Desmin characteristics of CD11b-positive fibers after eccentric contractions

2002 ◽  
Vol 34 (2) ◽  
pp. 274-281 ◽  
Author(s):  
BARBARA ST. PIERRE SCHNEIDER ◽  
HEATHER SANNES ◽  
JASON FINE ◽  
THOMAS BEST
Keyword(s):  
Eccentric Contractions

scholarly journals Investigating The Repeated-bout Effect To Eccentric Contractions For Females And Males

2019 ◽  
Vol 51 (Supplement) ◽  
pp. 83
Author(s):  
Christina D. Bruce ◽  
Luca Ruggiero ◽  
Gabriel U. Dix ◽  
Paul D. Cotton ◽  
Chris J. McNeil
Keyword(s):  
Eccentric Contractions ◽  
Repeated Bout Effect ◽  
Repeated Bout

scholarly journals Effects of trunk extensor eccentric exercise on lipid profile and glycaemic response

2020 ◽  
Vol 6 (1) ◽  
pp. e000861
Author(s):  
Ho-Seong Lee ◽  
Takayuki Akimoto ◽  
Ah-Ram Kim
Keyword(s):  
Lipid Profile ◽  
Muscle Soreness ◽  
Blood Lipid ◽  
Eccentric Contraction ◽  
Trunk Muscles ◽  
Eccentric Contractions ◽  
Glycaemic Response ◽  
Concentric Contractions ◽  
Positive Effects ◽  
Trunk Extensor

ObjectivesA number of previous studies reported physiological responses and adaptations after eccentric muscle contraction of limb muscles. In contrast, no study has determined physiological response after eccentric contraction of trunk muscles. The purpose of the present study was to compare the functional and metabolic changes after eccentric or concentric exercises of trunk extensor muscles.MethodsIn this randomised, crossover study, 10 men performed a single bout of 50 maximal voluntary concentric and eccentric contractions of the trunk extensor with an interval of 2 weeks between bouts. The activities of the paraspinal muscles were recorded during concentric and eccentric contractions. Muscle soreness, muscle function, blood lipid profiles and glycaemic responses were measured before, immediately after and at 24, 48, 72 and 96 hours after each bout.ResultsThe lumbar multifidus and iliocostalis lumborum activities during eccentric contractions were significantly higher than those during concentric contractions (p<0.05). The maximal strength and muscle endurance of the trunk extensor were not decreased even after the eccentric contractions. Compared with concentric contractions, muscle soreness was significantly increased at 24, 48, 72 and 96 hours after eccentric contractions (p<0.05). The TG, TC and LDL-C were significantly lower at 48, 72 and 96 hours after eccentric contractions (p<0.05), while blood glucose levels and HOMA-IR were significantly greater at 48 and 72 hours after eccentric contractions (p<0.05).ConclusionThis study indicated that eccentric contractions of the trunk extensor had positive effects on the lipid profile and the glycaemic response.

Incomplete Muscle Activation After Training With Electromyostimulation

1998 ◽  
Vol 23 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Tibor Hortobágyi ◽  
Jean Lambert ◽  
Kevin Scott
Keyword(s):  
Key Words ◽  
Muscle Activation ◽  
Motor Units ◽  
Eccentric Contraction ◽  
Key Words Exercise ◽  
Eccentric Contractions ◽  
Control Group ◽  
Force Ratio ◽  
Evoked Force ◽  
Large Motor

Training with voluntary or electromyostimulation (EMS)-evoked eccentric contractions should produce complete muscle activation, since EMS and eccentric contractions preferentially recruit large motor units. Subjects (22 women ages 18-40) were randomly assigned to a voluntary (VOL; n = 8), EMS (n = 8), or control group. VOL and EMS groups trained the quadriceps at the same, increasing force levels 4 times/week for 6 weeks using voluntary or EMS-evoked eccentric contractions. VOL improved voluntary more than EMS-evoked eccentric strength. EMS improved EMS-evoked strength more than voluntary. EMS training improved EMS-evoked eccentric strength more than VOL training improved voluntary eccentric strength. EMS-evoked to voluntary force ratio increased from 0.57 (±0.11) to 1.20 (±0.35) in EMS and did not change in VOL (all changes p < .05). Six of eight EMS subjects produced greater EMS-evoked force posttraining, suggesting incomplete muscle activation after EMS training. Key words: exercise, eccentric contraction, muscle activation

