Resistance Training Alters the Proportion of Skeletal Muscle Fibers but Not Brain Neurotrophic Factors in Young Adult Rats

Abstract

Antonio-Santos, J, Ferreira, DJS, Gomes Costa, GL, Matos, RJB, Toscano, AE, Manhães-de-Castro, R, and Leandro, CG. Resistance training alters the proportion of skeletal muscle fibers but not brain neurotrophic factors in young adult rats. J Strength Cond Res 30(12): 3531–3538, 2016—Resistance training (RT) is related to improved muscular strength and power output. Different programs of RT for rats have been developed, but peripheral and central response has not been evaluated directly in the same animal. To test the hypothesis that RT induces central and peripheral adaptations, this study evaluated the effects of a RT on the performance of a weekly maximum overload test, fiber-type typology, and brain neurotrophic factors in young adult rats. Thirty-one male Wistar rats (65 ± 5 days) were divided in 2 groups: nontrained (NT, n = 13) and trained (T, n = 18). Trained group was submitted to a program of RT ladder climbing, gradually added mass, 5 days per week during 8 weeks at 80% of individual maximum overload. This test was weekly performed to adjust the individual load throughout the weeks for both groups. After 48 hours from the last session of exercise, soleus and extensor digital longus (EDL) muscles were removed for myofibrillar ATPase staining analysis. Spinal cord, motor cortex, and cerebellum were removed for RT-PCR analysis of BDNF and insulin-like growth factor-1 (IGF-1) gene expression. In EDL muscle, T animals showed an increase in the proportion of type IIb fibers and a reduction of type IIa fibers. Insulin-like growth factor-1 gene expression was reduced in the cerebellum of T animals (NT: 1.025 ± 0.12; T: 0.57 ± 0.11). Our data showed that 8 weeks of RT were enough to increase maximum overload capacity and the proportion of glycolytic muscle fibers, but there were no associations with the expression of growth neurotrophic factors.

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

“…Rodent sample number per group varied from 4 to 18 rats. Twenty‐three articles described the rat's initial body mass (Antonio‐Santos et al., 2016; Cassilhas et al., 2013; Deus et al., 2012; Deschenes et al., 1994; Deschenes, Sherman, Roby, Glass, & Harris, 2015; Domingos et al., 2012; Gil & Kim, 2015; Grans et al., 2014; Hornberger & Farrar, 2004; Jung et al., 2015; Krause Neto & Gama, 2017; Lee, Hong, & Kim, 2016; Mônico‐Neto et al, 2015; Nascimento et al., 2013; Neves et al, 2019; Padilha et al, 2017; Padilha et al., 2019; Prestes et al, 2009, 2012; Ribeiro et al, 2017; Shamsi et al, 2013; Souza et al., 2014; Tibana et al, 2017). Ladder‐based equipment structure varied from 1–1.3 m of height and 70–90° of inclination between studies.…”

“…Nineteen articles published data about the maximum load‐carrying tests protocol (Antonio‐Santos et al., 2016; Carbone et al., 2017; Chi et al., 2020; Deus et al., 2012; Domingos et al., 2012; Gil & Kim, 2015; Gomes, Borges, Rossi, Moura, & Medeiros, 2017; Grans et al., 2014; Hornberger & Farrar, 2004; Kwon et al, 2018; Lim et al, 2018; Mônico‐Neto et al, 2015; Neves et al, 2019; Padilha et al, 2017; Padilha et al., 2019; Perrilhão et al, 2019; Prestes et al, 2009; Souza et al., 2014; Souza et al, 2017). LRT presented a positive effect on the maximum load‐carrying capacity (16 studies, SMD 12.37, 95% CI [9.36, 15.37], p < .00001, I 2 = 90%, Figure 11).…”

Myotendinous junction plasticity in aged ovariectomized rats submitted to aquatic training

“…According to Gobbi (1997), in order to optimize the quality of life in elderly and the prevention of pathologies in this process, it is fundamental the preservation of muscular functional capacity. The soleus presents anti‐gravitational postural function because of the high constitution of type I muscle fibers (Antonio‐Santos et al, ). The strength generated by the soleus muscle plays an important role in position and locomotion.…”

Muscle hypertrophy and muscle strength: dependent or independent variables? A provocative review

“…a training based on the movement of body segments with application of a progressively increasing load. Various protocols have been designed for this purpose, for example inviting rats to climb a vertical ladder carrying a progressive load on the tail (5 days per week, during 8 weeks, 44 or 4 days per week for 26 weeks 45 ) to receive a reward. With this protocol, hypertrophy of EDL (+ 12% ) and soleus (+ 15% ) was not accompanied by any change in specific tension and by a modest improvement in fatigue resistance.…”