Research article - (2022)21, 200 - 213
DOI:
https://doi.org/10.52082/jssm.2022.200
Effects of Upper Body Eccentric versus Concentric Strength Training and Detraining on Maximal Force, Muscle Activation, Hypertrophy and Serum Hormones in Women
Keijo Häkkinen1,, Robert U. Newton2, Simon Walker1, Arja Häkkinen3, Sonja Krapi1, Rebekka Rekola1, Päivi Koponen3, William J. Kraemer4, G. Gregory Haff5, Anthony J. Blazevich5, Kazunori Nosaka2,5, Juha Ahtiainen1
1Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
2Exercise Medicine Research Institute, School of Medical and Health Sciences, Edith Cowan University, Australia
3Faculty of Sport and Health Sciences, University of Jyväskylä, Finland
4Department of Human Sciences, The Ohio State University, Columbus, OH
5Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Australia

Keijo Häkkinen
✉ PhD. Professor Emeritus, Neuromuscular Research Center Biology of Physical Activity, Faculty of Sport and Health Sciences 40014 University of Jyväskylä, Finland
Email: keijo.hakkinen@jyu.fi
Received: 07-02-2022 -- Accepted: 25-03-2022
Published (online): 01-06-2022

ABSTRACT

Effects of eccentric (ECC) versus concentric (CON) strength training of the upper body performed twice a week for 10 weeks followed by detraining for five weeks on maximal force, muscle activation, muscle mass and serum hormone concentrations were investigated in young women (n = 11 and n = 12). One-repetition bench press (1RM), maximal isometric force and surface electromyography (EMG) of triceps brachii (TB), anterior deltoid (AD) and pectoralis major (PM), cross-sectional area (CSA) of TB (Long (LoH) and Lateral Head (LaH)) and thickness of PM, as well as serum concentrations of free testosterone, cortisol, follicle-stimulating hormone, estradiol and sex hormone-binding globulin were measured. ECC and CON training led to increases of 17.2 ± 11.3% (p < 0.001) and 13.1 ± 5.7% (p < 0.001) in 1RM followed by decreases of -6.6 ± 3.6% (p < 0.01) and -8.0 ± 4.5% (p < 0.001) during detraining, respectively. Isometric force increased in ECC by 11.4 ± 9.6 % (p < 0.05) from week 5 to 10, while the change in CON by 3.9±6.8% was not significant and a between group difference was noted (p < 0.05). Maximal total integrated EMG of trained muscles increased only in the whole subject group (p < 0.05). CSA of TB (LoH) increased in ECC by 8.7 ± 8.0% (p < 0.001) and in CON by 3.4 ± 1.6% (p < 0.01) and differed between groups (p < 0.05), and CSA of TB (LaH) in ECC by 15.7 ± 8.0% (p < 0.001) and CON by 9.7 ± 6.6% (p < 0.001). PM thickness increased in ECC by 17.7 ± 10.9% (p < 0.001) and CON by 14.0 ± 5.9% (p < 0.001). Total muscle sum value (LoH + LaH + PM) increased in ECC by 12.4 ± 6.9% (p < 0.001) and in CON by 7.1 ± 2.9% (p < 0.001) differing between groups (p < 0.05) and decreased during detraining in ECC by -6.5 ± 4.3% (p < 0.001) and CON by -6.1 ± 2.8% (p < 0.001). The post detraining combined sum value of CSA and thickness was in ECC higher (p < 0.05) than at pre training. No changes were detected in serum hormone concentrations, but baseline free testosterone levels in the ECC and CON group combined correlated with changes in 1RM (r = 0.520, p < 0.016) during training. Large neuromuscular adaptations of the upper body occurred in women during ECC, and CON training in 10 weeks. Isometric force increased only in response to ECC, and total muscle sum value increased more during ECC than CON training. However, no changes occurred in serum hormones, but individual serum-free testosterone baseline concentrations correlated with changes in 1RM during strength training in the entire group. Both groups showed significant decreases in neuromuscular performance and muscle mass during detraining, while post detraining muscle sum value was only in ECC significantly higher than at pre training.

Key words: Muscle force, training, EMG, mass, females, testosterone

Key Points
  • Maximal eccentric and concentric strength training in women for 10 weeks (only twice a week) led to great gains in dynamic strength of upper body.
  • Upper body muscle mass increased more after eccentric than concentric strength training.
  • During detraining for 5 weeks both groups showed decreases in strength and muscle mass.
  • However, post-detraining combined sum muscle mass value was only in ECC higher than at pre-training.








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