scholarly journals Skeletal Muscle Adaptations and Performance Outcomes Following a Step and Exponential Taper in Strength Athletes

2021 ◽  
Vol 12 ◽  
Author(s):  
S. Kyle Travis ◽  
Kevin A. Zwetsloot ◽  
Iñigo Mujika ◽  
Michael H. Stone ◽  
Caleb D. Bazyler
Keyword(s):  
Skeletal Muscle ◽  
Vastus Lateralis ◽  
Performance Outcomes ◽  
Maximal Strength ◽  
Cross Sectional ◽  
Time Effects ◽  
Muscle Adaptations ◽  
Skeletal Muscle Adaptations ◽  
Whole Muscle ◽  
Mhc Iia

Before major athletic events, a taper is often prescribed to facilitate recovery and enhance performance. However, it is unknown which taper model is most effective for peaking maximal strength and positively augmenting skeletal muscle. Thus, the purpose of this study was to compare performance outcomes and skeletal muscle adaptations following a step vs. an exponential taper in strength athletes. Sixteen powerlifters (24.0 ± 4.0 years, 174.4 ± 8.2 cm, 89.8 ± 21.4 kg) participated in a 6-week training program aimed at peaking maximal strength on back squat [initial 1-repetition-maximum (1RM): 174.7 ± 33.4 kg], bench press (118.5 ± 29.9 kg), and deadlift (189.9 ± 41.2 kg). Powerlifters were matched based on relative maximal strength, and randomly assigned to either (a) 1-week overreach and 1-week step taper or (b) 1-week overreach and 3-week exponential taper. Athletes were tested pre- and post-training on measures of body composition, jumping performance, isometric squat, and 1RM. Whole muscle size was assessed at the proximal, middle, and distal vastus lateralis using ultrasonography and microbiopsies at the middle vastus lateralis site. Muscle samples (n = 15) were analyzed for fiber size, fiber type [myosin-heavy chain (MHC)-I, -IIA, -IIX, hybrid-I/IIA] using whole muscle immunohistochemistry and single fiber dot blots, gene expression, and microRNA abundance. There were significant main time effects for 1RM squat (p < 0.001), bench press (p < 0.001), and deadlift, (p = 0.024), powerlifting total (p < 0.001), Wilks Score (p < 0.001), squat jump peak-power scaled to body mass (p = 0.001), body mass (p = 0.005), fat mass (p = 0.002), and fat mass index (p = 0.002). There were significant main time effects for medial whole muscle cross-sectional area (mCSA) (p = 0.006) and averaged sites (p < 0.001). There was also a significant interaction for MHC-IIA fiber cross-sectional area (fCSA) (p = 0.014) with post hoc comparisons revealing increases following the step-taper only (p = 0.002). There were significant main time effects for single-fiber MHC-I% (p = 0.015) and MHC-IIA% (p = 0.033), as well as for MyoD (p = 0.002), MyoG (p = 0.037), and miR-499a (p = 0.033). Overall, increases in whole mCSA, fCSA, MHC-IIA fCSA, and MHC transitions appeared to favor the step taper group. An overreach followed by a step taper appears to produce a myocellular environment that enhances skeletal muscle adaptations, whereas an exponential taper may favor neuromuscular performance.

Eccentric ergometry: increases in locomotor muscle size and strength at low training intensities

2000 ◽  
Vol 278 (5) ◽  
pp. R1282-R1288 ◽  
Author(s):  
P. C. LaStayo ◽  
D. J. Pierotti ◽  
J. Pifer ◽  
H. Hoppeler ◽  
S. L. Lindstedt
Keyword(s):  
Energy Demand ◽  
Size Composition ◽  
Muscle Size ◽  
Trained Group ◽  
Cross Sectional ◽  
Functional Changes ◽  
Cycle Ergometers ◽  
Muscle Adaptations ◽  
Fiber Size ◽  
Skeletal Muscle Adaptations

Lengthening (eccentric) muscle contractions are characterized by several unusual properties that may result in unique skeletal muscle adaptations. In particular, high forces are produced with very little energy demand. Eccentrically trained muscles gain strength, but the specific nature of fiber size and composition is poorly known. This study assesses the structural and functional changes that occur to normal locomotor muscle after chronic eccentric ergometry at training intensities, measured as oxygen uptake, that do not influence the muscle when exercised concentrically. Male subjects trained on either eccentric or concentric cycle ergometers for 8 wk at a training intensity starting at 54% and ending at 65% of their peak heart rates. The isometric leg strength increased significantly in the eccentrically trained group by 36%, as did the cross-sectional area of the muscle fiber by 52%, but the muscle ultrastructure remained unchanged. There were no changes in either fiber size, composition, or isometric strength in the concentrically trained group. The responses of muscle to eccentric training appear to be similar to resistance training.

Skeletal Muscle Adaptations to Prolonged Exposure to Extreme Altitude: A Role of Physical Activity?

