scholarly journals Fetal isovolumetric contraction time in a case of fetal tachyarrhythmia

2006 ◽  
Vol 28 (6) ◽  
pp. 854-855 ◽  
Author(s):  
Y. Fujita ◽  
B. Trudinger
Keyword(s):  
Contraction Time ◽  
Fetal Tachyarrhythmia

Measurement of Cardiac Contractility Using Fetal Isovolumetric Contraction Time in Fetal Tachyarrhythmia

2011 ◽  
Vol 37 (2) ◽  
pp. 184-188
Author(s):  
Yasuyuki Fujita ◽  
Neil Athayde ◽  
Shoji Tokunaga ◽  
Brian Trudinger
Keyword(s):  
Cardiac Contractility ◽  
Contraction Time ◽  
Fetal Tachyarrhythmia

scholarly journals The Influence of Countermovement Jump Protocol on Reactive Strength Index Modified and Flight Time: Contraction Time in Collegiate Basketball Players

Sports ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 37 ◽  
Author(s):  
Aaron Heishman ◽  
Brady Brown ◽  
Bryce Daub ◽  
Ryan Miller ◽  
Eduardo Freitas ◽  
...  
Keyword(s):  
Force Plate ◽  
Flight Time ◽  
Contraction Time ◽  
Strength Index ◽  
Countermovement Jump ◽  
Basketball Players ◽  
Arm Swing ◽  
Collegiate Basketball ◽  
Positive Correlations ◽  
The Relationship

The purpose of the present investigation was to evaluate differences in Reactive Strength Index Modified (RSIMod) and Flight Time to Contraction Time Ratio (FT:CT) during the countermovement jump (CMJ) performed without the arm swing (CMJNAS) compared to the CMJ with the arm swing (CMJAS), while exploring the relationship within each variable between jump protocols. A secondary purpose sought to explore the relationship between RSIMod and FT:CT during both jump protocols. Twenty-two collegiate basketball players performed both three CMJNAS and three CMJAS on a force plate, during two separate testing sessions. RSIMod was calculated by the flight-time (RSIModFT) and impulse-momentum methods (RSIModIMP). CMJ variables were significantly greater during the CMJAS compared to CMJNAS (p < 0.001). There were large to very large correlations within each variable between the CMJAS and CMJNAS. There were significant positive correlations among RSIModFT, RSIModIMP, and FT:CT during both the CMJAS (r ≥ 0.864, p < 0.001) and CMJNAS (r ≥ 0.960, p < 0.001). These findings identify an increase in RSIMod or FT:CT during the CMJAS, that may provide independent information from the CMJNAS. In addition, either RSIMod or FT:CT may be utilized to monitor changes in performance, but simultaneous inclusion may be unnecessary.

Shortening of muscle relaxation time after creatine loading

1999 ◽  
Vol 86 (3) ◽  
pp. 840-844 ◽  
Author(s):  
M. van Leemputte ◽  
K. Vandenberghe ◽  
P. Hespel
Keyword(s):  
Relaxation Time ◽  
Muscle Relaxation ◽  
Muscle Contractions ◽  
Contraction Time ◽  
Healthy Male ◽  
Healthy Male Volunteers ◽  
Torque Generation ◽  
Isometric Torque ◽  
The Mean ◽  
Isometric Muscle

The effect of creatine (Cr) supplementation on muscle isometric torque generation and relaxation was investigated in healthy male volunteers. Maximal torque (Tmax), contraction time (CT) from 0.25 to 0.75 of Tmax, and relaxation time (RT) from 0.75 to 0.25 of Tmax were measured during 12 maximal isometric 3-s elbow flexions interspersed by 10-s rest intervals. Between the pretest and the posttest, subjects ingested Cr monohydrate (4 × 5 g/day; n = 8) or placebo ( n = 8) for 5 days. Pretest Tmax, CT, and RT were similar in Cr and placebo groups. Also in the posttest, Tmax and CT were similar between groups. However, posttest RT was decreased consistently by ∼20% ( P < 0.05) in the Cr group from the first to the last of the 12 contractions. In addition, the mean decrease in RT after Cr loading was positively correlated with pretest RT ( r = 0.82). It is concluded that Cr loading facilitates the rate of muscle relaxation during brief isometric muscle contractions without affecting torque production.

scholarly journals Caffeine-Induced Effects on Human Skeletal Muscle Contraction Time and Maximal Displacement Measured by Tensiomyography

