Resistance Exercise for Muscle Growth

Overseen By Andrew McKiel, MSc

Age: < 65

Sex: Any

Trial Phase: Academic

Sponsor: Brock University

Must not be taking: Muscle function drugs

Disqualifiers: Diabetes, Heart, Breathing, Seizures, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 4

60 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to understand how resistance exercise training (RET) affects muscle growth in children, adolescents, and adults. Researchers seek to determine if the amino acid leucine can indicate muscle protein synthesis (MPS) through a simple breath test. The study will also explore whether adding protein supplements can enhance muscle growth. This trial suits healthy individuals without recent injuries or chronic health issues that limit exercise, such as asthma or heart problems. Participants should not have taken medications affecting muscle function in the past year. As an unphased trial, this study offers a unique opportunity to contribute to foundational research on exercise and nutrition.

Will I have to stop taking my current medications?

The trial requires that participants have not taken any medications in the past year that may affect muscle function, so you may need to stop taking certain medications to participate.

What prior data suggests that resistance exercise training is safe for children and adolescents?

Research shows that resistance exercise training (RET) is generally safe for children and teens when they follow age-appropriate guidelines. Studies have found a low risk of injury for kids and teens engaging in resistance training. This finding is crucial for parents and guardians considering these programs for their children.

Another review highlighted that traditional strength training ranks among the safest types of resistance training. With proper supervision and a well-designed program, resistance training can be both effective and safe for young participants.

Additionally, resistance training has increased muscle mass and strength, offering significant benefits for growing children. While some uncertainty remains about the exact changes in children's muscles, the overall evidence supports its safety and benefits for muscle growth. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about resistance exercise training for muscle growth because it naturally stimulates muscle development without relying on pharmaceuticals. Unlike traditional treatments that might involve medication or surgery, this approach leverages the body's own ability to build muscle through physical activity. Additionally, when combined with protein supplementation, this method could enhance muscle recovery and growth by providing the necessary nutrients directly to the muscles. This combination of exercise and nutrition represents a holistic approach to muscle growth that could be more accessible and sustainable for many individuals.

What evidence suggests that resistance exercise training is effective for muscle growth in children and adolescents?

Research shows that resistance exercise training (RET) effectively strengthens and enlarges muscles. Studies have found a 98.2% chance that high-load resistance training can boost muscle strength. Regular resistance training improves muscle size, strength, and physical ability compared to inactivity. Although it was once believed that children only gained strength through nerve improvements, some research suggests they can also build muscle with the right training. Muscle growth occurs when the body creates more protein than it breaks down, and consuming protein-rich foods can aid this process. In this trial, one group will receive protein supplementation to support muscle growth. New methods now allow researchers to measure this muscle-building process in children without invasive tests. ^{4 6 7 8 9}

Who Is on the Research Team?

Bareket Falk, PhD

Principal Investigator

Brock University

Are You a Good Fit for This Trial?

This trial is for healthy children, adolescents, and adults who can safely perform resistance exercise without any injury that would prevent them from doing so. It's not suitable for those with injuries affecting their ability to engage in such physical activity.

Inclusion Criteria

I am in good health.

I have no injuries that stop me from doing strength training.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

1 visit (in-person)

Familiarization and Baseline Testing

Participants and guardians are informed about the study, consent is obtained, and baseline measurements and familiarization with exercises are conducted.

1 day

1 visit (in-person)

Experimental Sessions

Participants undergo resistance exercise training (RET) and rest sessions in a counterbalanced order, with breath samples collected to measure leucine retention.

2 days

2 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after the experimental sessions.

2-4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Resistance Exercise Training

Trial Overview The study investigates the effects of a single session of resistance exercise on muscle protein synthesis (MPS) in different age groups. It uses a non-invasive breath test to measure leucine retention as an indicator of MPS.

How Is the Trial Designed?

Group I: Protein supplementation Experimental Treatment 1 Intervention

Protein supplementation

Who Is Running the Clinical Trial?

Brock University

Lead Sponsor

Trials

41

Recruited

6,500+

University of Toronto

Collaborator

Trials

739

Recruited

1,125,000+

Published Research Related to This Trial

High intensity resistance training can effectively increase strength in preadolescents, with children showing similar percentage improvements in strength as adolescents, but with smaller absolute gains.

