Comparative force-velocity relation and analyses of myosin of dog atria and ventricles

1982 ◽  
Vol 243 (3) ◽  
pp. H391-H397 ◽  
Author(s):  
J. Wikman-Coffelt ◽  
H. Refsum ◽  
G. Hollosi ◽  
L. Rouleau ◽  
L. Chuck ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Calcium Concentration ◽  
Maximum Velocity ◽  
Calcium Sensitivity ◽  
Myofibrillar Proteins ◽  
Maximal Velocity ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Normal Calcium ◽  
Actin Concentration

The isolated muscle and purified myofibrillar proteins of canine atria and ventricles were compared relative to force-velocity relations and rate of adenosine 5'-triphosphatase (ATPase) activity as a function of calcium concentrations. The maximal stress development of isolated trabeculae of canine atria was similar to that of canine right ventricular papillary muscles when analyzed at saturating calcium concentrations (7.5 mM); however, stress was less in the atria when studied at normal calcium concentrations (2.5 mM). The maximal velocity of shortening of atrial trabeculae was about 2.3 times higher than that of ventricular muscle. Regulated actomyosin characterized from the myofibrillar proteins of the two tissues gave directionally similar calcium sensitivity. The maximum velocity of shortening for actin-activated atrial myosin of the dog was approximately 1.8 times higher when the latter was analyzed as a function of actin concentration. Both maximal tension of isolated muscle and regulated actomyosin ATPase activity were dependent on calcium concentration.

scholarly journals Power Output and Force-Velocity Relationship of Live Fibres from White Myotomal Muscle of the Dogfish, Scyliorhinus Canicula

1988 ◽  
Vol 140 (1) ◽  
pp. 187-197 ◽  
Author(s):  
N. A. CURTIN ◽  
R. C. WOLEDGE
Keyword(s):  
Power Output ◽  
Maximum Velocity ◽  
Muscle Fibres ◽  
Fish Length ◽  
Skinned Fibres ◽  
Step Method ◽  
Velocity Relationship ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Myotomal Muscle

The relationship between force and velocity of shortening and between power and velocity were examined for myotomal muscle fibre bundles from the dogfish. The maximum velocity of shortening, mean value 4.8 ± 0.2 μms−1 half sarcomere−1 (±S.E.M., N = 13), was determined by the ‘slack step’ method (Edman, 1979) and was found to be independent of fish length. The force-velocity relationship was hyperbolic, except at the high-force end where the observations were below the hyperbola fitted to the rest of the data. The maximum power output was 91 ± 14 W kg−1 wet mass (±S.E.M., N = 7) at a velocity of shortening of 1.3 ± 0.13μms−1 halfsarcomere−1 (±S.E.M., N = 7). This power output is considerably higher than that previously reported for skinned fibres (Bone et al. 1986). Correspondingly the force-velocity relationship is less curved for intact fibres than for skinned fibres. The maximum swimming speed (normalized for fish length) predicted from the observed power output of the muscle fibres decreased with increasing fish size; it ranged from 12.9 to 7.8 fish lengths s−1 for fish 0155–0.645m in length.

Force-velocity shifts with repetitive isometric and isotonic contractions of canine gastrocnemius in situ

1992 ◽  
Vol 73 (5) ◽  
pp. 2105-2111 ◽  
Author(s):  
B. T. Ameredes ◽  
W. F. Brechue ◽  
G. M. Andrew ◽  
W. N. Stainsby
Keyword(s):  
Muscle Length ◽  
Isometric Tension ◽  
Maximal Velocity ◽  
Velocity Of Shortening ◽  
Low Load ◽  
Before And After ◽  
Force Velocity ◽  
The Hill ◽  
Isotonic Contractions

The force-velocity (F-V) relationships of canine gastrocnemius-plantaris muscles at optimal muscle length in situ were studied before and after 10 min of repetitive isometric or isotonic tetanic contractions induced by electrical stimulation of the sciatic nerve (200-ms trains, 50 impulses/s, 1 contraction/s). F-V relationships and maximal velocity of shortening (Vmax) were determined by curve fitting with the Hill equation. Mean Vmax before fatigue was 3.8 +/- 0.2 (SE) average fiber lengths/s; mean maximal isometric tension (Po) was 508 +/- 15 g/g. With a significant decrease of force development during isometric contractions (-27 +/- 4%, P < 0.01, n = 5), Vmax was unchanged. However, with repetitive isotonic contractions at a low load (P/Po = 0.25, n = 5), a significant decrease in Vmax was observed (-21 +/- 2%, P < 0.01), whereas Po was unchanged. Isotonic contractions at an intermediate load (P/Po = 0.5, n = 4) resulted in significant decreases in both Vmax (-26 +/- 6%, P < 0.05) and Po (-12 +/- 2%, P < 0.01). These results show that repeated contractions of canine skeletal muscle produce specific changes in the F-V relationship that are dependent on the type of contractions being performed and indicate that decreases in other contractile properties, such as velocity development and shortening, can occur independently of changes in isometric tension.

