Hamstring Flexibility Is Not Correlated with Isokinetic Knee Muscle Strength in Female Modern Dancers

2018 ◽  
Vol 33 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Ani Agopyan
Keyword(s):  
Muscle Strength ◽  
Knee Extensor ◽  
Peak Torque ◽  
Flexor Muscle ◽  
Work Production ◽  
University Level ◽  
Modern Dancers ◽  
Hamstring Flexibility ◽  
Knee Muscle ◽  
The Right

OBJECTIVE: To evaluate bilateral isokinetic knee extensor and flexor muscle strength relative to hamstring flexibility in female modern dancers. METHODS: 20 trained university-level female modern dance students (mean age 23.8±3.8 yrs) volunteered for the study. Concentric isokinetic peak torque (PT, in Nm), peak torque % of body weight (PT%BW, in Nm/kg), and total work (TW, in J) of the knee extensor and flexor muscles for each leg were measured with a dynamometer at a velocity of 60, 180, and 300°/s. Hamstring flexibility of both limbs was assessed by a goniometer with the subjects in a supine position using the active straight leg raise (SLR) test. Participants were divided into flexible (n=10) and highly flexible (n=10) groups based on their hamstring flexibility. RESULTS: The flexible and highly flexible groups had significant differences (p≤0.05) for the right (flexible, 119.7±4.3°; highly flexible, 137.7±2.6°) and left active SLR tests (flexible, 120.6±5.3°; highly flexible, 138.3±4.5°). No significant differences were found between the flexible and highly flexible dancers for concentric knee extensor and flexor muscle strength in all selected parameters (p≤0.05). There were also no significant correlations between flexibility and bilateral PT, PT%BW, and TW scores (60, 180, and 300°/s) of dancers at the concentric contraction (p≤0.05). CONCLUSION: These findings indicate that hamstring flexibility (for both the flexible and highly flexible groups) is not correlated with knee strength and has no impact on torque and work production during maximal concentric isokinetic knee muscle action in university-level female modern dancers.

Isokinetic Strength After ACL Reconstruction: Influence of Concomitant Anterolateral Ligament Reconstruction

2021 ◽  
pp. 194173812110054
Author(s):  
Benoit Gillet ◽  
Yoann Blache ◽  
Isabelle Rogowski ◽  
Grégory Vigne ◽  
Bertrand Sonnery-Cottet ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Ligament Reconstruction ◽  
Knee Extensor ◽  
Anterolateral Ligament ◽  
Flexor Muscle ◽  
Knee Flexor ◽  
Strength Recovery ◽  
Flexor Muscles ◽  
Knee Muscle ◽  
Knee Muscle Strength

Background: To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively. Hypothesis: The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively. Study Design: Retrospective cohort study. Level of Evidence: Level 2. Methods: A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping. Results: Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups. Conclusion: The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively. Clinical Relevance: Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR.

scholarly journals Velocity-specific knee strength between professional and under-17 female volleyball player

2019 ◽  
Vol 75 (1) ◽  
Author(s):  
Alexandre R.M. Pelegrinelli ◽  
Laís F. Dela Bela ◽  
Mariana F. Silva ◽  
Lucas C.R. Rodrigues ◽  
João P. Batista ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Knee Extensor ◽  
Peak Torque ◽  
Total Work ◽  
Flexor Muscle ◽  
Mean Power ◽  
Cross Sectional ◽  
Significant Group ◽  
Surface Maps ◽  
Volleyball Players

Background: Many studies have investigated isokinetic performance in volleyball players but not through surface maps.Objectives: The goals of this study were to assess velocity-specific isokinetic knee extensor–flexor muscle strength and to compare the isokinetic knee extensor–flexor muscles between professional (PRO) and under-17 (U17) female volleyball players.Method: This cross-sectional laboratory study was developed with two groups: PRO (n = 12), medianage = 21.3 years, and U17 (n = 9), medianage = 15 years. Peak torque, total work, mean power, angle of peak torque, hamstring–quadriceps torque ratio (H–Q ratio) and torque–angle–velocity surface maps were analysed from knee extension–flexion at 60, 120 and 300 degrees per second (°/s).Results: Significant differences were identified for extensor peak torque between PRO x = 202.3 Newton metre (N·m) (standard deviation [SD] = 24.4) and U17 x = 141.6 N·m (30.1) at 60 °/s (p < 0.001; d = 2.21) as well as flexor peak torque (PRO x = 75.7 N·m [10.3] and U17 x = 57.7 N·m [11.4]) at 120 °/s (p < 0.001; d = 1.65) for the dominant limb. There were also significant group differences for total work and mean power at all velocities for extension and flexion. Surface maps demonstrated higher torque at lower speeds for both groups with smaller torque changes across velocities for flexion.Conclusion: Different groups of female volleyball players showed contrasting concentric knee muscle strength across isokinetic velocities.Clinical implications: These results demonstrate the importance of specific strength training for different age groups, even within the same sport, and provide insight into muscle strength.

