scholarly journals Resistance Training does not Induce Uniform Adaptations to Quadriceps Muscles

2018 ◽  
Author(s):  
Gerald T. Mangine ◽  
Michael J. Redd ◽  
Adam M. Gonzalez ◽  
Jeremy R. Townsend ◽  
Adam J Wells ◽  
...  
Keyword(s):  
Resistance Training ◽  
High Intensity ◽  
Repeated Measures ◽  
Vastus Lateralis ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Muscle Size ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Resistance Training Program

AbstractResistance training may differentially affect morphological adaptations along the length of uni-articular and bi-articular muscles. The purpose of this study was to compare changes in muscle morphology along the length of the rectus femoris (RF) and vastus lateralis (VL) in response to resistance training. Following a 2-wk preparatory phase, 15 resistance-trained men (24.0 ± 3.0 y, 90.0 ± 13.8 kg, 174.9 ± 20.7 cm) completed pre-training (PRE) assessments of muscle thickness (MT), pennation angle (PA), cross-sectional area (CSA), and echo-intensity in the RF and VL at 30, 50, and 70% of each muscle’s length; fascicle length (FL) was estimated from respective measurements of MT and PA within each muscle and region. Participants then began a high intensity, low volume (4 × 3 − 5 repetitions, 3min rest) lower-body resistance training program, and repeated all PRE-assessments after 8 weeks (2 d · wk−1) of training (POST). Although three-way (muscle [RF, VL] × region [30, 50, 70%] × time [PRE, POST]) repeated measures analysis of variance did not reveal significant interactions for any assessment of morphology, significant simple (muscle × time) effects were observed for CSA (p = 0.002) and FL (p = 0.016). Specifically, average CSA changes favored the VL (2.96 ± 0.69 cm2, pp < 0.001) over the RF (0.59 ± 0.20 cm2, p = 0.011), while significant decreases in average FL were noted for the RF (–1.03 ± 0.30 cm, p = 0.004) but not the VL (–0.05 ± 0.36 cm, p = 0.901). No other significant differences were observed. The findings of this study demonstrate the occurrence of non-homogenous adaptations in RF and VL muscle size and architecture following 8 weeks of high-intensity resistance training in resistance-trained men. However, training does not appear to influence region-specific adaptations in either muscle.

Early skeletal muscle hypertrophy and architectural changes in response to high-intensity resistance training

2007 ◽  
Vol 102 (1) ◽  
pp. 368-373 ◽  
Author(s):  
O. R. Seynnes ◽  
M. de Boer ◽  
M. V. Narici
Keyword(s):  
Resistance Training ◽  
High Intensity ◽  
Muscle Hypertrophy ◽  
Muscle Architecture ◽  
Muscle Size ◽  
Training Period ◽  
Emg Activity ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Leg Extension

The onset of whole muscle hypertrophy in response to overloading is poorly documented. The purpose of this study was to assess the early changes in muscle size and architecture during a 35-day high-intensity resistance training (RT) program. Seven young healthy volunteers performed bilateral leg extension three times per week on a gravity-independent flywheel ergometer. Cross-sectional area (CSA) in the central (C) and distal (D) regions of the quadriceps femoris (QF), muscle architecture, maximal voluntary contraction (MVC), and electromyographic (EMG) activity were measured before and after 10, 20, and 35 days of RT. By the end of the training period, MVC and EMG activity increased by 38.9 ± 5.7 and 34.8% ± 4.7%, respectively. Significant increase in QF CSA (3.5 and 5.2% in the C and D regions, respectively) was observed after 20 days of training, along with a 2.4 ± 0.7% increase in fascicle length from the 10th day of training. By the end of the 35-day training period, the total increase in QF CSA for regions C and D was 6.5 ± 1.1 and 7.4 ± 0.8%, respectively, and fascicle length and pennation angle increased by 9.9 ± 1.2 and 7.7 ± 1.3%, respectively. The results show for the first time that changes in muscle size are detectable after only 3 wk of RT and that remodeling of muscle architecture precedes gains in muscle CSA. Muscle hypertrophy seems to contribute to strength gains earlier than previously reported; flywheel training seems particularly effective for inducing these early structural adaptations.

