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.

Influence of concentric and eccentric resistance training on architectural adaptation in human quadriceps muscles

2007 ◽  
Vol 103 (5) ◽  
pp. 1565-1575 ◽  
Author(s):  
Anthony J. Blazevich ◽  
Dale Cannavan ◽  
David R. Coleman ◽  
Sara Horne
Keyword(s):  
Resistance Training ◽  
Time Course ◽  
Close Association ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Mechanical Stimuli ◽  
Fascicle Length ◽  
And Shifts ◽  
Fascicle Angle ◽  
Training And Detraining

Studies using animal models have been unable to determine the mechanical stimuli that most influence muscle architectural adaptation. We examined the influence of contraction mode on muscle architectural change in humans, while also describing the time course of its adaptation through training and detraining. Twenty-one men and women performed slow-speed (30°/s) concentric-only (Con) or eccentric-only (Ecc) isokinetic knee extensor training for 10 wk before completing a 3-mo detraining period. Fascicle length of the vastus lateralis (VL), measured by ultrasonography, increased similarly in both groups after 5 wk (ΔCon = +6.3 ± 3.0%, ΔEcc = +3.1 ± 1.6%, mean = +4.7 ± 1.7%; P < 0.05). No further increase was found at 10 wk, although a small increase (mean ∼2.5%; not significant) was evident after detraining. Fascicle angle increased in both groups at 5 wk (ΔCon = +11.1 ± 4.0%, ΔEcc = +11.9 ± 5.4%, mean = 11.5 ± 3.2%; P < 0.05) and 10 wk (ΔCon = +13.3 ± 3.0%, ΔEcc = +21.4 ± 6.9%, mean = 17.9 ± 3.7%; P < 0.01) in VL only and remained above baseline after detraining (mean = 13.2%); smaller changes in vastus medialis did not reach significance. The similar increase in fascicle length observed between the training groups mitigates against contraction mode being the predominant stimulus. Our data are also strongly indicative of 1) a close association between VL fascicle length and shifts in the torque-angle relationship through training and detraining and 2) changes in fascicle angle being driven by space constraints in the hypertrophying muscle. Thus muscle architectural adaptations occur rapidly in response to resistance training but are strongly influenced by factors other than contraction mode.

scholarly journals Effects of strength training and detraining on knee extensor strength, muscle volume and muscle quality in elderly women

AGE ◽  
2012 ◽  
Vol 35 (5) ◽  
pp. 1899-1904 ◽  
Author(s):  
Cleiton Silva Correa ◽  
Bruno Manfredini Baroni ◽  
Régis Radaelli ◽  
Fábio Juner Lanferdini ◽  
Giovani Dos Santos Cunha ◽  
...  
Keyword(s):  
Strength Training ◽  
Elderly Women ◽  
Knee Extensor ◽  
Muscle Volume ◽  
Muscle Quality ◽  
Knee Extensor Strength ◽  
Training And Detraining

Effects of a Low-Intensity Strength-Training Program on Knee-Extensor Strength and Functional Ability of Frail Older People

2000 ◽  
Vol 8 (4) ◽  
pp. 325-342 ◽  
Author(s):  
Marja H. Westhoff ◽  
Lysander Stemmerik ◽  
Hendriek C. Boshuizen
Keyword(s):  
Older People ◽  
Strength Training ◽  
Training Program ◽  
Functional Ability ◽  
Knee Extensor ◽  
Knee Extensors ◽  
Control Group ◽  
Frail Older People ◽  
Low Intensity ◽  
Knee Extensor Strength

This study’s purpose was to investigate whether a 10-week low-intensity strength-training program could improve strength of the knee extensors and functional ability. Participants 65 years and older with low knee-extensor muscle strength were randomized into an exercise (n = 11) and a control group (n = 10). Knee-extensor strength and functional ability were measured before and after the program and again 6 months later. Knee-extensor strength (Nm) increased by 54% (13% in the control) by the end of the training program (F = 13.02, p = .01), and most of this improvement was still present 6 months later. The program had a beneficial effect on functional tasks, especially the time taken to rise from a chair in combination with a 3-m walk (F = 3.99, p = .03) and self-reported ability related to lower extremity performance (F = 6.97, p = .02). It seems that this program could contribute to improving functional ability in frail older people.

