Contractile force of canine airway smooth muscle during cyclical length changes

1983 ◽  
Vol 55 (3) ◽  
pp. 759-769 ◽  
Author(s):  
S. J. Gunst
Keyword(s):  
Muscle Force ◽  
Isometric Force ◽  
Smooth Muscles ◽  
Rate Of Change ◽  
Dynamic Force ◽  
Airway Caliber ◽  
Length Changes ◽  
Isometric Muscle ◽  
Isometric Muscle Force

Strips of tonically contracted canine tracheal and bronchial airway smooth muscles (AWSM) were studied in vitro to compare dynamic muscle force during stretch-retraction cycles with static isometric muscle force at various length points within the cycling range. At any particular rate, a characteristic force-length loop was obtained by cycling over a given range of lengths. Dynamic muscle force dropped well below static isometric muscle force at lengths short of the peak length at all rates of cycling. When stretch or retraction of the muscle was stopped at any point along either path of the cycle, muscle force rose to approach the isometric force at that length. Dynamic force at the peak length of the cycle remained close to, or slightly greater than, the static isometric force. The results suggest that the velocity of shortening of tonically contracted AWSM is very slow relative to the rates of cycling employed. A slow rate of shortening of AWSM relative to the rate of change in airway caliber during breathing could account for well-known effects of volume history on airway tone.

Absence of myofibrillar creatine kinase and diaphragm isometric function during repetitive activation

1998 ◽  
Vol 84 (4) ◽  
pp. 1166-1173 ◽  
Author(s):  
John J. Labella ◽  
Monica J. Daood ◽  
A. P. Koretsky ◽  
Brian B. Roman ◽  
Gary C. Sieck ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Creatine Kinase ◽  
Muscle Function ◽  
Isometric Force ◽  
Force Generation ◽  
Fatigue Properties ◽  
Specific Force ◽  
Null Mutant ◽  
Isometric Muscle

Creatine kinase (CK) provides ATP buffering in skeletal muscle and is expressed as 1) cytosolic myofibrillar CK (M-CK) and 2) sarcomeric mitochondrial CK (ScCKmit) isoforms that differ in their subcellular localization. We compared the isometric contractile and fatigue properties of 1) control CK-sufficient (Ctl), 2) M-CK-deficient (M-CK[−/−]), and 3) combined M-CK/ScCKmit-deficient null mutant (CK[−/−]) diaphragm (Dia) to determine the effect of the absence of M-CK activity on Dia performance in vitro. Baseline contractile properties were comparable across groups except for specific force, which was ∼16% lower in CK[−/−] Dia compared with M-CK[−/−] and Ctl Dia. During repetitive activation (40 Hz, [Formula: see text] duty cycle), force declined in all three groups. This decline was significantly greater in CK[−/−] Dia compared with Ctl and M-CK[−/−] Dia. The pattern of force decline did not differ between M-CK[−/−] and Ctl Dia. We conclude that Dia isometric muscle function is not absolutely dependent on the presence of M-CK, whereas the complete absence of CK acutely impairs isometric force generation during repetitive activation.

ISOMETRIC MUSCLE FORCE AS A PREDICTOR OF A MAXIMAL MUSCLE EFFORT IN THE LEG PRESS TEST

sportlogia ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 81-89
Author(s):  
Borko Petrović ◽  
◽  
Aleksandar Kukrić ◽  
Radenko Dobraš ◽  
Nemanja Zlojutro ◽  
...  
Keyword(s):  
Muscle Force ◽  
Leg Press ◽  
Isometric Muscle ◽  
Isometric Muscle Force

scholarly journals Hamstring Stiffness Returns More Rapidly After Static Stretching Than Range of Motion, Stretch Tolerance, and Isometric Peak Torque

2019 ◽  
Vol 28 (4) ◽  
pp. 325-331 ◽  
Author(s):  
Genki Hatano ◽  
Shigeyuki Suzuki ◽  
Shingo Matsuo ◽  
Satoshi Kataura ◽  
Kazuaki Yokoi ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Range Of Motion ◽  
Muscle Force ◽  
Static Stretching ◽  
Passive Stiffness ◽  
Hamstring Injuries ◽  
Isometric Muscle ◽  
Torque Angle ◽  
Isometric Muscle Force ◽  
Rest Intervals