Muscle strength and hypertrophy occur independently of protein supplementation during short-term resistance training in untrained men

2015 ◽  
Vol 40 (8) ◽  
pp. 797-802 ◽  
Author(s):  
Carleigh H. Boone ◽  
Jeffrey R. Stout ◽  
Kyle S. Beyer ◽  
David H. Fukuda ◽  
Jay R. Hoffman
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Repeated Measures ◽  
Vastus Lateralis ◽  
Protein Supplementation ◽  
Muscle Size ◽  
Short Term ◽  
Cross Sectional ◽  
Muscle Morphology ◽  
Leg Extension

Short-term resistance training has consistently demonstrated gains in muscular strength, but not hypertrophy. Post-resistance training protein ingestion is posited to augment the acute anabolic stimulus, thus potentially accelerating changes in muscle size and strength. The purpose of this investigation was to examine the effects of 4 weeks of resistance training with protein supplementation on strength and muscle morphology changes in untrained men. Participants (mean ± SD; N = 18; age, 22.0 ± 2.5 years; body mass index, 25.1 ± 5.4 kg·m−2) were randomly assigned to a resistance training + protein group (n = 9; whey (17 g) + colostrum (3 g) + leucine (2 g)) or a resistance training + placebo group (n = 9). One-repetition maximum (1RM) strength in the leg press (LP) and leg extension (LE) exercises, maximal isometric knee extensor strength (MVIC), and muscle morphology (thickness (MT), cross-sectional area (CSA), pennation angle) of the dominant rectus femoris (RF) and vastus lateralis (VL) was assessed before and after training. Participants performed LP and LE exercises (3 × 8–10; at 80% 1RM) 3 days/week for 4 weeks. Data were analyzed using 2-way ANOVA with repeated measures. Four weeks of resistance training resulted in significant increases in LP (p < 0.001), LE (p < 0.001), MVIC (p < 0.001), RF MT (p < 0.001), RF CSA (p < 0.001), VL MT (p < 0.001), and VL CSA (p < 0.001). No between-group differences were observed. Although nutrition can significantly affect training adaptations, these results suggest that short-term resistance training augments muscle strength and size in previously untrained men with no additive benefit from postexercise protein supplementation.

scholarly journals Resistance training with different repetition duration to failure: effect on hypertrophy, strength and muscle activation

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10909
Author(s):  
Lucas Túlio Lacerda ◽  
Rodrigo Otávio Marra-Lopes ◽  
Marcel Bahia Lanza ◽  
Rodrigo César Ribeiro Diniz ◽  
Fernando Vitor Lima ◽  
...  
Keyword(s):  
Resistance Training ◽  
Muscle Activation ◽  
Muscle Hypertrophy ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Angle Measurement ◽  
Knee Angle ◽  
Maximal Voluntary Isometric Contraction ◽  
Cross Sectional ◽  
Emg Amplitude

Background This study investigated the effects of two 14-week resistance training protocols with different repetition duration (RD) performed to muscle failure (MF) on gains in strength and muscle hypertrophy as well as on normalized electromyographic (EMG) amplitude and force-angle relationships. Methods The left and right legs of ten untrained males were assigned to either one of the two protocols (2-s or 6-s RD) incorporating unilateral knee extension exercise. Both protocols were performed with 3–4 sets, 50–60% of the one-repetition maximum (1RM), and 3 min rest. Rectus femoris and vastus lateralis cross-sectional areas (CSA), maximal voluntary isometric contraction (MVIC) at 30o and 90o of knee flexion and 1RM performance were assessed before and after the training period. In addition, normalized EMG amplitude-angle and force-angle relationships were assessed in the 6th and 39th experimental sessions. Results The 6-s RD protocol induced larger gains in MVIC at 30o of knee angle measurement than the 2-s RD protocol. Increases in MVIC at 90o of knee angle, 1RM, rectus femoris and vastus lateralis CSA were not significant between the 2-s and 6-s RD protocols. Moreover, different normalized EMG amplitude-angle and force-angle values were detected between protocols over most of the angles analyzed. Conclusion Performing longer RD could be a more appropriate strategy to provide greater gains in isometric maximal muscle strength at shortened knee positions. However, similar maximum dynamic strength and muscle hypertrophy gains would be provided by protocols with different RD.

