scholarly journals Knee Muscles Isokinetic Evaluation after a Six-Month Regular Combined Swim and Dry-Land Strength Training Period in Adolescent Competitive Swimmers

2015 ◽  
Vol 49 (1) ◽  
pp. 195-200 ◽  
Author(s):  
Athanasios A. Dalamitros ◽  
Vasiliki Manou ◽  
Kosmas Christoulas ◽  
Spiros Kellis
Keyword(s):  
Strength Training ◽  
Knee Extensor ◽  
Peak Torque ◽  
Knee Extension ◽  
Training Period ◽  
Similar Data ◽  
Dry Land ◽  
Isokinetic Testing ◽  
Torque Values ◽  
Competitive Swimmers

Abstract Previous studies demonstrated significant increases in the shoulder internal rotators’ peak torque values and unilateral muscular imbalances of the shoulder rotators after a competitive swim period. However, there are no similar data concerning the knee muscles. The purpose of the current study was to examine the effects of a six-month training period on knee flexor and extensor peak torque values, examine a possible bilateral strength deficit and evaluate the unilateral strength balance in competitive swimmers. Eleven male adolescent swimmers (age: 14.82 ± 0.45 years) were tested for concentric knee extension and flexion peak torque (60°/s) with an isokinetic dynamometer, before and after a regular combined swim and dry-land strength training period. A trend towards greater improvements in the knee extensor compared to flexor muscles peak torque was observed. Furthermore, the bilateral strength deficit remained almost unchanged, whereas unilateral strength imbalance was increased for both limbs. However, all results were nonsignificant (p > 0.05). According to the data presented, a six-month regular combined swim and dry-land strength training period caused non-significant alterations for all the parameters evaluated during isokinetic testing. This study highlights the fact that competitive adolescent swimmers demonstrated unilateral knee strength imbalances throughout a long period of their yearly training macrocycle.

Adaptations in skeletal muscle following strength training

1979 ◽  
Vol 46 (1) ◽  
pp. 96-99 ◽  
Author(s):  
D. L. Costill ◽  
E. F. Coyle ◽  
W. F. Fink ◽  
G. R. Lesmes ◽  
F. A. Witzmann
Keyword(s):  
Strength Training ◽  
Exercise Program ◽  
Knee Extensor ◽  
Peak Torque ◽  
Knee Extension ◽  
Type I ◽  
Muscle Area ◽  
Muscle Enzymes ◽  
Muscle Enzyme ◽  
Before And After

Five men were studied before and after 7 wk of isokinetic strength training to determine its effects on muscle enzyme activities and fiber composition. One of the subject's legs was trained using 10 repeated 6-s maximal work bouts, while the other leg performed repeated 30-s maximal knee extension exercise. The total work accomplished by each leg was constant. Training 4 times/wk achieved similar gains in peak torque for both legs at the training velocity (3.14 rad/s) and at slower speeds. Fatigability of the knee extensor muscles, as measured by a 60-s exercise test, was similar in both legs after training. Biopsy specimens showed significant changes in the % of the muscle area composed of type I and IIa fibers as a result of both strength training programs. In terms of muscle enzymes, only the 30 s exercise program resulted in elevated glycolytic, ATP-CP and mitochondrial activities. Despite these changes, none of the parameters measured were found to be related to the gains in either muscle strength or fatigability during maximal isokinetic contractions.

Validity of Isokinetic and Isometric Testing modalities for Assessing Short-term Resistance Exercise Strength Gains

1992 ◽  
Vol 1 (4) ◽  
pp. 275-283 ◽  
Author(s):  
Andrew C. Fry ◽  
Dawn R. Powell ◽  
William J. Kraemer
Keyword(s):  
Resistance Exercise ◽  
Human Performance ◽  
Peak Torque ◽  
Quadriceps Strength ◽  
Short Term ◽  
Isokinetic Testing ◽  
Leg Extension ◽  
Leg Flexion ◽  
Isokinetic Torque ◽  
Torque Values

Although it is generally accepted that human performance must be assessed in a manner specific to the training, previous studies have violated this principle. In order to determine the validity of evaluating short-term resistance training programs with isometric and isokinetic measures, 23 recreationally active males participated in an 8-week training program. Subjects were randomly divided into barbell squat, hip sled, leg extension, and control groups. Pre- and posttesting of quadriceps strength was performed with a Cybex isokinetic dynamometer. Six angle-specific torques (N.m) were determined at 0 rad-s-1 and 1.05 rad-s-1. Ten RM training loads increased significantly for all groups that trained. Isometric torque values differed significantly from isokinetic torque values at 30, 60, 75, and 90° of leg flexion for all groups. No significant torque increases from pre- to posttest were observed for any group at any limb angle for either isometric or isokinetic testing, or for isokinetic peak torque. This indicates that strength increases during short-term dynamic external resistance exercise are not adequately assessed with either isometric or isokinetic evaluations.