Context: Hamstring injuries are common, and lack of hamstring flexibility may predispose to injury. Static stretching not only increases range of motion (ROM) but also results in reduced muscle strength after stretching. The effects of stretching on the hamstring muscles and the duration of these effects remain unclear. Objective: To determine the effects of static stretching on the hamstrings and the duration of these effects. Design: Randomized crossover study. Setting: University laboratory. Participants: A total of 24 healthy volunteers. Interventions: The torque–angle relationship (ROM, passive torque [PT] at the onset of pain, and passive stiffness) and isometric muscle force using an isokinetic dynamometer were measured. After a 60-minute rest, the ROM of the dynamometer was set at the maximum tolerable intensity; this position was maintained for 300 seconds, while static PT was measured continuously. The torque–angle relationship and isometric muscle force after rest periods of 10, 20, and 30 minutes were remeasured. Main Outcome Measures: Change in static PT during stretching and changes in ROM, PT at the onset of pain, passive stiffness, and isometric muscle force before stretching were compared with 10, 20, and 30 minutes after stretching. Results: Static PT decreased significantly during stretching. Passive stiffness decreased significantly 10 and 20 minutes after stretching, but there was no significant prestretching versus poststretching difference after 30 minutes. PT at the onset of pain and ROM increased significantly after stretching at all rest intervals, while isometric muscle force decreased significantly after all rest intervals. Conclusions: The effect of static stretching on passive stiffness of the hamstrings was not maintained as long as the changes in ROM, stretch tolerance, and isometric muscle force. Therefore, frequent stretching is necessary to improve the viscoelasticity of the muscle–tendon unit. Muscle force decreased for 30 minutes after stretching; this should be considered prior to activities requiring maximal muscle strength.

47 ISOMETRIC MUSCLE FORCE PRODUCTION CHARACTERISTICS AS A

1990 ◽  
Vol 22 (2) ◽  
pp. S8
Author(s):  
M. G. Bemben ◽  
B. H. Massey ◽  
R. A. Boileau ◽  
J. E. Misner ◽  
P. J. Bechtel ◽  
...  
Keyword(s):  
Muscle Force ◽  
Force Production ◽  
Muscle Force Production ◽  
Isometric Muscle ◽  
Isometric Muscle Force ◽  
Production Characteristics

scholarly journals Explosive isometric muscle force of different muscle groups of cadet judo athletes in function of gender

2018 ◽  
Vol 72 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Stefan Marković ◽  
Milivoj Dopsaj ◽  
Stevan Jovanović ◽  
Tijana Rusovac ◽  
Nataša Cvetkovski
Keyword(s):  
Muscle Force ◽  
Judo Athletes ◽  
Muscle Groups ◽  
Isometric Muscle ◽  
Isometric Muscle Force

scholarly journals ACTN3 R577X Genotype and Exercise Phenotypes in Recreational Marathon Runners

Genes ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 413 ◽  
Author(s):  
Juan Del Coso ◽  
Victor Moreno ◽  
Jorge Gutiérrez-Hellín ◽  
Gabriel Baltazar-Martins ◽  
Carlos Ruíz-Moreno ◽  
...  
Keyword(s):  
Energy Cost ◽  
Isometric Force ◽  
Weight Bearing ◽  
Fat Percentage ◽  
Body Fatness ◽  
Marathon Runners ◽  
Recreational Athletes ◽  
Energy Cost Of Running ◽  
Isometric Muscle ◽  
Isometric Muscle Force

Background: Homozygosity for the X-allele in the ACTN3 R577X (rs1815739) polymorphism results in the complete absence of α-actinin-3 in sarcomeres of fast-type muscle fibers. In elite athletes, the ACTN3 XX genotype has been related to inferior performance in speed and power-oriented sports; however, its influence on exercise phenotypes in recreational athletes has received less attention. We sought to determine the influence of ACTN3 genotypes on common exercise phenotypes in recreational marathon runners. Methods: A total of 136 marathoners (116 men and 20 women) were subjected to laboratory testing that included measurements of body composition, isometric muscle force, muscle flexibility, ankle dorsiflexion, and the energy cost of running. ACTN3 genotyping was performed using TaqMan probes. Results: 37 runners (27.2%) had the RR genotype, 67 (49.3%) were RX and 32 (23.5%) were XX. There was a difference in body fat percentage between RR and XX genotype groups (15.7 ± 5.8 vs. 18.8 ± 5.5%; effect size, ES, = 0.5 ± 0.4, p = 0.024), whereas the distance obtained in the sit-and-reach-test was likely lower in the RX than in the XX group (15.3 ± 7.8 vs. 18.4 ± 9.9 cm; ES = 0.4 ± 0.4, p = 0.046). Maximal dorsiflexion during the weight-bearing lunge test was different in the RR and XX groups (54.8 ± 5.8 vs. 57.7 ± 5.1 degree; ES = 0.5 ± 0.5, p = 0.044). Maximal isometric force was higher in the RR than in the XX group (16.7 ± 4.7 vs. 14.7 ± 4.0 N/kg; ES = −0.5 ± 0.3, p = 0.038). There was no difference in the energy cost of running between genotypes (~4.8 J/kg/min for all three groups, ES ~0.2 ± 0.4). Conclusions: The ACTN3 genotype might influence several exercise phenotypes in recreational marathoners. Deficiency in α-actinin-3 might be accompanied by higher body fatness, lower muscle strength and higher muscle flexibility and range of motion. Although there is not yet a scientific rationale for the use of commercial genetic tests to predict sports performance, recreational marathon runners who have performed such types of testing and have the ACTN3 XX genotype might perhaps benefit from personalized strength training to improve their performance more than their counterparts with other ACTN3 genotypes.