Increased muscle oxidative potential following resistance training induced fibre hypertrophy in young men

2006 ◽  
Vol 31 (5) ◽  
pp. 495-501 ◽  
Author(s):  
Jason E. Tang ◽  
Joseph W. Hartman ◽  
Stuart M. Phillips
Keyword(s):  
Resistance Training ◽  
Muscle Fibre ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Atp Synthesis ◽  
Acid Oxidation ◽  
Mitochondrial Enzymes ◽  
Oxidative Potential ◽  
Cross Sectional ◽  
Resistance Training Program

Some evidence suggests that resistance training may lower relative muscle mitochondrial content via “dilution” of the organelle in a larger muscle fibre. Such an adaptation would reduce fatigue resistance, as well as compromise oxidative ATP synthesis and the capacity for fatty-acid oxidation. We investigated the effect of resistance training on mitochondrial enzymes of the citric acid cycle (citrate synthase; CS) and β-oxidation (β-hydroxyacyl CoA dehydrogenase; β-HAD), as well as markers of the potential for glucose phosphorylation (hexokinase; HK) and glycolysis (phosphofructokinase; PFK). Twelve untrained men (21.9 ± 0.5 y; 1.79 ± 0.03 m; 83.2 ± 3.2 kg) participated in a 12 week progressive resistance-training program. Muscle biopsies were taken from the vastus lateralis before (PRE) and after (POST) training. Training increased mean muscle fibre cross-sectional area (p < 0.05) and the activities of CS (PRE = 4.53 ± 0.44 mol·kg protein–1·h–1; POST = 5.63 ± 0.40 mol·kg protein–1·h–1; p < 0.001) and β-HAD (PRE = 2.55 ± 0.28 mol·kg protein–1·h–1; POST = 3.11 ± 0.21 mol·kg protein–1·h–1; p < 0.05). The activity of HK increased 42% (p < 0.05), whereas the activity of PFK remained unchanged. We conclude that resistance training provides a stimulus for improving muscle oxidative potential, as reflected by the increased activities of CS and β-HAD following resistance training induced hypertrophy.

scholarly journals PO-140 Physiological and Molecular Adaptations to Concurrent Training in Combination with High Protein Availability

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Baubak Shamim ◽  
Brooke Devlin ◽  
Ryan Timmins ◽  
Connor Lee Dow ◽  
Vernon Coffey ◽  
...  
Keyword(s):  
Resistance Training ◽  
Aerobic Capacity ◽  
Repeated Measures ◽  
Protein Intake ◽  
Vastus Lateralis ◽  
Cell Signalling ◽  
Anaerobic Power ◽  
Muscle Thickness ◽  
High Protein ◽  
Concurrent Training