Comparison of Isometric Portable Fixed Dynamometry to Isokinetic Dynamometry for Assessment of Hip Strength

2013 ◽  
Vol 18 (6) ◽  
pp. 1-6 ◽  
Author(s):  
Roger O. Kollock ◽  
Bonnie Van Lunen ◽  
Jennifer L. Linza ◽  
James A. Onate
Keyword(s):  
Outcome Measures ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Peak Torque ◽  
Hip Strength ◽  
Isokinetic Testing ◽  
Testing Procedures ◽  
Hip Motion ◽  
Torque Values ◽  
Isokinetic Peak Torque

Context:Assessment of hip strength can be performed with either isokinetic or isometric testing procedures, but the degree of association between values derived from the alternative testing methods has not been previously documented.Objective:To investigate the relationship between isometric peak torque and isokinetic peak torque at 60°·s-1 for various hip motions.Participants:Eighteen physically active males (N = 9) and females (N = 9) participated (22 ± 3 years, 173.0 ± 10.5 cm, 73.8 ± 16.7 kg).Intervention(s):Three isokinetic repetitions at 60°·s-1 and three isometric contractions of 5 s each for the hip fexors (HFs), hip extensors (HEs), hip abductors (ABs), hip adductors (ADs), hip external rotators (ERs), and hip internal rotators (IRs).Outcome Measures:Pearson correlation coefficients and coefficients of determination were calculated for both absolute and allometric-scaled peak torque values.Results:Meaningful associations between isometric and isokinetic peak torque values were found for each hip motion. Allometric-scaled strength values demonstrated stronger correlations than absolute strength values.Conclusions:The results suggest that portable fixed isometric testing of hip strength is an alternative to isokinetic testing at 60°·s-1.

scholarly journals ACTN3 genotype is associated with muscle phenotypes in women across the adult age span

2008 ◽  
Vol 105 (5) ◽  
pp. 1486-1491 ◽  
Author(s):  
Sean Walsh ◽  
Dongmei Liu ◽  
E. Jeffrey Metter ◽  
Luigi Ferrucci ◽  
Stephen M. Roth
Keyword(s):  
Muscle Strength ◽  
Knee Extensor ◽  
Peak Torque ◽  
Fat Free Mass ◽  
Isokinetic Dynamometry ◽  
Adult Age ◽  
Encoding Gene ◽  
Total Body ◽  
Torque Values ◽  
Adult Volunteers

The R577X polymorphism in the α-actinin-3 encoding gene ( ACTN3) has been associated with elite athletic performance, and recently with differences in isometric and dynamic muscle strength and power in the general population. In this study we sought to determine the association of ACTN3 R577X genotype with muscle strength and mass phenotypes in men and women across the adult age span. Eight hundred forty-eight ( n = 848) adult volunteers (454 men and 394 women) aged 22–90 yr were genotyped for ACTN3 R577X. Knee extensor (KE) shortening and lengthening peak torque values were determined using isokinetic dynamometry and fat-free mass (FFM) by dual-energy X-ray absorptiometry. Women deficient in α-actinin-3 (X/X; n = 53) displayed lower KE shortening peak torque (30°/s: 89.5 ± 3.5 vs. 99.3 ± 1.4 N·m, P = 0.011; 180°/s: 60.3 ± 2.6 vs. 67.0 ± 1.0 N·m, P = 0.019) and KE lengthening peak torque (30°/s: 122.8 ± 5.7 vs. 137.0 ± 2.2 N·m, P = 0.022; 180°/s: 121.8 ± 5.8 vs. 138.5 ± 2.2 N·m, P = 0.008) compared with R/X + R/R women ( n = 341). Women X/X homozygotes also displayed lower levels of both total body FFM (38.9 ± 0.5 vs. 40.1 ± 0.2 kg, P = 0.040) and lower limb FFM (11.9 ± 0.2 vs. 12.5 ± 0.1 kg, P = 0.044) compared with R/X + R/R women. No genotype-related differences were observed in men. In conclusion, our results indicate that the absence of α-actinin-3 protein (i.e., ACTN3 X/X genotype) influences KE peak torque and FFM in women but not men.

scholarly journals The Effect of Applying Rigid Taping to Quadriceps Muscles on Knee Extension Strength and Jumping Distance

