RibOSE - Glucose and Resistance Exercise Training
Condition: Healthy
Study type: Interventional

Summary: 
      The aim of the study is to investigate the effects of ingesting glucose during five bouts of
      resistance exercise on muscle biological charateristics in m. vastus lateralis of moderately
      trained healthy individuals (20-45 years of age, n=20)
    

Detailed description: 
      Muscular responses to resistance training vary extensively between humans, with many showing
      impaired growth. In such individuals, cellular plasticity is compromised, leading to reduced
      functional and health-beneficial outcomes of training. While this is likely due to a range of
      determinants, including epigenetic, genetic and physiological variables, recent studies
      suggest that it involves reduced ability to produce novel ribosomes in response to training.
      This eventually leads to less pronounced increases in protein synthesis, and thus decreased
      growth rates, and makes ribosomal content in muscle a potential proxy marker for
      training-associated muscle hypertrophy.

      In a recent study, the investigators showed that increased resistance training volume was
      associated with more pronounced muscle growth, a trait that was associated with increased
      ribosomal biogenesis. Despite this, ~50 % of the participants did not exhibit true beneficial
      effects of increased training volume, which in turn coincided with reduced abilities to
      accumulate ribosomes. In such individuals, other means are likely necessary to circumvent the
      negative influence of genetic and epigenetic predispositions on muscle plasticity. Nutrient
      supplementation stand out as a potential therapy. However, at present, knowledge with regard
      to this perspective is limited to a selected few nutrients, with protein ingestion being the
      best studied potential adjuvant, for which adequate intake seems to be essential for
      achieving optimal muscle growth, potentially being interconnected with ribosomal synthesis.
      For other nutrients, such as glucose, little is know about their importance for muscle
      plasticity and ribosomal biogenesis.

      In cell types such as cultivated kidney cells, exposure to high levels of glucose is an
      efficient mean to increase ribosomal biogenesis (and growth rates). This suggests that
      glucose is an important signaling molecule for increasing ribosomal production per se,
      perhaps acting as a ligand for signaling proteins or by acting to increase energy
      availability. In the human body (as opposed to cultured cells), glucose may also exert
      growth-stimulating effects by increasing insulin levels in blood. Overall, it thus seems
      plausible that glucose intake during resistance training may stimulate ribosomal biogenesis,
      in turn having beneficial effects for protein synthesis and muscle plasticity, perhaps acting
      in an additive manner to protein supplementation. At present, we do not know if this is the
      case, though studies have suggested that glucose ingestion during acute resistance training
      sessions may reduce training-induced muscle damage without affecting within-session work
      output (i.e. volume). This lack of knowledge is surprising given the long-standing
      appreciation of the beneficial effects of glucose intake for endurance performance, acting to
      delay muscular fatigue.
    

Intervention name(s): Glucose
Intervention type(s): Dietary Supplement
Intervention description(s): To investigate the effects of glucose intake during resistance training on muscle biological adaptations
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The study will be conducted as a 12-day placebo-controlled randomized clinical trial. Each day will consist of concomitant dietary intervention and resistance training. The dietary intervention consists of alternating days of ingesting glucose (GLU, 90 g) or placebo (PLAC) in connection with training. Likewise, training consists of alternating days of resistance training of the two legs (using identical training protocols), with Day 1 involving training of the first leg, Day 2 involving training of the second leg, Day 3 involving training of the first leg, etc. In this way, each of the two dietary interventions will be associated with training of one particular leg, allowing within-subject comparisons of the effects of GLU vs PLAC on muscle biology and recovery.
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science
Keywords: Strength/resistance training; Glucose supplementation; Skeletal muscle