Multivariate genetic analysis of maximal isometric muscle force at different elbow angles

1997 ◽  
Vol 82 (3) ◽  
pp. 959-967 ◽  
Author(s):  
Martine A. Thomis ◽  
Marc Van Leemputte ◽  
Hermine H. Maes ◽  
Cameron J. R. Blimkie ◽  
Albrecht L. Claessens ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Genetic Analysis ◽  
Muscle Force ◽  
Isometric Strength ◽  
Muscle Area ◽  
Male Adult ◽  
Flexion Extension ◽  
Multivariate Genetic Analysis ◽  
Isometric Muscle ◽  
Isometric Muscle Force

Thomis, Martine A., Marc Van Leemputte, Hermine H. Maes, Cameron J. R. Blimkie, Albrecht L. Claessens, Guy Marchal, Eustachius Willems, Robert F. Vlietinck, and Gaston P. Beunen. Multivariate genetic analysis of maximal isometric muscle force at different elbow angles. J. Appl. Physiol. 82(3): 959–967, 1997.—The maximal isometric moment at five different elbow joint angles was measured in 25 monozygotic and 16 dizygotic male adult twin pairs (22.4 ± 3.7 yr). Genetic model fitting was used to quantify the genetic and environmental contributions to individual differences in isometric strength. Additive genetic factors explained 66–78% of the variance in maximal torque at 170–140–110 and 80° flexion (extension = 180°). At 50° flexion, common and subject-specific environmental factors contributed equally to the variation. The contribution of unique environmental factors concurs with the level of variability in muscle activation and (dis)-comfort of torque production in the specific angle. The relative contribution of lever arm and force-length relationship in torque varies according to the angle. Because these factors might be genetic, this variability is reflected in the genetic contribution at the extreme angles of 170 and 50°. Multivariate analyses suggested a general set of genes that control muscle area and isometric strength, together with a more specific strength factor. Genetic correlations were high (0.82–0.99). Genes responsible for arm-segment lengths did not contribute to muscle area nor to isometric strength.

PECTORALIS MUSCLE FORCE AND POWER OUTPUT DURING FLIGHT IN THE STARLING

1992 ◽  
Vol 164 (1) ◽  
pp. 1-18 ◽  
Author(s):  
ANDREW A. BIEWENER ◽  
KENNETH P. DIAL ◽  
G. E. GOSLOW
Keyword(s):  
Power Output ◽  
Muscle Force ◽  
Muscle Power ◽  
Isometric Force ◽  
Attachment Site ◽  
Bone Strain ◽  
Pectoralis Muscle ◽  
Live Animal ◽  
Level Flight ◽  
Length Changes

Force recordings of the pectoralis muscle of European starlings have been made in vivo during level flight in a wind tunnel, based on bone strain recordings at the muscle's attachment site on the humerus (deltopectoral crest). This represents the first direct measurement of muscle force during activity in a live animal based on calibrated bone strain recordings. Our force measurements confirm earlier electromyographic data and show that the pectoralis begins to develop force during the final one-third of the upstroke, reaches a maximal level halfway through the downstroke, and sustains force throughout the downstroke. Peak forces generated by the pectoralis during level flight at a speed estimated to be 13.7ms−1 averaged 6.4N (28% of maximal isometric force), generating a mean mass-specific muscle power output of 104 W kg−1. Combining our data for the power output of the pectoralis muscle with data for the metabolic power of starlings flying at a similar speed yields an overall flight efficiency of 13 %. The force recordings and length changes of the muscle, based on angular displacements of the humerus, indicate that the pectoralis muscle undergoes a lengthening--shortening contraction sequence during its activation and that, in addition to lift and thrust generation, overcoming wing inertia is probably an important function of this muscle in flapping flight.

Sign in / Sign up

Export Citation Format

Share Document