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.

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.

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.

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 Muscle architecture and morphology as determinants of explosive strength

2021 ◽  
Author(s):  
T. M. Maden-Wilkinson ◽  
T. G. Balshaw ◽  
G. J. Massey ◽  
J. P. Folland
Keyword(s):  
Late Phase ◽  
Knee Extension ◽  
Muscle Architecture ◽  
Muscle Size ◽  
Moment Arm ◽  
Neural Drive ◽  
Fascicle Length ◽  
Explosive Strength ◽  
Independent Variable ◽  
Maximum Voluntary Torque

Abstract Purpose Neural drive and contractile properties are well-defined physiological determinants of explosive strength, the influence of muscle architecture and related morphology on explosive strength is poorly understood. The aim of this study was to examine the relationships between Quadriceps muscle architecture (pennation angle [ΘP] and fascicle length [FL]) and size (e.g., volume; QVOL), as well as patellar tendon moment arm (PTMA) with voluntary and evoked explosive knee extension torque in 53 recreationally active young men. Method Following familiarisation, explosive voluntary torque at 50 ms intervals from torque onset (T50, T100, T150), evoked octet at 50 ms (8 pulses at 300-Hz; evoked T50), as well as maximum voluntary torque, were assessed on two occasions with isometric dynamometry. B-mode ultrasound was used to assess ΘP and FL at ten sites throughout the quadriceps (2–3 sites) per constituent muscle. Muscle size (QVOL) and PTMA were quantified using 1.5 T MRI. Result There were no relationships with absolute early phase explosive voluntary torque (≤ 50 ms), but θP (weak), QVOL (moderate to strong) and PTMA (weak) were related to late phase explosive voluntary torque (≥ 100 ms). Regression analysis revealed only QVOL was an independent variable contributing to the variance in T100 (34%) and T150 (54%). Evoked T50 was also related to QVOL and θP. When explosive strength was expressed relative to MVT there were no relationships observed. Conclusion It is likely that the weak associations of θP and PTMA with late phase explosive voluntary torque was via their association with MVT/QVOL rather than as a direct determinant.

scholarly journals Effect of aging on human muscle architecture

2003 ◽  
Vol 95 (6) ◽  
pp. 2229-2234 ◽  
Author(s):  
M. V. Narici ◽  
C. N. Maganaris ◽  
N. D. Reeves ◽  
P. Capodaglio
Keyword(s):  
The Elderly ◽  
Muscle Architecture ◽  
Cross Sectional Area ◽  
Elderly Group ◽  
Sectional Area ◽  
Morphometric Measurements ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Physically Active ◽  
Structural Alterations

The effect of aging on human gastrocnemius medialis (GM) muscle architecture was evaluated by comparing morphometric measurements on 14 young (aged 27–42 yr) and on 16 older (aged 70–81 yr) physically active men, matched for height, body mass, and physical activity. GM muscle anatomic cross-sectional area (ACSA) and volume (Vol) were measured by computerized tomography, and GM fascicle length ( Lf) and pennation angle (θ) were assessed by ultrasonography. GM physiological cross-sectional area (PCSA) was calculated as the ratio of Vol/ Lf. In the elderly, ACSA and Vol were, respectively, 19.1% ( P < 0.005) and 25.4% ( P < 0.001) smaller than in the young adults. Also, Lf and θ were found to be smaller in the elderly group by 10.2% ( P < 0.01) and 13.2% ( P < 0.01), respectively. When the data for the young and elderly adults were pooled together, θ significantly correlated with ACSA ( P < 0.05). Because of the reduced Vol and Lf in the elderly group, the resulting PCSA was found to be 15.2% ( P < 0.05) smaller. In conclusion, this study demonstrates that aging significantly affects human skeletal muscle architecture. These structural alterations are expected to have implications for muscle function in old age.

Evidence of a Ceiling Effect for Training Volume in Muscle Hypertrophy and Strength in Trained Men—Less is More?

2020 ◽  
Vol 15 (2) ◽  
pp. 268-277 ◽  
Author(s):  
Matheus Barbalho ◽  
Victor S. Coswig ◽  
James Steele ◽  
James P. Fisher ◽  
Jurgen Giessing ◽  
...  
Keyword(s):  
Resistance Training ◽  
Muscle Hypertrophy ◽  
Biceps Brachii ◽  
Gluteus Maximus ◽  
Muscle Thickness ◽  
Muscle Performance ◽  
Muscle Size ◽  
Triceps Brachii ◽  
Less Is More ◽  
Time Interaction

Purpose: To compare the effects of different resistance training volumes on muscle performance and hypertrophy in trained men. Methods: Thirty-seven volunteers performed resistance training for 24 weeks, divided into groups that performed 5 (G5), 10 (G10), 15 (G15), and 20 (G20) sets per muscle group per week. Ten-repetition maximum (10RM) tests were performed for the bench press, lat pulldown, 45° leg press, and stiff-legged deadlift. Muscle thickness was measured using ultrasound at biceps brachii, triceps brachii, pectoralis major, quadriceps femoris, and gluteus maximus. All measurements were performed at the beginning (pre), 12 (mid), and 24 weeks (post) of training. Results: All groups showed significant increases in all 10RM tests and muscle thickness measures after 12 and 24 weeks when compared with pre (P < .05). There were no significant differences in any 10RM test or changes between G5 and G10 after 12 and 24 weeks. G5 and G10 showed significantly greater increases for 10RM than G15 and G20 for most exercises at 12 and 24 weeks. There was no group by time interaction for any muscle thickness measure. Conclusions: The results bring evidence of an inverted “U-shaped” curve for the dose–response curve for muscle strength. Although the same trend was noted for muscle hypertrophy, the results did not reach significance. Five to 10 sets per week might be sufficient for bringing about optimal gains in muscle size and strength in trained men over a 24-week period.

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.

Individual Muscle Adaptations in different Resistance Training Systems in Well-Trained Men

2021 ◽  
Author(s):  
Vitor Angleri ◽  
Carlos Ugrinowitsch ◽  
Cleiton Augusto Libardi
Keyword(s):  
Resistance Training ◽  
Cross Sectional ◽  
Leg Extension ◽  
Leg Press ◽  
Training Systems ◽  
Subject Design ◽  
Muscle Adaptations ◽  
Traditional Resistance Training ◽  
The Individual ◽  
Muscle Cross Sectional Area

AbstractUsing a within-subject design we compared the individual responses between drop-set (DS) vs. traditional resistance training (TRAD) (n=16) and crescent pyramid (CP) vs. TRAD (n=15). Muscle cross-sectional area (CSA), leg press and leg extension 1 repetition maximum (1-RM) were assessed pre and post training. At group level, CSA increased from pre to post (DS: 7.8% vs. TRAD: 7.5%, P=0.02; CP: 7.5% vs. TRAD: 7.8%, P=0.02). All protocols increased the 1-RM from pre to post for leg press (DS: 24.9% vs. TRAD: 26.8%, P < 0.0001; CP: 27.3% vs. TRAD:2 6.3%, P < 0.0001) and leg extension (DS: 17.1% vs. TRAD: 17.3%, P < 0.0001; CP: 17.0% vs. TRAD: 16.6%, P < 0.0001). Individual analysis for CSA demonstrated no differences between protocols in 15 subjects. For leg press 1-RM, 5 subjects responded more to TRAD, 2 to DS and 9 similarly between protocols. In TRAD vs. CP, 4 subjects responded more to CP, 1 to TRAD and 10 similarly between protocols. For leg extension 1-RM 2 subjects responded more to DS, 3 to TRAD and 11 similarly between protocols. Additionally, 2 subjects responded more to CP, 2 to TRAD and 11 similarly between protocols. In conclusion, all protocols induced similar individual responses for CSA. For 1-RM, some subjects experience greater gains for the protocol performed with higher loads, such as CP.

Men Exhibit Greater Pain Pressure Thresholds and Times to Task Failure but Not Performance Fatigability Following Self-Paced Exercise

2021 ◽  
pp. 003151252110350
Author(s):  
Karina Noboa ◽  
Joshua Keller ◽  
Kipp Hergenrader ◽  
Terry Housh ◽  
John Paul Anders ◽  
...  
Keyword(s):  
Sex Differences ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Muscle Size ◽  
Maximal Voluntary Isometric Contraction ◽  
Cross Sectional ◽  
Task Failure ◽  
Leg Extension ◽  
Pressure Threshold ◽  
Pain Pressure Threshold

The purpose of the current study was to determine if, and to what extent, sex differences in performance fatigability after a sustained, bilateral leg extension, anchored to a moderate rating of perceived exertion (RPE), could be attributed to muscle size, muscular strength, or pain pressure threshold (PPT) in young, healthy adults. Thirty adults (men: n = 15, women: n = 15) volunteered to complete a sustained leg extension task anchored to RPE = 5 (10-point OMNI scale) as well as pretest and posttest maximal voluntary isometric contraction (MVIC) trials. The fatigue-induced decline in MVIC force was defined as performance fatigability. We used muscle cross-sectional area (mCSA) to quantify muscle size and a dolorimeter to assess PPT. The sustained task induced fatigue such that both men and women exhibited significant ( p < 0.05) decreases in MVIC force from pretest to posttest ( M = 113.3, SD =24.2 kg vs. M = 98.3, SD = 23.1 kg and M = 73.1, SD =14.5 kg vs. M = 64.1, SD = 16.2 kg, respectively), with no significant sex differences in performance fatigability (grand M = 12.6, SD =10.6%). Men, however, exhibited significantly ( p < 0.05) longer time to task failure (TTF) than women ( M = 166.1, SD =83.0 seconds vs. M = 94.6, SD =41.7) as well as greater PPT ( M = 5.9, SD = 2.2 kg vs. M = 3.4, SD =1.1 kg). The only significant predictor of performance fatigability was PPT. In conclusion, differences in PPT, at least in part, mediate variations in TTF during self-paced exercise anchored to a specific RPE and resulting in performance fatigability.

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