It is yet to be established when equating for total work performed that isotonic compared to isokinetic eccentric contractions elicits a differential response in regards to surrogate markers of skeletal muscle damage. Purpose: To directly compare between isotonic- and isokinetic-type eccentric contractions for differences in markers of muscle damage. Methods: 24 men were placed into a control (C), isotonic (IT) or isokinetic (IK) group. The IT (110% of maximal isometric torque) and IK (120°/sec) groups performed 200 eccentric contractions of each knee extensor and had serial measurements taken for strength, perceived muscular soreness and creatine kinase activity up to 48-h post exercise. Results: Total work (~1,700 J) and peak torque (~ 265 Nm) significantly decreased over the 200 repetitions (p < 0.01), but was not different between the groups. All surrogate markers of muscle damage were significantly changed 48-h post exercise (p < 0.05): peak isometric torque (-13%), creatine kinase activity (+200%) and self-perceived muscular soreness (+5 unit change), however, significant group × interactions (p < 0.001) indicated that peak isometric torque, plasma creatine kinase activity and self-perceived muscular soreness exhibited a differential response between the two protocols 48-hours post exercise. Conclusion: The current protocol suggests that when equating for total work during distinct modes of muscular contractions that differential outcomes are evident in markers of skeletal muscle damage. These data have implications for appropriateness of protocols to promote muscle damage, exploration of neuromuscular mechanisms associated with distinct contractions types and integration of biomechanical, neurological and physiological parameters to elucidate mechanisms to provide evidence in explaining the observed findings.
","abstract_html":"<p>It is yet to be established when equating for total work performed that isotonic compared to isokinetic eccentric contractions elicits a differential response in regards to surrogate markers of skeletal muscle damage. Purpose: To directly compare between isotonic- and isokinetic-type eccentric contractions for differences in markers of muscle damage. Methods: 24 men were placed into a control (C), isotonic (IT) or isokinetic (IK) group. The IT (110% of maximal isometric torque) and IK (120├é┬░/sec) groups performed 200 eccentric contractions of each knee extensor and had serial measurements taken for strength, perceived muscular soreness and creatine kinase activity up to 48-h post exercise. Results: Total work (~1,700 J) and peak torque (~ 265 Nm) significantly decreased over the 200 repetitions (p < 0.01), but was not different between the groups. All surrogate markers of muscle damage were significantly changed 48-h post exercise (p < 0.05): peak isometric torque (-13%), creatine kinase activity (+200%) and self-perceived muscular soreness (+5 unit change), however, significant group ├â┬ù interactions (p < 0.001) indicated that peak isometric torque, plasma creatine kinase activity and self-perceived muscular soreness exhibited a differential response between the two protocols 48-hours post exercise. Conclusion: The current protocol suggests that when equating for total work during distinct modes of muscular contractions that differential outcomes are evident in markers of skeletal muscle damage. These data have implications for appropriateness of protocols to promote muscle damage, exploration of neuromuscular mechanisms associated with distinct contractions types and integration of biomechanical, neurological and physiological parameters to elucidate mechanisms to provide evidence in explaining the observed findings.</p>","abstract_has_math":false,"creators":["Alemany, Joseph Anthony"],"institution":null,"degree_name":"M.S.","degree_level":"Campus Access Thesis","degree_discipline":"Exercise Science","degree_department":null,"school":null,"contributors":["Matthew C Kostek"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-01-01T08:00:00Z","date_published":"2011-01-01T08:00:00Z","updated_at":"2026-07-24T04:37:56Z","subjects":["Exercise Science","Kinesiology","Life Sciences","eccentric action","exercise","isokinetic","isotonic","muscle damage","soreness"],"languages":[],"rights":["© 2011, Joseph Anthony Alemany"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarcommons.sc.edu/etd/1191","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Matthew C Kostek"]},{"key":"dc:creator","label":"Author","values":["Alemany, Joseph Anthony"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_discipline","label":"Discipline","values":["Exercise Science"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Campus Access Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Exercise Science","Kinesiology","Life Sciences","eccentric action","exercise","isokinetic","isotonic","muscle