{"id":{"repo_id":"brock","oai_identifier":"oai:brocku.scholaris.ca:10464/13966"},"canonical_url":"https://search.dev.ndltd.org/etd/brock/oai:brocku.scholaris.ca:10464/13966","repository":{"repo_id":"brock","name":"Brock University","base_url":"https://brocku.scholaris.ca/server/oai/request"},"display":{"title":"Sex differences in the neural control of muscle","abstract":"Sex-differences in muscle strength have been linked to differences in muscle size, involved limb, and daily activities. Early work has shown that sex-differences are greater in the upper compared to lower limb, making the upper limb an ideal model to investigate the best statistical approaches for sex comparison. Large differences in the upper limb reveals how biomechanical factors may impact neural control. Since males and females are more comparable with respect to strength in the lower limb, it allows for a determination of whether potential sex-differences in neural control exist without large differences in biomechanics. Understanding sex-differences allows for prescription of rehabilitation and training modalities, taking into account potential specificities in sex-related neuromuscular and musculoskeletal factors. The overall purpose was to examine neural and biomechanical differences that would account for sex-differences in neural control of muscle. Manuscript 1 examined normalization versus an ANCOVA to assess sex-differences. Sex-differences were seen in elbow flexor strength and rate of force development (RFD). Normalization by either maximum strength or neural factors couldn’t account for all sex-differences in RFD, resulting in an ambiguous interpretation. In contrast, both variables were able to be incorporated in an ANCOVA to determine their relative contribution. Manuscript 2 examined the effect of task familiarization and the contribution of maximum strength, twitch contraction time, muscle fiber condition velocity, and rate of muscle activation to sex-differences in the RFD during dorsiflexion. There were no significant differences between the sexes in muscle properties, but there were differences in neural control. Additionally, across days females exhibited a neural adaptation leading to an improvement in the RFD. Manuscript 3 directly assessed potential sex-differences in neural control during force gradation by recording motor unit activity during maximal and submaximal contractions. Females had less force steadiness (FS), which may have resulted from neural compensation for a less optimal pennation angle or a tendency towards greater joint laxity. Higher motor unit discharge rates and incidence of doublets may increase twitch force summation leading to a reduction in FS. Thus, biomechanical, not inherent sex-differences in neural drive led to neural compensation strategies manifesting as a difference in FS.","abstract_html":"Sex-differences in muscle strength have been linked to differences in muscle size, involved limb, and daily activities. Early work has shown that sex-differences are greater in the upper compared to lower limb, making the upper limb an ideal model to investigate the best statistical approaches for sex comparison. Large differences in the upper limb reveals how biomechanical factors may impact neural control. Since males and females are more comparable with respect to strength in the lower limb, it allows for a determination of whether potential sex-differences in neural control exist without large differences in biomechanics. Understanding sex-differences allows for prescription of rehabilitation and training modalities, taking into account potential specificities in sex-related neuromuscular and musculoskeletal factors. The overall purpose was to examine neural and biomechanical differences that would account for sex-differences in neural control of muscle. Manuscript 1 examined normalization versus an ANCOVA to assess sex-differences. Sex-differences were seen in elbow flexor strength and rate of force development (RFD). Normalization by either maximum strength or neural factors couldn’t account for all sex-differences in RFD, resulting in an ambiguous interpretation. In contrast, both variables were able to be incorporated in an ANCOVA to determine their relative contribution. Manuscript 2 examined the effect of task familiarization and the contribution of maximum strength, twitch contraction time, muscle fiber condition velocity, and rate of muscle activation to sex-differences in the RFD during dorsiflexion. There were no significant differences between the sexes in muscle properties, but there were differences in neural control. Additionally, across days females exhibited a neural adaptation leading to an improvement in the RFD. Manuscript 3 directly assessed potential sex-differences in neural control during force gradation by recording motor unit activity during maximal and submaximal contractions. Females had less force steadiness (FS), which may have resulted from neural compensation for a less optimal pennation angle or a tendency towards greater joint laxity. Higher motor unit discharge rates and incidence of doublets may increase twitch force summation leading to a reduction in FS. Thus, biomechanical, not inherent sex-differences in neural drive led to neural compensation strategies manifesting as a difference in FS.","abstract_has_math":false,"creators":["Inglis, J Greig"],"institution":"Brock University","degree_name":"Ph.D. Applied Health Sciences","degree_level":"Doctoral","degree_discipline":"Faculty of Applied Health Sciences","degree_department":"Applied Health Sciences Program","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-02-22T19:02:32Z","date_published":"2019-02-22T19:02:32Z","updated_at":"2026-07-24T01:23:12Z","subjects":["motor unit discharge rate, sex differences, force steadiness, rate of force development, neuromechanics"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10464/13966","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Applied Health Sciences Program"]},{"key":"dc:creator","label":"Author","values":["Inglis, J Greig"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2019-02-22T19:02:32Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2019-02-22T19:02:32Z"]},{"key":"dc:date.issued","label":"Date","values":["2019-02-22T19:02:32Z"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Faculty