scholarly journals Effect of long-term training adaptation on isokinetic strength in college male volleyball players

2019 ◽  
Vol 23 (5) ◽  
pp. 236-241
Author(s):  
A. Kafkas ◽  
M.E. Kafkas ◽  
S. Savaş
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Knee Extensor ◽  
Isokinetic Strength ◽  
Flexor Muscle ◽  
Knee Strength ◽  
Volleyball Players ◽  
Angular Velocities ◽  
Knee Muscle ◽  
Flexor Strength

Background and Study Aim: Most of this study focused on endurance, power, and anthropometric measurements but no research declared isokinetic strength changes during two years. The purpose of this study was to assess the effect of resistance exercises on two seasonal alters in isokinetic strength of knee muscles at different angular velocities, in college volleyball players. Material and Methods: Thirteen college volleyball players, (age: 21.75 years, body mass: 78.60 kg, and height: 187.0 cm) participated in the study. All college volleyball players take part in the two-year (8 month each year) volleyball-specific training and competitions. The measurement of peak isokinetic concentric knee extension and knee flexion torque in both legs were taken at 2 angular velocities of movement, low at 60° s-1, and intermediate at 180° s-1. Results: The pre- and post-test values of the peak isokinetic strength found that statistical significance difference, at 60° s-1 and 180° s-1 for knee extensor-flexor both dominant and non-dominant in favor of post-tests. Significant enhances were observed in the baseline dominant knee extensor-flexor muscle strength (extensor knee strength 60° s-1: 19.0%, 180° s-1: 20.5%, flexor knee strength, 60° s-1: 33.4%, 180° s-1: 31.4%) respectively. Non-dominant knee extensor-flexor muscle strength increased significantly over the two-year period (extensor knee strength 60° s-1: 21.3%, 180° s-1: 23.0%, flexor knee strength, 60° s-1: 37.4%, 180° s-1: 33.9%) respectively. Conclusion: As a result, our data suggests that the two-year planned program of specific volleyball and resistance training can increase the knee muscle extensor-flexor strength and H:Q ratios of volleyball players. Especially, at a 60° s-1 and 180° s-1 angular velocities, whilst the knee muscle extensor-flexor strength and H:Q ratios for dominant and non-dominant legs were increasing, also H:Q ratios disproportion were decreasing. Therefore, these alters indicated that regular specific-volleyball and resistance training can increase knee muscle extensor-flexor strength and H:Q ratios for dominant and non-dominant legs.

scholarly journals Pre- and Post-Operative Limb Symmetry Indexes and Estimated Preinjury Capacity Index of Muscle Strength as Predictive Factors for the Risk of ACL Reinjury: A Retrospective Cohort Study of Athletes after ACLR

2021 ◽  
Vol 11 (8) ◽  
pp. 3498
Author(s):  
Martin Rudolf Zore ◽  
Nevenka Kregar Velikonja ◽  
Mohsen Hussein
Keyword(s):  
Muscle Strength ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Peak Torque ◽  
Secondary Injury ◽  
Flexor Muscle ◽  
Acl Injuries ◽  
Secondary Injuries ◽  
Operative Limb ◽  
Torque Values

Long-term muscle weakness may increase the risk of knee reinjury after anterior cruciate ligament reconstruction (ACLR) and of osteoarthritis. The incidence of secondary injuries after ACLR and the predictive value of preoperative and postoperative limb symmetry index (LSI) and estimated preinjury capacity (EPIC) index were studied for predicting the risk of reinjury in a retrospective study. Sixty-three recreational and professional athletes after ACLR with hamstring autograft were followed for secondary injury in the period from 2012 to 2014, 5 years after ACLR. Peak torque values of knee extensor and flexor muscle strength of the involved and uninvolved limb were measured with an isokinetic dynamometer at 60 degrees per second before ACLR and 6 months after ACLR and were used to calculate LSI and EPIC index. The results suggest that the preoperative LSI and EPIC indexes predict a secondary ACL injury better than the postoperative LSI for extensor muscles which is often used as a criterion to determine the time for returning to normal sports activities. Individuals with secondary ACL injuries suffer greater loss of knee extensor muscle strength of the uninvolved limb between preoperative and postoperative ACLR testing compared to the individuals without secondary injury.

scholarly journals Associations of the Stair Climb Power Test With Muscle Strength and Functional Performance in People With Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study

