Muscle activation sequence in flywheel squats

Spudić, Darjan (author), Smajla, Darjan (author), Burnard, Michael David (author), Šarabon, Nejc (author)

Background: Muscle coordination is important for rational and effective planning of therapeutic and exercise interventions using equipment that mimics functional movements. Our study was the first to assess muscle coordination during flywheel (FW) squats. Methods: Time-ofpeak electromyographic activation order was assessed separately for 8, 4, and 3 leg muscles under four FW loads. A sequential rank agreement permutations tests (SRA) were conducted to assess activation order and Kendall’s tau was used to assess the concordance of activation order across subjects, loads and expected order of activation. Results: SRA revealed a latent muscle activation order at loads 0.05, 0.075, and 0.1, but not at 0.025 kg·m$^2$. Kendall’s tau showed moderate-to-strong concordance between the expected (proximal-to-distal) and the observed muscle activation order only at a load 0.025 kg·m$^2$, regardless of the number of muscles analyzed. Muscle activation order was highly concordant between loads 0.05, 0.075, and 0.1 kg·m$^2$. Conclusions: The results show a specific role of each muscle during the FW squat that is load-dependent. While the lowest load follows the proximal-to-distal principle of muscle activation, higher loads lead to a reorganization of the underlying muscle coordination mechanisms. They require a specific and stable muscle coordination pattern that is not proximal-to-distal.

• Language: English
• Keywords: isoinertial training, EMG, eccentric exercise, overload, muscle coordination
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FŠ - Faculty of Sport
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 12 str.
• Numbering: Vol. 18, iss. 6, art. 3168
• PID: 20.500.12556/RUL-135218
• UDC: 796/799
• ISSN on article: 1660-4601
• DOI: 10.3390/ijerph18063168
• COBISS.SI-ID: 56468227
• Publication date in RUL: 01.03.2022

Record is a part of a journal

• Title: International journal of environmental research and public health
• Shortened title: Int. j. environ. res. public health
• Publisher: MDPI
• ISSN: 1660-4601
• COBISS.SI-ID: 1818965

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 19.03.2021

Secondary language

• Language: Slovenian
• Keywords: isoinercijska vadba, EMG, ekscentrična vadba, preobremenitev, mišična koordinacija

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P5-0147
• Name: Kineziologija monostrukturnih, polistrukturnih in konvencionalnih športov

• Funder: ARRS - Slovenian Research Agency
• Project number: L5-1845
• Name: Telesne asimetrije kot dejavnik tveganja za nastanek mišično-skeletnih poškodb: proučevanje mehanizmov nastanka in razvoj korektivnih ukrepov za njihovo odpravljanje s ciljem primarne in terciarne preventive