scholarly journals Comparison of Muscle Activation and Kinematics in 6-RM Squatting With Low and High Barbell Placement

2020 ◽  
Vol 74 (1) ◽  
pp. 131-142
Author(s):  
Roland van den Tillaar ◽  
Eric Helms
Keyword(s):  
Knee Flexion ◽  
Average Velocity ◽  
Muscle Activation ◽  
Joint Kinematics ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
Muscular Development ◽  
Hip Flexion ◽  
Maximal Capacity ◽  
Over Time

Abstract The aim of this study was to compare 6-RM muscle activation and kinematics in back squats with low and high barbell placements. Twelve resistance-trained males (23.5 ± 2.6 years, 86.8 ± 21.3 kg, 1.81 ± 0.08 m) with a minimum of 2 years of squatting experience performed a 6-RM using high and low barbell placements while muscle activation of eight muscles and joint kinematics were measured. During high barbell placement squats, lifting time was longer, with lower average velocity than low barbell placement. This was accompanied by a lesser knee flexion angle at the lowest point of the squat, and larger hip flexion angles during high, compared to low barbell squats. Furthermore, peak angular ankle, knee and hip velocities in the descending phase developed differently between conditions. No significant differences in muscle activation were found between conditions. Thus, our data suggests gross muscular adaptations between barbell placements may be similar over time, and therefore, from a muscular development standpoint, both squat styles are valid. Furthermore, unlike the low barbell placement, fatigue may manifest earlier itself in the high barbell squats during 6-RMs as sets progress toward a lifter’s maximal capacity, altering kinematics, especially in the last repetition.

Correlation Between Quadriceps, Hamstring, Tibialis Anterior, and Gastrocnemius Muscle Activation, With Knee Flexion Angle In Basketball Athlete While Performing Double-Leg Landing Task

2020 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
Ditaruni Asrina Utami
Keyword(s):  
Knee Flexion ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
Cross Sectional ◽  
Activation Ratio

ABSTRACTBackground: Anterior cruciate ligament (ACL) injury cause great disability for athlete. Recent focus of ACL injury management is on prevention by identifying the risk factors. Most of basketball injury mechanism is non-contact, related to landing process with small knee flexion angle. Muscle activation and its ratio, which control movement pattern in sagittal plane, are said to play a role in dynamic movement such as landing.Aims: The purpose of this study is to analyze the correlation between muscles activation and their activation ratio of quadriceps, hamstring, tibialis anterior and gastrocnemius with knee flexion angle of basketball athlete while performing double-leg landing task.Material and methods: This study was an observational analytic, cross sectional study. Study subjects was basketball athletes age 16 – 25 years in Surabaya. Measurements of knee flexion angle done with digital measurements of reflective marker, and muscle activation was measured with sEMG while performing double-leg landing task.Result: There was no significant correlation between maximum knee flexion angle and muscle activation of quadriceps (p=0,562), hamstring (p=0,918), tibialis anterior (p=0,394) and gastrocnemius (p=0,419). There was also no significant correlation between maximum knee flexion angle and the muscle activation ratio of quadriceps-hamstring (p=0,347), quadriceps-tibialis (p=0,139), quadriceps-gastrocnemius (p=0,626), hamstring-tibialis anterior (p=0,365), hamstring-gastrocnemius (p=0,867), and tibialis anterior-gastrocnemius (p=0,109).Conclusions: There was no correlation between muscle activation and muscle activation ratio of quadriceps, hamstring, tibialis anterior and gastrocnemius with maximum knee flexion angle in basketball athlete while performing double-leg landing task.

scholarly journals Correlation Between Quadriceps, Hamstring, Tibialis Anterior, and Gastrocnemius Muscle Activation, With Knee Flexion Angle In Basketball Athlete While Performing Double-Leg Landing Task

2020 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
Ditaruni Asrina Utami
Keyword(s):  
Knee Flexion ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
Cross Sectional ◽  
Activation Ratio

ABSTRACTBackground: Anterior cruciate ligament (ACL) injury cause great disability for athlete. Recent focus of ACL injury management is on prevention by identifying the risk factors. Most of basketball injury mechanism is non-contact, related to landing process with small knee flexion angle. Muscle activation and its ratio, which control movement pattern in sagittal plane, are said to play a role in dynamic movement such as landing.Aims: The purpose of this study is to analyze the correlation between muscles activation and their activation ratio of quadriceps, hamstring, tibialis anterior and gastrocnemius with knee flexion angle of basketball athlete while performing double-leg landing task.Material and methods: This study was an observational analytic, cross sectional study. Study subjects was basketball athletes age 16 – 25 years in Surabaya. Measurements of knee flexion angle done with digital measurements of reflective marker, and muscle activation was measured with sEMG while performing double-leg landing task.Result: There was no significant correlation between maximum knee flexion angle and muscle activation of quadriceps (p=0,562), hamstring (p=0,918), tibialis anterior (p=0,394) and gastrocnemius (p=0,419). There was also no significant correlation between maximum knee flexion angle and the muscle activation ratio of quadriceps-hamstring (p=0,347), quadriceps-tibialis (p=0,139), quadriceps-gastrocnemius (p=0,626), hamstring-tibialis anterior (p=0,365), hamstring-gastrocnemius (p=0,867), and tibialis anterior-gastrocnemius (p=0,109).Conclusions: There was no correlation between muscle activation and muscle activation ratio of quadriceps, hamstring, tibialis anterior and gastrocnemius with maximum knee flexion angle in basketball athlete while performing double-leg landing task.

