Creatine Timing and Resistance Training Adaptations.
Condition: Healthy
Study type: Interventional

Summary: 
      Emerging evidence suggests that the timing of creatine supplementation may be an important
      regulator of muscle growth and strength. It is unclear whether creatine ingested before or
      after resistance training is more beneficial. A limitation of previous research is the use of
      a between subject design. A between subject design is associated with several potential
      confounders (habitual diet, genetics, activities of daily living, etc.) that may have masked
      the true effect. The purpose of this study is to examine the effect of creatine timing
      (creatine before vs. creatine after) using a randomized, double blind, repeated measures,
      within-subject design. Participants will resistance train their left arm and left leg one day
      and their right arm and right leg the next day. Participants will supplement with creatine
      BEFORE one of the training days (randomized to either left or right side) and on the opposite
      training day (opposite side of the body to the previous training day) supplement with
      creatine AFTER training. Having the same person in both conditions will control for genetics,
      habitual diet, other daily activities, and so on, that may have confounded previous research.
      Muscle mass and strength changes will be measured in each limb prior to and following 8 weeks
      of training to determine whether creatine timing influenced muscle growth.

      Research Question: To determine whether creatine supplementation timing (i.e., before versus
      after training) effects 8 weeks of resistance training adaptations (i.e., muscle growth and
      strength changes).
    

Detailed description: 
      Emerging evidence suggests that the timing of creatine supplementation may be an important
      regulator of muscle growth and strength. It is unclear whether creatine ingested before or
      after resistance training is more beneficial. A limitation of previous research is the use of
      a between subject design. A between subject design is associated with several potential
      confounders (habitual diet, genetics, activities of daily living, etc.) that may have masked
      the true effect. The purpose of this study is to examine the effect of creatine timing
      (creatine before vs. creatine after) using a randomized, double blind, repeated measures,
      within-subject design. Participants will resistance train their left arm and left leg one day
      and their right arm and right leg the next day. Participants will supplement with creatine
      BEFORE one of the training days (randomized to either left or right side) and on the opposite
      training day (opposite side of the body to the previous training day) supplement with
      creatine AFTER training. Having the same person in both conditions will control for genetics,
      habitual diet, other daily activities, and so on, that may have confounded previous research.
      Muscle mass and strength changes will be measured in each limb prior to and following 8 weeks
      of training to determine whether creatine timing influenced muscle growth.

      Methods:

      Day 1 - A 3-day dietary record (to determine typical energy intake and macronutrient
      breakdown for participant characteristics), anthropometric testing (height and weight), age,
      muscle thickness (via ultrasound for elbow flexors and leg extensors), and bicep curl and leg
      extension 1-repetition maximal strength will be determined. In addition, strength training
      experience and hand dominance will be determined via standardized questionnaires. Muscle
      thickness of the elbow flexors and leg extensors will be measured before and after the 8
      weeks training period using B-mode ultrasound (LOGIQ e BTO8, GE Healthcare, Milwaukee,
      Wisconsin, USA). Bicep curl and leg extension maximal strength will be assessed on each limb
      using a 1-repetition maximum (1-RM) standard testing procedure. Briefly, following 5 minutes
      of cycling on a stationary cycle ergometer, participants will perform 2 warm-up sets (to
      reduce the risk of injury) in the following order: 1 set of 10 repetitions using a weight
      determined by each subject to be comfortable and 1 set of 5 repetitions using increased
      weight. Two minutes after the warm-up sets, weight will be progressively increased for each
      subsequent 1-repetition maximum attempt with a 2-min rest interval. The 1-rep max will be
      reached in 4-6 sets, excluding the 2 warm-up sets. All exercise testing will be superivsed by
      a a trained research assistant or by a Canadian Society for Exericse Physiology certified
      exercise physiologist.

      Next 8 Weeks (Resistance Training Program):

      The Resistance Training will include 3 to 6 sets (progressing overtime; starting at 3 sets
      and increasing 1 set per week until a maximum of 6 sets) of 80% of 1 repetition maximum with
      a 3 second eccentric phase (i.e., 1-2 seconds up and 3 seconds down) until failure (unable to
      complete another repetition or form failure). Each participant will complete 3 training
      sessions per week per side (total of 6 sessions per week). Prior to each training session,
      but after the supplement had been consumed, each participant will perform a 5-min stationary
      cycling warm-up at a self-selected intensity. Resistance exercises will include bicep curls
      and leg extensions. These two exercises were selected because they are safe and easy to learn
      and include large upper body and lower body musculature that are known to respond to
      resistance training. Participants will maintain daily training logs that include the weight,
      number of sets, and number of repetitions.

      Supplementation Protocol:

      Participants will supplement with creatine on one of the training days (either when they are
      training their left or right side) BEFORE training in a dose previous shown to enhance
      training adaptations (0.1 grams of creatine per kilogram of body weight before training and a
      placebo - cornstarch maltodextrin after training). When the participants trains their
      opposite side of the body they will supplement with creatine AFTER training (0.1 grams per
      kilogram of placebo before and 0.1 grams per kilogram of creatine after). The placebo will be
      identical in color, texture, tast, and appearance. The purpose of the placebo is so the
      participants will not know which day they are receiving creatine before training and which
      day they are receiving creatine after training. The creatine is research grade and has been
      independtly tested and will be provided free of charge. Any adverse events related to the
      exercise or the supplement will be recorded.

      Post Testing:

      Following the 8 weeks of training. Participants will complete the baseline testing (Day 1)
      protocols to determine strength and muscle thickness changes in each limb.
    

Intervention name(s): Creatine
Intervention type(s): Dietary Supplement
Intervention description(s): Participants will resistance train their left arm and left leg one day and their right arm and right leg the next day. Participants will supplement with creatine BEFORE one of the training days (randomized to either left or right side) and on the opposite training day (opposite side of the body to the previous training day) supplement with creatine AFTER training. Having the same person in both conditions will control for genetics, habitual diet, other daily activities, and so on, that may have confounded previous research. Muscle mass and strength changes will be measured in each limb prior to and following 8 weeks of training to determine whether creatine timing influenced muscle growth.
Research Question: To determine whether creatine supplementation timing (i.e., before versus after training) effects 8 weeks of resistance training adaptations (i.e., muscle growth and strength changes).
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: creatine, hypertrophy, strength