Objective Attenuated muscle strength, hypertrophy and power adaptations with combined resistance and endurance (‘concurrent’) training may result from blunted cell signalling. Protein intake potentiates anabolic signalling pathways to facilitate adaptation. We hypothesized that 12 wk concurrent training with a high protein diet would elicit similar adaptations to a) strength, hypertrophy and power compared to resistance training alone, and b) aerobic capacity compared to endurance training. Methods Thirty-two recreationally active males (age 25±5y; BMI 24±3kg•m-2; mean±SD) performed 12 wk of either resistance (RES; n=10) or endurance (END; n=10) training (3x•w-1), or concurrent training (CET; n=12; 6x•w-1) with a high-protein (2g•kg-1•d-1) diet. Strength (1RM), aerobic capacity (VO2peak) and anaerobic power (Wingate) were assessed PRE and POST. Vastus lateralis biopsies (immunoblotting) and thickness (ultrasound) were assessed PRE, after week 4 (WK4) and 8 (WK8), and POST. Changes were analyzed by two-way ANOVA with repeated measures. Results Muscle thickness increased PRE to POST by 18% in CET, 14% in RES and 10% in END (P<0.001) and was greater in CET and RES compared to END (P<0.05). Leg press 1RM increased PRE to POST by 24% in CET and 33% in RES (P<0.01) but was not different between CET and RES. VO2peak (L•min-1) increased PRE to POST by 7% in CET and 12% in END (P<0.05) but was not different between CET and END. Wingate peak power (N•kg-1) increased PRE to POST by 10% in RES (P<0.01) and was greater compared to CET and END (P<0.05). Total mTORC1 increased PRE to POST in CET (P<0.001) and was greater in CET compared to RES and END (P<0.01) and RES compared to END (P<0.05). Conclusions Despite a high protein intake, concurrent training selectively attenuates developments to anaerobic power compared to resistance training. High protein availability may be effective for curtailing interferences to strength and hypertrophy with concurrent training.

Variability of Regional Quadriceps Architecture in Trained Men Assessed by B-Mode and Extended-Field-of-View Ultrasonography

2020 ◽  
Vol 15 (3) ◽  
pp. 430-436 ◽  
Author(s):  
Dustin J. Oranchuk ◽  
André R. Nelson ◽  
Adam G. Storey ◽  
John B. Cronin
Keyword(s):  
Vastus Lateralis ◽  
Intraclass Correlation ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Field Of View ◽  
Fascicle Length ◽  
Large Variability ◽  
Extended Field ◽  
Extended Field Of View ◽  
Regional Muscle

Purpose: Regional muscle-architecture measures are reported widely; however, little is known about the variability of these measurements in the rectus femoris, vastus lateralis, and anterior and lateral vastus intermedius. The aim of this study was to quantify this variability. Methods: Regional muscle thickness, pennation angle (PA), and calculated and extended-field-of-view–derived fascicle length (FL) were quantified in 26 participants using ultrasonography across 51 limbs on 3 occasions. To quantify variability, the typical error of measurement (TEM) was multiplied by 2, and thresholds of 0.2–0.6 (small), 0.6–1.2 (moderate), 1.2–2.0 (large), 2.0–4.0 (very large), and >4.0 (extremely large) were applied. In addition, variability was deemed large when the intraclass correlation coefficient (ICC) was <.67 and coefficient of variation (CV) >10%, moderate when ICC > .67 or CV < 10% (but not both), and small when both ICC > .67 and CV < 10%. Results: Muscle thickness of all muscles and regions had low to moderate variability (ICC = .88–.98, CV = 2.4–9.3%, TEM = 0.15–0.47). PA of the proximal and distal vastus lateralis had low variability (ICC = .85–.96, CV = 3.8–8%) and moderate to large TEM (TEM = 0.42–0.83). PA of the rectus femoris was found to have moderate to very large variability (ICC = .38–.74, CV = 11.4–18.5%, TEM = 0.61–1.29) regardless of region. Extended-field-of-view–derived FL (ICC = .57–.94, CV = 4.1–11.5%, TEM = 0.26–0.88) was superior to calculated FL (ICC = .37–.84, CV = 7.4–17.9%, TEM = 0.44–1.33). Conclusions: Variability of muscle thickness was low in all quadriceps muscles and regions. Only rectus femoris PA and FL measurements were highly variable. The extended-field-of-view technique should be used to assess FL where possible. Inferences based on rectus femoris architecture should be interpreted with caution.