Strength training counteracts motor performance losses during bed rest

2003 ◽  
Vol 95 (4) ◽  
pp. 1485-1492 ◽  
Author(s):  
Minoru Shinohara ◽  
Yasuhide Yoshitake ◽  
Motoki Kouzaki ◽  
Hideoki Fukuoka ◽  
Tetsuo Fukunaga
Keyword(s):  
Strength Training ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Bed Rest ◽  
Training Group ◽  
Medial Gastrocnemius ◽  
Knee Extensors ◽  
Extensor Muscles ◽  
Muscle Groups

The purpose of the study was to determine the effect of bed rest with or without strength training on torque fluctuations and activation strategy of the muscles. Twelve young men participated in a 20-day bed rest study. Subjects were divided into a non-training group (BRCon) and a strength-training group (BRTr). The training comprised dynamic calf-raise and leg-press exercises. Before and after bed rest, subjects performed maximal contractions and steady submaximal isometric contractions of the ankle extensor muscles and of the knee extensor muscles (2.5-10% of maximal torque). Maximal torque decreased for both the ankle extensors (9%, P < 0.05) and knee extensors (16%, P < 0.05) in BRCon but not in BRTr. For the ankle extensors, the coefficient of variation (CV) for torque increased in both groups ( P < 0.05), with a greater amount ( P < 0.05) in BRCon (88%) compared with BRTr (41%). For the knee extensors, an increase in the CV for torque was observed only in BRCon (22%). The increase in the CV for torque in BRCon accompanied the greater changes in electromyogram amplitude of medial gastrocnemius (122%) and vastus lateralis (59%) compared with BRTr ( P < 0.05). The results indicate that fluctuations in torque during submaximal contractions of the extensor muscles in the leg increase after bed rest and that strength training counteracted the decline in performance. The response varied across muscle groups. Alterations in muscle activation may lead to an increase in fluctuations in motor output after bed rest.

scholarly journals Shatavari Supplementation in Postmenopausal Women Improves Handgrip Strength and Increases Vastus Lateralis Myosin Regulatory Light Chain Phosphorylation But Does Not Alter Markers of Bone Turnover: A Randomised Controlled Trial

2021 ◽  
Author(s):  
Mary F. O’Leary ◽  
Sarah R. Jackman ◽  
Vlad R. Sabou ◽  
Matthew I Campbell ◽  
Jonathan C. Y. Tang ◽  
...  
Keyword(s):  
Bone Turnover ◽  
Postmenopausal Women ◽  
Light Chain ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Regulatory Light Chain ◽  
Myosin Regulatory Light Chain ◽  
Knee Extensor Strength ◽  
Markers Of Bone Turnover ◽  
Regulatory Light Chain Phosphorylation

AbstractBackgroundShatavari has long been used as an Ayurvedic herb for women’s health, but empirical evidence for its effectiveness has been lacking. Shatavari contains phytoestrogenic compounds that bind to the estradiol receptor, and may therefore benefit postmenopausal women since postmenopausal estradiol deficiency contributes to sarcopenia and osteoporosis.MethodsIn a randomised double-blind trial, 20 postmenopausal women (68.5 ± 6 y) ingested either placebo (N=10) or shatavari (N=10; 1000 mg/d, equivalent to 26,500 mg/d fresh weight shatavari) for 6 weeks. Handgrip and knee extensor strength were measured at baseline and at 6 weeks. Vastus lateralis (VL) biopsy samples were obtained. Data are presented and analysed (t test/Mann Whitney U) as difference scores (Week 6 – baseline, median ± interquartile range).ResultsHandgrip, (but not knee extensor) strength was improved by shatavari supplementation (shatavari +0.7 ± 1.1 kg, placebo -0.4 ± 1.3 kg; p=0.04). Myosin regulatory light chain phosphorylation, a known marker of improved myosin contractile function, was increased in VL following shatavari supplementation (immunoblotting; placebo -0.08 ± 0.5 a.u. shatavari +0.3 ± 1 arbitrary units (a.u.); p=0.03). Shatavari increased phosphorylation of Aktser473 (Aktser473 (placebo -0.6 ± 0.6 a.u. shatavari +0.2 ± 1.3 a.u; p=0.03) in VL. Shatavari supplementation did not alter plasma markers of bone turnover (P1NP, β-CTX) and stimulation of human osteoblasts with pooled sera (N=8 per condition) from placebo and shatavari supplementation conditions did not alter cytokine or metabolic markers of osteoblast activity.ConclusionsShatavari may improve muscle function and contractility via myosin conformational change and warrants further investigation of its utility in conserving musculoskeletal function in postmenopausal women.Trial RegistrationRetrospectively registered at clinicaltrials.gov as NCT05025917 on 30/08/21.

