Knee Flexor: Extensor Isokinetic Ratios in Young Male Gymnasts and Swimmers

2004 ◽  
Vol 16 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Theophanis Siatras ◽  
Dimitra Mameletzi ◽  
Spiros Kellis
Keyword(s):  
Young Male ◽  
Peak Torque ◽  
Antagonistic Activity ◽  
Lower Limbs ◽  
Training Context ◽  
Young Athletes ◽  
Isokinetic Testing ◽  
Angular Velocities ◽  
Muscle Groups ◽  
Isokinetic Peak Torque

The purpose of the study was to determine young male gymnasts’ and swimmers’ knee flexor:extensor (F:E) ratios during isokinetic testing at different velocities. Nine gymnasts (10.3 ± 0.5 years) and 14 swimmers (10.5 ± 0.5 years) participated. Concentric isokinetic peak torque was measured by a Cybex® Norm dynamometer at different angular velocities (60,120, and 180°/s) during unilateral knee extensions and flexions after gravity correction. Significant differences were found only in gymnasts’ knee F:E peak-torque ratios between the angular velocities of 60 and 120°/s (p < 0.01), as well as 60–180°/s (p < .01), whereas swimmers’ ratios were unchanged. Gymnasts presented significantly higher F:E ratios than swimmers did at the angular velocities of 120°/s (p < .01) and 180°/s (p < .001). The reciprocal ratios provided some indication that the training context of young athletes can influence the balance between agonistic and antagonistic activity of the lower limbs’ major muscle groups.

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 Can the Neuromuscular Performance of Young Athletes Be Influenced by Hormone Levels and Different Stages of Puberty?

2020 ◽  
Vol 17 (16) ◽  
pp. 5637 ◽  
Author(s):  
Paulo Francisco de Almeida-Neto ◽  
Dihogo Gama de Matos ◽  
Vanessa Carla Monteiro Pinto ◽  
Paulo Moreira Silva Dantas ◽  
Tatianny de Macêdo Cesário ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Young People ◽  
Young Male ◽  
Lower Limbs ◽  
Young Athletes ◽  
Testosterone Levels ◽  
Neuromuscular Performance ◽  
Lower Limb Strength ◽  
Determining Factor ◽  
Hormonal Levels

Background: Endocrine mechanisms can be a determining factor in the neuromuscular performance of young athletes. Objective: The objective of the present study was to relate maturational and hormonal markers to neuromuscular performance, as well as to verify whether young athletes with different testosterone levels show differences in muscle strength. Methods: The sample consisted of 37 young male Brazilian athletes (11.3 ± 0.94 years) who were members of a sports initiation project. Hormonal markers were analyzed biochemically by blood samples, and maturation markers by mathematical models based on anthropometry. Body composition was verified by tetrapolar bioimpedance. The performance of upper and lower limb strength and body speed were analyzed. Results: Hormonal and maturational markers were related to neuromuscular performance (p < 0.05). Young people with higher testosterone levels showed higher muscle strength (p < 0.05). Artificial neural networks showed that testosterone predicted the performance of upper limbs by 49%, and maturation by 60%. Maturation foreshadowed the performance of lower limbs by 30.3%. Conclusion: Biological maturation and hormonal levels can be related to neuromuscular performance, and young people with higher testosterone levels show superior muscle strength in relation to the others.

scholarly journals Contraction Type Influences Critical Ages for Declines In Lower Body Specific Force in Women Ages 20 to 89 Years

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 186-186
Author(s):  
Ryan Miller ◽  
Eduardo Freitas ◽  
Aaron Heishman ◽  
Debra Bemben ◽  
Michael Bemben
Keyword(s):  
Healthy Aging ◽  
Quantitative Computed Tomography ◽  
Peak Torque ◽  
Lower Leg ◽  
Specific Force ◽  
Muscle Area ◽  
Isokinetic Testing ◽  
Critical Age ◽  
Contraction Type ◽  
Muscle Groups