damage","soreness"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["© 2011, Joseph Anthony Alemany"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarcommons.sc.edu/etd/1191"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["It is yet to be established when equating for total work performed that isotonic compared to isokinetic eccentric contractions elicits a differential response in regards to surrogate markers of skeletal muscle damage. Purpose: To directly compare between isotonic- and isokinetic-type eccentric contractions for differences in markers of muscle damage. Methods: 24 men were placed into a control (C), isotonic (IT) or isokinetic (IK) group. The IT (110% of maximal isometric torque) and IK (120├é┬░/sec) groups performed 200 eccentric contractions of each knee extensor and had serial measurements taken for strength, perceived muscular soreness and creatine kinase activity up to 48-h post exercise. Results: Total work (~1,700 J) and peak torque (~ 265 Nm) significantly decreased over the 200 repetitions (p < 0.01), but was not different between the groups. All surrogate markers of muscle damage were significantly changed 48-h post exercise (p < 0.05): peak isometric torque (-13%), creatine kinase activity (+200%) and self-perceived muscular soreness (+5 unit change), however, significant group ├â┬ù interactions (p < 0.001) indicated that peak isometric torque, plasma creatine kinase activity and self-perceived muscular soreness exhibited a differential response between the two protocols 48-hours post exercise. Conclusion: The current protocol suggests that when equating for total work during distinct modes of muscular contractions that differential outcomes are evident in markers of skeletal muscle damage. These data have implications for appropriateness of protocols to promote muscle damage, exploration of neuromuscular mechanisms associated with distinct contractions types and integration of biomechanical, neurological and physiological parameters to elucidate mechanisms to provide evidence in explaining the observed findings.
"]},{"key":"dc:title","label":"Title","values":["Direct Comparison of Acute Responses to Isotonic Or Isokinetic Eccentric Muscle Action: Implications For Differential Outcomes In Skeletal Muscle Damage"]}]}],"canonical_facts":{"dc:contributor":["Matthew C Kostek"],"dc:creator":["Alemany, Joseph Anthony"],"dc:description.abstract":["It is yet to be established when equating for total work performed that isotonic compared to isokinetic eccentric contractions elicits a differential response in regards to surrogate markers of skeletal muscle damage. Purpose: To directly compare between isotonic- and isokinetic-type eccentric contractions for differences in markers of muscle damage. Methods: 24 men were placed into a control (C), isotonic (IT) or isokinetic (IK) group. The IT (110% of maximal isometric torque) and IK (120°/sec) groups performed 200 eccentric contractions of each knee extensor and had serial measurements taken for strength, perceived muscular soreness and creatine kinase activity up to 48-h post exercise. Results: Total work (~1,700 J) and peak torque (~ 265 Nm) significantly decreased over the 200 repetitions (p < 0.01), but was not different between the groups. All surrogate markers of muscle damage were significantly changed 48-h post exercise (p < 0.05): peak isometric torque (-13%), creatine kinase activity (+200%) and self-perceived muscular soreness (+5 unit change), however, significant group × interactions (p < 0.001) indicated that peak isometric torque, plasma creatine kinase activity and self-perceived muscular soreness exhibited a differential response between the two protocols 48-hours post exercise. Conclusion: The current protocol suggests that when equating for total work during distinct modes of muscular contractions that differential outcomes are evident in markers of skeletal muscle damage. These data have implications for appropriateness of protocols to promote muscle damage, exploration of neuromuscular mechanisms associated with distinct contractions types and integration of biomechanical, neurological and physiological parameters to elucidate mechanisms to provide evidence in explaining the observed findings.
"],"dc:identifier":["https://scholarcommons.sc.edu/etd/1191"],"dc:rights":["© 2011, Joseph Anthony Alemany"],"dc:subject":["Exercise Science","Kinesiology","Life Sciences","eccentric action","exercise","isokinetic","isotonic","muscle damage","soreness"],"dc:title":["Direct Comparison of Acute Responses to Isotonic Or Isokinetic Eccentric Muscle Action: Implications For Differential Outcomes In Skeletal Muscle Damage"],"thesis:degree_discipline":["Exercise Science"],"thesis:degree_level":["Campus Access Thesis"],"thesis:degree_name":["M.S."]},"updated_at":"2026-07-24T04:37:56Z"}