Specificity of Training on Computer-Obtained Isokinetic Measures (original) (raw)
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Acute effect of three different warm-up protocols on maximal isokinetic strength in young men
Revista Andaluza de Medicina del Deporte, 2019
Objective: To investigate the acute effect of three different warm-up protocols on a maximal isokinetic strength test. Methods: Twenty-two male, recreational athletes involved in regular resistance training were evaluated. Subjects performed a maximal isokinetic strength test of the knee extensors in an isokinetic dynamometer after completing a control session or one of the following warm-up protocols using a randomized design: a general warm-up, stretching warm-up, or specific warm-up. The comparison between treatments was completed through Repeated-Measures Analysis of Variance, followed by a Bonferroni “post hoc” test (p < 0.05). Results: The only difference found was the concentric peak moment following the application of the specific warm-up protocol, which was lower than the control session (12.94%; p < 0.05). No other differences were noted in eccentric peak movement or total work (concentric + eccentric) parameter after application of any the warm-up protocols within c...
Predicting 1-RM isotonic knee extension strength utilizing isokinetic dynamometry
Isokinetics and Exercise Science, 1998
The purpose of this study was twofold: determine which isokinetic determinants correlated best with an isotonic one-repetition maximum (1-RM) and to generate, based on these determinants a formula that will allow clinicians to utilize isokinetic testing to predict an isotonic 1-RM. Fifty female subjects, ranging from 18-35 years of age, participated in this study. Strength measurements using a Cybex II isokinetic dynamometer (peak torque, average peak torque, peak torque:body weight, work per repetition, and total work) and a Cybex isotonic knee extension machine were performed. The subject's height and body weight were recorded. Through linear regression analysis the variables peak torque and body weight were determined to be the best predictors of an isotonic 1-RM. These variables were incorporated in the following formula: Predicted 1-RM = 21.38 + (0.24 x Peak Torque) + (0.18 x Body Weight) which may used utilized by clinicians to predict an isotonic 1-RM.
Sports Biomechanics, 2020
This study investigated additional and traditional variables from isokinetic test of thigh muscles in soccer players across different field positions. One hundred and eighty-nine athletes performed maximal concentric isokinetic knee contractions on dominant (DL) and non-dominant limb (NDL) at 60º/s and 240º/s. The additional outcomes peak torque angle (AngPT), acceleration time (AcT) and time to peak torque (TPT) and traditional outcomes Peak torque (PT), total work (TW) and power (Pw) were extracted from the exam. Goalkeepers (GK), side backs (SB), central backs (CB), central defender midfielders (CDM), central attacking midfielders (CAM) and forwards (FW) were considered. Comparisons between limbs and positions demonstrated that SB extensors of the DL presented TPT lower (p = 0.006) and AngPT higher (p = 0.011) than NDL at 60°/s. CDM extensors of the DL showed lower TPT at 60°/s (p = 0.003) and 240°/s (p = 0.024). CAM flexors of the DL showed lower TPT (p = 0.026) and AcT (p = 0.021) at 240°/s than NDL. CB, CDM and CAM extensors of the NDL showed higher PT, TW and Pw than DL (p < 0.05). In conclusion, there are muscle imbalances between limbs in SB, CDM and CAM and across different field positions.
Acute effects of static stretching duration on isokinetic peak torque production of soccer players
Journal of Bodywork and Movement Therapies, 2006
Recent research demonstrates that stretching prior to physical activity decreases performance. However, these stretching bouts are not representative of athletes during warm up procedures, as they are usually time consuming. The aim of the present study was to examine whether the duration of acute static stretching is responsible for losses in isokinetic peak torque production.
Science of Gymnastics Journal
The aim of the research was to examine the effects of isokinetic training on knee stabilizer strength, and whether this increases the efficiency of performing basic gymnastics vaults. A total of 60 respondents, students of the Faculty of Sports and Physical Education (average age 19.7±1.5 years, weight 75.3±2.9 kg, height 179.8±6.7 cm) were included. The subjects were divided into two groups, experimental (EG) (n=30) and control (CG) (n=30). As part of the 12-week program, the experimental group (EG) in addition to exercises within the regular classes at the university had an additional concentric isokinetic training 3 times a week on the Biodex System 3 dynamometer, while the control group (CG) only had exercises within the regular classes at the university. The results showed statistically significant differences (p < 0.05) between (EG) and (CG), both, in increasing the strength of the knee stabilizers and in the performance of gymnastics vaults, and the strength of the knee ex...