Abstract The ability for a muscle to produce force relative to its size, specific force, is an important characteristic for healthy aging. Few studies have identified the influence that different muscle groups or contraction types may have on the onset of declines in specific force. Therefore, the aims of the current study were to identify critical ages for changes in upper (quadriceps and hamstrings) and lower leg (soleus and tibialis anterior) specific force and to determine if the onset of decline is influenced by contraction type (isometric or dynamic) in women aged 20 to 89 years. One-hundred and fifty-two women (47.1±17.7years, 164.2±7.0cm, 67.1±10.7kg) matched for physical activity with approximately 10 participants per five-year interval (20-24, 25-29years, etc.), were included in the present analysis. Specific force was calculated from peak torque values measured from isometric (ISOM) or isokinetic testing (60deg/s and 240deg/s) and made relative to muscle area measured by peripheral quantitative computed tomography. An iterative segmental modelling approach was performed to identify critical age periods for changes in specific force. For the upper leg, ISOM and 60deg/s specific force was maintained across the lifespan, whereas 240deg/s revealed a critical age of 35.2±5.3years. Critical ages were identified for all contraction types for the lower leg and occurred earlier with increasing velocity (ISOM: 63±6.6years, 60deg/s: 53.9±4.5years, and 240deg/s: 49±3.9years). These data suggest that muscle groups of the leg do not display uniform changes across different contraction types and that high velocity contractions display earlier declines across the lifespan.

scholarly journals The Effect of Dietary Nitrate Supplementation on Isokinetic Torque in Adults: A Systematic Review and Meta-Analysis

Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3022
Author(s):  
Ángel Lago-Rodríguez ◽  
Raúl Domínguez ◽  
Juan José Ramos-Álvarez ◽  
Francisco Miguel Tobal ◽  
Pablo Jodra ◽  
...  
Keyword(s):  
Systematic Review ◽  
Muscular Strength ◽  
Meta Analysis ◽  
Peak Torque ◽  
Gold Standard Method ◽  
Dietary Nitrate ◽  
Angular Velocities ◽  
Isokinetic Torque ◽  
Nitrate Supplementation ◽  
Isokinetic Peak Torque

Dietary nitrate (NO3−) supplementation, which can enhance performance in exercise settings involving repeated high-intensity efforts, has been linked to improved skeletal muscle contractile function. Although muscular strength is an important component of explosive movements and sport-specific skills, few studies have quantified indices of muscular strength following NO3− supplementation, particularly isokinetic assessments at different angular velocities. We performed a systematic review and meta-analysis to determine whether dietary NO3− supplementation improves peak torque, as assessed by the gold standard method of isokinetic dynamometry, and if this effect was linked to the angular velocity imposed during the assessment. Dialnet, Directory of Open Access Journals, MEDLINE, PubMed, SciELO, Scopus, and SPORTDiscus were searched for articles using the following search strategy: (nitrate OR beet*) AND (supplement* OR nutr* OR diet*) AND (isokinetic OR strength OR “resistance exercise” OR “resistance training” OR “muscular power”). The meta-analysis of data from 5 studies with 60 participants revealed an overall effect size of −0.01 for the effect of nitrate supplementation on isokinetic peak torque, whereas trivial effect sizes ranging from −0.11 to 0.16 were observed for independent velocity-specific (90°/s, 180°/s, 270°/s, and 360°/s) isokinetic peak torque. Four of the five studies indicated that dietary NO3− supplementation is not likely to influence voluntary knee extensor isokinetic torque across a variety of angular velocities. These results suggest that NO3− supplementation does not influence isokinetic peak torque, but further work is required to elucidate the potential of NO3− supplementation to influence other indices of muscular strength, given the dearth of experimental evidence on this topic.

