Effects of Short-Term Concentric vs. Eccentric Resistance Training on Single Muscle Fiber MHC Distribution in Humans

Abstract

The purpose of this investigation was to determine the effects of a concentric vs. eccentric resistance training program on single muscle fiber myosin heavy chain (MHC) adaptations in humans. Fifteen sedentary, healthy males were divided into three groups: concentric training (CTG) (n = 6, 24.2 +/- 1.7 y, 181 +/- 2 cm, 82.5 +/- 4.6 kg), eccentric training (ETG) (n = 6, 23.7 +/- 1.6 y, 178 +/- 3 cm, 90.4 +/- 6.1 kg), and control (CTL) (n = 3, 23 +/- 1.5 y, 181 +/- 2 cm, 97 +/- 13.2 kg). The subjects performed 4 sets of 8 unilateral repetitions starting at 80 % of concentric 1-RM, 3 days/week for a total of 4 weeks. Subjects were tested pre- and post-training for concentric 1-RM. Muscle biopsies were obtained from the vastus lateralis pre- and post-training for determination of single fiber MHC isoform distribution using SDS-PAGE/silver staining (100 fibers analyzed/subject pre- and post-training). Fibers expressing more than one MHC isoform (i.e., hybrid fibers) were analyzed for relative MHC isoform proportions via densitometry. The training program resulted in a 19 % 1-RM strength gain for CTG (p < 0.05) with no change in ETG or CTL. MHC-IIx fibers decreased by 7 % in CTG (p < 0.05) and ETG had an 11 % increase in total hybrids (MHC-I/IIa + MHC-IIa/IIx) (p < 0.05). No other differences were noted in MHC distribution among the three groups. Densitometry analysis of hybrid fibers showed no change in relative MHC isoform proportions pre- to post-training for any group. These data suggest that the MHC distribution did not change dramatically as a result of 4 weeks of concentric vs. eccentric resistance training despite the increase in whole muscle strength from concentric muscle actions.

The effect of varying the time of concentric and eccentric muscle actions during resistance training on skeletal muscle adaptations in women

“…The increases in maximal strength for the three test modes varied from 21 to 44% in the present study and are comparable to reports of increases ranging from 12 to 67% with other investigations using similar muscle actions during training (Dudley et al 1991b;BenSira et al 1995) or with manipulation of muscle action completion time (Young and Bilby 1993;Morrissey et al 1998;Gillies and Docherty 1999). Contrary to this, Raue et al (2005) found a signiWcant increase in CON 1 RM strength after 4 weeks of CON resistance training but no changes with ECC training. Unfortunately, this latter research did not perform an ECC strength test.…”

“…This Wnding is supported by research in our laboratory (Putman et al 2004) as well as by other investigators (Adams et al 1993;Sharman et al 2001;Williamson et al 2001). Conversely, Raue et al (2005) did not observe many changes in MHC content of single Wbres after 4 weeks of either CON only or ECC only resistance training. The alteration in MHC content observed in the present study may be related to a reduction in hybrid Wbres co-expressing multiple MHC isoforms, resulting in an increase in the proportion of Wbres expressing MHCIIa only (Williamson et al 2001;Putman et al 2004).…”

The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis

“…Following a review of titles and abstracts, 66 full text articles were reviewed. When exclusion criteria were applied, only 20 studies satisfied the criteria to be included in the review 27464748495051525354555657585960616263. The main reasons for exclusion were: eccentric and concentric exercises not performed separately (n = 26); potential crossover effect (n = 9); participants with clinical conditions enrolled (n = 4); not published in a peer-review journal (n = 1); age of the participants (n = 2); and insufficient or incomplete description of the parameters of training (n = 4).…”

“…The total number of repetitions per session was variable (10 to 80) depending on the study. In 17 studies, exercise was performed with an isokinetic device that allowed for the control of angular velocity 27474849505152535455565758596061. In two studies that used a dynamic device for training, spotters were used to isolate eccentric and concentric contractions (eg, the participant performed the eccentric part of the movement, and a spotter lifted the weight during the concentric part) 6263.…”

Maximal Eccentric and Concentric Strength Discrepancies Between Young Men and Women for Dynamic Resistance Exercise

“…Moreover, it has recently been reported that resistance training using concentric (CON) and ECC contractions, with greater ECC loading, produces specific adaptations for a stronger, faster muscle, as indicated by greater IIx myosin adenosine triphosphatase gene expression using primarily isokinetic protocols (11,35,42). These findings have been validated through enhanced performance in Olympic lifters who trained with loads that were between 10 and 30% above their CON 1 repetitions maximum (RMs) across 6 weeks (13).…”