Ultrastructural changes after concentric and eccentric contractions of human muscle

1983 ◽  
Vol 61 (1) ◽  
pp. 109-122 ◽  
Author(s):  
D.J. Newham ◽  
G. McPhail ◽  
K.R. Mills ◽  
R.H.T. Edwards
Keyword(s):  
Human Muscle ◽  
Eccentric Contractions ◽  
Ultrastructural Changes

Do muscles function as adaptable locomotor springs?

2002 ◽  
Vol 205 (15) ◽  
pp. 2211-2216 ◽  
Author(s):  
Stan L. Lindstedt ◽  
Trude E. Reich ◽  
Paul Keim ◽  
Paul C. LaStayo
Keyword(s):  
Skeletal Muscle ◽  
Elastic Strain ◽  
Strain Energy ◽  
Elastic Strain Energy ◽  
Normal Animal ◽  
Eccentric Contractions ◽  
Normal Muscle ◽  
Energetic Costs ◽  
Locomotor Muscles ◽  
Power Outputs

SUMMARYDuring normal animal movements, the forces produced by the locomotor muscles may be greater than, equal to or less than the forces acting on those muscles, the consequences of which significantly affect both the maximum force produced and the energy consumed by the muscles. Lengthening (eccentric)contractions result in the greatest muscle forces at the lowest relative energetic costs. Eccentric contractions play a key role in storing elastic strain energy which, when recovered in subsequent contractions, has been shown to result in enhanced force, work or power outputs. We present data that support the concept that this ability of muscle to store and recover elastic strain energy is an adaptable property of skeletal muscle. Further, we speculate that a crucial element in that muscle spring may be the protein titin. It too seems to adapt to muscle use, and its stiffness seems to be`tuned' to the frequency of normal muscle use.

Skeletal muscle collagen content in humans after high-force eccentric contractions

2004 ◽  
Vol 97 (1) ◽  
pp. 197-203 ◽  
Author(s):  
Abigail L. Mackey ◽  
Alan E. Donnelly ◽  
Taina Turpeenniemi-Hujanen ◽  
Helen P. Roper
Keyword(s):  
Creatine Kinase ◽  
Kinase Activity ◽  
Staining Intensity ◽  
Creatine Kinase Activity ◽  
Serum Creatine Kinase ◽  
Muscle Contractions ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Eccentric Contractions ◽  
Knee Extensors ◽  
Type Iv

The purpose of this study was to investigate the effects of high-force eccentric muscle contractions on collagen remodeling and on circulating levels of matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in humans. Nine volunteers [5 men and 4 women, mean age 23 (SD 4) yr] each performed a bout of 100 maximum voluntary eccentric contractions of the knee extensors. Muscle biopsies were taken before exercise and on days 4 and 22 afterward. Image analysis of stained tissue sections was used to quantify endomysial collagen staining intensity. Maximum voluntary contractile isometric force was recorded preexercise and on days 1, 2, 3, 4, 8, 11, and 14 postexercise. Venipuncture blood samples were also drawn on these days for measurement of serum creatine kinase activity and concentrations of MMP-9, TIMP-1, TIMP-2, and the MMP-2/TIMP-2 complex. Maximum voluntary contractile force declined by 39 ± 23% (mean ± SD) on day 2 postexercise and recovered thereafter. Serum creatine kinase activity peaked on day 4 postexercise ( P < 0.01). Collagen type IV staining intensity increased significantly on day 22 postexercise to 126 ± 29% (mean ± SD) of preexercise values ( P < 0.05). Serum MMP-9 levels increased on day 8 postexercise ( P < 0.01), and serum TIMP-1 was also significantly elevated on days 1, 2, 3, 4, and 14 postexercise ( P < 0.05). These results suggest that a single bout of eccentric muscle contractions results in remodeling of endomysial type IV collagen, possibly via the MMP pathway.

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