scholarly journals Comparison of two measurement devices for obtaining horizontal force-velocity profile variables during sprint running

2022 ◽  
pp. 174795412110672
Author(s):  
Erin Feser ◽  
Kyle Lindley ◽  
Kenneth Clark ◽  
Neil Bezodis ◽  
Christian Korfist ◽  
...  
Keyword(s):  
Random Error ◽  
Maximum Velocity ◽  
American Football ◽  
Systematic Bias ◽  
Maximal Velocity ◽  
Horizontal Force ◽  
Time Data ◽  
Measured Velocity ◽  
Theoretical Maximum ◽  
Force Velocity

This study established the magnitude of systematic bias and random error of horizontal force-velocity (F-v) profile variables obtained from a 1080 Sprint compared to that obtained from a Stalker ATS II radar device. Twenty high-school athletes from an American football training group completed a 30 m sprint while the two devices simultaneously measured velocity-time data. The velocity-time data were modelled by an exponential equation fitting process and then used to calculate individual F-v profiles and related variables (theoretical maximum velocity, theoretical maximum horizontal force, slope of the linear F-v profile, peak power, time constant tau, and horizontal maximal velocity). The devices were compared by determining the systematic bias and the 95% limits of agreement (random error) for all variables, both of which were expressed as percentages of the mean radar value. All bias values were within 6.32%, with the 1080 Sprint reporting higher values for tau, horizontal maximal velocity, and theoretical maximum velocity. Random error was lowest for velocity-based variables but exceeded 7% for all others, with slope of the F-v profile being greatest at ±12.3%. These results provide practitioners with the information necessary to determine if the agreement between the devices and the magnitude of random error is acceptable within the context of their specific application.

Mechanical properties of pulmonary arteries from sensitized dogs

1983 ◽  
Vol 55 (6) ◽  
pp. 1669-1673 ◽  
Author(s):  
S. K. Kong ◽  
N. L. Stephens
Keyword(s):  
Mechanical Properties ◽  
Pulmonary Arteries ◽  
Maximal Velocity ◽  
Shortening Velocity ◽  
Littermate Control ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Tetanic Tension ◽  
Isotonic Shortening

On the basis of isometric dose-response studies, we (J. Pharmacol. Exp. Ther. 219:551-557, 1981) have reported that the ovalbumin-sensitized (S) canine pulmonary artery (PA) is hypersensitive and hyperractive to histamine compared with that from a littermate control (C) in vitro. In this study, our aim was to determine whether the maximal velocity of shortening (Vmax) measured in strips of electrically stimulated SPA and CPA differed. Vmax (velocity at zero load) was obtained by analysis of force-velocity curves from these tissues using the equation (P + a) (V + b) = (Po + a)b, in which P is load, Po is maximum tetanic tension, V is shortening velocity, and a and b are asymptotic values in units of force and velocity. The Vmax values derived for SPA and CPA are 0.188 +/- 0.029 (SE) and 0.113 + 0.017 lo/s, respectively, lo being defined as that length at which Po is obtained. This result indicated that the Vmax value of SPA is significantly (P less than 0.05) different from that of CPA. The b values for SPA [0.034 +/- 0.003 lo/s] and for CPA [0.025 +/- 0.004 lo/s] were also significantly different. However, the force constants a and Po were unchanged in the SPA and CPA. SPA also had a greater isotonic shortening capacity than CPA. These findings indicate that mechanical properties of SPA are altered and lend an understanding of the hyperreactivity of these vessels in the sensitized model.

Decreased velocity of shortening in arterial smooth muscle from older (28- to 31-week-old) spontaneously hypertensive rats

1986 ◽  
Vol 64 (1) ◽  
pp. 96-100 ◽  
Author(s):  
C. S. Packer ◽  
M. L. Kagan ◽  
N. L. Stephens
Keyword(s):  
Smooth Muscle ◽  
Spontaneously Hypertensive Rats ◽  
Maximum Velocity ◽  
Hypertensive Rats ◽  
Arterial Smooth Muscle ◽  
Spontaneously Hypertensive ◽  
Velocity Of Shortening ◽  
Old Rats ◽  
Force Velocity ◽  
Arterial Muscle

