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.

Effect of Plyometrics on the Energy Cost of Running and MHC and Titin Isoforms

“…Unlike this investigation, most (20 of 22) of our subject population expressed both titin isoforms. The presence of two titin isoforms is consistent with previous findings in humans (9,25,28,29,37). Fry et al (10) showed that five of 15 subjects expressed both T1 and T2 isoforms.…”

“…For this reason, strict care was taken in the processing of muscle samples as explained previously by Granzier et al (15). We feel confident that our muscle processing resulted in optimized native titin isoform composition, since the appearance of two bands in human skeletal muscle is similar to that found by others (9,28,29,37). Another property of titin that may have been ignored by the current, and other studies of exercise training in humans, is that titin phosphorylation can also affect stiffness of this protein (18).…”

“…We show a trend toward greater nebulin in the plyometric training group, but not in the controls. Previously, Trappe et al (37) demonstrated that as the result of one bout of muscle damaging exercise, both total titin and nebulin decreased. Others showed that nebulin may be important in the remodeling of sarcomeres after eccentric contractions (40).…”

Effects of Eccentric Exercise on Passive Mechanical Properties of Human Gastrocnemius in vivo

“…Given that titin anchors myosin to the Z-disc, these observations suggest that titin could be damaged after eccentric exercise. Recent studies of human muscle biopsies taken after eccentric exercise have shown changes in the contents of titin and other myofibrillar protein components such as alpha-actin and desmin (26,31). These changes were thought to reflect myofibrillar remodeling rather than myofibril damage.…”

Does weightlifting increase residual force enhancement?

“…Titin content was reduced due to direct damage or degradation of titin following a single high-intensity eccentric resistance exercise of human M. vastus lateralis (Trappe et al, 2002). However, Lehti et al (2009) reported no change in titin mRNA expression 2 days after fatiguing jumping exercise.…”