Total training load may explain similar strength gains and muscle hypertrophy seen in aged rats submitted to resistance training and anabolic steroids

Neto, Walter Krause; Silva, Wellington de Assis; Ciena, Adriano Polican; Bocalini, Danilo Sales; Nucci, Ricardo Aparecido Baptista; Anaruma, Carlos Alberto; Gama, Eliane Florêncio

doi:10.1080/13685538.2017.1365832

Cited by 14 publications

(8 citation statements)

References 48 publications

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“…For example, in the fifth climb, 100% plus 30 g, in the sixth 100% plus 60 g, and so on, until the ninth climb were completed or until exhaustion, at 120‐s intervals between the climbs. The load was fixed to the proximal region of the tail (Krause Neto et al, 2016, 2018).…”

Section: Methodsmentioning

confidence: 99%

Repercussions on sarcomeres of the myotendinous junction and the myofibrillar type adaptations in response to different trainings on vertical ladder

Rocha

Neto

Sant'Ana

et al. 2020

Microscopy Res & Technique

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The myofibrillary types establish to the skeletal muscle functional and adaptive properties that influence the sarcomeric arrangement during muscle contraction and may have repercussions on an important related force transmission region of the locomotor apparatus, the myotendinous junction (MTJ). This study aimed to describe changes in myofibrillary type and sarcomeric lengths in the belly muscle and MTJ of the soleus and plantaris muscles associated with training protocols in vertical ladder. Thirty adults male Wistar rats were divided into three groups (n = 10): Control (CTR), No‐load Training (NLT), and Load Training (LT). Morphoquantitative analysis of different fibers types and sarcomere lengths were performed in distinct regions of plantaris and soleus muscles. In the plantaris muscle with both trainings, there was an increase in the cross‐sectional area (CSA) in Type I and II fibers (p < .0001) while sarcomeric lengths revealed greater lengths in the proximal and distal sarcomeres of NLT, although in the LT we found greater lengths in the belly and MTJ sarcomeres. The soleus muscle showed an increase in CSA muscle fiber only in the NLT (p < .0001) and revealed alterations in belly and MTJ sarcomere lengths with training. We concluded that plantaris muscle has an adaptive effect directly associated with training load, with hypertrophy in both trainings and sarcomere length inverse from belly and MTJ, in LT associated with increased force generation and transmission at the MTJ, although soleus muscle has a lower adaptive response to training stimuli with variation in the belly and distal sarcomere of the MTJ.

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Section: Methodsmentioning

confidence: 99%

Repercussions on sarcomeres of the myotendinous junction and the myofibrillar type adaptations in response to different trainings on vertical ladder

Rocha

Neto

Sant'Ana

et al. 2020

Microscopy Res & Technique

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“…From the 5th climb, rats were subjected to 100% load plus 30 g of extra weight by climb until the nine climbs were completed or exhaustion occurred. The protocol was repeated 3×/week for 8 weeks, for a total of 24 training sessions 41 .…”

Section: Methodsmentioning

confidence: 99%

Myotendinous junction adaptations to ladder-based resistance training: identification of a new telocyte niche