An increased maximum velocity of shortening (Vmax) and increased shortening ability (ΔLmax) have been reported for caudal arterial smooth muscle from 16- to 18-week-old spontaneously hypertensive rats (SHR) compared with age-matched Wistar-Kyoto (WKY) control rats. It is known that hypertension results in hypertrophy of vascular smooth muscle. It is plausible that the faster Vmax of 16- to 18-week-old SHR arterial smooth muscle may slow down with age due to hypertrophy. The force–velocity (F–V) study done previously on caudal arterial strips from 16- to 18-week-old SHR and WKY rats was repeated on preparations from 28- to 31-week-old rats. An electromagnetic muscle lever was employed in recording force–velocity data. Analysis of these data revealed that the 28- to 31-week-old SHR (n = 7) mean F–V curve was not different from the 28- to 31-week-old WKY (n = 5) mean F–V curve (p > 0.05), and the shortening ability of 28- to 31-week-old SHR arterial muscle was significantly depressed compared with 28- to 31-week-old WKY arterial muscle (p < 0.01). In conclusion, (i) although Vmax is faster in younger (16- to 18-week-old) SHR compared with age-matched WKY caudal arterial smooth muscle, SHR Vmax is not different from WKY Vmax in the older (28- to 31-week-old) rats, (ii) Shortening ability is greater in 16- to 18-week-old SHR caudal arterial strips compared with 16- to 18-week-old WKY strips, but is significantly depressed in 28- to 31-week-old SHR compared with 28- to 31-week-old WKY preparations. It can also be concluded that the decrease in SHR Vmax from once elevated speeds is not due simply to ageing, for if this were the case, the WKY Vmax should also decline with age and the relative difference between SHR and WKY F–V curves seen in younger rats should not have been obliterated when comparing the older rats.

Force–velocity constants in smooth muscle: afterloaded isotonic and quick-release methods

1985 ◽  
Vol 63 (1) ◽  
pp. 48-51 ◽  
Author(s):  
N. L. Stephens
Keyword(s):  
Smooth Muscle ◽  
Muscle Length ◽  
Maximum Velocity ◽  
Electrical Stimulus ◽  
Active State ◽  
Quick Release ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Release Method ◽  
Tetanic Tension

In using pharmacologic stimuli, force–velocity (FV) curves are usually obtained by the method of quick release (QR) and redevelopment of shortening at peak tetanic tension; the advantage of the method being that the active state is at maximum. However, the QR may itself reduce the intensity of the active state and result in reduced values of FV constants. We tested this by delineating FV curves in canine tracheal smooth muscle using both conventional afterloaded isotonic contractions (ALI), and redevelopment of shortening after QR methods. For both these studies a supramaximal tetanizing electrical stimulus was used. The analysis of 11 experiments revealed that the latter method resulted in statistically significant reductions of all FV constants except for Po (maximum isometric tetanic tension). The means and standard errors for the sets of constants for the ALI and QR, respectively, are as follows: Vmax (maximum velocity of shortening) = 0.275 lo (optimal muscle length)/s ± 0.024 (SE), and 0.216 lo/s + 0.023; a (hyperbolic constant with units of force) = 294 g/cm2 ± 35 and 236 g/cm2 ± 32; b (hyperbolic constant with units of velocity) = 0.059 lo ± 0.004 and 0.039 lo/s ± 0.005; a/Po = 0.214 ± 0.028 and 0.182 ± 0.026; and Po = 1.362 kg/cm2 ± 0.106 and 1.294 kg/cm2 ± 0.097. These data clearly show that the quick-release method for measuring force–velocity relationships in canine smooth muscle results in significant underestimates of muscle shortening properties.

Ontogeny of shortening velocity in porcine trachealis

1992 ◽  
Vol 262 (3) ◽  
pp. L280-L285 ◽  
Author(s):  
K. Ikeda ◽  
R. W. Mitchell ◽  
K. A. Guest ◽  
C. Y. Seow ◽  
C. F. Kirchhoff ◽  
...  
Keyword(s):  
Isometric Force ◽  
Electrical Field Stimulation ◽  
Contractile Force ◽  
Postnatal Life ◽  
Maximal Velocity ◽  
Shortening Velocity ◽  
Lever System ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
The Relationship

