Adaptation of the transcriptional response to resistance exercise over 4 weeks of daily training

Abstract

We present the time course of change in the muscle transcriptome 1 h after the last exercise bout of a daily resistance training program lasting 2, 10, 20, or 30 days. Daily exercise in rat tibialis anterior muscles (5 sets of 10 repetitions over 20 min) induced progressive muscle growth that approached a new stable state after 30 days. The acute transcriptional response changed along with progressive adaptation of the muscle phenotype. For example, expression of type 2B myosin was silenced. Time courses recently synthesized from human exercise studies do not demonstrate so clearly the interplay between the acute exercise response and the longer‐term consequences of repeated exercise. We highlight classes of transcripts and transcription factors whose expression increases during the growth phase and declines again as the muscle adapts to a new daily pattern of activity and reduces its rate of growth. Myc appears to play a central role.

A molecular signature defining exercise adaptation with ageing and in vivo partial reprogramming in skeletal muscle

“…We recently reported that Myc induction specifically in muscle fibres is central to the acute mechanical loading‐induced transcriptome in the plantaris of young mice (Murach et al., 2022). A corroborating result in muscle tissue was reported with frequent resistance‐type training in rats (Viggars et al., 2022). Furthermore, the induction of Myc was recently linked to ‘biological immortality’ in hydrozoans (Pascual‐Torner et al., 2022).…”

Increased mitochondrial surface area and cristae density in the skeletal muscle of strength athletes

“…Muscle adaptations are thought to stem from the molecular response to each exercise session (Perry et al ., 2010; Viggars et al ., 2023), which when repeated over time leads to phenotypical differences (Chapman et al ., 2020). Our results show that a single extensive resistance exercise session in strength athletes, leads to mild changes in mitochondrial morphological variables, in the SS and to a lower extent in the SMF, associated with mitochondrial stress (Figure 6).…”

“…Phenotypical adaptations following months or years of training stem from the accumulative effect of repeated exercise over time (Perry et al ., 2010; Viggars et al ., 2023). The acute molecular cascade initiated following an acute resistance exercise bout involves the upregulation of a large number of genes including ribosomal and myogenic pathways that will support the increased synthesis of myofibrillar proteins (Bamman et al ., 2018).…”

Increased mitochondrial surface area and cristae density in the skeletal muscle of strength athletes

“…Phenotypical adaptations following months or years of training stem from the cumulative effect of repeated exercise over time (Perry et al., 2010; Viggars et al., 2023). The acute molecular cascade initiated following an acute resistance exercise bout involves the upregulation of a large number of genes including ribosomal and myogenic pathways that will support the increased synthesis of myofibrillar proteins (Bamman et al., 2018).…”