Does the Early and Late Rate of Torque Development, Change in Relation to the Quadriceps Angle?

The rate of torque development (RTD), which determines the force that can be developed in the early phase of muscle contraction (0-200 ms), is very important in terms of tracking explosive strength improvement and preventing knee injuries. The purpose of this study was to investigate the relationship of quadriceps angle which affects the structural alignment of the lower extremity with early (0-100 ms) and late (100-200 ms) rate of torque development of the knee extensor muscles and myoelectrical activity. The study was carried out with 38 well-trained male basketball players (mean age: 22.3±2.5 years). The participants were divided into two groups with normal (<11°) and abnormal (>10°) values. RTD was measured in concentric/concentric mode at 60, 120 and 180°/s angular velocities in an isokinetic dynamometer. Surface electromyography (sEMG) was used to determine the myoelectrical activity. When RTD0-100 and RTD100-200 were examined, statistically significant difference was observed at 60 and 120°/s (p<0.05). However, no difference was observed at 180°/s. In addition, sEMG data did not have a statistically significant difference between groups. Negative correlation was found between all RTD at 60, 10 and 180°/s with Q angle (180°/s RTD0-100 r= -0.34, 180°/s RTD100-200 r= -0.35, 120°/s RTD0-100 r= -0.40, 120°/s RTD100-200 r= -0.48, 60°/s RTD0-100 r= -0.55, 60°/s RTD100-200 r= -0.59; p<0.05). There was a negative correlation between the structural differences of the lower extremity and the early and late rate of torque development of the knee extensor muscles. Considering the structural variables, it is thought that it is important to improve the rate of torque development with appropriate resistance training in athletes with variables such as abnormal Q angle, and thus knee injuries can be prevented through athletic development.

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Twelve- to Thirteen-Year-Old Boys Are More Resistant to Low-Frequency Fatigue than Young Men

Pediatric Exercise Science ◽

10.1123/pes.17.4.399 ◽

2005 ◽

Vol 17 (4) ◽

pp. 399-409 ◽

Cited By ~ 3

Author(s):

Vytautas Streckis ◽

Albertas Skurvydas ◽

Aivaras Ratkevicius

Keyword(s):

Low Frequency ◽

Knee Extensor ◽

Ground Reaction Forces ◽

Extensor Muscles ◽

Significant Difference ◽

Drop Jumps ◽

Generating Capacity ◽

Reaction Forces ◽

Low Frequency Fatigue ◽

Knee Extensor Muscles

The aim of this study was to compare low-frequency fatigue (LFF) after 100 drop jumps in boys (age = 12.7 ± 0.7 years, mean ± SD) and men (age = 25.6 ± 1.7 years). The force-generating-capacity test (FGCT) of knee extensor muscles was performed before the exercise, as well as 3 and 20 min after the exercise. Before exercise, men were stronger than boys, but twitch time characteristics did not differ between the groups. The 20:50 Hz torque ratio was similar in boys and men as well (0.71 ± 0.08 and 0.73 ± 0.08, respectively). After exercise, at 20 min of recovery, the 20:50 Hz ratio was depressed to 48.9 ± 11.6% of initial in men and to 74.5 ± 10.0% of initial in boys (p < .05). There was no significant difference between boys and men in ground-reaction forces of drop jumps when the values were normalized to body mass. It is argued that intrinsic differences in the muscle-tendon complex are responsible for less severe LFF in boys compared with men.

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Biomechanical Characteristics on the Lower Extremity of Three Typical Yoga Manoeuvres

Applied Bionics and Biomechanics ◽

10.1155/2021/7464719 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Elizabeth Whissell ◽

Lin Wang ◽

Pan Li ◽

Jing Xian Li ◽

Zhen Wei

Keyword(s):

Knee Joint ◽

Lower Extremity ◽

Hip Joint ◽

Sagittal Plane ◽

Knee Injuries ◽

Three Dimensional ◽

Knee Extensor ◽

Frontal Plane ◽

Significant Difference ◽

Angular Impulse

This study was aimed at exploring the biomechanical characteristics of the lower extremity amongst three typical yoga manoeuvres. A total of thirteen experienced female yoga practitioners were recruited in the current study; they were all certified with the Yoga Alliance. A three-dimensional motion capture system with 10 cameras combined with four synchronised force plates was used to collect kinematics of the lower extremity and ground reactive force whilst the participants performed the crescent lunge pose, warrior II pose, and triangle pose. One-way repeated ANOVA was used in exploring the differences amongst the three yoga movements, and the significance was set to alpha < 0.05 . The triangle pose performed the largest range of motion (ROM) of the hip ( 90.5 ° ± 22.9 ° ), knee ( 68.8 ° ± 23.1 ° ), and ankle ( 46.4 ° ± 11.3 ° ) in the sagittal plane and the hip ( 54.8 ° ± 6.5 ° ), knee ( 42.4 ° ± 12.8 ° ), and ankle ( 4.8 ° ± 1.7 ° ) in the frontal plane amongst the three manoeuvres ( P < 0.05 ). No significant difference was found for the hip and ankle joint moment amongst the three manoeuvres ( P > 0.05 ). Knee joint travelled into 9.5° of extension and slight adduction of 1.94° whilst expressing the largest knee joint adduction moments ( 0.30 ± 0.22 Nm / kg ) in the triangle pose. The distribution of the angular impulse of the lower limb joints indicated that the hip joint contributed significantly the most in the sagittal and frontal planes of the three yoga manoeuvres ( P < 0.05 ), ranging from 51.67% to 70.56%. Results indicated that triangle pose may be superior to the other two manoeuvres, which improved hip joint ROM, strength, and dynamic stability. However, knee injuries such as osteoarthritis (OA) should be considered because of the large knee extensor angle and adductor moments.

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