Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04263714 |
| Other study ID # |
2196 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
April 1, 2020 |
| Est. completion date |
May 1, 2024 |
Study information
| Verified date |
June 2024 |
| Source |
McMaster University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Generally, resistance exercise increases muscle mass and strength, and fatigue resistance.
How resistance exercise achieves these adaptations remains understudied, but what is known is
that skeletal muscle translates the physical and biochemical stresses of resistance exercise
into morphological and metabolic adaptations. While resistance exercise activates signaling
pathways (i.e., proteins) that increase the synthesis of specific proteins to cause
adaptations, thousands of proteins are likely involved, and their interactions are
complicated. The investigators aim to study these processes.
Description:
Skeletal muscle is a highly plastic tissue, capable of adapting to changes in nutritional
intake and contractile activity. For instance, resistance exercise results in a mild
stimulation of rates of muscle protein breakdown (MPB) but a greater stimulation of the rates
of muscle protein synthesis (MPS). When resistance exercise is performed prior to protein
ingestion there is a synergistic combination of the two stimuli such that rates of MPS are
stimulated over and above those of MPB. Thus, repeated bouts of resistance exercise, when
coupled with protein ingestion, result in the accretion of skeletal muscle protein referred
to as hypertrophy. Importantly, by changing the nature of the exercise stimulus, it is
possible to redirect the focus of the type of skeletal muscle proteins that are being
synthesized. For example, prolonged and repeated lower-load dynamic stimulation of skeletal
muscle (i.e., endurance exercise training) results in an increase in the expression of
mitochondrial genes, proteins, and ultimately enhanced mitochondrial content, leading to a
shift towards an oxidative phenotype, and improved fatigue resistance. Resistance exercise
training also stimulates the transcription of genes and accrual of new muscle proteins, but
these genes and proteins are largely associated with the myofibrillar protein fraction, and
regular resistance exercise leads to muscle hypertrophy and increased force-generating
capacity. However, during the early stages of exercise training, particularly in
training-naïve participants there is a significant increase in the expression of genes common
to both modalities of exercise. It is only with sustained exercise training that there is a
'fine-tuning' of the transcriptome, the protein synthetic response, and then the proteome
that gives rise to divergent hypertrophic and oxidative phenotypes.