Purpose and hypothesis: The purpose of this thesis is to compare the effects of HVRT and CR
supplementation to HVRT and placebo in healthy aging males. It is hypothesized that HVRT and
CR supplementation will increase muscle mass, strength, power and tasks of functionality
compared to HVRT and placebo.
Participants: An a priori power analysis (G*Power v. 3.1.5.1) indicated that 34 participants
are required. This is based on a moderate effect size (Cohen's d = 0.25), an alpha level of
.05, a ß-value of 0.8 for a repeated measures, within-between analysis of variance (ANOVA)
design. Males (≥ 50 years) who are not engaged in resistance training for ≥ 6 weeks prior to
the start of the study will be recruited. Participants will be informed of the risks and
purposes of the study before written consent is obtained. The study will be approved by the
Research Ethics Board at the University of Regina.
Methods and Research Design: The study will be a double-blind, repeated measures design.
Participants will be randomized on a 1:1 basis to one of two groups: HVRT and CR or HVRT and
placebo. The CR dosage will be 0.1g/kg/day as this dosage is effective for increasing muscle
mass in aging males without resulting in adverse effects. On training days, participants will
consume their supplement immediately after each training session mixed in water, juice or
milk as post-exercise CR ingestion enhances its uptake into muscle and promotes increased
muscle mass.
High-velocity Resistance Training Program: Participants will perform 3 sets of repetitions at
80% baseline 1-repetition maximum (1-RM) for the leg press, leg extension, leg curl, chest
press, biceps curl, and triceps extension 2 times per week, for 8 weeks. Participants will
perform the concentric phase of each muscle contraction as quickly as possible and will take
2 seconds to perform the eccentric phase.
Primary Dependent Variables
Muscle thickness: Muscle thickness will be assessed by B-mode ultrasound (LOGIQ e, GE
Medical Systems) on knee flexors, knee extensors, elbow flexors, and elbow extensors in
the Aging Muscle and Bone Health Laboratory, University of Regina.
Muscle strength: Leg press and chest press strength will be assessed using a 1-RM
testing procedure in the Aging Muscle and Bone Health Laboratory, University of Regina.
Muscle power: Torque (Nm) and power (watts) will be measured for the knee flexors and
extensors using an isokinetic dynamometer (Biodex System 3, Biodex Medical Systems
Inc.).
Functionality tests: Dynamic balance will be measured as the time taken to perform
backwards tandem walking over a distance of 6m on a 10cm-wide board that is raised about
4cm off the ground. Walking speed will be assessed by the time needed to walk an 80 m
course.
Statistical Analyses: A 2 (group: CR vs. placebo) x 2 (time: pre- vs. post-training) repeated
measures ANOVA will be used to determine differences between groups over time for the
dependent variables. A one-factor ANOVA will be used to assess baseline characteristics and
total training volume between groups. Significance will be set at an alpha level of 0.05 and
all results will be expressed as means ± standard deviation. The magnitude of the difference
between significant means will be determined by eta squared (η2). Statistical analyses will
be performed using IBM SPSS Statistics, v. 24.