When properly supervised, resistance training poses a low risk of injury for preadolescents and does not negatively impact growth, body composition, or cardiorespiratory fitness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Resistance training during preadolescence. Issues and controversies. Blimkie, CJ.[2018]

Resistance training (RT) significantly reduces all-cause mortality and the incidence of cardiovascular disease while improving physical functioning in adults, based on an analysis of 11 systematic reviews involving over 382,000 participants.

Although adverse events were not consistently reported, serious adverse events related to RT were uncommon, suggesting that the benefits of resistance training outweigh the potential harms.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Resistance training and health in adults: an overview of systematic reviews. El-Kotob, R., Ponzano, M., Chaput, JP., et al.[2021]

Resistance training is a safe and effective method for improving muscle strength and aerobic endurance, particularly beneficial for healthy adults, the elderly, and patients with cardiac and pulmonary conditions.

Proper assessment and tailored exercise programs enhance the safety and long-term effectiveness of resistance training, contributing to better health outcomes and reduced risk factors for cardiovascular and metabolic diseases.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Resistance (strength) training in health promotion and rehabilitation]. Kostka, T.[2006]

A 16-week upper-body resistance training program combined with a self-efficacy intervention led to a 46% increase in muscle strength in COPD patients, compared to a 36% increase with health education alone, highlighting the efficacy of targeted resistance training.

Participants in the resistance training groups maintained 21-24% of their strength gains over 12 months of home maintenance, while those doing gentle chair exercises lost strength, indicating that resistance training is effective for long-term strength retention in COPD.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Upper-Body Resistance Training and Self-Efficacy Enhancement in COPD. Covey, MK., McAuley, E., Kapella, MC., et al.[2021]

Whole-body resistance training during hospitalization significantly improved lower-limb muscle strength and the 6-minute walking distance (6MWD) in patients with chronic obstructive pulmonary disease, with benefits observed both during and 30 days post-hospitalization.

Patients who participated in the training also reported better health-related quality of life (HRQOL) after hospitalization, while no changes in systemic inflammation levels were noted, indicating that resistance training can enhance recovery without increasing inflammation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impact of resistance training in chronic obstructive pulmonary disease patients during periods of acute exacerbation. Borges, RC., Carvalho, CR.[2022]

After 6 weeks of training, both moderate load (ML) and low-load blood flow restricted (BFR) resistance exercises improved strength and muscle size in young adults, with ML showing greater effectiveness.

Isometric peak torque and neuromuscular function did not significantly change in any group, suggesting that while strength and hypertrophy were achieved, further research is needed to understand the underlying neuromuscular adaptations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Neuromuscular Adaptations to Low-Load Blood Flow Restricted Resistance Training. Cook, SB., Scott, BR., Hayes, KL., et al.[2019]

In a study involving 64 young resistance-trained men over 8 weeks, resistance training with higher velocity loss thresholds (20% and 40%) led to significant increases in muscle hypertrophy, indicating that these thresholds can enhance muscle growth.

However, the highest threshold (40%) also resulted in negative neuromuscular adaptations, such as a slower rate of force development, suggesting that moderate velocity loss thresholds are preferable for maximizing strength gains while minimizing adverse effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Velocity Loss as a Critical Variable Determining the Adaptations to Strength Training. Pareja-Blanco, F., Alcazar, J., Sánchez-Valdepeñas, J., et al.[2021]

Progressive high-resistance exercise, especially with 8-12 repetitions to near failure, can significantly boost muscle protein synthesis for up to 72 hours, particularly when combined with approximately 20 grams of protein intake immediately after exercise.

Muscle growth is primarily regulated by the mTOR signaling pathway, which responds to various factors like IGF-1, mechanical signals, and amino acids, while its action is countered by myostatin signaling that inhibits growth.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Signal transduction pathways that regulate muscle growth. Wackerhage, H., Ratkevicius, A.[2021]

Ten weeks of resistance training can lead to significant health benefits, including an increase in lean muscle mass by 1.4 kg, a 7% boost in resting metabolic rate, and a reduction in fat weight by 1.8 kg.

