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Characteristics of isometric and dynamic strength loss following eccentric exercise-induced muscle damage.
Scand J Med Sci Sports. 2001 Jun; 11(3):134-40.SJ

Abstract

Angle-specific isometric strength and angular velocity-specific concentric strength of the knee extensors were studied in eight subjects (5 males and 3 females) following a bout of muscular damaging exercise. One hundred maximal voluntary eccentric contractions of the knee extensors were performed in the prone position through a range of motion from 40 degrees to 140 degrees (0 degrees = full extension) at 1.57 rads(-1). Isometric peak torque was measured whilst seated at 10 degrees and 80 degrees knee flexion, corresponding to short and optimal muscle length, respectively. Isokinetic concentric peak torque was measured at 0.52 and 3.14 rad x s(-1). Plasma creatine kinase (CK) activity was also measured from a fingertip blood sample. These measures were taken before, immediately after and on days 1, 2, 4, and 7 following the eccentric exercise. The eccentric exercise protocol resuited in a greater relative loss of strength (P< 0.05) at short muscle length (76.3 +/- 2.5% of pre-exercise values) compared to optimal length (82.1 +/- 2.7%). There were no differences in the relative strength loss between isometric strength at optimal length and isokinetic concentric strength at 0.52 and 3.14 rad x s(-1). CK activity was significantly elevated above baseline at days 4 (P < 0.01) and 7 (P < 0.01). The greater relative strength loss at short muscle length appeared to persist throughout the seven-day testing period and provides indirect evidence of a shift in the angle-torque relationship towards longer muscle lengths. The results lend partial support to the popping sarcomere hypothesis of muscle damage, but could also be explained by an impairment of activation at short muscle lengths.

Authors+Show Affiliations

School of Sport, Health and Exercise Sciences, University of Wales, Bangor, Gwynedd, UK.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

11374426

Citation

Byrne, C, et al. "Characteristics of Isometric and Dynamic Strength Loss Following Eccentric Exercise-induced Muscle Damage." Scandinavian Journal of Medicine & Science in Sports, vol. 11, no. 3, 2001, pp. 134-40.
Byrne C, Eston RG, Edwards RH. Characteristics of isometric and dynamic strength loss following eccentric exercise-induced muscle damage. Scand J Med Sci Sports. 2001;11(3):134-40.
Byrne, C., Eston, R. G., & Edwards, R. H. (2001). Characteristics of isometric and dynamic strength loss following eccentric exercise-induced muscle damage. Scandinavian Journal of Medicine & Science in Sports, 11(3), 134-40.
Byrne C, Eston RG, Edwards RH. Characteristics of Isometric and Dynamic Strength Loss Following Eccentric Exercise-induced Muscle Damage. Scand J Med Sci Sports. 2001;11(3):134-40. PubMed PMID: 11374426.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characteristics of isometric and dynamic strength loss following eccentric exercise-induced muscle damage. AU - Byrne,C, AU - Eston,R G, AU - Edwards,R H, PY - 2001/5/26/pubmed PY - 2001/9/28/medline PY - 2001/5/26/entrez SP - 134 EP - 40 JF - Scandinavian journal of medicine & science in sports JO - Scand J Med Sci Sports VL - 11 IS - 3 N2 - Angle-specific isometric strength and angular velocity-specific concentric strength of the knee extensors were studied in eight subjects (5 males and 3 females) following a bout of muscular damaging exercise. One hundred maximal voluntary eccentric contractions of the knee extensors were performed in the prone position through a range of motion from 40 degrees to 140 degrees (0 degrees = full extension) at 1.57 rads(-1). Isometric peak torque was measured whilst seated at 10 degrees and 80 degrees knee flexion, corresponding to short and optimal muscle length, respectively. Isokinetic concentric peak torque was measured at 0.52 and 3.14 rad x s(-1). Plasma creatine kinase (CK) activity was also measured from a fingertip blood sample. These measures were taken before, immediately after and on days 1, 2, 4, and 7 following the eccentric exercise. The eccentric exercise protocol resuited in a greater relative loss of strength (P< 0.05) at short muscle length (76.3 +/- 2.5% of pre-exercise values) compared to optimal length (82.1 +/- 2.7%). There were no differences in the relative strength loss between isometric strength at optimal length and isokinetic concentric strength at 0.52 and 3.14 rad x s(-1). CK activity was significantly elevated above baseline at days 4 (P < 0.01) and 7 (P < 0.01). The greater relative strength loss at short muscle length appeared to persist throughout the seven-day testing period and provides indirect evidence of a shift in the angle-torque relationship towards longer muscle lengths. The results lend partial support to the popping sarcomere hypothesis of muscle damage, but could also be explained by an impairment of activation at short muscle lengths. SN - 0905-7188 UR - https://www.unboundmedicine.com/medline/citation/11374426/Characteristics_of_isometric_and_dynamic_strength_loss_following_eccentric_exercise_induced_muscle_damage_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&amp;sid=nlm:pubmed&amp;issn=0905-7188&amp;date=2001&amp;volume=11&amp;issue=3&amp;spage=134 DB - PRIME DP - Unbound Medicine ER -