Publicação
Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities
| Resumo: | Force complexity is a key indicator of the neuromuscular system’s adaptability and motor control. Although an inverted U-shaped relationship between force complexity and contraction intensity is established, its underlying mechanisms remain unclear. To investigate whether changes in motor unit behaviour (recruitment and firing rate) would accompany and explain this relationship, 25 young male adults performed a 30-second knee extensors’ hold-isometric task at 50%, 75%, 100%, 150% and 175% of their End-Test Torque (ETT), at individual’s optimal angle. Force complexity and motor unit behaviour were assessed through Sample Entropy (SampEn) and high-density surface electromyography, respectively. We demonstrated a trend for an inverted U-shaped relationship between force complexity and contraction intensity, with SampEn at ETT and 150%ETT being significantly higher than at 50%ETT and 75%ETT (all p < 0.05). This pattern was accompanied by an increase in motor unit actions potentials and firing rate as the intensity increased up to 150%ETT (all p < 0.05). A multiple linear regression analysis showed that force complexity was explained in 18% by the vastus lateralis’ motor unit behaviour. The findings suggest that changes in force complexity depend on contraction intensity and are partly explained by alterations in motor unit behaviour, influencing the neuromuscular system’s adaptability to meet task demands. |
|---|---|
| Autores principais: | Oliveira, João H. |
| Outros Autores: | Gomes, João S.; Bauer, Philipp; Pezarat-Correia, Pedro; Vaz, João R. |
| Assunto: | complexity variability entropy motor control force control neuromuscular coordination |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | contribuição para revista |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Egas Moniz - Cooperativa de Ensino Superior, CRL |
| Idioma: | inglês |
| Origem: | Egas Moniz - Cooperativa de Ensino Superior, CRL |
| _version_ | 1868695868645834752 |
|---|---|
| author | Oliveira, João H. |
| author2 | Gomes, João S. Bauer, Philipp Pezarat-Correia, Pedro Vaz, João R. |
| author2_role | author author author author |
| author_facet | Oliveira, João H. Gomes, João S. Bauer, Philipp Pezarat-Correia, Pedro Vaz, João R. |
| author_role | author |
| contributor_name_str_mv | Repositório Comum |
| country_str | PT |
| creators_json_txt | [{\"Person.name\":\"Oliveira, João H.\"},{\"Person.name\":\"Gomes, João S.\"},{\"Person.name\":\"Bauer, Philipp\"},{\"Person.name\":\"Pezarat-Correia, Pedro\"},{\"Person.name\":\"Vaz, João R.\"}] |
| datacite.contributors.contributor.contributorName.fl_str_mv | Repositório Comum |
| datacite.creators.creator.creatorName.fl_str_mv | Oliveira, João H. Gomes, João S. Bauer, Philipp Pezarat-Correia, Pedro Vaz, João R. |
| datacite.date.Accepted.fl_str_mv | 2025-08-01T00:00:00Z |
| datacite.date.available.fl_str_mv | 2026-05-08T11:05:26Z |
| datacite.date.embargoed.fl_str_mv | 2026-05-08T11:05:26Z |
| datacite.rights.fl_str_mv | http://purl.org/coar/access_right/c_abf2 |
| datacite.subjects.subject.fl_str_mv | complexity variability entropy motor control force control neuromuscular coordination |
| datacite.titles.title.fl_str_mv | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| dc.contributor.none.fl_str_mv | Repositório Comum |
| dc.creator.none.fl_str_mv | Oliveira, João H. Gomes, João S. Bauer, Philipp Pezarat-Correia, Pedro Vaz, João R. |
| dc.date.Accepted.fl_str_mv | 2025-08-01T00:00:00Z |
| dc.date.available.fl_str_mv | 2026-05-08T11:05:26Z |
| dc.date.embargoed.fl_str_mv | 2026-05-08T11:05:26Z |
| dc.format.none.fl_str_mv | application/pdf |
| dc.identifier.none.fl_str_mv | http://hdl.handle.net/10400.26/63037 |
| dc.language.none.fl_str_mv | eng |
| dc.publisher.none.fl_str_mv | Springer Nature |
| dc.rights.cclincense.fl_str_mv | http://creativecommons.org/licenses/by/4.0/ |
| dc.rights.none.fl_str_mv | http://purl.org/coar/access_right/c_abf2 |
| dc.subject.none.fl_str_mv | complexity variability entropy motor control force control neuromuscular coordination |
| dc.title.fl_str_mv | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| dc.type.none.fl_str_mv | http://purl.org/coar/resource_type/c_3e5a |
| description | Force complexity is a key indicator of the neuromuscular system’s adaptability and motor control. Although an inverted U-shaped relationship between force complexity and contraction intensity is established, its underlying mechanisms remain unclear. To investigate whether changes in motor unit behaviour (recruitment and firing rate) would accompany and explain this relationship, 25 young male adults performed a 30-second knee extensors’ hold-isometric task at 50%, 75%, 100%, 150% and 175% of their End-Test Torque (ETT), at individual’s optimal angle. Force complexity and motor unit behaviour were assessed through Sample Entropy (SampEn) and high-density surface electromyography, respectively. We demonstrated a trend for an inverted U-shaped relationship between force complexity and contraction intensity, with SampEn at ETT and 150%ETT being significantly higher than at 50%ETT and 75%ETT (all p < 0.05). This pattern was accompanied by an increase in motor unit actions potentials and firing rate as the intensity increased up to 150%ETT (all p < 0.05). A multiple linear regression analysis showed that force complexity was explained in 18% by the vastus lateralis’ motor unit behaviour. The findings suggest that changes in force complexity depend on contraction intensity and are partly explained by alterations in motor unit behaviour, influencing the neuromuscular system’s adaptability to meet task demands. |
