car to the entrance. Intermittent physical activity (NEPA included) adds up.

References

Ghiarone, T., Andrade-Souza, V.A., Learsi, S.K., Tomazini, F., Ataide-Silva, T., Sansonio, A., Fernandes, M.P., Saraiva, K.L., Figueiredo, R.C.B.Q., Tourneur, Y., Kuang, J., Lima-Silva, A.E., & Bishop, D.J. (2019). Twice-a-day training improves mitochondrial efficiency, but not mitochondrial biogenesis, compared with once-daily training. Journal of Applied Physiology, 127(3), 713–725. https://doi.org/10.1152/japplphysiol.00060.2019

Meixner, B., Filipas, L., Holmberg, H.-C., & Sperlich, B. (2025). Zone 2 intensity: a critical comparison of individual variability in different submaximal exercise intensity boundaries. Translational Sports Medicine, 2008291.https://doi.org/10.1155/tsm2/2008291

About the author

Joseph Giandonato, PhD, MBA, CSCS is an Assistant Professor of Exercise Science at an institution in the Northeastern US. Previously, Giandonato supported an award-winning employee wellness program at a major university in the Mid-Atlantic US while serving as an adjunct faculty member at several colleges and universities where he taught exercise physiology, statistics, and research methods. Giandonato previously served as a strength and conditioning coach and has extensive experience working with professional, collegiate, and high school athletes. His research interests include ergogenic aids, concurrent training, and exploring health behaviors of non-traditional undergraduate students.