Acute elevations in serum hormones are attenuated after chronic training with traditional isoinertial but not accentuated eccentric loads in strength-trained men

Abstract

It has been proposed that the maintenance of acute hormonal responses reveal an efficacy of a training stimulus to evoke ongoing increases in strength and muscle mass. We previously observed that maximum strength continued to improve throughout a 10‐week period in an accentuated eccentric loading group (AEL) but not a traditional isoinertial loading (ISO) group. Therefore, this study investigated whether the magnitude of acute hormonal responses was greater (i.e., maintained) in AEL compared to ISO at the end of the training period. Subjects in AEL (eccentric load = concentric load + 40%) and ISO performed experimental loading tests (three sets of 10 repetitions in the leg press and knee extension exercises) during weeks 2 and 9 of the training period. Blood samples collected during these experimental loadings were analyzed for serum testosterone, growth hormone and cortisol concentrations. Maximum isometric knee extension torque (MVC) and lower‐limb lean mass were assessed before and after 5 and 10 weeks of training. Acute testosterone, growth hormone and cortisol responses to traditional isoinertial loading were reduced at the end of the training period but were not reduced after accentuated eccentric load training (P < 0.05‒0.1 between‐groups). Increases in MVC and lower‐limb lean mass over weeks 6‒10 were greater in AEL compared to ISO (MVC: 7.3 ± 5.4 vs. −0.4 ± 7.2%, P = 0.026 for between‐group difference; lower‐limb lean mass: 1.6 ± 2.2 vs. −0.2 ± 1.4%, P = 0.063 for between‐group difference). The maintenance of acute hormonal responses and continued strength gain in AEL but not ISO are consistent with the hypothesis that maintained acute responses indicate an efficacy of a training stimulus to evoke ongoing adaptation. However, since relationships between hormonal responses and training‐induced adaptations were not statistically significant, the data suggest that tracking of acute hormonal responses on an individual level may not provide a sensitive enough guide for decisions regarding program design and periodization.

Increased fascicle length but not patellar tendon stiffness after accentuated eccentric-load strength training in already-trained men

“…One possibility, therefore, is that increases in fascicle length might be induced by the imposition of fiber/fascicle strains. In contrast to other studies targeting the quadriceps muscles (Franchi et al 2014(Franchi et al , 2017, both total exercise volume and total work performed were similar in AEL and TRAD in the current study (Walker et al 2017), so training volume/work could not have impacted the results. Therefore, the greater training load may have been a stimulus.…”

Acute responses of comprehensive gonadosteroids and corticosteroids to resistance exercise before and after 10 weeks of supervised strength training

“…Of final note, the training‐induced changes in strength and muscle mass have been reported in a previous article (Walker et al., ). Those results indicated that, for some of the well‐trained subjects, the training programme did not improve strength and muscle mass after the 5 week time point, which is not unexpected in already‐trained subjects but should be considered when interpreting the acute hormonal responses presented.…”

“…Of final note, the training-induced changes in strength and muscle mass have been reported in a previous article (Walker et al, 2017).…”

“…The experimental exercise sessions took place before and after a 10 week period of supervised resistance training. This intervention consisted of training twice per week with a session of three × 6‐RM once per week and a session of three × 10‐RM once per week using bilateral leg‐press, unilateral knee‐extension and bilateral knee‐flexion exercises (for further details, see Walker et al., ). As noted in our previous publication, maximal isometric strength increased by 14.3 ± 10.7%, lower‐limb lean mass increased by 3.2 ± 2.4%, and volume load during the experimental resistance exercise sessions increased by 31.4 ± 29.3% as a consequence of training.…”

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“…The most frequently used methods are those revealing the characteristics of the endocrine system and the energy supply system reactions to physical loads of different intensity (Philippou et al, 2017). Thus, for example, an increase in the concentration of glucocorticoid hormone cortisol in the serum of athletes indicates a normal response to a stress stimulus (Walker et al, 2017). On the other hand, a decrease in the concentration of this hormone indicates that the load exceeds the primary level of adaptive capacity of the body.…”