scholarly journals The Effect of Patient Sex and Graft Type on Postoperative Functional Outcomes After Primary ACL Reconstruction

2020 ◽  
Vol 8 (6) ◽  
pp. 232596712092605
Author(s):  
Milos Lesevic ◽  
Michelle E. Kew ◽  
Stephan G. Bodkin ◽  
David R. Diduch ◽  
Stephen F. Brockmeier ◽  
...  
Keyword(s):  
Patellar Tendon ◽  
Cruciate Ligament ◽  
Return To Sport ◽  
Knee Extensor ◽  
Postoperative Rehabilitation ◽  
Knee Flexor ◽  
Female Patients ◽  
Bptb Graft ◽  
Knee Extensor Strength ◽  
Male Patients

Background: Graft choice in anterior cruciate ligament reconstruction (ACLR) and postoperative rehabilitation may affect strength recovery differently in men than women and therefore affect a timely and successful return to sport. Purpose: To compare knee extensor and flexor strength between men and women who underwent isolated ACLR with either patellar tendon or hamstring tendon (HST) autografts. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 166 patients (87 women, 79 men) with primary unilateral and uncomplicated ACLRs were recruited for participation. A total of 100 patients had bone–patellar tendon–bone (BPTB) autografts and 66 had HST autografts. At 6 months postoperatively, all patients completed the Tegner activity scale and International Knee Documentation Committee Subjective Knee Evaluation as well as underwent bilateral isokinetic (90 deg/s) tests of the knee extensor and flexor groups. Outcomes were recorded in a single session as part of a return-to-sport test battery. Surgical notes were obtained to determine the type of autograft and nerve block used at the time of ACLR. Results: There was a significant sex × graft type interaction for mass-normalized knee flexor torque ( P = .017). Female patients with an HST graft had a significantly lower knee flexor torque compared with female patients with a BPTB graft (0.592 ± 0.49 N·m/kg vs 0.910 ± 0.24 N·m/kg; Cohen d [95% CI] = 0.91 [0.45, 1.36]). They also had a significantly lower knee flexor torque when compared with male patients with an HST graft (0.592 ± 0.49 N·m/kg vs 0.937 ± 0.35 N·m/kg; Cohen d [95% CI]= 0.88 [0.45, 1.31]). There were significant main effects for graft type with knee flexion ( P = .001) and extension ( P = .008) symmetry. Patients with a BPTB graft demonstrated lower knee extensor symmetry (65.7% ± 17.0%) and greater knee flexor symmetry (98.7% ± 18.0%) compared with patients with an HST graft (extension: 77.1% ± 32%, Cohen d [95% CI] = 0.47 [0.16, 0.79]; flexion: 82.9% ± 33.3%, Cohen d [95% CI] = 0.63 [0.31, 0.95]). We also observed a significant main effect for sex ( P = .028) and graft type ( P = .048) for mass-normalized knee extensor strength. Female participants and patients of either sex with BPTB grafts had lower knee extensor strength compared with male participants and patients with HST grafts, respectively. Conclusion: At approximately 6 months after ACLR, female patients reconstructed with HST autografts demonstrated weaker HST strength compared with female patients with a BPTB autograft. There were no differences in HST strength between graft types in male patients. Female patients appear to be recovering HST strength differently than male patients when using an HST autograft. These findings may have implications in surgical planning, postoperative rehabilitation, and return-to-sport decision making.

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 Muscle Architecture Predicts Maximum Strength and Is Related to Activity Levels in Cerebral Palsy

2010 ◽  
Vol 90 (11) ◽  
pp. 1619-1630 ◽  
Author(s):  
Noelle G. Moreau ◽  
Kit N. Simpson ◽  
Sharlene A. Teefey ◽  
Diane L. Damiano
Keyword(s):  
Cerebral Palsy ◽  
Children And Adolescents ◽  
Knee Extensor ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Typical Development ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
Fascicle Angle ◽  
Gmfcs Level

