EMG-pants in Sports: Concept Validation of Textile-integrated EMG Measurements

Five women and 5 men performed maximal isometric and concentric dorsiflexion actions on an isokinetic dynamometer. The concentric actions were done at 10 preset velocities ranging from 0.26 to 5.23 rad∙s−1. Electromyographic (EMG) recordings were made from one agonist (tibialis anterior [TA]) and two antagonists (saleus [S], lateral gastrocnemius [LG]). The men produced greater absolute torque than the women, but there was no gender difference in the torque/body mass ratio. The shape of the torque-velocity relation was similar in men and women and approximated, but did not match, that obtained in animal preparations or in human studies using electrical stimulation. Agonist TA activation (integrated EMG/movement time) decreased with increasing velocity over the same range of velocities as torque. Antagonist S, but not LG, activation also decreased. The S/TA activation ratio was greater in men than women. In men the S/TA ratio tended to be greater than the LG/TA ratio, whereas the converse was true for women. These data indicate that velocity influences the relative activation of two antagonists in maximal dorsiflexion muscle actions, and that there is an apparent gender difference in the relative activation of two antagonists. Key words: torque-velocity relation, coactivation, electromyography

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Multidimensional Self Concept Validation: A Three-Instrument Investigation

Journal of Psychoeducational Assessment ◽

10.1177/073428299100900403 ◽

1991 ◽

Vol 9 (4) ◽

pp. 319-328 ◽

Cited By ~ 14

Author(s):

Bruce A. Bracken ◽

Karen Kuehn Howell

Keyword(s):

Self Concept ◽

Concept Validation

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Antagonist Muscle Co-Activation during Kettlebell Single Arm Swing Exercise

Applied Sciences ◽

10.3390/app11094033 ◽

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.

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Less-skilled pilot decision support

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-12-2017-0269 ◽

2019 ◽

Vol 91 (5) ◽

pp. 790-802

Author(s):

Jozsef Rohacs ◽

Istvan Jankovics ◽

Daniel Rohacs

Keyword(s):

Control System ◽

Decision Support ◽

Total System ◽

Workload Management ◽

Content Type ◽

Subjective Analysis ◽

Supporting System ◽

Safety Aspects ◽

Concept Validation ◽

Small Aircraft

PurposeThe purpose of this paper is to overview the systems and their elements developing for supporting the less-skilled pi-lots.Design/methodology/approachSeveral European (like EPATS, SAT-Rdmp, Pplane, Esposa, Clean Sky2) and national projects (NASA SATS, Hungarian SafeFly) develop the personal/small aircraft and personal/small aircraft transportation systems. The projects had analysed the safety aspects, too, and they underlined the aircraft will be controlled by so-called less-skilled pilots (owners, renters), having less experiences. The paper defines the cross-connected controls, introduces the methods of subjective analysis in pilot decision processes, improves the pilot workload model, defines the possible workload management and describes the developing pilot decision support system.FindingsAnalysing the personal/small aircraft safety aspects, a unique and important safety problem induced by less-skilled pilots has been identified. The considerable simplification of the air-craft control system, supporting the pilot subjective decisions and introducing the pilot work-load management, may eliminate this problem.Research limitations/implicationsOnly the system elements have been used in concept validation tests.Practical implicationsThe developing pilot supporting system in its general form has on - board and ground sub-systems, too, except a series of elements integrated into the pilot cockpit environment and control system. Several system elements (sensors, integrated controls, etc.) might be implement now, but the total system need further studies. The subjective decision process needs further development of the methodology and concept validation.Social implicationsThe system may catalyse the society acceptance of the personal aircraft and their safer piloting, applicability.Originality/valueThe paper introduces an original supporting system for less-skilled pilots.

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