PloS one, 2018
The current study aimed to examine the reliability of the conventional and functional ratios derived from peak torques (PTs) and those obtained from the combination of knee flexors torque at the angle of knee extensors PT. Twenty-six male athletes (mean of 24.0±0.7 years) from different sports completed a test-to-test variation in isokinetic strength (Biodex, System 3) within a period of one week. Anthropometry and body composition assessed by Dual Energy X-ray Absorptiometry were also measured. The proposed isokinetic strength ratio measurements appeared to be highly reliable: conventional ratio at PT angle (intra-class correlation, ICC = 0.98; 95% confidence interval; 95%CI: 0.95 to 0.99); functional extension ratio at PT angle (ICC = 0.98; 95%CI: 0.96 to 0.99); and, functional flexion ratio at PT angle (ICC = 0.95; 95%CI: 0.89 to 0.98). Technical error of measurement (TEM) and associated percentage of the coefficient of variation (%CV) were as follows: conventional ratio at PT an...
Seasonal Variation in Isokinetic Peak Torque in Youth Soccer Players
The aim of the study was to investigate the seasonal variation in the strength of the knee flexors and extensors in highly trained youth soccer players. The players (n=16; age 16.7±0.7) were measured at the end of the competitive season, at the beginning of the off-season and during the sixth week of a new competitive season. Isokinetic concentric peak torque was measured at 60°•s-1 , 180°•s-1 , 360°•s-1 in a sitting position. The testing range of motion was set from 10-90° of knee flexion. Players performed a set of six maximal repetitions for both dominant and nondominant limb. Average values of peak torque significantly changed during the observed periods. Significant differences (p<.05) between the three measurement sessions were noted with respect to the knee flexors at all angular velocities. A post-hoc test confirmed a significant increase between the first and the second measurement for flexion in both dominant (180°•s-1 ; p=.033) and non-dominant legs (360°•s-1 ; p=.004). A significant increase was also found between the first and the third session for both limbs during knee flexion at all angular velocities. The results indicate that peak torque values of knee flexors and extensors varied differently in trained youth soccer players depending on muscle group and movement velocity with statistically significant changes in knee flexors only.
ISOKINETIC PERFORMANCE IN ELITE VOLLEYBALL AND BASKETBALL PLAYERS
The aim of this study was to determine and compare the maximal voluntary peak torque of the hamstring and quadriceps muscles, and the torque ratio between these muscles in volleyball and basketball players across a spectrum of speeds in their dominant legs. Twenty male volleyball players, 20 male basketball players, and 20 controls were evaluated using an isokinetic dynamometer at angular velocities of 60º, 180º and 300°s-1. No significant quadriceps and hamstring muscles concentric peak torque was found between volleyball and basketball players with the exception of quadriceps at 300°s-1 (volleyball: 139.9±0.7 Nm, basketball: 117.2±1.9 Nm). The mean hamstring/quadriceps muscles (H/Q) ratios at 60°s-1 were similar to each other. No significant differences were found between volleyball and basketball players for H/Q muscles ratio at 180°s-1. Volleyball players demonstrated higher differences compared to the basketball players and control groups only at 300°s-1 (p=.001 and p=.000, respectively). Our data suggest that the sport's demands seem to influence isokinetic concentric H/Q ratio.
Effects of different isokinetic knee extension warm-up protocols on muscle performance
The Journal of sports medicine and physical fitness
Aim: The optimal warm-up protocol for isokinetic strength performance assessment remains unclear. Therefore, the purpose of this study was to analyze the effects of different warm-up routines on strength production in young adults. Methods: Fifteen healthy young men (24.8±3.5 years) were exposed to five different isokinetic warm-up protocols. Isokinetic strength was assessed after each protocol at 60°.s-1. The warm-up protocols were: (1) submaximal, 10 submaximal consecutive repetitions (50% of maximum effort) at 60°.s-1; (2) intermittent, one set of 10 maximal intermittent contractions (30 s between contractions) at 60°.s-1; (3) 180, 10 maximal consecutive repetitions at 180°.s-1; (4) 300, 10 maximal consecutive repetitions at 300°.s-1 and (5) control session (no warm-up). Results: Peak torque was greater (P<0.05) after the intermittent (295.3±53.2 N.m) when compared to 300 (267.5±47.3 N.m) and 180 (275.2±48.6 N.m) warm-up protocols. Also, peak torque was higher (P<0.05) in t...