We examined the effect of maturation on force-velocity (F-V) parameters in porcine tracheal smooth muscle (TSM) to determine the relationship between maximal isometric contractile force (Po) and maximal velocity of shortening (Vmax). Strips of TSM excised from 1-day-old neonatal swine (neo; n = 8), 2-wk-old swine (2ws; n = 7), and 10-wk-old swine (10ws; n = 7) were tethered to an electromagnetic lever system for F-V analysis of contractility. TSM strips were activated by electrical field stimulation at optimal resting tension, voltage, and length (Lo) so that maximal reproducible contractile force (Po) was elicited. Velocities were measured at the early phase of isometric contraction (3.1 +/- 0.1 s for neo, 2.9 +/- 0.1 s for 2ws, and 3.1 +/- 0.1 s for 10ws; P = NS). Shortening velocity increased progressively with maturation; Vmax was 0.164 +/- 0.011 Lo/s for neo, 0.194 +/- 0.013 Lo/s for 2ws (P less than 0.05 vs. neo), and 0.260 +/- 0.024 Lo/s for 10ws (P less than 0.01 vs. neo; P less than 0.05 vs. 2ws). Maximal isometric force generation increased substantially during the first 2 wk of postnatal life and thereafter returned to neonatal levels; Po was 71.5 +/- 2.1 mN/mm2 for neo, 95.4 +/- 7.0 mN/mm2 for 2ws, and 74.7 +/- 6.2 mN/mm2 for 10ws (P less than 0.05, 2ws vs. neo and 10ws). In separate studies, we also determined whether differences in Vmax occurred during the normal cycling phase of the cross bridge (3 s) or during the slowly cycling phase of the latch bridge (8 s) in tissue from 12 additional animals.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Force-Velocity Profile of Competitive Kayakers: Evaluation of a Novel Single Kayak Stroke Test

2021 ◽  
Vol 80 (1) ◽  
pp. 49-59
Author(s):  
Milos Petrovic ◽  
Amador Garcia-Ramos ◽  
Danica Janicijevic ◽  
Alejandro Perez-Castilla ◽  
Olivera M. Knezevic ◽  
...  
Keyword(s):  
Bench Press ◽  
Maximum Velocity ◽  
Maximum Power ◽  
Maximum Force ◽  
Upper Body ◽  
Maximal Velocity ◽  
Female Age ◽  
Fatigue Monitoring ◽  
Force Velocity ◽  
The Individual

Abstract The assessment of the force-velocity (F-V) profile in athletes may have important applications for training prescription, injury management, and fatigue monitoring. This study aimed to assess whether a novel single kayak stroke test (SKST) is able to provide the F-V relationship variables (maximum force, maximum velocity and maximum power) of competitive kayakers with acceptable reliability and external validity. Six female (age: 20.3 ± 3.7 years) and eight male (age: 20.8 ± 2.4 years) elite kayakers performed the SKST, bench press, bench pull, and short Wingate kayak test. The individual F-V relationships were highly linear [median r (range): left stroke = 0.986 (0.897 - 0.998); right stroke = 0.987 (0.971 - 0.999)]. The reliability of the F-V relationship parameters obtained during the SKST was high (within-session: CV ≤ 4.48% and ICC ≥ 0.93; between-session: CV ≤ 8.06% and ICC ≥ 0.65). The validity of the F-V relationship parameters obtained during the SKST was generally very high for maximum power (r range = 0.825 - 0.975), high for maximum force during both the bench press and the bench pull (r range = 0.751 - 0.831), and high or moderate for maximal velocity during the bench pull (r = 0.770 - 0.829) and the bench press (r = 0.355 - 0.471), respectively. The SKST can be considered a feasible procedure for testing the maximal upper-body muscle mechanical capacities of kayakers.

scholarly journals Force-velocity relations in mammalian heart muscle

1962 ◽  
Vol 202 (5) ◽  
pp. 931-939 ◽  
Author(s):  
Edmund H. Sonnenblick
Keyword(s):  
Work Performance ◽  
Muscle Length ◽  
Isometric Tension ◽  
Velocity Curve ◽  
Maximal Velocity ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Length Changes ◽  
Mammalian Heart Muscle ◽  
Inotropic Intervention

Force-velocity relations were studied in the cat papillary muscle. As with skeletal muscle, a characteristic relation has been demonstrated between the velocity of shortening (V) and the force developed (Po). Two generalities have been shown to pertain. First, increasing initial muscle length increases the maximal developed force (Po) without a change in the maximal velocity of shortening (Vmax). Secondly, at any one muscle length, changes in frequency of contraction and chemical environment (increased calcium and norepinephrine) increase Vmax with a variable change in Po. Changes in Vmax thus help to characterize an inotropic intervention (altered contractility). Work and power, at any one muscle length, are functions of afterload, with maxima when the load is approximately 40% of isometric tension. With increasing initial muscle length, the work and power at any one afterload as well as the maximal work and power of the muscle are both increased. At constant initial length, positive inotropic interventions (increased frequency, increased calcium, and norepinephrine) increase the work at any one afterload as well as shift the maximal work potential to a higher afterload. Work performance thus depends on muscle length, the prevailing force-velocity curve, and the afterload at which the muscle is operating.

Sign in / Sign up

Export Citation Format

Share Document