Dairy Consumption During a High-intensity, High-volume Training Week in Young Athletes
Condition: Inflammatory Response; Sports Performance
Study type: Interventional

Summary: 
      Our proposed study is a 5-d double-blind randomised cross-over trial, seeking to simulate a
      training identification camp in competitive adolescent soccer players

      The purpose of the proposed study is to investigate whether increased protein consumption by
      Greek yogurt, compared to an isoenergetic carbohydrate (CHO) control supplement, consumed
      immediately following exercise training, prior to sleep and between breakfast and lunch, for
      a week during an intense training period (high volume, high intensity) will:

        -  Attenuate the pro-inflammatory response (cytokines, acute phase proteins)

        -  Reduced the severity of muscle damage and impairment (creatine kinase)

        -  Maintain performance

      Secondary outcome measures:

      - Increase bone turnover (in favour of formation)
    

Detailed description: 
      The proposed study is a randomized, double-blinded, cross-over trial. The protocol will
      consist of an information session, two identical training camps consisting of 5 consecutive
      days of intensified soccer training, differing only by nutritional intervention, and
      identical pre-and post-training session testing. Each testing block will be separated by 28-d
      to allow for an adequate wash-out and recovery period, during which participants would resume
      their regular soccer activities

      Study Procedures:

      All tests and measurements will be performed within eight-weeks. Specifically, participants
      will attend 1 information session, two identical pre- and post- training/testing sessions and
      two identical soccer specific training camps.

      Information session:

      One week prior to the initial soccer specific training camp, participants will be informed of
      all tests and procedures that will take place and be familiarized with all testing protocols.

      Pre- and Post-training testing:

      All participants will be tested twice: on the day before (pre) and day following (post) the
      5-d soccer specific training camp. Specifically, Participants, will arrive at the University
      for pre- and post-training testing in the morning at the same time. Body composition
      measurements will be performed (e.g., standing/seated height, mass, % body fat) followed by
      fasted venous blood and saliva sampling. A standardized breakfast would then be provided
      followed by an adequate rest and digest period before performance testing (~1.5h).
      Performance testing would include a battery of soccer specific tests that cover, power
      (counter-movement jump, broad jump), speed (10m and 20m sprint), agility (modified 5-0-5) and
      aerobic capacity (beep-test). During both pre-and-post-testing sessions participants would
      consume the same standardised breakfast and perform the same tests in the same order for
      consistency amongst trials which would be repeated between the two testing blocks.

      Soccer training:

      The simulated 5-d soccer-specific training will be structured to mimic a heavy-volume,
      high-intensity training camp. Training sessions would occur at the same time each day in the
      evening for consistency. Drills/exercises will be administered by a certified technical
      soccer coach and knowledgeable training staff. Each session will began with a 15 min dynamic
      warm-up followed by 90 min of soccer-specific training, ending with a 15 min cool-down. The
      90 min of soccer-specific training will be performed at maximal effort and consist of
      agility, sprinting and plyometric exercises as well as ball-handling, small-sided games
      (rondo) and shooting. Following each training session rating of perceived exertion (RPE) will
      be measured as an indicator of internal load.

      Food/Drink supplement consumption:

      During the study, three servings of 160 g of 0% plain GY (~115 kcals, 17 g protein, ~11.5 g
      carbs, 0 fat), or 30 g of isoenergetic CHO (~115 kcal, 0.04 g protein, ~28.6 g carbs, 0 fat)
      will be provided to participants immediately following the training session, 1 h prior to
      bedtime, as well as one serving between breakfast and lunch on the subsequent day. The yogurt
      will be sweetened or flavored with a non-caloric vanilla flavouring to match the taste of the
      control supplement. The CHO control supplement group will be an isoenergetic dose of a
      maltodextrin-based semi-solid pudding. This product will be made from non-fat vanilla pudding
      powder (1 part), maltodextrin (4 parts) and water. This product has been designed to resemble
      the consistency and texture of Greek yogurt.

      Measurements

      Questionnaires: Participant Screening and Medical History, Training History, Food frequency
      Questionnaire (FFQ), sessional RPE.

      Anthropometric and body composition measurements: height, seated height, body mass and body
      fat percentage (%) using bioelectrical impedance analysis (BIA, InBody520; Biospace Co.,
      Ltd., Seoul, S. Korea).

      Somatic maturity: maturity offset (years from the age of peak height velocity) will be
      calculated based on height, seated height and weight measurements.

      Exercise performance: will be examined prior to, as well as following each training
      intervention week. These tests are common in soccer and athletes are familiar with them. To
      limit confounding exercise influence on both biochemical and performance parameters,
      participants will be asked to refrain from other activities outside those prescribed to them
      during the training sessions and 48h prior to the initial pre-assessment visit.

      Venous blood and saliva samples: will be collected on 4 separate occasions (24h prior and 24h
      following the last training session of each training intervention week). To control for
      circadian rhythm, the exercise session and related blood and saliva samples will be conducted
      at the same time of day. Saliva samples will be used to examine endocrine response. Venous
      blood samples will be used to examine inflammatory markers (cytokines - IL-6, IL-10 and
      TNF-α), c-reactive protein (CRP), IGF-I and indicators of muscle fatigue/damage (CK).
      Secondary measures may include irisin, oxidative stress (TBARS and ROS) and bone turnover by
      examining circulating markers of bone formation (PINP, Osteocalcin, BAP, OPG) and of bone
      resorption (CTX, TRAP, RANKL).
    

Intervention name(s): Greek Yogurt; Isoenergetic carbohydrate
Intervention type(s): Other; Other
Intervention description(s): Female competitive soccer players (11-16y) will consume 0% plain Greek yogurt immediately following the training session, 1 h prior to bedtime, as well as one serving between breakfast and lunch on the subsequent day.; Female competitive soccer players (11-16y) will consume an isoenergetic carbohydrate supplement immediately following the training session, 1 h prior to bedtime, as well as one serving between breakfast and lunch on the subsequent day.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Other
Keywords: Greek Yogurt; Adolescent Athletes