scholarly journals QUALITATIVE AND QUANTITATIVE EVALUATION OF THE CHARACTERISTICS OF THE ISOMETRIC MUSCLE FORCE OF DIFFERENT MUSCLE GROUPS IN CADET JUDO ATHLETES: A GENDER-BASED MULTIDIMENSIONAL MODEL

Author(s):  
Stefan Marković ◽  
Milivoj Dopsaj ◽  
Vladimir Koprivica ◽  
Goran Kasum

The aim of this paper is to define the initial quantitative and qualitative multidimensional model for evaluating basic contractile characteristics of isometric muscle force in systematically trained and selected cadet judo athletes. In this research absolute values of the obtained results, and values derived by relativization of absolute values in relation to skeletal muscle mass (SMM) were considered. The basic method used in this research was laboratory testing. All data sampling was performed by the dynamometry method, using tensiometric probes. The research sample in this study consisted of 21 cadet judo athletes, of which 14 were male and 7 were female. All measurements were performed using standardized testing procedures on the following muscle groups: flexor muscles of the left (HGL) and the right hand (HGR), back (DL) and leg extensor muscles (LE) and ankle joint plantar flexor muscles (PF). Based on the obtained results, separate multidimensional mathematical models for the estimation of contractile potential and development level were defined for both basic characteristics of isometric muscle force: maximal isometric muscle force (Fmax) and maximal explosive isometric muscle force (RFDmax). A qualitative assessment of contractile potential for each of the tested muscle groups, i.e. variables, was enabled by defining standard values for 7 distinct preparedness levels for both basic isometric muscle force contractile characteristics of male and female cadet judo athletes.

2018 ◽  
Vol 72 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Stefan Marković ◽  
Milivoj Dopsaj ◽  
Stevan Jovanović ◽  
Tijana Rusovac ◽  
Nataša Cvetkovski

2001 ◽  
Vol 17 (2) ◽  
pp. 113-128 ◽  
Author(s):  
Akinori Nagano ◽  
Karin G.M. Gerritsen

The purpose of this study was twofold: (a) to systematically investigate the effect of altering specific neuromuscular parameters on maximum vertical jump height, and (b) to systematically investigate the effect of strengthening specific muscle groups on maximum vertical jump height. A two-dimensional musculoskeletal model which consisted of four rigid segments, three joints, and six Hill-type muscle models, representing the six major muscles and muscle groups in the lower extremity that contribute to jumping performance, was trained systematically. Maximum isometric muscle force, maximum muscle shortening velocity, and maximum muscle activation, which were manipulated to simulate the effects of strength training, all had substantial effects on jumping performance. Part of the increase in jumping performance could be explained solely by the interaction between the three neuromuscular parameters. It appeared that the most effective way to improve jumping performance was to train the knee extensors among all lower extremity muscles. For the model to fully benefit from any training effects of the neuromuscular system, it was necessary to continue to reoptimize the muscle coordination, in particular after the strength training sessions that focused on increasing maximum isometric muscle force.


1983 ◽  
Vol 55 (3) ◽  
pp. 759-769 ◽  
Author(s):  
S. J. Gunst

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.


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

2019 ◽  
Vol 28 (4) ◽  
pp. 325-331 ◽  
Author(s):  
Genki Hatano ◽  
Shigeyuki Suzuki ◽  
Shingo Matsuo ◽  
Satoshi Kataura ◽  
Kazuaki Yokoi ◽  
...  

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.


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

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 ◽  
...  

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.


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