2014 ◽  
Vol 2 (11_suppl3) ◽  
pp. 2325967114S0017
Author(s):  
Burak Yasin Yasar ◽  
Tuba Kaplan ◽  
Sabriye Ercan ◽  
Erkan Alp ◽  
Cem Cetin
Keyword(s):  
Lower Limb ◽  
Performance Enhancement ◽  
Knee Extensor ◽  
Peak Torque ◽  
Knee Extension ◽  
Knee Extension Strength ◽  
Jump Distance ◽  
Before And After ◽  
Isokinetic Torque ◽  
Work Done

Objectives: The scientific literature is insufficient to support the use of elastic or rigid taping for the prevention or treatment of musculoskeletal injury or performance enhancement. The aim of this study was to analyze the effects of applying rigid taping on the knee extension strength and lower limb function in healthy subjects. Methods: Twenty eight healthy volunteers (age: 20.9 ± 1.1 years) were randomly assigned to two groups of 14 subjects each: Placebo/sham tape and rigid tape (Rigid tape application over the same muscles). All individuals were assessed for single and double leg hops and peak isometric and concentric isokinetic torque before and after interventions. Results: There were no statistically significant differences in jumping distances, isometric peak torque, isokinetic peak torque and total work done between groups. Conclusion: Application of rigid tape to quadriceps muscles did not significantly change lower limb functions, jump distance and knee extensor peak torque in healthy sedentary subjects.

Effect of Ankle Position on EMG Activity and Peak Torque of the Knee Extensors and Flexors during Isokinetic Testing

1997 ◽  
Vol 6 (4) ◽  
pp. 335-342 ◽  
Author(s):  
John P. Miller ◽  
Kerriann Catlaw ◽  
Robert Confessore
Keyword(s):  
Female Athletes ◽  
Peak Torque ◽  
Knee Extension ◽  
Knee Extensors ◽  
Emg Activity ◽  
Isokinetic Testing ◽  
Surface Electrodes ◽  
Activity Peak ◽  
Peak Knee ◽  
Healthy Female

The purpose of this study was to examine the effect of ankle position on the electromyographic (EMG) activity, peak torque, and peak knee flexion to extension torque ratio during isokinetic testing of the knee. Twelve healthy female athletes performed six maximal knee extension and flexion repetitions with their dominant legs at 60 and 180°/s with the ankle in a plantar flexed position and again in a dorsiflexed position. Root mean square EMG (rmsEMG) activity was determined by placing bipolar surface electrodes on the quadriceps and the hamstrings. Ankle position had no effect on the rmsEMG activity of the quadriceps or the hamstrings at either 60 or 180°/s. Significant differences were noted for peak flexor torque at 607s (p <.001) and 180°/s (p<.01) and for peak torque flexor/extensor ratio (p <.01), with higher values observed with ankle dorsiflexion. This suggests that ankle position affects knee flexor torque and flexor/extensor ratio but not hamstring activity during isokinetic testing of the knee.

scholarly journals Isokinetic Performance of Knee Flexor and Extensor Muscles in American Football Players from Brazil

2017 ◽  
Vol 19 (4) ◽  
pp. 426 ◽  
Author(s):  
Lucas Severo-Silveira ◽  
Carolina Gassen Fritsch ◽  
Bruno Manfredini Baroni ◽  
Vanessa Bernardes Marques ◽  
Maurício Pinto Dornelles
Keyword(s):  
Cruciate Ligament ◽  
Production Capacity ◽  
Knee Extensor ◽  
Peak Torque ◽  
Primary Objective ◽  
American Football ◽  
Football Players ◽  
Thigh Muscles ◽  
Torque Values ◽  
Isokinetic Performance

DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n4p426 The isokinetic performance of thigh muscles has been related to athletic performance and risk for non-contact injuries, such as anterior cruciate ligament ruptures and hamstring strains. Although isokinetic profile of American football players from United States (USA) is widely described, there is a lack of studies comprising players acting outside the USA. The primary objective of this study was to describe the isokinetic performance of thigh muscles in elite American football players in Brazil. Secondarily, we aimed to compare the playing positions and compare the Brazilian players with high-level athletes from USA. Knee extensor (KE) and flexor (KF) muscles of 72 Brazilian players were assessed through isokinetic tests at 60°·s-1. KE concentric peak torque was 276±56 N·m, while KF had concentric and eccentric peak torques of 151±37 N·m and 220±40 N·m, respectively. Offensive linemen players presented greater peak torque values than defensive lineman, halfbacks, and wide receivers (all comparisons are provided in the article). Brazilian players had lower scores than USA athletes for KE and KF peak torque values. In addition, a conventional torque ratio (concentric/concentric) lower than 0.6 was found in 76-83% of athletes, and a functional ratio (eccentric/eccentric) below to 1.0 in 94%. Bilateral asymmetry greater than 10% was verified in 26% and 43% of athletes for KE and KF muscles, respectively. Elite players in Brazil present high incidence of strength imbalance in thigh muscles, and they are below USA players in relation to torque production capacity of KE and KF muscles.

