Thigh muscle activity and anterior cruciate ligament insufficiency

Dvir, Zeevi; Eger, G.; Halperin, Nahum; Shklar, Arie

doi:10.1016/0268-0033(89)90044-2

Cited by 97 publications

(51 citation statements)

References 16 publications

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“…This relationship has led to the development of the so-called functional strength ratio (H:Q FUNC ) (i.e. the ratio between eccentric hamstring strength and concentric quadriceps strength) [21]. While the H:Q CONV ratio has the ability to identify a muscle imbalance, the H:Q FUNC ratio specifically describes the ability of the knee flexors to decelerate rapid knee extension that is initiated by the quadriceps [20].…”

Section: Introductionmentioning

confidence: 99%

Changes in Isokinetic Muscle Strength in Adolescent Soccer Players after 10 Weeks of Pre-Season Training

Lehnert¹,

Šťastný²,

Tufano³

et al. 2017

TOSSJ

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Section: Introductionmentioning

confidence: 99%

Changes in Isokinetic Muscle Strength in Adolescent Soccer Players after 10 Weeks of Pre-Season Training

Lehnert¹,

Šťastný²,

Tufano³

et al. 2017

TOSSJ

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“…The functional H/Q ratio may dictate dynamic joint stabilization [25], which potentially protects the knee during sports-related tasks. For example, Aagaard et al [14,21] demonstrated the potential 1:1 hamstring to quadriceps strength relationship for fast knee extension, reflecting a significant functional capacity of the hamstring muscles for providing muscular stability at the knee joint.…”

Section: Discussionmentioning

confidence: 99%

“…Another proposed muscle strength ratio is functional H/Q, which is calculated by dividing the hamstrings peak torque during eccentric contraction by the quadriceps peak torque during concentric contraction at a specified angular velocity [14,16,17,24]. This dynamic control ratio is considered more useful in determining injury risk than conventional H/Q [16,25]. Furthermore, the functional H/Q may better reflect the flexors and extensors coactivation pattern and the injury mechanism of the knee ligamentous structures [14,19].…”

Section: Introductionmentioning

confidence: 99%

A comparison of isokinetic knee strength and power output ratios between female basketball and volleyball players

Kabaciński¹,

Murawa²,

Fryzowicz³

et al. 2018

Hum Mov.

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Purpose. Tests such as the counter movement jump (cMJ) and squat jump (sJ) allow for determining the ratio of maximal power output generated during sJ to cMJ (s/c). The isokinetic peak torque ratio of the hamstrings contracting eccentrically to the quadriceps contracting concentrically (H/Q) is defined as functional H/Q. The purpose of this study was to compare the s/c and functional H/Q between female basketball and volleyball players. Methods. The total of 14 female basketball players (age, 19.8 ± 1.4 years) and 12 female volleyball players (age, 22.3 ± 4.2 years) participated in the study. A piezoelectric force platform was used for the cMJ and sJ. Moreover, isokinetic tests of the hamstrings and quadriceps muscle torque during eccentric and concentric contraction were performed. Results. The results of the s/c and functional H/Q at 90 deg · s -1 /60 deg · s -1 velocities were higher in basketball players (87.3 ± 9.1% and 91.4 ± 9.3%, respectively) than in volleyball players (83.1 ± 9.8% and 83.6 ± 16.5%, respectively). No significant differences in s/c or functional H/Q values between the two groups were found (p > 0.05). Conclusions. Decreasing the s/c may result from an improvement in the power output during cMJ and a better utilization of the stretch-shortening cycle effect. Balancing the functional H/Q through increasing the eccentric hamstrings strength can provide dynamic knee joint stabilization.

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“…The acceleration and deceleration phases (beginning and end of the motion amplitude) were excluded to eliminate the torque that was not generated in an isokinetic condition 24,25 . Thus, the corrected isokinetic joint range of motion ranged from 30° to 80° and was normalized in order to facilitate the results interpretation.…”

Section: Methodsmentioning

confidence: 99%

Knee Isokinetic Torque Imbalance in Female Futsal Players

Rodrigues

Vieira

Marche

et al. 2017

Rev Bras Med Esporte

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Introduction: The specificity of sports training can lead to muscle specialization with a possible change in the natural hamstring/quadriceps torque ratio (HQ ratio), constituting a risk factor for muscle injury at the joint angles in which muscle imbalance may impair dynamic stability. Objective: The aim was to evaluate the torque distribution of the hamstrings and quadriceps and the HQ ratio throughout the range of motion in order to identify possible muscle imbalances at the knee of female futsal athletes. Methods: Nineteen amateur female futsal athletes had their dominant limb HQ ratio evaluated in a series of five maximum repetitions of flexion/extension of the knee at 180°/second in the total joint range of motion (30° to 80°). The peak flexor and extensor torque and the HQ ratio (%) were compared each 5° of knee motion using one-way repeated measures ANOVA and Tukey's post hoc test (p<0.05) to determine the joint angles that present muscular imbalance. Results: Quadriceps torque was higher than 50° to 60° of knee flexion, while hamstrings torque was higher than 55° to 65°. The HQ ratio presented lower values than 30° to 45° of knee flexion and four athletes presented values lower than 60%, which may represent a risk of injury. However, the HQ ratio calculated by the peak torque showed only one athlete with less than 60%. Conclusion: The HQ ratio analyzed throughout the knee range of motion allowed identifying muscle imbalance at specific joint angles in female futsal players.

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Thigh muscle activity and anterior cruciate ligament insufficiency

Cited by 97 publications

References 16 publications

Changes in Isokinetic Muscle Strength in Adolescent Soccer Players after 10 Weeks of Pre-Season Training

Changes in Isokinetic Muscle Strength in Adolescent Soccer Players after 10 Weeks of Pre-Season Training

A comparison of isokinetic knee strength and power output ratios between female basketball and volleyball players

Knee Isokinetic Torque Imbalance in Female Futsal Players

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