Different squatting positions after total knee arthroplasty: a video-based observational study

2020 ◽  
Author(s):  
Jing-yang Sun ◽  
Guo-qiang Zhang ◽  
Tie-jian Li ◽  
Jun-min Shen ◽  
Yin-qiao Du ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
Ankle Dorsiflexion ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
Total Knee ◽  
The Mean ◽  
Hip Flexion ◽  
Deep Squat

Abstract Aims There are no methods to assess patient’s squatting ability after TKA (total knee arthroplasty), this study aimed to evaluate the different squatting position of a series of patients who underwent primary TKA.Methods From May 2018 to October 2019, we retrospectively reviewed 154 videos recording the squattin-related motions of patients after TKA. Among the included patients, 119 were women and 35 were men. Their mean age at the index surgery was 61.4 years (range, 30 to 77). The median follow-up was 12 months (range, 6 to 156). We classified those squatting-related motions into three major variations according to squatting depth: half squat, parallel squat, and deep squat. The angle of hip flexion, knee flexion and ankle dorsiflexion were measured in the screenshots captured from the videos at the moment of squatting nadir.Results A total of 26 patients were classified as half squat, 75 as parallel squat, and 53 as deep squat. The angle of hip flexion, knee flexion and ankle dorsiflexion all differed significantly among the three squatting positions (p<0.001). In the parallel squat group, the mean knee flexion angle(°) was 116.5 (SD, 8.1; range, 97 to 137). In the deep squat group, the mean knee flexion angle(°) was 132.5 (SD, 9.3; range, 116 to 158). Among the three squatting positions, deep squat showed the highest hip, knee and ankle flexion angle. And the next was parallel squat.Conclusion Our squatting position classification offers a pragmatic approach to evaluating patient’s squatting ability after TKA. However, the relation between squatting position and daily activity requires further investigation.

scholarly journals A high degree of knee flexion after TKA promotes the ability to perform high-flexion activities and patient satisfaction in Asian population

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hyuk-Soo Han ◽  
Jong Seop Kim ◽  
Bora Lee ◽  
Sungho Won ◽  
Myung Chul Lee
Keyword(s):  
Quality Of Life ◽  
Patient Satisfaction ◽  
Clinical Data ◽  
Knee Flexion ◽  
Male Gender ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
High Flexion ◽  
Standing Up

Abstract Background This study investigated whether achieving a higher degree of knee flexion after TKA promoted the ability to perform high-flexion activities, as well as patient satisfaction and quality of life. Methods Clinical data on 912 consecutive primary TKA cases involving a single high-flexion posterior stabilized fixed-bearing prosthesis were retrospectively analyzed. Demographic and clinical data were collected, including knee flexion angle, the ability to perform high-flexion activities, and patient satisfaction and quality of life. Results Of the cases, 619 (68%) achieved > 130° of knee flexion after TKA (high flexion group). Knee flexion angle and clinical scores showed significant annual changes, with the maximum improvement seen at 5 years and slight deterioration observed at 10 years postoperatively. In the high flexion group, more than 50% of the patients could not kneel or squat, and 35% could not stand up from on the floor. Multivariate analysis revealed that > 130° of knee flexion, the ability to perform high-flexion activities (sitting cross-legged and standing up from the floor), male gender, and bilateral TKA were significantly associated with patient satisfaction after TKA, while the ability to perform high-flexion activities (sitting cross-legged and standing up from the floor), male gender, and bilateral TKA were significantly associated with patient quality of life after TKA. Conclusions High knee flexion angle (> 130°) after TKA increased the ease of high-flexion activities and patient satisfaction. The ease of high-flexion activities also increased quality of life after TKA in our Asian patients, who frequently engage in these activities in daily life.

scholarly journals Kinematic Comparison between Medially Congruent and Posterior-Stabilized Third-Generation TKA Designs

2021 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
Stefano Ghirardelli ◽  
Jessica L. Asay ◽  
Erika A. Leonardi ◽  
Tommaso Amoroso ◽  
Thomas P. Andriacchi ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Knee Kinematics ◽  
Primary Total Knee Arthroplasty ◽  
Flexion Angle ◽  
Heel Strike ◽  
Third Generation ◽  
Knee Flexion Angle ◽  
Posterior Stabilized ◽  
Rotational Angle ◽  
Peak Knee

