Titin and nebulin content in human skeletal muscle following eccentric resistance exercise

Abstract

We measured titin and nebulin content in muscle biopsies from the vastus lateralis before and 24 h after one bout of high-intensity eccentric knee extensor resistance exercise in seven men (26 ± 3 years). Titin and nebulin content were significantly (P < 0.05) reduced after exercise by 30 and 15%, respectively. These results suggest that the structural components of the myofibrillar apparatus are degraded following high-intensity eccentric resistance exercise in humans. Loss of these proteins may have important implications for the mechanisms regulating the adaptive response of skeletal muscle to resistance exercise.

Effects of fatiguing jumping exercise on mRNA expression of titin-complex proteins and calpains

“…After lengthening contractions, abnormal staining of titin was observed consistently with unorganized contractile filaments in animal studies (32,45). In human skeletal muscle, titin staining disappears from some myofibers within 3 days after eccentrically biased exercise (54) and protein content falls by 30% 24 h postexercise (47). In this study, we did not see any changes in the mRNA expression of titin.…”

“…However, little is known about the effect of physical exercise on these proteins in human muscle. Titin staining has been found to disappear from some myofibers within 3 days after eccentrically biased exercise (54) and protein content to be reduced by 30% in human skeletal muscle 24 h postexercise (47). Calpains are known to respond differentially to eccentric muscle action at the mRNA level (14).…”

Eccentric Muscle Contractions: Their Contribution to Injury, Prevention, Rehabilitation, and Sport

“…148 Supporting this idea is the fact that novel high-force eccentric contractions damage the cytoskeleton, 64 by including titin failure, and a bout of eccentric exercise results in diminished titin content. 168 As well, recent evidence suggests that small heat shock proteins that protect the cytoskeleton structures (eg, titin) increase dramatically after repeated eccentric bouts. 98 If titin is functioning as a locomotor spring, then it should be tuned to the frequency of muscle use.…”

Alterations in peak torque occur without hematological changes after muscle fatigue

“…Differences between muscle actions have already been investigated in the literature [16][17][18][19][20][21] demonstrating greater impairment in concentric muscle activation 3,19,20 , increased metabolic burden evaluated by lactate concentration 3 in concentric muscle actions and of elastic components specifically in the titin protein 16,21 have been recognized as indicators of this difference.…”