The Effect of Antioxidant Vitamin Supplementation on Muscle Performance and Redox Status After Eccentric Training
Condition: Muscle Damage; Oxidative Stress; Hemolysis
MeSH terms: Hemolysis
Study type: Interventional

Summary: 
      Consumption of vitamin supplements is a common practice among athletes or people
      participating in health promoting exercise programs. The reason for this interest in vitamin
      supplements is primarily because of the observation that enhanced production of reactive
      oxygen and nitrogen species (RONS) influence fundamental biological processes, such as gene
      expression, signal transduction and enzyme activity. In a muscle and exercise physiology
      context, a low level of RONS is required for normal force production, whereas marked
      increases in RONS can cause contractile dysfunction, resulting in muscle weakness and
      fatigue. On the other hand RONS are involved in signaling pathways and serve to up-regulate
      the expression of a number of genes and can exert favorable effects such as training
      adaptations.

      The present study will employ a valid eccentric exercise model to examine the influence of
      combined vitamin C and E supplementation after acute and chronic eccentric exercise on muscle
      damage and performance, redox status, hemolysis and lipid and lipoprotein profile.
    

Detailed description: 
      Historically there was a shift in the paradigm regarding the effects of antioxidant
      supplementation on muscle performance and redox status. In fact, back in the 80's and 90's
      most of the relevant studies reported "positive" effects of antioxidant supplementation on
      muscle performance, muscle damage and redox status. On the other hand, the last five years,
      an increasing number of well-received studies are appearing pointing towards the negative
      impact of antioxidant supplementation. Moreover, much more studies than the past are now
      specifically addressing the effects of antioxidant supplementation on the exercise
      adaptations that take place after chronic exercise. Regarding the latter, it has been
      reported recently that antioxidant supplementation greatly decreases training efficiency and
      prevents many cellular adaptations to chronic exercise. Nevertheless, the debate is still
      open and an equal number of recent studies have reported the reverse i.e. positive effects of
      antioxidant supplementation on exercise adaptations or virtually no effect of antioxidant
      supplementation on exercise adaptations.

      Eccentric muscle work is an essential part of daily activities of humans, such as walking,
      and in particular, when walking downhill or descending stairs. The most notable and
      well-described effect of eccentric exercise is the muscle damage that peaks one to three days
      after exercise. Eccentric exercise can cause effects other than just muscle damage, from
      activation of several transcription factors to favorable changes on lipid and lipoproteins
      profile.

      In a double-blinded fashion, men will receive either a daily oral supplementation of vitamin
      C (1g) and vitamin E (400IU) or placebo for eleven weeks. Following baseline tests,
      volunteers will have to perform an eccentric exercise session two times per week for four
      weeks. Before and after the chronic eccentric exercise volunteers will be subject to one
      session of acute eccentric exercise, and physiological measurements will be performed as well
      as blood samples and muscle biopsies will be collected.

      The aims of the present research are to investigate:

        -  the effect of antioxidant vitamin supplementation for 4 weeks on muscle performance,
           redox status, hemolysis and lipids and lipoprotein profile,

        -  the effect of an acute bout of eccentric exercise on muscle performance, redox status,
           hemolysis and lipid and lipoproteins profile of untrained individuals supplemented with
           or without antioxidant vitamins,

        -  the effect of 4 weeks of eccentric training on muscle performance, redox status,
           hemolysis and lipid and lipoproteins profile of untrained individuals supplemented with
           or without antioxidant vitamins,

        -  the effect of an acute bout of eccentric exercise on muscle performance, redox status,
           hemolysis and lipid and lipoproteins profile of individuals trained for 4 weeks and
           supplemented with or without antioxidant vitamins.
    

Intervention name(s): Antioxidant vitamins
Intervention type(s): Dietary Supplement
Intervention description(s): Oral supplementation with one tablet of 1 g of vitamin C (Lamberts Healthcare Ltd, UK) and one tablet of 400 IU of vitamin E (Lamberts Healthcare Ltd, UK)
Other intervention name(s): For vitamin C ascorbic acid; For vitamin E d-alpha tocopherol
Intervention MeSH terms: Vitamins; Ascorbic Acid; Vitamin E; Tocopherols; alpha-Tocopherol; Antioxidants
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Keywords: Eccentric training; Free radicals; Antioxidant supplements; Training adaptations; Lipid profile