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 815
Author(s):  
Przemysław Domaszewski ◽  
Paweł Pakosz ◽  
Mariusz Konieczny ◽  
Dawid Bączkowicz ◽  
Ewa Sadowska-Krępa
Keyword(s):  
Skeletal Muscle ◽  
Muscle Activation ◽  
Electric Pulse ◽  
Professional Athletes ◽  
Mechanical Activity ◽  
The Novel ◽  
Contraction Time ◽  
Novel Approach ◽  
Skeletal Muscle Contraction ◽  
Maximal Displacement

Studies on muscle activation time in sport after caffeine supplementation confirmed the effectiveness of caffeine. The novel approach was to determine whether a dose of 9 mg/kg/ body mass (b.m.) of caffeine affects the changes of contraction time and the displacement of electrically stimulated muscle (gastrocnemius medialis) in professional athletes who regularly consume products rich in caffeine and do not comply with the caffeine discontinuation period requirements. The study included 40 professional male handball players (age = 23.13 ± 3.51, b.m. = 93.51 ± 15.70 kg, height 191 ± 7.72, BMI = 25.89 ± 3.10). The analysis showed that in the experimental group the values of examined parameters were significantly reduced (p ≤ 0.001) (contraction time: before = 20.60 ± 2.58 ms/ after = 18.43 ± 3.05 ms; maximal displacement: before = 2.32 ± 0.80 mm/after = 1.69 ± 0.51 mm). No significant changes were found in the placebo group. The main achievement of this research was to demonstrate that caffeine at a dose of 9 mg/kg in professional athletes who regularly consume products rich in caffeine has a direct positive effect on the mechanical activity of skeletal muscle stimulated by an electric pulse.

scholarly journals OP04.25: Current aspects of intrauterine therapy of fetal tachyarrhythmia

2006 ◽  
Vol 28 (4) ◽  
pp. 445-446
Author(s):  
M. Krapp ◽  
R. Axt-Fliedner ◽  
C. Berg ◽  
A. Geipel ◽  
U. Germer ◽  
...  
Keyword(s):  
Fetal Tachyarrhythmia

Contractile properties of expiratory abdominal muscles: effect of elastase-induced emphysema

1987 ◽  
Vol 62 (6) ◽  
pp. 2314-2319 ◽  
Author(s):  
J. S. Arnold ◽  
A. J. Thomas ◽  
S. G. Kelsen
Keyword(s):  
Relaxation Time ◽  
Contractile Function ◽  
Isometric Tension ◽  
Contractile Properties ◽  
Abdominal Muscles ◽  
Force Frequency ◽  
Contraction Time ◽  
Transverse Abdominis ◽  
External Oblique

The present study examined the intrinsic contractile properties and endurance of the transverse abdominis and external oblique abdominal expiratory muscles in adult hamsters and compared their performance with the diaphragm. Experiments were performed in vitro on isolated bundles of muscle stimulated electrically. In control animals peak twitch tension was similar in the two muscles. In contrast, the twitch contraction time and one-half relaxation time of the transverse abdominis were significantly greater than that of the external oblique. The isometric tension generated over a range of stimulus frequencies (i.e., the force-frequency relationship) was a greater percent of the maximum value in response to subtetanizing frequencies (10–40 Hz) in the transverse abdominis than in the external oblique. For both abdominal muscles, however, the tension generated over this range of stimulus frequencies was less than that of the diaphragm. The endurance of the transverse abdominis during repeated contractions was significantly greater than that of the external oblique but similar to the diaphragm. The effect of chronic hyperinflation produced by elastase-induced emphysema on the contractile function of the two muscles was assessed in a second group of adult hamsters. In emphysematous animals peak twitch tension, contraction time, and one-half relaxation time of the twitch and force-frequency curves of muscles from emphysematous animals were similar to values obtained in control animals for both the external oblique and transverse abdominis. However, the endurance of both the transverse abdominis and external oblique muscles was greater in emphysematous than control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Nonuniform fatigue characteristics of slow-twitch motor units activated at a fixed percentage of their maximum tetanic tension

1991 ◽  
Vol 66 (5) ◽  
pp. 1483-1492 ◽  
Author(s):  
T. C. Cope ◽  
C. B. Webb ◽  
A. K. Yee ◽  
B. R. Botterman
Keyword(s):  
Relaxation Time ◽  
Conduction Velocity ◽  
Motor Units ◽  
Contraction Time ◽  
Stimulation Rate ◽  
Axonal Conduction ◽  
Slow Twitch ◽  
Force Clamp ◽  
Highly Correlated ◽  
Tetanic Tension