Neto

Rocha

Barbosa

et al. 2020

Sci Rep

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The present study shows chronic adjustments in the myotendinous junction (MTJ) in response to different ladder-based resistance training (LRT) protocols. Thirty adult male Wistar rats were divided into groups: sedentary (S), calisthenics (LRT without additional load [C]), and resistance-trained (LRT with extra weight [R]). We demonstrated longer lengths of sarcoplasmatic invaginations in the trained groups; however, evaginations were seen mainly in group R. We showed a greater thickness of sarcoplasmatic invaginations in groups C and R, in addition to greater evaginations in R. We also observed thinner basal lamina in trained groups. The support collagen layer (SCL) adjacent to the MTJ and the diameters of the transverse fibrils were larger in R. We also discovered a niche of telocytes in the MTJ with electron micrographs of the plantar muscle and with immunostaining with CD34+ in the gastrocnemius muscle near the blood vessels and pericytes. We concluded that the continuous adjustments in the MTJ ultrastructure were the result of tissue plasticity induced by LRT, which is causally related to muscle hypertrophy and, consequently, to the remodeling of the contact interface. Also, we reveal the existence of a collagen layer adjacent to MTJ and discover a new micro anatomic location of telocytes. The myotendinous junction (MTJ) consists of a highly specific anatomical region in which the sarcoplasmatic membranes connect to bundles of extracellular matrix (ECM) collagen fibers 1. Due to its functionality, MTJ represents the region with the highest transmission of force 2,3. Morphologically, MTJ presents projections that penetrate the muscle tissue, parallel and directed to the myofibrils, forming sarcoplasmatic invaginations. Currently, we know that its development is mainly influenced by the interactions between myoblasts and ECM elements 4,5. The basal lamina of muscle fiber creates a supramolecular connection structure composed of different levels of proteins from the laminin and collagen polymers located in the ECM 6. This arrangement contributes structurally to the transmission of force, adapting, remodeling, and consequently affecting the macroscopic tendon structure to different stimuli 7,8. Initially, telocytes were described as interstitial Cajal cells 9. Telocytes are interstitial cells of stromal origin with an oval shape, and a heterochromatic nucleus with moniliform projections denominated telopodes, which characterize its morphological classification according to the number of projections 9,10. They are founded in the interstitium of tissues such as the testicle 9 , smooth and cardiac muscle 11 , human tongue 10 , pancreas 12 , and liver 13. It can be identified by the electronic microscopy, immunohistochemistry, and CD34+/immunostaining 14. Recently, telocytes have been found in proximity to and engaging in possible interactions with satellite cells 10. The telocytes projections have terminals (pods) with mitochondria that form junctions with adjacent cells, and they have caveolae that perform exocytos...

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“…Such controversy was generated from the apparent differences found between the equipment used for the training of rodents and humans. However, since the ladder‐based resistance training model (LRT) proposed by Hornberger and Farrar (2004), a large amount of evidence has emerged, and greater control of training variables has been investigated and better controlled in experimental resistance training (Krause Neto et al., 2016, 2018; Luciano et al, 2017; Tibana et al, 2017). Despite this, there is still some doubt as to the efficiency of this training model in stimulating muscle hypertrophy of different muscle types in young and adult rats (Hornberger & Farrar, 2004; Son et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Muscle hypertrophy and ladder‐based resistance training for rodents: A systematic review and meta‐analysis

et al. 2020

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This study aimed to review the effects of ladder‐based resistance training (LRT) on muscle hypertrophy and strength in rodents through a systematic review with meta‐analysis. We systematically searched PubMed/Medline, SportDiscuss, Scopus, Google Scholar, Science Direct, and Scielo database on May 18, 2020. Thirty‐four studies were included measuring total (mCSA) or mean muscle fibers cross‐sectional area (fCSA) or maximum load‐carrying capacity (MLCC) or muscle mass (MM). About the main results, LRT provides sufficient mechanical stimulation to increase mCSA and fCSA. Meta‐analysis showed a significant overall effect on the fCSA (SMD 1.89, 95% CI [1.18, 2.61], p < .00001, I2 = 85%); however, subgroup analysis showed that some muscle types might not be hypertrophied through the LRT. Meta‐analysis showed a significant training effect on the MM (SMD 0.92, 95% CI [0.52, 1.32], p < .00001, I2 = 72%). Sub‐group analysis revealed that soleus (SMD 1.32, 95% CI [0.11, 2.54], p = .03, I2 = 86%) and FHL (SMD 1.92, 95% CI [1.00, 2.85], p < .0001, I2 = 71%) presented significant training effects, despite moderate heterogeneity levels (I2 = 72%). MLCC increases considerably after a period of LRT, regardless of its duration and the characteristics of the protocols (SMD 12.37, 95% CI [9.36, 15.37], p < .00001, I2 = 90%). Through these results, we reach the following conclusions: (a) LRT is efficient to induce muscle hypertrophy, although this effect varies between different types of skeletal muscles, and; (b) the ability of rodents to carry load increases regardless of the type and duration of the protocol used.

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Total training load may explain similar strength gains and muscle hypertrophy seen in aged rats submitted to resistance training and anabolic steroids

Cited by 14 publications

References 48 publications

Repercussions on sarcomeres of the myotendinous junction and the myofibrillar type adaptations in response to different trainings on vertical ladder

Repercussions on sarcomeres of the myotendinous junction and the myofibrillar type adaptations in response to different trainings on vertical ladder

Myotendinous junction adaptations to ladder-based resistance training: identification of a new telocyte niche

Muscle hypertrophy and ladder‐based resistance training for rodents: A systematic review and meta‐analysis

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