Effect of Acute Static Stretching Duration on Isokinetic Peak Torque in Pubescent Soccer Players

2006 ◽  
Vol 18 (2) ◽  
pp. 252-261 ◽  
Author(s):  
Athanasios Zakas ◽  
George Doganis ◽  
Christos Galazoulas ◽  
Efstratios Vamvakoudis
Keyword(s):  
Knee Flexion ◽  
Force Production ◽  
Peak Torque ◽  
Soccer Players ◽  
Static Stretching ◽  
Warm Up ◽  
Angular Velocities ◽  
Leg Extensors ◽  
Isokinetic Peak Torque ◽  
Stretching Exercises

Although athletes routinely perform warm-up and stretching exercises, it has been suggested that prolonged stretching immediately before an activity might negatively affect the force production. Sixteen male pubescent soccer players participated in the study to examine whether a routine duration of acute static stretching is responsible for losses in isokinetic peak torque production. All participants performed two static stretching protocols in nonconsecutive training sessions. The first stretching protocol was performed three times for 15 s (volume 45) and the second 20 times for 15 s (volume 300). Range of motion (ROM) was determined during knee flexion with the use of a goniometer. The peak torque of the dominant leg extensors was measured on a Cybex NORM dynamometer at various angular velocities. The statistical analysis showed that peak torque did not change following the static stretching for 45 s in all angular velocities, while it decreased (p < .001) in all angular velocities following the static stretching for 5 min. The findings suggest that strength decreases after static stretching exercises may be the result of the performed stretching duration.

Muscle architecture and force-velocity relationships in humans

1984 ◽  
Vol 57 (2) ◽  
pp. 435-443 ◽  
Author(s):  
T. L. Wickiewicz ◽  
R. R. Roy ◽  
P. L. Powell ◽  
J. J. Perrine ◽  
V. R. Edgerton
Keyword(s):  
Peak Torque ◽  
Knee Extensors ◽  
Major Influence ◽  
Inhibitory Mechanism ◽  
Cross Sectional ◽  
Isokinetic Testing ◽  
Force Velocity ◽  
Muscle Groups ◽  
Knee Flexors

The in vivo torque-velocity relationships of the knee extensors (KE), knee flexors (KF), ankle plantarflexors (PF), and ankle dorsiflexors (DF) were determined in 12 untrained subjects using an isokinetic testing device (Cybex II). These data were then matched to the predicted maximum forces and shortening velocities derived from muscle architectural determinations made on three hemipelvectomies (36). The torque-velocity curves of all muscle groups resembled that predicted by Hill's (19, 20) equation except at the higher forces and lower velocities. The peak torques occurred at mean velocities ranging from 41–62 rad X s-1 for the KE, KF, and PF. Although the peak torque of the DF occurred at the isometric loading condition, it was also lower than that predicted by Hill's equation. The muscle fiber length and physiological cross-sectional area measurements indicate that the architecture of the human leg musculature has a major influence on the torque-velocity characteristics. These data corroborate previous findings (24) that some neural inhibitory mechanism exists in the control of the leg musculature, which limits the maximum forces that could be produced under optimal stimulating conditions.

scholarly journals The Characteristics of Shoulder Muscles in Archery Athletes

2018 ◽  
Vol 21 (3) ◽  
pp. 145-150 ◽  
Author(s):  
Ri Na Kim ◽  
Jin Hyuck Lee ◽  
Seok Ha Hong ◽  
Jin Ho Jeon ◽  
Woong Kyo Jeong
Keyword(s):  
External Rotation ◽  
Peak Torque ◽  
Shoulder Girdle ◽  
Left Shoulder ◽  
Shoulder Muscles ◽  
Adductor Muscles ◽  
Angular Velocities ◽  
Muscle Groups ◽  
Shoulder Girdle Muscles ◽  
High Level

BACKGROUND: This study evaluated the shoulder girdle muscle characteristics of elite archery athletes and provides suggestions for archery training programs.METHODS: This study enrolled 15 cases of high level archery athletes (7 males, 8 females) and 30 cases of (15 males, 15 females) sex, age-matched, healthy, non-athletic individuals. We measured peak torques of flexion (FL), extension (EX), abduction (ABD), adduction (ADD), external rotation (ER) and internal rotation (IR) of both shoulders at an angular velocity of 30°/sec, 60°/sec, and 180°/sec. The peak torques and peak torque ratios of FL/EX, ABD/ADD, and ER/IR of the two groups were compared.RESULTS: The archer group had a greater peak torque of IR and ADD, but only in the left shoulder (p < 0.05). In the same group, both shoulders had greater peak torque of EX and lower peak torque of FL. The peak torque ratios of FL/EX of both shoulders were significantly lower in the archer group at all three angular velocities (p < 0.05). The peak torque ratios of ABD/ADD were significantly greater in only the left shoulder of the archer group (p < 0.05).CONCLUSIONS: The prominent characteristics of the shoulder girdle muscles of an elite archer are stronger adductor muscles of the bow shoulder and stronger extensors of both shoulders, as compared to healthy, non-athletic individuals. These muscle groups of the shoulder probably contribute a major role in maintaining the accuracy and stability during archery shooting. Hence, a training program that selectively enhances the adductor and extensor muscles could prove helpful in enhancing the archery skills of the athlete.

