scholarly journals Muscle Activation Profiles and Co-Activation of Quadriceps and Hamstring Muscles around Knee Joint in Indian Primary Osteoarthritis Knee Patients

2017 ◽  
Author(s):  
Sanjeev Kumar Sharma
Keyword(s):  
Knee Joint ◽  
Muscle Activation ◽  
Primary Osteoarthritis ◽  
Hamstring Muscles ◽  
Co Activation ◽  
Osteoarthritis Knee

scholarly journals Antagonist Muscle Co-Activation during Kettlebell Single Arm Swing Exercise

2021 ◽  
Vol 11 (9) ◽  
pp. 4033
Author(s):  
Ahmed Salem ◽  
Amr Hassan ◽  
Markus Tilp ◽  
Abdel-Rahman Akl
Keyword(s):  
Muscle Activation ◽  
Surface Emg ◽  
Antagonist Muscle ◽  
Arm Swing ◽  
Shoulder Muscles ◽  
Antagonist Muscles ◽  
Co Activation ◽  
Integrated Emg ◽  
Post Hoc ◽  
Electrical Muscle

The purpose of this study was to determine the muscle activation and co-activation of selected muscles during the kettlebell single arm swing exercise. To the best of our knowledge, this is the first study investigating the muscle co-activation of a kettlebell single arm swing exercise. Nine volunteers participated in the present study (age: 22.6 ± 3.8 years; body mass: 80.4 ± 9.2 kg; height: 175.6 ± 7.5 cm). The electrical muscle activity of eight right agonist/antagonist muscles (AD/PD, ESL/RA, ESI/EO, and GM/RF) were recorded using a surface EMG system (Myon m320RX; Myon, Switzerland) and processed using the integrated EMG to calculate a co-activation index (CoI) for the ascending and descending phases. A significant effect of the ascending and descending phases on the muscles’ CoI was observed. Post hoc analyses showed that the co-activation was significantly higher in the descending phase compared to that in the ascending phase of AD/PD CoI (34.25 ± 18.03% and 24.75 ± 13.03%, p < 0.001), ESL/RA CoI (34.97 ± 17.86% and 24.19 ± 10.32%, p < 0.001), ESI/EO CoI (41.14 ± 10.72% and 30.87 ± 11.26%, p < 0.001), and GM/RF CoI (27.49 ± 12.97% and 34.98 ± 14.97%, p < 0.001). In conclusion, the co-activation of the shoulder muscles varies within the kettlebell single arm swing. The highest level of co-activation was observed in the descending phase of AD/PD and GM/RF CoI, and the lowest level of co-activation was observed during the descending phase, ESL/RA and ESI/EO CoI. In addition, the highest level of co-activation was observed in the ascending phase of ESL/RA and ESI/EO CoI, and the lowest level of co-activation was observed during the ascending phase, AD/PD and GM/RF CoI. The co-activation index could be a useful method for the interpretation of the shoulder and core muscles’ co-activity during a kettlebell single arm swing.

scholarly journals Relative index of ankle muscle activations on agonistic phase between subjects with and without flat foot

2015 ◽  
Vol 2 (1) ◽  
pp. 129 ◽  
Author(s):  
Paul S. Sung
Keyword(s):  
Muscle Activation ◽  
Time Window ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Flat Foot ◽  
Relative Index ◽  
Ankle Motion ◽  
Co Activation ◽  
Relative Activation ◽  
Ankle Muscle

Background: Although co-activation of ankle muscles has been reported, relative ankle muscle activation in subjects with flat foot has not been carefully investigated. The aim of this study was to compare the relative activation index (RAI) on the tibialis anterior (TA) and medial gastrocnemius (GTN) muscles during active ankle range of motion (ROM) between subjects with and without flat foot. Methods: There were 17 subjects with flat foot and 17 age- and gender-matched control subjects who participated in this study. The RAI based on electromyography (EMG) was measured during the agonist phase at a controlled velocity of ankle motion (10°/second). The subject was seated upright with the tested foot held firmly onto a footplate that was attached to a torque sensor. The ankle being measured was strapped to the leg support of the Intel stretch device at 60° of knee flexion. The RAI was analyzed by the summation of EMG activity from the agonistic time window divided by the total EMG activity during full active ankle ROM. Results: The RAI was significantly different on the TA muscle (t = 3.08, P = 0.004), but no difference was found on the GTN muscle (t = -1.24, P = 0.23) in subjects with flat foot. There was an interaction between group and RAI (F =7.89, P = 0.007); however, the RAI demonstrated no interaction with age (F = 2.59, P = 0.14), height (F = 3.73, P = 0.06), or weight (F = 2.96, P = 0.09). Conclusions: The RAI indicated a lack of TA muscle activation in the flat foot group. Such dissociated activation in the flat foot group might be relevant to the inefficiency of synergistic motions. The relative activation of the agonistic phase needs to be further investigated to compare co-activation of synergistic muscle activation with various functional tasks. 

scholarly journals The anterolateral ligament is a secondary stabilizer in the knee joint

2019 ◽  
Vol 8 (11) ◽  
pp. 509-517 ◽  
Author(s):  
Kyoung-Tak Kang ◽  
Yong-Gon Koh ◽  
Kyoung-Mi Park ◽  
Chong-Hyuck Choi ◽  
Min Jung ◽  
...  
Keyword(s):  
Knee Joint ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Knee Kinematics ◽  
Anterolateral Ligament ◽  
Loading Conditions ◽  
Joint Stability ◽  
Musculoskeletal Models ◽  
Subject Specific ◽  
Cycle Loading

Objectives The aim of this study was to investigate the biomechanical effect of the anterolateral ligament (ALL), anterior cruciate ligament (ACL), or both ALL and ACL on kinematics under dynamic loading conditions using dynamic simulation subject-specific knee models. Methods Five subject-specific musculoskeletal models were validated with computationally predicted muscle activation, electromyography data, and previous experimental data to analyze effects of the ALL and ACL on knee kinematics under gait and squat loading conditions. Results Anterior translation (AT) significantly increased with deficiency of the ACL, ALL, or both structures under gait cycle loading. Internal rotation (IR) significantly increased with deficiency of both the ACL and ALL under gait and squat loading conditions. However, the deficiency of ALL was not significant in the increase of AT, but it was significant in the increase of IR under the squat loading condition. Conclusion The results of this study confirm that the ALL is an important lateral knee structure for knee joint stability. The ALL is a secondary stabilizer relative to the ACL under simulated gait and squat loading conditions. Cite this article: Bone Joint Res 2019;8:509–517.

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