ACTN3 genotype is associated with increases in muscle strength in response to resistance training in women

2005 ◽  
Vol 99 (1) ◽  
pp. 154-163 ◽  
Author(s):  
Priscilla M. Clarkson ◽  
Joseph M. Devaney ◽  
Heather Gordish-Dressman ◽  
Paul D. Thompson ◽  
Monica J. Hubal ◽  
...  
Keyword(s):  
Resistance Training ◽  
Body Mass ◽  
Biceps Brachii ◽  
Elbow Flexor ◽  
Muscle Performance ◽  
Muscle Size ◽  
P Value ◽  
Ratio Test ◽  
Cross Sectional ◽  
Resistance Training Program

The α-actinin 3 (ACTN3) gene encodes a protein of the Z disk of myofibers, and a polymorphism of ACTN3 results in complete loss of the protein. The ACTN3 genotype (R577X) has been found to be associated with performance in Australian elite athletes (Yang N, MacArthur DG, Gulbin JP, Hahn AG, Beggs AH, Easteal S, and North K. Am J Hum Genet 73: 627–631, 2003). We studied associations between ACTN3 genotype and muscle size [cross-sectional area of the biceps brachii via magnetic resonance imaging (MRI)] and elbow flexor isometric (MVC) and dynamic [1-repetition maximum (1-RM)] strength in a large group of men ( N = 247) and women ( N = 355) enrolled in a 12-wk standardized elbow flexor/extensor resistance training program of the nondominant arm at one of eight study centers. We found no association between ACTN3 R577X genotype and muscle phenotype in men. However, women homozygous for the ACTN3 577X allele (XX) had lower baseline MVC compared with heterozygotes ( P < 0.05) when adjusted for body mass and age. Women homozygous for the mutant allele (577X) demonstrated greater absolute and relative 1-RM gains compared with the homozygous wild type (RR) after resistance training when adjusted for body mass and age ( P < 0.05). There was a trend for a dose-response with genotype such that gains were greatest for XX and least for RR. Significant associations were validated in at least one ethnic subpopulation (Caucasians, Asians) and were independent of training volume. About 2% of baseline MVC and of 1-RM strength gain after training were attributable to ACTN3 genotype (likelihood-ratio test P value, P = 0.01), suggesting that ACTN3 is one of many genes contributing to genetic variation in muscle performance and adaptation to exercise.

Age-, sex-, and region-specific differences in skeletal muscle size and quality

2020 ◽  
Vol 45 (11) ◽  
pp. 1253-1260 ◽  
Author(s):  
Matt S. Stock ◽  
Dustin J. Oranchuk ◽  
Adam M. Burton ◽  
David C. Phan
Keyword(s):  
Vastus Lateralis ◽  
Subcutaneous Fat ◽  
Rectus Femoris ◽  
Older Men ◽  
Muscle Size ◽  
Cross Sectional ◽  
Proximal Site ◽  
Younger Men ◽  
Subcutaneous Fat Thickness ◽  
Fat Thickness

Ultrasonography-derived cross-sectional area (CSA) and echo intensity (EI) are increasingly utilized by investigators to study muscle size and quality, respectively. We sought to examine age, sex, and region (proximal, middle, distal) differences in vastus lateralis and rectus femoris CSA and EI, and determine whether correction for subcutaneous fat thickness influences the magnitude of EI differences. Fifteen younger men (mean age = 23 years), 15 younger women (aged 21 years), 11 older men (aged 74 years), and 15 older women (aged 70 years) participated. Clear differences were observed among age, sex, and region for vastus lateralis CSA (p ≤ 0.013, d = 0.38–0.73), whereas rectus femoris CSA was only different between younger and older participants at the proximal region (p = 0.017, d = 0.65). Uncorrected EI was greatest at the distal region of both muscles (p < 0.001, d = 0.59–1.38), with only the younger men having significantly lower EI values than the other groups (p ≤ 0.043, d = 0.37–0.63). Subcutaneous fat correction resulted in a marked increase in the magnitude of sex-specific EI differences (p ≤ 0.032, d ≥ 0.42). Additionally, subcutaneous fat correction increased the uniformity of EI throughout the thigh. These findings highlight considerable region-specific differences in muscle size and quality among younger and older men and women and highlight the need to correct for subcutaneous fat thickness when examining EI. Novelty Rectus femoris CSA is similar between younger and older adults except at the most proximal site evaluated. Age- and sex-specific differences in uncorrected EI are nonuniform across the thigh. Correction for subcutaneous fat thickness substantially increased EI in women, resulting in greater sex differences.