scholarly journals Assessment of Post-Rehabilitation ACL Reconstructed Knees

2020 ◽  
Vol 8 (2) ◽  
pp. 33
Author(s):  
Kevin Carlson
Keyword(s):  
Range Of Motion ◽  
Knee Flexion ◽  
Knee Extensor ◽  
Peak Torque ◽  
Isokinetic Strength ◽  
Isokinetic Testing ◽  
Rehabilitation Protocols ◽  
Dependent Variables ◽  
Hop Test ◽  
Main Effects

Background: Understanding objective measures of ACL-reconstructed knee function is important in determining the efficacy of rehabilitation protocols and a patient’s return to activities of daily living and sport activities. Objective: To assess the range of motion (ROM), isokinetic strength (torque) and functional performance measures (hop test) of ACL-reconstructed and ACL-intact knees. Methods: Twelve volunteers (5 females, 7 males) with unilateral ACL injury and reconstruction were given a battery of tests (hop test for distance, knee range of motion, knee extensor isokinetic testing to assess both affected and unaffected lower limb function, flexibility and strength. Main effects and interactions were analyzed by mixed-model repeated measures ANCOVA. Dependent variables included hop test for distance, knee flexion and extension range of motion, and knee extensor isokinetic torque. The independent variables were the intact/reconstructed ACL knee and time from surgery. Sex was the covariate. Results: No statistically significant differences (p>0.05) were found across all dependent variables hop test for distance (P = 0.939), knee flexion (P = 0.576) and extension (P = 0.431) ROM, and knee extensor torque (eccentric P = 0.923 and concentric P = 0.723) for the main effects and interactions of knee (ACL-reconstructed and ACL-intact) and time (0-12 months, 13-24 months, 25-36 months and 37+ months). The covariate, sex, did produce significant differences for the hop test (P < 0.0001) and isokinetic testing (eccentric peak torque P = 0.003 and concentric peak torque P=0.012). Conclusions: Clinicians may consider present rehabilitation protocols to be adequate in developing ROM and isokinetic strength following ACL reconstruction. However, greater improvements in ROM and strength may be achieved over an extended period following ACL reconstruction surgery.

Ability of Isokinetic Dynamometer to Predict Isotonic Knee Extension 1-Repetition Maximum

2020 ◽  
Vol 29 (5) ◽  
pp. 616-620
Author(s):  
Joseph B. Lesnak ◽  
Dillon T. Anderson ◽  
Brooke E. Farmer ◽  
Dimitrios Katsavelis ◽  
Terry L. Grindstaff
Keyword(s):  
Resistance Training ◽  
Knee Injury ◽  
Peak Torque ◽  
Knee Extension ◽  
Prediction Equation ◽  
Isokinetic Dynamometer ◽  
Physically Active ◽  
Repetition Maximum ◽  
Knee Rehabilitation ◽  
Torque Values

Context: Resistance training exercise prescription is often based on exercises performed at a percentage of a 1-repetition maximum (1RM). Following knee injury, there is no consensus when a patient can safely perform 1RM testing. Resistance training programs require the use of higher loads, and loads used in knee injury rehabilitation may be too low to elicit gains in strength and power. A maximum isometric contraction can safely be performed during early stages of knee rehabilitation and has potential to predict an isotonic knee extension 1RM. Objective: To determine whether a 1RM on an isotonic knee extension machine can be predicted from isometric peak torque measurements. Design: Descriptive laboratory study. Setting: University research laboratory. Participants: A total of 20 (12 males and 8 females) healthy, physically active adults. Main Outcome Measures: An isokinetic dynamometer was used to determine isometric peak torque (in N·m). 1RM testing was performed on a knee extension machine. Linear regression was used to develop a prediction equation, and Bland–Altman plots with limits of agreement calculations were used to validate the equation. Results: There was a significant correlation (P < .001, r = .926) between peak torque (283.0 [22.6] N·m) and the knee extension 1RM (69.1 [22.6] kg). The prediction equation overestimated the loads (2.3 [9.1] kg; 95% confidence interval, −15.6 to 20.1 kg). Conclusions: The results show that isometric peak torque values obtained on an isokinetic dynamometer can be used to estimate 1RM values for isotonic knee extension. Although the prediction equation tends to overestimate loads, the relatively wide confidence intervals indicate that results should be viewed with caution.

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