Background Muscle architecture is known to be predictive of muscle function. However, it is unknown whether this relationship is similar in children and adolescents with and without cerebral palsy (CP). Objective The objective of this study was to determine whether the architecture of the rectus femoris (RF) and vastus lateralis (VL) muscles was predictive of maximum voluntary knee extensor torque in children and adolescents with and without CP and whether these measures were related to activity and participation levels. Design A case-control design was used. Methods Eighteen participants with CP (mean age=12.0 years, SD=3.2) at Gross Motor Function Classification System (GMFCS) levels I through IV and 12 age-matched peers with typical development (mean age=12.3 years, SD=3.9) were evaluated. Muscle thickness, fascicle length, and fascicle angle of the RF and VL muscles were measured with 2-dimensional, B-mode ultrasound imaging. The activity and participation measures used for participants with CP were the Pediatric Outcomes Data Collection Instrument (PODCI) and the Activities Scale for Kids, Performance Version (ASKp). Results When age and GMFCS level were controlled for, VL muscle thickness was the best predictor of knee extensor isometric torque in the group with CP (R2=.85). This prediction was similar to the prediction from VL muscle thickness and age in participants with typical development (R2=.91). Rectus femoris muscle fascicle length was significantly correlated with the Sports and Physical Functioning Scale of the PODCI (ρ=.49), and VL muscle fascicle angle was correlated with the Transfers and Basic Mobility Scale of the PODCI (r=.47) and with ASKp Locomotion subdomain (r=.50). Limitations A limitation of this study was the small sample size. Conclusions Ultrasound measures of VL muscle thickness, adjusted for age and GMFCS level, were highly predictive of maximum torque and have the potential to serve as surrogate measures of voluntary strength (force-generating capacity) in children and adolescents with and without CP.

Vastus Intermedius And Vastus Lateralis Fascicle Length Changes During Maximal Eccentric Knee Extensor Contractions

2016 ◽  
Vol 48 ◽  
pp. 184 ◽  
Author(s):  
Ryosuke Ando ◽  
Kazunori Nosaka ◽  
Aya Tomita ◽  
Kohei Watanabe ◽  
Anthony J. Blazevich ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Knee Extensor ◽  
Fascicle Length ◽  
Vastus Intermedius ◽  
Length Changes

scholarly journals Shatavari Supplementation in Postmenopausal Women Improves Handgrip Strength and Increases Vastus lateralis Myosin Regulatory Light Chain Phosphorylation but Does Not Alter Markers of Bone Turnover

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4282
Author(s):  
Mary F. O’Leary ◽  
Sarah R. Jackman ◽  
Vlad R. Sabou ◽  
Matthew I. Campbell ◽  
Jonathan C. Y. Tang ◽  
...  
Keyword(s):  
Bone Turnover ◽  
Postmenopausal Women ◽  
Light Chain ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Regulatory Light Chain ◽  
Myosin Regulatory Light Chain ◽  
Knee Extensor Strength ◽  
Markers Of Bone Turnover ◽  
Regulatory Light Chain Phosphorylation

Shatavari has long been used as an Ayurvedic herb for women’s health, but empirical evidence for its effectiveness has been lacking. Shatavari contains phytoestrogenic compounds that bind to the estradiol receptor. Postmenopausal estradiol deficiency contributes to sarcopenia and osteoporosis. In a randomised double-blind trial, 20 postmenopausal women (68.5 ± 6 years) ingested either placebo (N = 10) or shatavari (N = 10; 1000 mg/d, equivalent to 26,500 mg/d fresh weight shatavari) for 6 weeks. Handgrip and knee extensor strength were measured at baseline and at 6 weeks. Vastus lateralis (VL) biopsy samples were obtained. Data are presented as difference scores (Week 6—baseline, median ± interquartile range). Handgrip (but not knee extensor) strength was improved by shatavari supplementation (shatavari +0.7 ± 1.1 kg, placebo −0.4 ± 1.3 kg; p = 0.04). Myosin regulatory light chain phosphorylation, a known marker of improved myosin contractile function, was increased in VL following shatavari supplementation (immunoblotting; placebo −0.08 ± 0.5 a.u., shatavari +0.3 ± 1 arbitrary units (a.u.); p = 0.03). Shatavari increased the phosphorylation of Aktser473 (Aktser473 (placebo −0.6 ± 0.6 a.u., shatavari +0.2 ± 1.3 a.u; p = 0.03) in VL. Shatavari supplementation did not alter plasma markers of bone turnover (P1NP, β-CTX) and stimulation of human osteoblasts with pooled sera (N = 8 per condition) from placebo and shatavari supplementation conditions did not alter cytokine or metabolic markers of osteoblast activity. Shatavari may improve muscle function and contractility via myosin conformational change and further investigation of its utility in conserving and enhancing musculoskeletal function, in larger and more diverse cohorts, is warranted.

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