Studies done in trained individuals already make it abundantly clear that very little progress and signs of adaptation occur in response to shifting resistance training-related variables, but regardless, studies do often produce some results that suggest that some degree of muscle size and/or strength gains are indeed possible beyond the first year of training. However, upon closer inspection, some of these results are indeed dependent on the changing variable(s) they are subjected to, and how measures of size & strength are conducted.
![[1]](https://i0.wp.com/fizeek.com/wp-content/uploads/2023/08/image-3.png?resize=660%2C146&ssl=1)
![[1]](https://i0.wp.com/fizeek.com/wp-content/uploads/2023/08/image-5.png?resize=660%2C72&ssl=1)
![[1]](https://i0.wp.com/fizeek.com/wp-content/uploads/2023/08/image-4.png?resize=660%2C119&ssl=1)
The Glycogen Variable
During both aerobic & anaerobic exercise, a muscle’s glycogen reserves dwindle as glycogen oxidation (glycogenolysis) is carried out in endeavors to supply the working tissue with the energy substrates it needs to stay operational, and only after a resupply of carbohydrates in the aftermath of these training sessions do these reserves not only reattain previous stature, but also grow beyond what once was in certain circumstances. But because every gram of glycogen holds at minimum 3g of water, and potentially as much as 17g of water, the more expansive the glycogen reserves of a muscle tissue, the inevitably larger the cross-sectional area of the tissue will be.
Fernández-Elías VE et. al.
Now consider that many studies involve untrained individuals who will obligatorily experience glycogen storage expansion in response to the training they undergo. Consider even the studies that involve trained individuals who are taking on a training protocol that is often very different than what they’re accustomed to, again creating the potential for an obligatory glycogen storage expansion to meet the needs of the body in the face of this new training stimulus. Surely, glycogen metabolism is impacting the results of measurements of muscle size in most Exercise Science studies being pushed out, whether the authors are acknowledging it or not.
![[2]](https://i0.wp.com/fizeek.com/wp-content/uploads/2023/08/image-27.png?resize=508%2C443&ssl=1)
References
- Gentil P, Fisher J, Steele J, Campos MH, Silva MH, Paoli A, Giessing J, Bottaro M. Effects of equal-volume resistance training with different training frequencies in muscle size and strength in trained men. PeerJ. 2018 Jun 22;6:e5020. doi: 10.7717/peerj.5020. PMID: 29942690; PMCID: PMC6016534.
- Fernández-Elías VE, Ortega JF, Nelson RK, Mora-Rodriguez R. Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. Eur J Appl Physiol. 2015 Sep;115(9):1919-26. doi: 10.1007/s00421-015-3175-z. Epub 2015 Apr 25. PMID: 25911631.