Background: This study compares knee kinematics in two groups of patients who have undergone primary total knee arthroplasty (TKA) using two different modern designs: medially congruent (MC) and posterior-stabilized (PS). The aim of the study is to demonstrate only minimal differences between the groups. Methods: Ten TKA patients (4 PS, 6 MC) with successful clinical outcomes were evaluated through 3D knee kinematics analysis performed using a multicamera optoelectronic system and a force platform. Extracted kinematic data included knee flexion angle at heel-strike (KFH), peak midstance knee flexion angle (MSKFA), maximum and minimum knee adduction angle (KAA), and knee rotational angle at heel-strike. Data were compared with a group of healthy controls. Results: There were no differences in preferred walking speed between MC and PS groups, but we found consistent differences in knee function. At heel-strike, the knee tended to be more flexed in the PS group compared to the MC group; the MSKFA tended to be higher in the PS group compared to the MC group. There was a significant fluctuation in KAA during the swing phase in the PS group compared to the MC group, PS patients showed a higher peak knee flexion moment compared to MC patients, and the PS group had significantly less peak internal rotation moments than the MC group. Conclusions: Modern, third-generation TKA designs failed to reproduce normal knee kinematics. MC knees tended to reproduce a more natural kinematic pattern at heel-strike and during axial rotation, while PS knees showed better kinematics during mid-flexion.

scholarly journals Quadriceps Strength Symmetry Does Not Modify Gait Mechanics After Anterior Cruciate Ligament Reconstruction, Rehabilitation, and Return-to-Sport Training

2020 ◽  
pp. 036354652098007
Author(s):  
Elanna K. Arhos ◽  
Jacob J. Capin ◽  
Thomas S. Buchanan ◽  
Lynn Snyder-Mackler
Keyword(s):  
Knee Flexion ◽  
Cruciate Ligament ◽  
Return To Sport ◽  
Quadriceps Muscle ◽  
Quadriceps Strength ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
Sport Training ◽  
Gait Biomechanics ◽  
Peak Knee

Background: After anterior cruciate ligament (ACL) reconstruction (ACLR), biomechanical asymmetries during gait are highly prevalent, persistent, and linked to posttraumatic knee osteoarthritis. Quadriceps strength is an important clinical measure associated with preoperative gait asymmetries and postoperative function and is a primary criterion for return-to-sport clearance. Evidence relating symmetry in quadriceps strength with gait biomechanics is limited to preoperative and early rehabilitation time points before return-to-sport training. Purpose/Hypothesis: The purpose was to determine the relationship between symmetry in isometric quadriceps strength and gait biomechanics after return-to-sport training in athletes after ACLR. We hypothesized that as quadriceps strength symmetry increases, athletes will demonstrate more symmetric knee joint biomechanics, including tibiofemoral joint loading during gait. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Of 79 athletes enrolled in the ACL-SPORTS Trial, 76 were participants in this study after completing postoperative rehabilitation and 10 return-to-sport training sessions (mean ± SD, 7.1 ± 2.0 months after ACLR). All participants completed biomechanical walking gait analysis and isometric quadriceps strength assessment using an electromechanical dynamometer. Quadriceps strength was calculated using a limb symmetry index (involved limb value / uninvolved limb value × 100). The biomechanical variables of interest included peak knee flexion angle, peak knee internal extension moment, sagittal plane knee excursion at weight acceptance and midstance, quadriceps muscle force at peak knee flexion angle, and peak medial compartment contact force. Spearman rank correlation (ρ) coefficients were used to determine the relationship between limb symmetry indexes in quadriceps strength and each biomechanical variable; alpha was set to .05. Results: Of the 76 participants, 27 (35%) demonstrated asymmetries in quadriceps strength, defined by quadriceps strength symmetry <90% (n = 23) or >110% (n = 4) (range, 56.9%-131.7%). For the biomechanical variables of interest, 67% demonstrated asymmetry in peak knee flexion angle; 68% and 83% in knee excursion during weight acceptance and midstance, respectively; 74% in internal peak knee extension moment; 57% in medial compartment contact force; and 74% in quadriceps muscle force. There were no significant correlations between quadriceps strength index and limb symmetry indexes for any biomechanical variable after return-to-sport training ( P > .129). Conclusion: Among those who completed return-to-sport training after ACLR, subsequent quadriceps strength symmetry was not correlated with the persistent asymmetries in gait biomechanics. After a threshold of quadriceps strength is reached, restoring strength alone may not ameliorate gait asymmetries, and current clinical interventions and return-to-sport training may not adequately target gait.

