Clinical trial NCT06666127: The Effect of Peak Force At Long and Short Muscle Lengths and the Impact on Muscle Growth and Strength
Official title: Determining the Effect of Muscle Length At Peak Force on Resistance Training Induced Hypertrophy
Study type: INTERVENTIONAL
Overall status: ENROLLING_BY_INVITATION
Phase: NA
Conditions: Muscle Hypertrophy
Muscular Strength
Keywords: Muscle Hypertrophy
Muscular Strength
Long Muscle Lengths
Peak Force
Length-Tension Relationship
Range of Motion
Neuromechanical Matching
Resistance Training
Muscle Oxygenation
Lead sponsor: University of British Columbia
Sponsor class: OTHER
First posted: 2024-10-30
Enrollment: 20
Sex: ALL
Minimum age (years): 19
Maximum age (years): 30
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Within-Subject Design: Each participant will have the left arm and leg as well as the right arm and leg randomly assigned to the LONG or SHORT condition. Each participant will perform both conditions, exclusively for the left or right sided limbs. This helps to control for genetics, nutrition, recovery, stress management and training history as each participant acts as a self-control group as well as both experimental conditions.
Primary purpose: OTHER

Brief summary: The goal of this clinical trial is to learn the effect of applying peak force/resistance to skeletal muscles during resistance exercise training in young and healthy adults. Participants will undergo two types of resistance training conditions that are randomly assigned to the left arm and leg and the right arm and leg. The LONG condition refers to Prime Fitness machines set to setting number '3' which applies peak force at a long muscle length. The SHORT condition refers to Prime Fitness machines set to setting number '2' which applies peak force at a short muscle length.

The main questions the trial aims to answer are:

1. Does applying peak force at a longer or shorter muscle length during resistance exercise training result in greater muscle growth?
2. Does applying peak force at a longer or shorter muscle length during resistance exercise training result in greater muscle growth?

We hypothesize that:

1. LONG will induce greater hypertrophy compared to SHORT conditions
2. LONG will result in greater increases in 1RM strength compared to SHORT
3. LONG and SHORT training will result in angle specific increases in isokinetic strength
4. Muscle oxygenation will decline to a greater degree during LONG compared to SHORT exercise and this will be maintained between weeks 1 and 12 of training

The investigators will compare the change in muscle volume and muscular strength between the LONG and SHORT training conditions, which each participant will have the left arm and leg as well as the right arm and leg randomly assigned to either exclusively LONG or SHORT conditions.

Participants will:

* Resistance train the left and right arm and leg with two separate conditions; LONG and SHORT for 12 weeks, with the first and last weeks dedicated to only strength testing (Isotonic and Isokinetic) and measuring muscle volume via magnetic resonance imaging (MRI)
* Visit the gym for resistance training 2 times per week
* Visit the UBC MRI Research Facility in weeks 1 and 12 for MRI of muscle volume

Detailed description: Statistical Analysis:

Null Hypothesis Significance Testing (NHST) will be used to measure differences in hypertrophy, differences in 1RM strength, Isokinetic strength and muscle oxygenation between LONG and SHORT conditions.

It is anticipated that this study will require at least 20 participants to be screened and registered into the trial. Data will be analyzed on the basis that all participants will be included in the analysis. Participants who drop out (withdraw from treatment) will be followed up with to collect all available data and will not be replaced. Missing data will be assumed missing at random.

Sample Size Calculation:

Based on the effect size reported by Maeo et al. (2023) for difference in triceps brachia long head hypertrophy between training performed in the lengthened compared to shortened position using a within participant design, (d=0.61) a sample size of 20 participants was calculated to achieve an a priori power of 90%.

Eligibility criteria: Inclusion Criteria:

1. Any sex
2. Able to understand and communicate in English
3. 19-30 years of age
4. All "No" answers on the CSEP Get Active questionnaire or doctors' approval to participate
5. Untrained participants: no structured resistance training over the past 12-months (i.e. \> 2 hours per week of structured/periodized training)

Exclusion Criteria:

1. BMI lower than 18 or greater than 30
2. Difficulty to understand and communicate in English
3. Current use of cigarettes or other nicotine devices
4. Any major uncontrolled cardiovascular, muscular, metabolic, and/or neurological disorders
5. Any medical condition impacting the ability to participate in maximal exercise
6. Type one or type two diabetes
7. Diagnosis of cancer or undergoing cancer treatment in the past 12 months
8. Drug therapy with any drugs that alter skeletal muscle metabolism (i.e., Metformin, Benzodiazepines)
9. Omega-3 (EPA, DHA, fish oil) supplementation within the previous 6 weeks
10. Implants containing ferrous metal
11. Surgery or tattoos (including tattooed eyeliner) in the last 6 weeks
12. Pregnancy

Primary outcomes:
measure: Muscle Volume
timeFrame: From enrolment to the end of the intervention at 12 weeks
Secondary outcomes:
measure: Isotonic Strength testing
timeFrame: Initial testing in week 1 and final testing in week 12
measure: Isokinetic Strength Testing
timeFrame: Initial testing in week 1 and final testing in week 12
measure: Muscle Oxygenation
timeFrame: Week 2 and week 11.
Other outcomes:
measure: Visual Analog Scale of Perceived Rating of Muscular Discomfort
timeFrame: From week 2 to week 4 and week 11 only.
Locations:
city: Vancouver
country: Canada
facility: University of British Columbia
state: British Columbia
Study officials:
affiliation: University of British Columbia, School of Kinesiology
name: Dr. Cameron Mitchell
role: PRINCIPAL_INVESTIGATOR
References:
citation: Maeo S, Wu Y, Huang M, Sakurai H, Kusagawa Y, Sugiyama T, Kanehisa H, Isaka T. Triceps brachii hypertrophy is substantially greater after elbow extension training performed in the overhead versus neutral arm position. Eur J Sport Sci. 2023 Jul;23(7):1240-1250. doi: 10.1080/17461391.2022.2100279. Epub 2022 Aug 11.