1. The endurance of slow-twitch motor units from the soleus (SOL) and medial gastrocnemius (MG) muscles of the cat were tested by determining the length of time (endurance time, Et) that a unit could maintain its tension output at 85% of maximum. Motor-unit tension was clamped at the target level by altering the stimulation rate of a unit's motor axon through computer feedback control. Tested in this way, units of both muscles displayed a wide range of Ets, approximately 40- to 50-fold. 2. Electromyographic (EMG) waveforms of motor units subjected to force-clamp contractions were analyzed to access whether any activity-dependent changes in their waveform shape might predict Et. Three measurements of waveform shape were determined: baseline-to-baseline duration, peak-to-peak amplitude, and area. Typically, amplitude decreased and duration increased as a contraction proceeded, whereas area remained fairly constant. Because changes in each measure were very similar for units of widely different Ets, it was concluded that neuromuscular junction failure and changes in the excitability of the sarcolemma (excluding the t-tubule system) play a minor role in determining Et. 3. Et was highly correlated with the mean stimulation rate (Et/number of stimuli) used during the force-clamp contractions. Mean rate was seen to progressively decrease with increasing Et. This correlation could not be explained by measures of isometric contractile speed or relaxation (e.g., twitch contraction time or half-relaxation time) measured before the force-clamp contractions. Both contraction time and half-relaxation time were found to be unrelated to both Et and the rate used to stimulate the unit during the force-clamp contraction. 4. Among type S units of SOL and MG, maximum tetanic tension and Et were not related. A significant relation (r = -0.49) was found between axonal conduction velocity and Et for SOL units (n = 38). In addition, a significant correlation (r = 0.47) was found between conduction velocity and tetanic tension for SOL units. Perhaps because of the small sample of type S units from MG (n = 10), conduction velocity was found not be related to either Et or tetanic tension. 5. Others have shown that a motor unit's maximum tetanic tension and axonal conduction velocity are correlated with its order of recruitment among motoneurons innervating a muscle. Recent work has further shown that among type F units the order in which a motoneuron is recruited is highly correlated with the fatigue resistance of its muscle unit.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Muscle Contractile Properties Measured at Submaximal Electrical Amplitudes and Not at Supramaximal Amplitudes Are Associated with Repeated Sprint Performance and Fatigue Markers

2021 ◽  
Vol 18 (21) ◽  
pp. 11689
Author(s):  
Alejandro Muñoz-López ◽  
Moisés de Hoyo ◽  
Borja Sañudo
Keyword(s):  
Rectus Femoris ◽  
Peak Torque ◽  
Sprint Performance ◽  
Contractile Properties ◽  
Practical Significance ◽  
Contraction Time ◽  
Repeated Sprints ◽  
Muscle Contractile Properties ◽  
Repeated Sprint ◽  
Muscle Contractile

Background: The present study analyzes the associations between the muscle contractile properties (MCP) measured at different neuromuscular electrical stimulation amplitudes (NMESa) and the performance or transient fatigue after a bout of repeated sprints. Methods: Seventeen physically active male subjects performed six repeated sprints of 30 m with 30 s of passive recovery. Capillary blood creatine kinase (CK) concentration, knee extension or flexion isometric peak torque, tensiomyography, and repeated sprint performance were assessed. Results: Muscle displacement and contraction time were different in relation to the NMESa used in the rectus femoris and biceps femoris muscles. At rest, significant (p < 0.05) associations were found between muscle displacement and the loss of time in the repeated sprints (sprint performance) at 20 or 40 mA in the rectus femoris. At post +24 h or +48 h, the highest significant associations were found between the muscle displacement or the contraction time and CK or peak torques also at submaximal amplitudes (20 mA). The NMESa which elicits the peak muscle displacement showed lack of practical significance. Conclusion: Although MCP are typically assessed in tensiomyography using the NMESa that elicit peak muscle displacement, a submaximal NMESa may have a higher potential practical application to assess neuromuscular fatigue in response to repeated sprints.

scholarly journals P31.07: Maternal complex congenital cardiac defect and fetal tachyarrhythmia

2008 ◽  
Vol 32 (3) ◽  
pp. 419-419
Author(s):  
M. Small ◽  
L. R. Brancazio ◽  
M. Decker ◽  
B. K. Boyd ◽  
B. Fitzpatrick ◽  
...  
Keyword(s):  
Cardiac Defect ◽  
Congenital Cardiac Defect ◽  
Fetal Tachyarrhythmia
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