of Applied Health Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D. Applied Health Sciences"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Brock University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["motor unit discharge rate, sex differences, force steadiness, rate of force development, neuromechanics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10464/13966"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Sex-differences in muscle strength have been linked to differences in muscle size, involved limb, and daily activities. Early work has shown that sex-differences are greater in the upper compared to lower limb, making the upper limb an ideal model to investigate the best statistical approaches for sex comparison. Large differences in the upper limb reveals how biomechanical factors may impact neural control. Since males and females are more comparable with respect to strength in the lower limb, it allows for a determination of whether potential sex-differences in neural control exist without large differences in biomechanics. Understanding sex-differences allows for prescription of rehabilitation and training modalities, taking into account potential specificities in sex-related neuromuscular and musculoskeletal factors. The overall purpose was to examine neural and biomechanical differences that would account for sex-differences in neural control of muscle. Manuscript 1 examined normalization versus an ANCOVA to assess sex-differences. Sex-differences were seen in elbow flexor strength and rate of force development (RFD). Normalization by either maximum strength or neural factors couldn’t account for all sex-differences in RFD, resulting in an ambiguous interpretation. In contrast, both variables were able to be incorporated in an ANCOVA to determine their relative contribution. Manuscript 2 examined the effect of task familiarization and the contribution of maximum strength, twitch contraction time, muscle fiber condition velocity, and rate of muscle activation to sex-differences in the RFD during dorsiflexion. There were no significant differences between the sexes in muscle properties, but there were differences in neural control. Additionally, across days females exhibited a neural adaptation leading to an improvement in the RFD. Manuscript 3 directly assessed potential sex-differences in neural control during force gradation by recording motor unit activity during maximal and submaximal contractions. Females had less force steadiness (FS), which may have resulted from neural compensation for a less optimal pennation angle or a tendency towards greater joint laxity. Higher motor unit discharge rates and incidence of doublets may increase twitch force summation leading to a reduction in FS. Thus, biomechanical, not inherent sex-differences in neural drive led to neural compensation strategies manifesting as a difference in FS."]},{"key":"dc:title","label":"Title","values":["Sex differences in the neural control of muscle"]}]}],"canonical_facts":{"dc:contributor.department":["Applied Health Sciences Program"],"dc:creator":["Inglis, J Greig"],"dc:date.accessioned":["2019-02-22T19:02:32Z"],"dc:date.available":["2019-02-22T19:02:32Z"],"dc:date.issued":["2019-02-22T19:02:32Z"],"dc:description.abstract":["Sex-differences in muscle strength have been linked to differences in muscle size, involved limb, and daily activities. Early work has shown that sex-differences are greater in the upper compared to lower limb, making the upper limb an ideal model to investigate the best statistical approaches for sex comparison. Large differences in the upper limb reveals how biomechanical factors may impact neural control. Since males and females are more comparable with respect to strength in the lower limb, it allows for a determination of whether potential sex-differences in neural control exist without large differences in biomechanics. Understanding sex-differences allows for prescription of rehabilitation and training modalities, taking into account potential specificities in sex-related neuromuscular and musculoskeletal factors. The overall purpose was to examine neural and biomechanical differences that would account for sex-differences in neural control of muscle. Manuscript 1 examined normalization versus an ANCOVA to assess sex-differences. Sex-differences were seen in elbow flexor strength and rate of force development (RFD). Normalization by either maximum strength or neural factors couldn’t account for all sex-differences in RFD, resulting in an ambiguous interpretation. In contrast, both variables were able to be incorporated in an ANCOVA to determine their relative contribution. Manuscript 2 examined the effect of task familiarization and the contribution of maximum strength, twitch contraction time, muscle fiber condition velocity, and rate of muscle activation to sex-differences in the RFD during dorsiflexion. There were no significant differences between the sexes in muscle properties, but there were differences in neural control. Additionally, across days females exhibited a neural adaptation leading to an improvement in the RFD. Manuscript 3 directly assessed potential sex-differences in neural control during force gradation by recording motor unit activity during maximal and submaximal contractions. Females had less force steadiness (FS), which may have resulted from neural compensation for a less optimal pennation angle or a tendency towards greater joint laxity. Higher motor unit discharge rates and incidence of doublets may increase twitch force summation leading to a reduction in FS. Thus, biomechanical, not inherent sex-differences in neural drive led to neural compensation strategies manifesting as a difference in FS."],"dc:identifier.uri":["http://hdl.handle.net/10464/13966"],"dc:language.iso":["eng"],"dc:subject":["motor unit discharge rate, sex differences, force steadiness, rate of force development, neuromechanics"],"dc:title":["Sex differences in the neural control of muscle"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Faculty of Applied Health Sciences"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Ph.D. Applied Health Sciences"],"thesis:institution_name":["Brock University"]},"updated_at":"2026-07-24T01:23:12Z"}