2010 ◽  
Vol 90 (12) ◽  
pp. 1774-1782 ◽  
Author(s):  
Marc Roig ◽  
Janice J. Eng ◽  
Donna L. MacIntyre ◽  
Jeremy D. Road ◽  
W. Darlene Reid
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Muscle Strength ◽  
Functional Performance ◽  
Knee Extensor ◽  
Chronic Obstructive ◽  
Flexor Muscle ◽  
Cross Sectional ◽  
Obstructive Pulmonary Disease ◽  
Power Test ◽  
Muscle Torque

Background The Stair Climb Power Test (SCPT) is a functional test associated with leg muscle power in older people. Objective The purposes of this study were to compare the results of the SCPT in people with chronic obstructive pulmonary disease (COPD) and people who were healthy and to explore associations of the SCPT with muscle strength (force-generating capacity) and functional performance. Design The study was a cross-sectional investigation. Methods Twenty-one people with COPD and a predicted mean (SD) percentage of forced expiratory volume in 1 second of 47.2 (12.9) and 21 people who were healthy and matched for age, sex, and body mass were tested with the SCPT. Knee extensor and flexor muscle torque was assessed with an isokinetic dynamometer. Functional performance was assessed with the Timed “Up & Go” Test (TUG) and the Six-Minute Walk Test (6MWT). Results People with COPD showed lower values on the SCPT (28%) and all torque measures (∼32%), except for eccentric knee flexor muscle torque. In people with COPD, performance on the TUG and 6MWT was lower by 23% and 28%, respectively. In people with COPD, the SCPT was moderately associated with knee extensor muscle isometric and eccentric torque (r≥.46) and strongly associated (r=.68) with the 6MWT. In people who were healthy, the association of the SCPT with knee extensor muscle torque tended to be stronger (r≥.66); however, no significant relationship between the SCPT and measures of functional performance was found. Limitations The observational design of the study and the use of a relatively small convenience sample limit the generalizability of the findings. Conclusions The SCPT is a simple and safe test associated with measures of functional performance in people with COPD. People with COPD show deficits on the SCPT. However, the SCPT is only moderately associated with muscle torque and thus cannot be used as a simple surrogate for muscle strength in people with COPD.

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 Resistance training-induced gains in knee extensor strength are related to increased neural cell adhesion molecule expression in older adults with knee osteoarthritis

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Thomas B. Voigt ◽  
Timothy W. Tourville ◽  
Michael J. Falcone ◽  
James R. Slauterbeck ◽  
Bruce D. Beynnon ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Strength ◽  
Cell Adhesion Molecule ◽  
Knee Extensor ◽  
Peak Torque ◽  
Neural Adaptations ◽  
Mhc Ii ◽  
Neural Cell Adhesion ◽  
Fiber Size ◽  
Whole Muscle

Abstract Objective Resistance training (RT) can improve whole muscle strength without increasing muscle fiber size or contractility. Neural adaptations, which lead to greater neural activation of muscle, may mediate some of these improvements, particularly in older adults, where motor neuron denervation is common. The purpose of this study was to explore the relationship of neural adaptations, as reflected by neural cell adhesion molecule (NCAM) expression, to improvements in (1) whole muscle strength and (2) muscle fiber size following RT in older adults with knee osteoarthritis. We performed whole muscle strength measurements and immunohistochemical analysis of fiber size, type, and NCAM expression before and after a 14-week RT program. Results RT increased whole-muscle strength as measured by 1-repetition maximum (1-RM) leg press (P = 0.01), leg extension (P = 0.03), and knee extensor peak torque (P = 0.050), but did not alter NCAM expression. Greater NCAM expression in myosin heavy chain (MHC) II fibers was associated with greater whole muscle strength gains (knee extensor peak torque r = 0.93; P < 0.01) and greater MHC II fiber size (r = 0.79; P < 0.01). Our results suggest that training-induced NCAM expression, and neural adaptations more generally, may be important for RT-induced morphological and functional improvements in older adults. Trial registration NCT01190046

scholarly journals Determination of the isokinetic muscle strength profile of knee flexors and extensors in visually impaired long-distance athletes: Pilot studyGörme engelli uzun mesafe atletizm sporcularında diz fleksör ve ekstansörlerinin izokinetik kas kuvvet profilinin belirlenmesi: Pilot çalışma

2017 ◽  
Vol 14 (2) ◽  
pp. 2111
Author(s):  
Tuğba Kocahan ◽  
Bihter Akınoğlu ◽  
Çağlar Soylu ◽  
Necmiye Ün Yıldırım ◽  
Adnan Hasanoğlu
Keyword(s):  
Muscle Strength ◽  
Knee Flexion ◽  
Visually Impaired ◽  
Peak Torque ◽  
Long Distance ◽  
Long Distance Running ◽  
The Right ◽  
Dominant Side ◽  
Knee Flexors ◽  
Flexion And Extension

