Effects of Exercise Frequency on Muscle Size and Strength in Healthy, Untrained Young Adults

Cameron Mitchell40 enrolled

Overview

Resistance training (RT) is important for building and maintaining healthy muscles. An exercise frequency called "exercise snacks" involves short bursts of exercise throughout the day (\~5-15 minutes), but no studies have examined a gym-based RT exercise snack program. The invetigators will randomize 40 participants into one of two groups for 10 weeks: the control group will complete two full-body workouts per week (standard-frequency) and the experimental group will complete 10 mini-workouts per week (high-frequency). Muscle hypertrophy (size) and strength will be measured before and after the exercise program to determine if the participants had the same or different results.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Healthy Adult Male and Female Volunteers

Interventions

Two sessions per week of resistance trainingBEHAVIORAL

Full-body resistance training consisting of 10 sets per week for all major muscle groups with progressive overload in a gym-based setting. Training at an exercise frequency of two sessions per week (around 45-60 minutes per session).

Eligibility

Sex: ALLMin age: 19 YearsMax age: 39 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Can fluently read and write in English * Lives, works, and/or studies at or near the Gateway Health Building (where all study visits will occur) * Willing and able to commit to 2 or 10 in-person training sessions per week for 10 continuous weeks, as well as one week of testing before the training period and one week of testing after the training period * Has continuous access to smartphone or other device that they can use to access the Technogym app * Answers "No" to all questions on the Canadian Society for Exercise Physiology - Get Active Questonnaire (CSEP-GAQ) or has their doctor's approval to participate Exclusion Criteria: * Any major uncontrolled cardiovascular, muscular, metabolic, and/or neurological disorders * Lung disease, kidney disease, or liver disease * Current diagnosis of type 1 diabetes, type 2 diabetes, or cancer * Medical conditions that limit their ability to undertake strenuous physical activity * Regular use of any medications that may affect muscle physiology or body composition (i.e. benzodiazepines, hormone replacement therapy, ADHD medication, Metformin, Ozempic) * Participated in consistent resistance exercise training more than twice per month in the previous 12 months * Participated in consistent moderate or vigorous aerobic training more than twice per week in the previous 12 months, or planning to start consistent training in the next few months * Significant gain or loss of body mass in the past 6 months (greater than 2 kg) * Current smoker (including but not limited to cigarettes, e-cigarettes, or vaping) * Body Mass Index of less than 18 kg/m2 or over 30 kg/m2 * Pregnancy or breastfeeding * Currently taking blood thinners * Allergic to Tegaderm medical tape (used with the activity trackers)

Outcomes

Primary Outcomes

Change in Total Body Skeletal Muscle Mass Measured using the D3-Creatine Dilution Method

Time frame: From enrolment (Week 1) to the end of the exercise training phase (Week 12)

Secondary Outcomes

Change in Total Body Muscle Size Measured as Cross-sectional Area using Muscle Ultrasound Imaging

Muscle ultrasound imaging will be conducted on one randomly selected side of the body (left or right) for each participant. Scans will be analyzed to determine the cross-sectional area of the following seven muscles: rectus femoris, vastus lateralis, biceps brachii, pectoralis major, latissimus dorsi, triceps brachii, and hamstring group (semitendinosus, semimembranosus, and long head of biceps femoris).

Time frame: From enrolment (Week 1) to the end of the exercise training phase (Week 12)

Change in Muscle Strength Measured as the One-Repetition Maximum of Back Squat and Bench Press

One-repetition maximums will be measured using a Quantum Synchro Smith Machine.

Time frame: From enrolment (Week 1) to the end of the exercise training phase (Week 12)

Change in Skeletal Muscle Power Measured at Various Relative Loads for Back Squat and Bench Press

At enrolment (Week 1), power will be measured using a Quantum Synchro Smith Machine at 40%, 50%, 60%, 70%, and 80% of the participant's initial one-repetition maximum (1RM) for back squat and bench press. At the end of the exercise training phase (Week 12), if a participant's 1RM has increased by less than 25%, power will be measured at the same relative loads. If a participant's 1RM has increased by 25-49%, power will be measured at 50%, 60%, 70%, 80%, and 90% of the participant's initial 1RM (in this case, 90% of the participant's initial 1RM would not exceed 80% of the participant's post-training 1RM). If a participant's 1RM has increased by 50% or greater, power will be measured at 60%, 70%, 80%, 90%, and 100% of the participant's initial 1RM (in this case, 100% of the participant's initial 1RM would not exceed 80% of the participant's post-training 1RM).

Time frame: From enrolment (Week 1) to the end of the exercise training phase (Week 12)

Participant Satisfaction with the Exercise Program

Participant satisfaction with the exercise program will be measured using a modified Intrinsic Motivation Inventory (subscales of "Interest/Enjoyment", "Percieved Competence", "Effort/Importance", and "Value/Usefullness").

Time frame: At the end of the exercise training phase (Week 12)

Effects of Exercise Frequency on Muscle Size and Strength in Healthy, Untrained Young Adults

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts