scholarly journals Effect of resistance training on skeletal muscle-specific force in elderly humans

2004 ◽  
Vol 96 (3) ◽  
pp. 885-892 ◽  
Author(s):  
N. D. Reeves ◽  
M. V. Narici ◽  
C. N. Maganaris
Keyword(s):  
Skeletal Muscle ◽  
Strength Training ◽  
Old Age ◽  
Vastus Lateralis ◽  
Muscle Volume ◽  
Electromyographic Activity ◽  
Specific Force ◽  
Fascicle Length ◽  
Leg Extension ◽  
Muscle Fascicle

This study assessed muscle-specific force in vivo following strength training in old age. Subjects were assigned to training ( n = 9, age 74.3 ± 3.5 yr; mean ± SD) and control ( n = 9, age 67.1 ± 2 yr) groups. Leg-extension and leg-press exercises (2 sets of 10 repetitions at 80% of the 5 repetition maximum) were performed three times/wk for 14 wk. Vastus lateralis (VL) muscle fascicle force was calculated from maximal isometric voluntary knee extensor torque with superimposed stimuli, accounting for the patella tendon moment arm length, ultrasound-based measurements of muscle architecture, and antagonist cocontraction estimated from electromyographic activity. Physiological cross-sectional area (PCSA) was calculated from the ratio of muscle volume to fascicle length. Specific force was calculated by dividing fascicle force by PCSA. Fascicle force increased by 11%, from 847.9 ± 365.3 N before to 939.3 ± 347.8 N after training ( P < 0.05). Due to a relatively greater increase in fascicle length (11%) than muscle volume (6%), PCSA remained unchanged (pretraining: 30.4 ± 8.9 cm2; posttraining: 29.1 ± 8.4 cm2; P > 0.05). Activation capacity and VL muscle root mean square electromyographic activity increased by 5 and 40%, respectively, after training ( P < 0.05), indicating increased agonist neural drive, whereas antagonist cocontraction remained unchanged ( P > 0.05). The VL muscle-specific force increased by 19%, from 27 ± 6.3 N/cm2 before to 32.1 ± 7.4 N/cm2 after training ( P < 0.01), highlighting the effectiveness of strength training for increasing the intrinsic force-producing capacity of skeletal muscle in old age.

scholarly journals Nature of the coupling between neural drive and force-generating capacity in the human quadriceps muscle

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151908 ◽  
Author(s):  
François Hug ◽  
Clément Goupille ◽  
Daniel Baum ◽  
Brent J. Raiteri ◽  
Paul W. Hodges ◽  
...  
Keyword(s):  
Muscle Force ◽  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Myoelectric Activity ◽  
Neural Drive ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Muscle Fascicle ◽  
Generating Capacity ◽  
The Relationship

The force produced by a muscle depends on both the neural drive it receives and several biomechanical factors. When multiple muscles act on a single joint, the nature of the relationship between the neural drive and force-generating capacity of the synergistic muscles is largely unknown. This study aimed to determine the relationship between the ratio of neural drive and the ratio of muscle force-generating capacity between two synergist muscles (vastus lateralis (VL) and vastus medialis (VM)) in humans. Twenty-one participants performed isometric knee extensions at 20 and 50% of maximal voluntary contractions (MVC). Myoelectric activity (surface electromyography (EMG)) provided an index of neural drive. Physiological cross-sectional area (PCSA) was estimated from measurements of muscle volume (magnetic resonance imaging) and muscle fascicle length (three-dimensional ultrasound imaging) to represent the muscles' force-generating capacities. Neither PCSA nor neural drive was balanced between VL and VM. There was a large ( r = 0.68) and moderate ( r = 0.43) correlation between the ratio of VL/VM EMG amplitude and the ratio of VL/VM PCSA at 20 and 50% of MVC, respectively. This study provides evidence that neural drive is biased by muscle force-generating capacity, the greater the force-generating capacity of VL compared with VM, the stronger bias of drive to the VL.

scholarly journals Increased fascicle length but not patellar tendon stiffness after accentuated eccentric-load strength training in already-trained men

2020 ◽  
Vol 120 (11) ◽  
pp. 2371-2382 ◽  
Author(s):  
Simon Walker ◽  
Joanne Trezise ◽  
Guy Gregory Haff ◽  
Robert U. Newton ◽  
Keijo Häkkinen ◽  
...  
Keyword(s):  
Strength Training ◽  
Patellar Tendon ◽  
External Load ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Fascicle Length ◽  
Tendon Stiffness ◽  
Knee Extensor Strength ◽  
Tendon Properties ◽  
Fascicle Angle