scholarly journals Relationship between Quadriceps Tendon Young’s Modulus and Maximum Knee Flexion Angle in the Swing Phase of Gait in Patients with Severe Knee Osteoarthritis

Medicina ◽  
2020 ◽  
Vol 56 (9) ◽  
pp. 437
Author(s):  
Bungo Ebihara ◽  
Takashi Fukaya ◽  
Hirotaka Mutsuzaki
Keyword(s):  
Young’S Modulus ◽  
Gait Speed ◽  
Knee Flexion ◽  
Young's Modulus ◽  
Quadriceps Tendon ◽  
Swing Phase ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
Knee Oa ◽  
Analysis System

Background and objectives: Decreased knee flexion in the swing phase of gait can be one of the causes of falls in severe knee osteoarthritis (OA). The quadriceps tendon is one of the causes of knee flexion limitation; however, it is unclear whether the stiffness of the quadriceps tendon affects the maximum knee flexion angle in the swing phase. The purpose of this study was to clarify the relationship between quadriceps tendon stiffness and maximum knee flexion angle in the swing phase of gait in patients with severe knee OA. Materials and Methods: This study was conducted from August 2018 to January 2020. Thirty patients with severe knee OA (median age 75.0 (interquartile range 67.5–76.0) years, Kellgren–Lawrence grade: 3 or 4) were evaluated. Quadriceps tendon stiffness was measured using Young’s modulus by ShearWave Elastography. The measurements were taken with the patient in the supine position with the knee bent at 60° in a relaxed state. A three-dimensional motion analysis system measured the maximum knee flexion angle in the swing phase. The measurements were taken at a self-selected gait speed. The motion analysis system also measured gait speed, step length, and cadence. Multiple regression analysis by the stepwise method was performed with maximum knee flexion angle in the swing phase as the dependent variable. Results: Multiple regression analysis identified quadriceps tendon Young’s modulus (standardized partial regression coefficients [β] = −0.410; p = 0.013) and gait speed (β = 0.433; p = 0.009) as independent variables for maximum knee flexion angle in the swing phase (adjusted coefficient of determination = 0.509; p < 0.001). Conclusions: Quadriceps tendon Young’s modulus is a predictor of the maximum knee flexion angle. Clinically, decreasing Young’s modulus may help to increase the maximum knee flexion angle in the swing phase in those with severe knee OA.

Interobserver Reliability and Change in the Sagittal Tibial Tubercle–Trochlear Groove Distance with Increasing Knee Flexion Angles

2021 ◽  
Author(s):  
Ian S. MacLean ◽  
Taylor M. Southworth ◽  
Ian J. Dempsey ◽  
Neal B. Naveen ◽  
Hailey P. Huddleston ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Sagittal Plane ◽  
Interobserver Reliability ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Flexion Angle ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Knee Flexion Angle ◽  
Intraclass Correlation Coefficients

AbstractThe tibial tubercle–trochlear groove (TT-TG) distance is currently utilized to evaluate knee alignment in patients with patellar instability. Sagittal plane pathology measured by the sagittal tibial tubercle–trochlear groove (sTT-TG) distance has been described in instability but may also be important to consider in patients with cartilage injury. This study aims to (1) describe interobserver reliability of the sTT-TG distance and (2) characterize the change in the sTT-TG distance with respect to changing knee flexion angles. In this cadaveric study, six nonpaired cadaveric knees underwent magnetic resonance imaging (MRI) studies at each of the following degrees of knee flexion: −5, 0, 5, 10, 15, and 20. The sTT-TG distance was measured on the axial T2 sequence. Four reviewers measured this distance for each cadaver at each flexion angle. Intraclass correlation coefficients were calculated to determine interobserver reliability and reproducibility of the sTT-TG measurement. Analysis of variance (ANOVA) tests and Friedman's tests with a Bonferroni's correction were performed for each cadaver to compare sTT-TG distances at each flexion angle. Significance was defined as p < 0.05. There was excellent interobserver reliability of the sTT-TG distance with all intraclass correlation coefficients >0.9. The tibial tubercle progressively becomes more posterior in relation to the trochlear groove (more negative sTT-TG distance) with increasing knee flexion. The sTT-TG distance is a measurement that is reliable between attending surgeons and across training levels. The sTT-TG distance is affected by small changes in knee flexion angle. Awareness of knee flexion angle on MRI is important when this measurement is utilized by surgeons.

Comparison of 2D video and electrogoniometry measurements of knee flexion angle during a countermovement jump and landing task

2012 ◽  
Vol 15 (3) ◽  
pp. 159-166 ◽  
Author(s):  
Erich Petushek ◽  
Chris Richter ◽  
David Donovan ◽  
William P. Ebben ◽  
Phillip B. Watts ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Flexion Angle ◽  
Knee Flexion Angle ◽  
Countermovement Jump
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