scholarly journals Bilateral torque asymmetry analysis of lower limbs of active and insufficiently active older adults

2020 ◽  
Vol 14 (2) ◽  
pp. 62-72
Author(s):  
Milena Razuk ◽  
Juliana Canuto Lorete ◽  
Leonardo Araujo Vieira ◽  
Natalia Madalena Rinaldi
Keyword(s):  
Physical Activity ◽  
Older Adults ◽  
Angular Velocity ◽  
Peak Torque ◽  
Lower Limbs ◽  
Mean Power ◽  
Ankle Joints ◽  
Angular Velocities ◽  
The Mean ◽  
Hip Extension

BACKGROUND:Physical activity is an important tool for positively impacting physical, cognitive, and social aspects and is linked to the capacity to develop muscle strength and power. However, no studies have observed the effects of physical activity on the bilateral torque asymmetry at different movement velocities in older adults. AIM:Investigate the effects of different angular velocities on bilateral torque asymmetry for hip, knee, and ankle joints in active and insufficiently active older adults. METHOD:Forty-four older adults were distributed into two groups: active and insufficiently active. An isokinetic dynamometer was used. The tests consisted of maximal concentric contractions of hip, knee, and ankle flexors and extensors at velocities of 60º/s and 120º/s. The variables were asymmetry of peak torque and of mean power. RESULTS:Results showed greater asymmetry in hip extension and ankle flexion for peak torque and mean power, as well as increased asymmetry in flexion movement at the higher angular velocity compared with the lower angular velocity for the mean power. Furthermore, there were no differences in asymmetry between groups. CONCLUSION:The conclusion of the present study was that older adults showed similar behavior for bilateral torque asymmetry, regardless of the level of physical activity. 

Intersession Reliability of Isokinetic Strength Testing in Knee and Elbow Extension and Flexion Using the BTE PrimusRS

2017 ◽  
Vol 26 (4) ◽  
Author(s):  
Alexander Törpel ◽  
Tim Becker ◽  
Angelina Thiers ◽  
Dennis Hamacher ◽  
Lutz Schega
Keyword(s):  
High Reliability ◽  
Intraclass Correlation ◽  
Young Male ◽  
Peak Torque ◽  
Male Students ◽  
Clinical Settings ◽  
Isokinetic Testing ◽  
Sports Science ◽  
Isokinetic Strength Testing ◽  
Absolute Reliability

Context:The use of isokinetic dynamometers playing an important role in different settings of sports and medicine. Therefore, a high reliability of these devices is required. Objective: The aim of this study was to examine the intersession reliability of the dynamometer BTE PrimusRS regarding to the isolated single-joint exercises extension/flexion of the knee and elbow for isokinetic testing. Design: Intersession reliability. Setting: Clinical settings and sports science. Participants: 16 young male students. Intervention: The testing protocol includes 5 consecutive repetitions (concentric/concentric) at a velocity of 60°/s for the exercises. Main Outcome Measures: Raw data of torque curves were used to determine the peak torque. Reliability was evaluated with the intraclass correlation coefficient (ICC), the limits of agreement (LoA), and the bias and the variability of measurements (V). Results: High ICC values (.954-.991) were found for the used exercises. However, the LoAs yielded up to over 16 Nm and the V yielded up to nearly 9 % in several testing exercises, indicating poor absolute reliability. Conclusion: The BTE PrimusRS shows good to excellent reliability. However, regarding the absolute measures of reliability, the users must decide as experts in their fields whether this reliability is sufficient for their purposes.

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