Abstract Purpose This study examined whether additional external load during the eccentric phase of lower limb strength training exercises led to greater adaptations in knee extensor strength, muscle architecture, and patellar tendon properties than traditional concentric–eccentric training in already-trained men. Methods Twenty-eight men accustomed to strength training were randomized to undertake 10 weeks of supervised traditional (TRAD) or accentuated eccentric loading (AEL) or continue their habitual unsupervised (CON) strength training. TRAD and AEL trained 2∙week−1 with a six-repetition maximum (RM) session and a ten-RM session. TRAD used the same external load in both concentric and eccentric phases, while AEL used 40% greater load during the eccentric than concentric phase. Tests were performed at pre- and post-training, including: maximum unilateral isokinetic (30°·s−1) concentric, eccentric and isometric torques by isokinetic dynamometry, unilateral isometric ramp contractions with muscle–tendon ultrasound imaging to measure tendon stiffness and hysteresis, and resting vastus lateralis and medialis fascicle angle and length measured by extended-field-of-view ultrasound. Results After training, both TRAD and AEL significantly increased maximum concentric and isometric torque (p < 0.05), but only AEL increased eccentric torque (AEL: + 10 ± 9%, TRAD: + 4 ± 9%) and vastus lateralis (AEL: + 14 ± 14%, TRAD: + 1 ± 10%) and medialis (AEL: + 19 ± 8%, TRAD: + 5 ± 11%) fascicle length. Conclusion Both TRAD and AEL increased maximum knee extensor strength but only AEL increased VL and VM fascicle length. Neither training program promoted changes in fascicle angle or changes in patellar tendon properties in our already-trained men.

scholarly journals P-43 Titin genotype is associated with skeletal muscle fascicle length in recreationally active men and running performance in habitually trained marathon runners

2016 ◽  
Vol 50 (Suppl 1) ◽  
pp. A55-A56
Author(s):  
Georgina K Stebbings ◽  
Alun G Williams ◽  
Adam J Herbert ◽  
Sarah J Lockey ◽  
Shane M Heffernan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fascicle Length ◽  
Marathon Runners ◽  
Running Performance ◽  
Muscle Fascicle

Neuromuscular and hormonal adaptations in athletes to strength training in two years

1988 ◽  
Vol 65 (6) ◽  
pp. 2406-2412 ◽  
Author(s):  
K. Hakkinen ◽  
A. Pakarinen ◽  
M. Alen ◽  
H. Kauhanen ◽  
P. V. Komi
Keyword(s):  
Strength Training ◽  
Vastus Lateralis ◽  
Serum Testosterone ◽  
Weight Lifting ◽  
Sex Hormone Binding Globulin ◽  
Strength Development ◽  
Vastus Lateralis Muscle ◽  
Leg Extension ◽  
Intensive Training

Neuromuscular and hormonal adaptations to prolonged strength training were investigated in nine elite weight lifters. The average increases occurred over the 2-yr follow-up period in the maximal neural activation (integrated electromyogram, IEMG; 4.2%, P = NS), maximal isometric leg-extension force (4.9%, P = NS), averaged concentric power index (4.1%, P = NS), total weight-lifting result (2.8%, P less than 0.05), and total mean fiber area (5.9%, P = NS) of the vastus lateralis muscle, respectively. The training period resulted in increases in the concentrations of serum testosterone from 19.8 +/- 5.3 to 25.1 +/- 5.2 nmol/l (P less than 0.05), luteinizing hormone (LH) from 8.6 +/- 0.8 to 9.1 +/- 0.8 U/l (P less than 0.05), follicle-stimulating hormone (FSH) from 4.2 +/- 2.0 to 5.3 +/- 2.3 U/l (P less than 0.01), and testosterone-to-serum sex hormone-binding globulin (SHBG) ratio (P less than 0.05). The annual mean value of the second follow-up year for the serum testosterone-to-SHBG ratio correlated significantly (r = 0.84, P less than 0.01) with the individual changes during the 2nd yr in the averaged concentric power. The present results suggest that prolonged intensive strength training in elite athletes may influence the pituitary and possibly hypothalamic levels, leading to increased serum levels of testosterone. This may create more optimal conditions to utilize more intensive training leading to increased strength development.

scholarly journals A novel diffusion-tensor MRI approach for skeletal muscle fascicle length measurements

2016 ◽  
Vol 4 (24) ◽  
pp. e13012 ◽  
Author(s):  
Jos Oudeman ◽  
Valentina Mazzoli ◽  
Marco A. Marra ◽  
Klaas Nicolay ◽  
Mario Maas ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Diffusion Tensor ◽  
Diffusion Tensor Mri ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
Length Measurements

Skeletal muscle architectural adaptations to marathon run training

2015 ◽  
Vol 40 (1) ◽  
pp. 99-102 ◽  
Author(s):  
Kevin Murach ◽  
Cory Greever ◽  
Nicholas D. Luden
Keyword(s):  
Skeletal Muscle ◽  
Vastus Lateralis ◽  
Pennation Angle ◽  
Fascicle Length ◽  
Lateral Gastrocnemius ◽  
Marathon Training ◽  
Architectural Features ◽  
Before And After ◽  
Recreational Runners ◽  
Lactate Levels

We assessed lateral gastrocnemius (LG) and vastus lateralis (VL) architecture in 16 recreational runners before and after 12 weeks of marathon training. LG fascicle length decreased 10% while pennation angle increased 17% (p < 0.05). There was a significant correlation between diminished blood lactate levels and LG pennation angle change (r = 0.90). No changes were observed in VL. This is the first evidence that run training can modify skeletal muscle architectural features.

scholarly journals What makes long-term resistance-trained individuals so strong? A comparison of skeletal muscle morphology, architecture, and joint mechanics

2020 ◽  
Vol 128 (4) ◽  
pp. 1000-1011 ◽  
Author(s):  
Thomas M. Maden-Wilkinson ◽  
Thomas G. Balshaw ◽  
Garry J. Massey ◽  
Jonathan P. Folland
Keyword(s):  
Skeletal Muscle ◽  
Muscle Volume ◽  
Sectional Area ◽  
Joint Mechanics ◽  
Moment Arm ◽  
Trained Group ◽  
Patella Tendon ◽  
Fascicle Length ◽  
Cross Sectional

Here we demonstrate that the larger muscle strength (+60%) of a long-term (4+ yr) resistance-trained group compared with untrained controls was due to their similarly larger muscle volume (+56%), primarily due to a larger physiological cross-sectional area and modest differences in fascicle length, as well as modest differences in maximum voluntary specific tension and patella tendon moment arm. In addition, the present study refutes the possibility of regional hypertrophy, despite large differences in muscle volume.

scholarly journals The Effect of Strength Training on Vastus Lateralis’ Stiffness: An Ultrasound Quasi-Static Elastography Study

2020 ◽  
Vol 17 (12) ◽  
pp. 4381 ◽  
Author(s):  
Rute Santos ◽  
Maria João Valamatos ◽  
Pedro Mil-Homens ◽  
Paulo Armada-da-Silva
Keyword(s):  
Skeletal Muscle ◽  
Strength Training ◽  
Ultrasound Imaging ◽  
Sports Medicine ◽  
Vastus Lateralis ◽  
Young Male ◽  
Training Group ◽  
Muscle Stiffness ◽  
Ultrasound Elastography ◽  
Knee Extensors

Ultrasound imaging allows the evaluation of musculoskeletal morphology and function. Ultrasound elastography can also offer semi-quantitative and/or quantitative assessment of tissue stiffness providing relevant information about adaptations of skeletal muscle mechanical properties. In this study we aimed to explore the feasibility of elastography ultrasound imaging in assessing the effect of strength training on vastus lateralis stiffness. Twenty-eight young male adults were separated in a control (n = 9) and strength-training (n = 20) groups. The strength-training group completed 15 weeks of either concentric (n = 10) or eccentric (n = 10) isokinetic training of the knee extensors. Ultrasound scans of the vastus lateralis for quasi-static elastography were collected. All image acquisitions and measurements were done by the same experienced sonographer. After 15 weeks, knee maximal extension isometric torque increased in the strength-training groups. After strength training, there was a decrease in the amount of red pixels in vastus lateralis region of interest [F(1,18) = 25.490; p < 0.001; η2 = 0.586], whereas the amount of green and blue pixels increased F(1,18) = 17.179; p < 0.01; η2 = 0.488; F(1,18) = 6.522; p < 0.05; η2 = 0.266], suggesting higher vastus lateralis stiffness. We conclude that concentric and eccentric strength training increases skeletal muscle stiffness, which can be evaluated by quasi-static elastography. Ultrasound elastography is suitable for non-invasive evaluation of skeletal muscle functional adaptations, which can be of importance for sports medicine and in designing optimal training and rehabilitation programs.