| dirty | 0 |
| eu_rights_str_mv | openAccess |
| format | contributionToPeriodical |
| fulltext.url.fl_str_mv | https://comum.rcaap.pt/bitstreams/242994c1-05ce-42c7-b66c-abae159431ed/download |
| id | em_5d8d444aae1c6eda8132fc9d308f00a5 |
| identifier.url.fl_str_mv | http://hdl.handle.net/10400.26/63037 |
| instacron_str | em |
| institution | Egas Moniz - Cooperativa de Ensino Superior, CRL |
| instname_str | Egas Moniz - Cooperativa de Ensino Superior, CRL |
| language | eng |
| network_acronym_str | em |
| network_name_str | Egas Moniz - Cooperativa de Ensino Superior, CRL |
| oai_identifier_str | oai:comum.rcaap.pt:10400.26/63037 |
| organization_str_mv | urn:organizationAcronym:em |
| person_str_mv | Oliveira, João H. Gomes, João S. Bauer, Philipp Pezarat-Correia, Pedro Vaz, João R. |
| publishDate | 2025 |
| publisher.none.fl_str_mv | Springer Nature |
| reponame_str | Egas Moniz - Cooperativa de Ensino Superior, CRL |
| repository_id_str | urn:repositoryAcronym:em |
| service_str_mv | urn:repositoryAcronym:em |
| spelling | engSpringer NatureengForce complexity is a key indicator of the neuromuscular system’s adaptability and motor control. Although an inverted U-shaped relationship between force complexity and contraction intensity is established, its underlying mechanisms remain unclear. To investigate whether changes in motor unit behaviour (recruitment and firing rate) would accompany and explain this relationship, 25 young male adults performed a 30-second knee extensors’ hold-isometric task at 50%, 75%, 100%, 150% and 175% of their End-Test Torque (ETT), at individual’s optimal angle. Force complexity and motor unit behaviour were assessed through Sample Entropy (SampEn) and high-density surface electromyography, respectively. We demonstrated a trend for an inverted U-shaped relationship between force complexity and contraction intensity, with SampEn at ETT and 150%ETT being significantly higher than at 50%ETT and 75%ETT (all p < 0.05). This pattern was accompanied by an increase in motor unit actions potentials and firing rate as the intensity increased up to 150%ETT (all p < 0.05). A multiple linear regression analysis showed that force complexity was explained in 18% by the vastus lateralis’ motor unit behaviour. The findings suggest that changes in force complexity depend on contraction intensity and are partly explained by alterations in motor unit behaviour, influencing the neuromuscular system’s adaptability to meet task demands.application/pdfengForce fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensitiesOliveira, João H.Gomes, João S.Bauer, PhilippPezarat-Correia, PedroVaz, João R.HostingInstitutionOrganizationalRepositório Comume-mailmailto:comum@rcaap.ptcomum@rcaap.ptISSNIsPartOf2045-2322DOIIsPartOf10.1038/s41598-025-14543-62026-05-08T11:05:26Z2025-082025-08-01T00:00:00ZHandlehttp://hdl.handle.net/10400.26/63037http://purl.org/coar/access_right/c_abf2open accesscomplexityvariabilityentropymotor controlforce controlneuromuscular coordination2206338 bytesother research producthttp://purl.org/coar/resource_type/c_3e5acontribution to journal2025-08http://creativecommons.org/licenses/by/4.0/http://purl.org/coar/access_right/c_abf2application/pdffulltexthttps://comum.rcaap.pt/bitstreams/242994c1-05ce-42c7-b66c-abae159431ed/downloadScientific Reports1528442 |
| spellingShingle | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities Oliveira, João H. complexity variability entropy motor control force control neuromuscular coordination |
| status | SINGLETON |
| subject.fl_str_mv | complexity variability entropy motor control force control neuromuscular coordination |
| title | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| title_full | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| title_fullStr | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| title_full_unstemmed | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| title_short | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| title_sort | Force fluctuations regulation and the role of neurophysiological mechanisms throughout different isometric contraction intensities |
| topic | complexity variability entropy motor control force control neuromuscular coordination |
| topic_facet | complexity variability entropy motor control force control neuromuscular coordination |
| url | http://hdl.handle.net/10400.26/63037 |
| visible | 1 |