2008 ◽  
Vol 9 (4) ◽  
pp. 311-317 ◽  
Author(s):  
Masao Mizuno ◽  
Gabrielle K Savard ◽  
Nils-Holger Areskog ◽  
Carsten Lundby ◽  
Bengt Saltin
Keyword(s):  
Physical Activity ◽  
Skeletal Muscle ◽  
Prolonged Exposure ◽  
Muscle Adaptations ◽  
Extreme Altitude ◽  
Skeletal Muscle Adaptations

scholarly journals Training program-induced skeletal muscle adaptations in two men with myotonic dystrophy type 1

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Marie-Pier Roussel ◽  
Marika Morin ◽  
Mélina Girardin ◽  
Anne-Marie Fortin ◽  
Mario Leone ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Training Program ◽  
Myotonic Dystrophy ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Muscle Adaptations ◽  
Skeletal Muscle Adaptations

scholarly journals The ontogeny of skeletal muscle adaptations that enable long deep dives in Weddell seals

2008 ◽  
Vol 22 (S1) ◽  
Author(s):  
Shane B Kanatous ◽  
Thomas J Hawke ◽  
Stephen J Trumble ◽  
Linnea E Pearson ◽  
Randall W Davis
Keyword(s):  
Skeletal Muscle ◽  
Weddell Seals ◽  
Muscle Adaptations ◽  
Skeletal Muscle Adaptations

Skeletal muscle adaptations in elastic resistance-trained young men and women

2001 ◽  
Vol 86 (2) ◽  
pp. 112-118 ◽  
Author(s):  
David Hostler ◽  
Chris Schwirian ◽  
Gerson Campos ◽  
Kumika Toma ◽  
Matthew Crill ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Young Men ◽  
Men And Women ◽  
Elastic Resistance ◽  
Muscle Adaptations ◽  
Skeletal Muscle Adaptations

scholarly journals Pterostilbene Enhances Endurance Capacity via Promoting Skeletal Muscle Adaptations to Exercise Training in Rats

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 186 ◽  
Author(s):  
Jiawei Zheng ◽  
Wujian Liu ◽  
Xiaohui Zhu ◽  
Li Ran ◽  
Hedong Lang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Mitochondrial Biogenesis ◽  
C2c12 Myotubes ◽  
Endurance Capacity ◽  
Muscle Adaptations ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Skeletal Muscle Adaptations

It has been demonstrated that skeletal muscle adaptions, including muscle fibers transition, angiogenesis, and mitochondrial biogenesis are involved in the regular exercise-induced improvement of endurance capacity and metabolic status. Herein, we investigated the effects of pterostilbene (PST) supplementation on skeletal muscle adaptations to exercise training in rats. Six-week-old male Sprague Dawley rats were randomly divided into a sedentary control group (Sed), an exercise training group (Ex), and exercise training combined with 50 mg/kg PST (Ex + PST) treatment group. After 4 weeks of intervention, an exhaustive running test was performed, and muscle fiber type transformation, angiogenesis, and mitochondrial content in the soleus muscle were measured. Additionally, the effects of PST on muscle fiber transformation, paracrine regulation of angiogenesis, and mitochondrial function were tested in vitro using C2C12 myotubes. In vivo study showed that exercise training resulted in significant increases in time-to-exhaustion, the proportion of slow-twitch fibers, muscular angiogenesis, and mitochondrial biogenesis in rats, and these effects induced by exercise training could be augmented by PST supplementation. Moreover, the in vitro study showed that PST treatment remarkably promoted slow-twitch fibers formation, angiogenic factor expression, and mitochondrial function in C2C12 myotubes. Collectively, our results suggest that PST promotes skeletal muscle adaptations to exercise training thereby enhancing the endurance capacity.

scholarly journals Low-load resistance training to task failure with and without blood flow restriction: muscular functional and structural adaptations

2020 ◽  
Vol 318 (2) ◽  
pp. R284-R295 ◽  
Author(s):  
Christopher Pignanelli ◽  
Heather L. Petrick ◽  
Fatemeh Keyvani ◽  
George J. F. Heigenhauser ◽  
Joe Quadrilatero ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Resistance Training ◽  
Resistance Exercise ◽  
Load Resistance ◽  
Muscle Endurance ◽  
Flow Restriction ◽  
Muscle Adaptations ◽  
Low Load ◽  
Skeletal Muscle Adaptations

The application of blood flow restriction (BFR) during resistance exercise is increasingly recognized for its ability to improve rehabilitation and for its effectiveness in increasing muscle hypertrophy and strength among healthy populations. However, direct comparison of the skeletal muscle adaptations to low-load resistance exercise (LL-RE) and low-load BFR resistance exercise (LL-BFR) performed to task failure is lacking. Using a within-subject design, we examined whole muscle group and skeletal muscle adaptations to 6 wk of LL-RE and LL-BFR training to repetition failure. Muscle strength and size outcomes were similar for both types of training, despite ~33% lower total exercise volume (load × repetition) with LL-BFR than LL-RE (28,544 ± 1,771 vs. 18,949 ± 1,541 kg, P = 0.004). After training, only LL-BFR improved the average power output throughout the midportion of a voluntary muscle endurance task. Specifically, LL-BFR training sustained an 18% greater power output from baseline and resulted in a greater change from baseline than LL-RE (19 ± 3 vs. 3 ± 4 W, P = 0.008). This improvement occurred despite histological analysis revealing similar increases in capillary content of type I muscle fibers following LL-RE and LL-BFR training, which was primarily driven by increased capillary contacts (4.53 ± 0.23 before training vs. 5.33 ± 0.27 and 5.17 ± 0.25 after LL-RE and LL-BFR, respectively, both P < 0.05). Moreover, maximally supported mitochondrial respiratory capacity increased only in the LL-RE leg by 30% from baseline ( P = 0.006). Overall, low-load resistance training increased indexes of muscle oxidative capacity and strength, which were not further augmented with the application of BFR. However, performance on a muscle endurance test was improved following BFR training.

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