Effects of Post-exercise Protein Supplementation in Young Athletes
Condition: Fatigue; Inflammation; Bone Resorption
MeSH terms: Bone Resorption; Inflammation
Study type: Interventional

Summary: 
      This randomised double blind, placebo-controlled study examined the effects of post-exercise
      consumption of whey protein (PRO) or carbohydrate (CHO) on performance recovery, muscle
      damage and inflammatory cytokine responses following a high intensity interval swim (HIIS) in
      10-17-year old male and female swimmers.
    

Detailed description: 
      Study Procedures: All tests and measurements were performed during three visits at the given
      swim teams training/practice facility.

      During Visit 1, participants were informed of all tests and procedures that will take place
      and were familiarised with all testing protocols. All anthropometric measurements were also
      performed during this meeting (see below). Visit one took ~ 60-90 minutes.

      During visit 2, Participants arrived at the testing centre for 06:00h, provided a fasted
      venous blood sample (for biochemical markers - see below). Following the saliva and blood
      samples, a light breakfast (~300-400 kcal, depending on body mass) (e.g. banana, apple, plain
      granola bar, water etc.) was provided. Following breakfast (approximately 45-60 min),all
      participants performed a standardised warm-up in the pool (1000m - short course) followed by
      5min of rest and the subsequent performance test in the form of a maximal 200m-front-crawl.
      Following the maximal 200m performance test, participants underwent a maximal high intensity
      interval swim protocol (HIIS). The HIIS consisted of 15 high-intensity swimming repetitions
      (5x100m, 5x50m and 5x25m at maximal intensity) with a work-to-rest ratio of 1:1. Immediately
      following the HIIS participants exited the pool and provided a second blood sample (blood
      samples were collected pre-, 30min, 2, 6 and 24h post-HIIS). This was then followed by the
      first supplement drink ~30-40. 1.5h after consuming the first supplement drink, participants
      returned to the pool to complete a second maximal 200m swim, followed by a blood test and
      received their second supplement drink. 1.5h following the supplement drink, a standardised
      vegetarian lunch was provided, 1.5h following lunch participant provided another blood sample
      and performed the final 200m swim of that day. Prior to departure participants were provided
      with a food record sheet to track all food consumption that evening and were instructed to
      return it to a study investigator the following day.

      During visit 3, Participants returned to the testing location at 06:00h, provided a fasted
      Blood and saliva samples, were given the same breakfast as they received on day 2 and were
      administered a muscle soreness questionnaire. Following breakfast (approximately 45-60
      min),all participants performed the same standardised warm-up as they did in day 2 (1000m -
      short course) followed by 5min of rest and the subsequent performance test in the form of a
      maximal 200m-front-crawl.

      Groups and supplementation protocol - Participants matched into one of three groups: Protein
      (0.3g/kg - whey protein isolate), Carbohydrate (0.3g/kg - maltodextrin) or placebo control
      (flavoured water) (H2O), matched for age, sex and body mass. All groups consumed a total of
      two supplements, both the investigators and the participants themselves were blinded to the
      contents of the drink. All drinks were chocolate flavoured and served in black opaque protein
      shaker cups. For the protein and carbohydrate groups, each participant received an
      isoenergetic amount of supplement (2 x 0.3g/kg - whey protein isolate or maltodextrin)
      throughout the duration of the study at the given time-points outlined above.

      Biochemical measurements:

      Venous blood samples and a saliva sample will be collected on 5 separate occasions (pre-,
      30min, 2, 6 and 24h post-HIIS). To control for circadian rhythm, the exercise session and
      related blood samples will be performed at the same time of day.

      Venous blood samples were collected from the antecubital fossa of each participant using a
      standard venipuncture technique. Endocrine response such as anabolic/hormonal markers,
      inflammatory markers (cytokines - IL-6, IL-10, TNF-α) and indicators of muscle fatigue/damage
      (CK) were examined.
    

Intervention name(s): Experimental:Whey protein; Active Comparator: Isoenergetic control - Carbohydrate; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement; Other
Intervention description(s): Each participant in the protein group received 2 protein drinks immediately following exercise. The supplement was given using a relative quantity of whey protein isolate (0.3g/kg) and was chocolate flavoured.; Each participant in the carbohydrate group received 2 drinks immediately following exercise. The supplement was given using a relative quantity of maltodextrin (0.3g/kg), non-caloric chocolate flavouring was added to mask the drinks contents.; Each participant in the water group received 2 drinks immediately following exercise. The water was provided in a similar volume using the same non-caloric chocolate flavouring as the other drinks.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants were divided into three groups: PRO (0.3g/kg - whey protein isolate), CHO (0.3g/kg - maltodextrin) or placebo control (H2O), matched for age, sex and body mass
Masking: Double (Participant, Investigator)
Primary purpose: Treatment