Purpose: The aim of this study is to determine the isokinetic muscle strength profile of knee flexor and extensor muscles of visually impaired long distance running athletes and compare them with the literature.Methods: The study consisted of 7 male visually impaired long distance running athletes aged between 19-28 (means 24,14±3,23), who complied with the criteria and voluntarily participated in the study. İsokinetic measurement was performed with Isomed 2000® device. İn isokinetic evaluation, maximal muscle strength, muscle strength ratios, percentage of right-left strength difference ratio of knee flexors and extensors were recorded. İsokinetic testing protocol; before the test all athletes performed the knee flexion and extension isokinetic test with the 5 repeating at 90 º/sec as a warm-up and for comprehenting the test. Then, knee flexion and extension concentric-concentric strength measurements were performed with the 5 repeating at 60 º/sec and with the 15 repeating at 180 º/sec with the angle between 90 degrees of knee flexion and 10 degrees of knee extension. The evaluations were performed bilaterally, first dominant side and after 3 minutes non dominant side was evaluated.Results: The H / Q peak torque ratio of the athletes is 53.55% for the dominant side and 55.47% for the non-dominant side at 60º / sec. velocity while 59.05% for the dominant side and 61.34% for the non-dominant side at 180º / sec. velocity. When the H / Q peak torque ratio of the athletes was compared between dominant and non-dominant sides, there was no difference in both angular velocities (p>0.05). Knee flexion and extension isokinetic muscle strength’s difference were determined lower than %10 for both angular angles when compared to the asymmetry of the right and left extremities. It was found that this was in accordance with the literature and there was no asymmetry between the right and left sides.Conclusion: In visually impaired long distance runners, having H/Q ratio lower than normal borders against knee flexors for both sides at 180°/sec. angular velocity poses a risk for injuries. In terms of prevention of sports injuries, it is necessary for the athletes to maintain muscle force balance which is specific to each angular velocity and to exercise with sports-specific exercises.Extended English abstract is in the end of PDF (TURKISH) file.ÖzetAmaç: Bu çalışmanın amacı görme engelli uzun mesafe atletizm sporcularının diz fleksör ve ekstansör kaslarının izokinetik kas kuvvet profilini belirlemek ve literatürdeki bilgilerle karşılaştırmaktır.Method: Çalışmamıza; 19-28 (Ort. 24,14±3,23) yaş aralığında 7 erkek görme engelli uzun mesafe atletizm sporcusu dâhil edildi. İzokinetik kas kuvveti Isomed 2000® cihazı ile değerlendirildi. İzokinetik değerlendirmede diz fleksör ve ekstansörlerinin maksimum kas kuvveti, kas kuvvet oranları, sağ-sol kuvvet farkı oranı yüzdesi kaydedildi. Değerlendirmede 90-10 º fleksiyon açılarında konsantrik-konsantrik kuvvet ölçümü yapıldı. İzokinetik test protokolü olarak; 5 tekrarlı 90º/sn. hızla testi anlama ve submaksimal ısınma hareketinden sonra, 5 tekrarlı 60º/sn. hızla ve 15 tekrarlı 180º/sn. hızla maksimal diz fleksiyon ve ekstansiyon hareketleri yaptırıldı. Değerlendirmeler bilateral olarak gerçekleştirildi ve öncelikle dominant taraf, 3 dk sonra non-dominant taraf değerlendirildi.Bulgular: Sporcuların H/Q peak tork oranı 60º/sn. hızda dominant taraf için % 53.55, non-dominant taraf için % 55.47 bulunurken 180º/sn. hızda dominant taraf için % 59.05, non-dominant taraf için % 61.34 bulundu. H/Q peak tork oranı dominant ve non-dominant taraf arasında karşılaştırıldığında her iki açısal hızda da farklılık bulunmadı (p>0,05). Sağ ve sol ekstremiteler asimetri açısından karşılaştırıldığında diz fleksiyon ve ekstansiyon izokinetik kas kuvveti farkının her iki açısal hızda da %10 un altında olduğu belirlendi. Bu durumun literatür ile uyumlu olduğu ve sağ-sol taraf arasında bir asimetri olmadığı sonucuna varıldı.Sonuç: Çalışmamız sonucunda Görme engelli uzun mesafe koşucularında 180º/sn. açısal hızda H/Q oranının normal sınırlardan daha düşük ve her iki tarafta diz fleksörleri aleyhinde olması yaralanma açısından risk oluşturmaktadır. Spor yaralanmalarının önlenmesi açısından sporcuların her açısal hıza özgü olan kas kuvvet dengesinin korunması ve spora özgü egzersizlerle çalıştırılması gereklidir.

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