Mechanical behavior of the quadriceps femoris muscle tendon unit during low-load contractions

2008 ◽  
Vol 104 (5) ◽  
pp. 1320-1328 ◽  
Author(s):  
Taija Finni ◽  
Marko Havu ◽  
Shantanu Sinha ◽  
Jussi-Pekka Usenius ◽  
Sulin Cheng
Keyword(s):  
Vastus Lateralis ◽  
Single Point ◽  
Frontal Plane ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Quadriceps Femoris ◽  
Thigh Muscle ◽  
Cross Sectional ◽  
Quadriceps Femoris Muscle ◽  
Femoris Muscle

We examined the relationships between morphology and muscle-tendon dynamics of the quadriceps femoris muscle of 11 men using velocity-encoded phase-contrast magnetic resonance imaging (MRI). Thigh muscle electromyography and joint range of motion were first measured outside the MRI scanner during knee extension-flexion tasks that were performed at a rate of 40 times/min with elastic bands providing peak resistance of 5.2 kp (SD 0.4) to the extension. The same movement was repeated inside the MRI scanner bore where tissue velocities and muscle morphology were recorded. The average displacement in the proximal and distal halves of the rectus femoris and vastus intermedius aponeuroses was different ( P = 0.049), reflecting shortening (1.6%), but the tensile strain along the length of the aponeuroses was uniform. The aponeurosis behavior varied among individuals, and these individual patterns were best explained by the differences in relative cross-sectional area of rectus femoris to vastus muscles ( r = 0.71, P = 0.014). During dynamic contraction, considerable deformation of muscles in the axial plane caused an anatomic measure such as muscle thickness to change differently (decrease or increase) in different sites of measurement. For example, when analyzed from the axial images, the vastus lateralis thickness did not change ( P = 0.946) in the frontal plane through femur but increased in a 45° oblique plane between the frontal and sagittal planes ( P = 0.004). The present observations of the heterogeneity and individual behavior emphasize the fact that single-point measurements do not always reflect the overall behavior of muscle-tendon unit.

scholarly journals Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity

2008 ◽  
Vol 105 (5) ◽  
pp. 1454-1461 ◽  
Author(s):  
L. Holm ◽  
S. Reitelseder ◽  
T. G. Pedersen ◽  
S. Doessing ◽  
S. G. Petersen ◽  
...  
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Resistance Exercise ◽  
Muscle Hypertrophy ◽  
Vastus Lateralis ◽  
Load Resistance ◽  
Muscle Size ◽  
Heavy Load ◽  
Cross Sectional ◽  
Light Load

Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 ± 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60°/s. Quadriceps muscle cross-sectional area increased ( P < 0.05) 8 ± 1% and 3 ± 1% in HL and LL legs, respectively, with a greater gain in HL than LL ( P < 0.05). Likewise, 1RM strength increased ( P < 0.001) in both legs (HL: 36 ± 5%, LL: 19 ± 2%), albeit more so with HL ( P < 0.01). Isokinetic 60°/s muscle strength improved by 13 ± 5% ( P < 0.05) in HL but remained unchanged in LL (4 ± 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.

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