Resistance training not only improves physical performance and cognitive abilities but also helps in managing type 2 diabetes and enhancing cardiovascular health by reducing visceral fat and improving cholesterol levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Resistance training is medicine: effects of strength training on health. Westcott, WL.[2022]

Regular weight-training can lead to positive adaptations in cardiovascular health, including decreased heart rate during maximal work and improved myocardial structure, which may help reduce the risk of cardiovascular disease.

Resistance training can also enhance aerobic capacity and improve metabolic health markers like glucose tolerance and insulin sensitivity, although caution is advised for individuals with existing cardiovascular conditions due to potential blood pressure responses.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Health- and performance-related potential of resistance training. Stone, MH., Fleck, SJ., Triplett, NT., et al.[2022]

Elastic band resistance exercise training (EB-RET) significantly increased integrated myofibrillar protein synthesis (iMyoPS) in young males but did not produce the same effect in older males, suggesting age-related differences in muscle adaptive responses.

Despite the lack of increase in iMyoPS in older males, EB-RET activated similar anabolic signaling pathways in both young and older participants, indicating that while the muscle's response may be impaired with age, the signaling mechanisms are still engaged.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Myofibrillar Protein Synthesis and Acute Intracellular Signaling with Elastic Band Resistance Exercise in Young and Older Men. Marshall, RN., Morgan, PT., Smeuninx, B., et al.[2023]

Resistance exercise (RE) significantly improves lower-limb muscular strength in cancer patients undergoing neoadjuvant or adjuvant therapy, with an average increase of 26.22 kg compared to controls.

RE also leads to increases in lean body mass (0.8 kg) and decreases in body fat (-1.3 kg), making it an effective strategy to combat muscle loss and improve overall health during cancer treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evaluation of resistance training to improve muscular strength and body composition in cancer patients undergoing neoadjuvant and adjuvant therapy: a meta-analysis. Padilha, CS., Marinello, PC., Galvão, DA., et al.[2022]

Resistance training (RT) significantly improves muscular strength in elderly cancer patients, with a strong effect size of 0.87 based on a review of 13 studies involving 717 participants.

However, RT does not significantly increase muscle hypertrophy, indicating that while strength gains are achievable, increases in muscle size may not occur in this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effects of resistance training on muscular strength and hypertrophy in elderly cancer patients: A systematic review and meta-analysis. Lee, J.[2022]

Citations

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Resistance Training Load Effects on Muscle Hypertrophy ... The results of the consistency models indicate that high-load resistance training has a probability of 98.2% to induce greater effects on muscle strength, also ...

2. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/27102172/

Effects of Resistance Training Frequency on Measures ... Results: Analysis using binary frequency as a predictor variable revealed a significant impact of training frequency on hypertrophy effect size (P = 0.002), ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S2095254623000601

The influence of resistance exercise training prescription ... Compared with a non-exercising control group, resistance training consistently improved muscle mass, strength and physical function. •. Resistance training ...

4. bjsm.bmj.com bjsm.bmj.com/content/57/18/1211

a systematic review and Bayesian network meta-analysis All RTxs were superior to CTRL for muscle strength and hypertrophy. Higher-load (>80% of single repetition maximum) prescriptions maximised strength gains.

5. frontiersin.org frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2022.949021/full

Resistance Training Variables for Optimization of Muscle ... This umbrella review aimed to analyze the different variables of resistance training and their effect on hypertrophy, and to provide practical recommendations.

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC3483033/

Resistance training among young athletes: safety, efficacy ... Current research findings indicate a relatively low risk of injury in children and adolescents who follow age-appropriate resistance training guidelines, which ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10099898/

Which resistance training is safest to practice? A systematic ... This systematic review showed that traditional strength training is the safest RT method, and strongman is the least safe regarding injuries.

8. ahajournals.org ahajournals.org/doi/10.1161/CIR.0000000000001189

Resistance Exercise Training in Individuals With and ... Resistance training is a safe and effective approach for improving cardiovascular health in adults with and without cardiovascular disease.

9. nature.com nature.com/articles/s41598-025-11076-w

Effects of resistance training and aerobic ... Resistance training increases muscle mass and elevates resting metabolic rate (RMR), which contributes to higher energy expenditure even at rest ...