scholarly journals Exercise Training Enhances Angiogenesis-Related Gene Responses in Skeletal Muscle of Patients with Chronic Heart Failure

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1915
Author(s):  
Andrea Tryfonos ◽  
Giorgos Tzanis ◽  
Theodore Pitsolis ◽  
Eleftherios Karatzanos ◽  
Michael Koutsilieris ◽  
...  
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Strength Training ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Vascular Endothelial ◽  
Related Factors ◽  
Endothelial Growth Factor

Peripheral myopathy consists of a hallmark of heart failure (HF). Exercise enhanced skeletal muscle angiogenesis, and thus, it can be further beneficial towards the HF-induced myopathy. However, there is limited evidence regarding the exercise type that elicits optimum angiogenic responses of skeletal muscle in HF patients. This study aimed to (a) compare the effects of a high-intensity-interval-training (HIIT) or combined HIIT with strength training (COM) exercise protocol on the expression of angiogenesis-related factors in skeletal muscle of HF patients, and (b) examine the potential associations between the expression of those genes and capillarization in the trained muscles. Thirteen male patients with chronic HF (age: 51 ± 13 y; BMI: 27 ± 4 kg/m2) were randomly assigned to a 3-month exercise program that consisted of either HIIT (N = 6) or COM training (N = 7). Vastus lateralis muscle biopsies were performed pre- and post-training. RT-PCR was used to quantify the fold changes in mRNA expression of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 2 (VEGFR-2), hypoxia-inducible factor 1 alpha (HIF-1α), angiopoietin 1 (Ang-1), angiopoietin 2 (Ang-2), angiopoietin receptor (Tie2), and matrix metallopeptidase 9 (MMP-9), and immunohistochemistry to assess capillarization in skeletal muscle post-training. There was an overall increase in the expression levels of VEGF, VEGFR-2, HIF-1α, Ang2, and MMP9 post-training, while these changes were not different among groups. Changes in capillary-to-fibre ratio were found to be strongly associated with Tie2 and HIF-1α expression. This was the first study demonstrating that both HIIT and combined HIIT with strength training enhanced similarly the expression profile of angiogenic factors in skeletal muscle of HF patients, possibly driving the angiogenic program in the trained muscles, although those gene expression increases were found to be only partially related with muscle capillarization.

Ultrastructural muscle damage in young vs. older men after high-volume, heavy-resistance strength training

1999 ◽  
Vol 86 (6) ◽  
pp. 1833-1840 ◽  
Author(s):  
Stephen M. Roth ◽  
Gregory F. Martel ◽  
Frederick M. Ivey ◽  
Jeffrey T. Lemmer ◽  
Brian L. Tracy ◽  
...  
Keyword(s):  
Strength Training ◽  
Muscle Damage ◽  
Vastus Lateralis ◽  
High Volume ◽  
Older Men ◽  
Group Differences ◽  
Strength Increase ◽  
Significant Group ◽  
Leg Extension ◽  
Old Men

This study assessed ultrastructural muscle damage in young (20–30 yr old) vs. older (65–75 yr old) men after heavy-resistance strength training (HRST). Seven young and eight older subjects completed 9 wk of unilateral leg extension HRST. Five sets of 5–20 repetitions were performed 3 days/wk with variable resistance designed to subject the muscle to near-maximal loads during every repetition. Biopsies were taken from the vastus lateralis of both legs, and muscle damage was quantified via electron microscopy. Training resulted in a 27% strength increase in both groups ( P < 0.05). In biopsies before training in the trained leg and in all biopsies from untrained leg, 0–3% of muscle fibers exhibited muscle damage in both groups ( P = not significant). After HRST, 7 and 6% of fibers in the trained leg exhibited damage in the young and older men, respectively ( P < 0.05, no significant group differences). Myofibrillar damage was primarily focal, confined to one to two sarcomeres. Young and older men appear to exhibit similar levels of muscle damage at baseline and after chronic HRST.

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