Eccentric Resistance Exercise for Skeletal Muscle Response

Overseen By Stephen M Cornish, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: University of Manitoba

Disqualifiers: Health conditions affecting exercise

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

Compensation: Varies

Number of Visits: 3

12 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to understand how thigh muscles react to eccentric resistance exercise, which involves lengthening the muscle while it contracts. Researchers measure certain biomarkers in the muscle to assess how this exercise affects muscle inflammation. Individuals aged 18-35 who are healthy and engage in regular moderate to vigorous exercise may be suitable for this study.

As an unphased study, this trial offers a unique opportunity to contribute to the scientific understanding of muscle health and exercise.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

What prior data suggests that this exercise protocol is safe?

Research has shown that eccentric resistance exercise is generally safe. However, incorrect execution can lead to muscle soreness and even muscle damage. This exercise involves stretching the muscle while it is working, which can challenge the muscles. Some studies have found that after just one session, participants might feel more tired or experience temporary muscle weakness. Despite these effects, eccentric exercise is known to improve strength and some heart health markers over time. Following the exercise instructions carefully can reduce potential discomfort. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about eccentric resistance exercise for muscle response because it focuses on the lengthening phase of muscle contraction, which is different from traditional resistance exercises that emphasize muscle shortening. This method uses an isokinetic dynamometer to perform 300 eccentric knee extensions, potentially offering a more efficient way to build muscle strength and mass. Unlike typical resistance exercises that can lead to quicker fatigue, eccentric training might allow for greater muscle overload with less energy expenditure, making it a promising alternative for improving muscle health and rehabilitation outcomes.

What evidence suggests that eccentric resistance-exercise is effective for skeletal muscle response?

Research shows that eccentric resistance exercise, which participants in this trial will perform, can increase muscle strength and function. This type of exercise has improved strength in various groups, including stroke patients. Eccentric exercise involves muscles lengthening as they contract, leading to better strength gains compared to traditional exercises. Studies have found that it can also benefit heart health. Overall, eccentric resistance training effectively boosts muscle performance and strength. ^{1 4 5 6 7}

Who Is on the Research Team?

Stephen M Cornish, PhD

Principal Investigator

University of Manitoba

Are You a Good Fit for This Trial?

This trial is for individuals who are interested in participating in a study to understand how their thigh muscles respond after doing specific resistance exercises that involve muscle lengthening during contraction. The details about who can join or reasons why someone might not be able to participate are not provided.

Inclusion Criteria

Healthy

Recreationally active (≥ 150 minutes of moderate to vigorous physical activity per week for at least the past three months)

Exclusion Criteria

Answered 'yes' to the Get Active Questionnaire which screens for health conditions that may affect exercise ability

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1 week

Pre-Exercise Rest

Participants rest for 30 minutes before exercise and provide a baseline muscle biopsy

30 minutes

1 visit (in-person)

Exercise

Participants perform 300 repetitions of maximal isokinetic eccentric knee extensions

1 session

1 visit (in-person)

Post-Exercise Rest

Participants rest for 3 hours post-exercise before a second muscle biopsy is taken

3 hours

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after the exercise intervention

1 week

What Are the Treatments Tested in This Trial?

Interventions

• Eccentric resistance-exercise

Trial Overview

The study is testing the body's response, specifically looking at inflammation markers called myokines, released by thigh muscles after a session of eccentric resistance-exercise using specialized gym equipment known as an isokinetic dynamometer.

How Is the Trial Designed?

Group I: Eccentric Exercise Experimental Treatment 1 Intervention

300 repetitions of isokinetic dynamometer eccentric knee extensions.

Who Is Running the Clinical Trial?

University of Manitoba

Lead Sponsor

Trials

628

Recruited

209,000+

Published Research Related to This Trial

Unilateral eccentric-only training significantly increased eccentric strength in both the trained limb (29% increase) and the untrained limb (17% increase) after eight weeks of training, indicating a cross-training effect.

The gains in eccentric strength were maintained even after eight weeks of detraining, suggesting that this type of training can lead to lasting improvements in muscle strength.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of eccentric-only resistance training and detraining. Housh, TJ., Housh, DJ., Weir, JP., et al.[2004]

Isokinetic dynamometers, like the Biodex, can effectively measure increased muscle stiffness after eccentric exercises, as shown by a 52% increase in passive resistive torque (PRT) in a study of nine young women.

This method provides a promising way to assess group changes in muscle stiffness due to eccentric exercise, but further research is needed to confirm its reliability for individual assessments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Passive resistive torque of the plantar flexors following eccentric loading as assessed by isokinetic dynamometry. Porter, MM., Andersson, M., Hellström, U., et al.[2013]

In a study involving 22 young men, both isoload (IL) and isokinetic (IK) eccentric exercises resulted in similar levels of muscle damage and neuromuscular function changes, indicating that the type of resistance exercise may not significantly affect acute muscle responses.

Both exercise modalities led to comparable decreases in voluntary isometric peak torque, muscle soreness, and creatine kinase activity, suggesting that either method can be effectively used without major differences in immediate muscle recovery outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Neuromuscular Changes and Damage after Isoload versus Isokinetic Eccentric Exercise. Doguet, V., Nosaka, K., Plautard, M., et al.[2018]

Researchers in resistance training studies often lack clear guidance and motivation for thorough adverse event (AE) reporting, which can lead to inconsistent practices.

There is a need for exercise-specific guidelines for AE reporting, as current standards are perceived as not applicable to exercise trials, highlighting the importance of tailored strategies to improve reporting consistency.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Researchers' perspectives on adverse event reporting in resistance training trials: a qualitative study. El-Kotob, R., Pagcanlungan, JR., Craven, BC., et al.[2022]

In a study involving 15 resistance-trained men, both concentric (CON) and eccentric (ECC) exercises led to similar losses in isometric strength, indicating that both types of exercise can impact muscle strength.

However, ECC exercise resulted in a greater loss of force steadiness compared to CON, suggesting that ECC exercises may impair the ability to maintain a steady force output even in trained individuals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Acute effects of concentric vs. eccentric exercise on force steadiness and electromyographic responses of the forearm flexors. Ye, X., Beck, TW., Wages, NP.[2018]

Eccentric exercise, which involves lengthening muscles under tension, has been shown to improve both concentric (shortening) and eccentric strength, although the effects can vary and are not always velocity-specific.

Isokinetic dynamometers, which measure muscle strength during eccentric actions, may lead to less muscle soreness compared to other exercise types, suggesting potential benefits for rehabilitation and injury prevention, but more research is needed in clinical applications.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Isokinetic eccentric exercise. Kellis, E., Baltzopoulos, V.[2018]

The study demonstrated that the Exerbotics eSQ provides moderate-to-high reliability for measuring peak and mean force during maximal concentric and eccentric squats in 17 resistance-trained men, indicating it is a dependable tool for performance assessment.

Test-retest reliability statistics showed no significant differences between trials, with intraclass correlation coefficients ranging from 0.696 to 0.804, suggesting consistent results across multiple testing sessions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Consistency of peak and mean concentric and eccentric force using a novel squat testing device. Stock, MS., Luera, MJ.[2022]

The Cybex 6000 isokinetic dynamometer demonstrated high reliability in measuring knee muscle performance, particularly showing peak torque with an interclass correlation coefficient (ICC) ranging from 0.82 to 0.91 across 30 subjects with no prior knee injuries.

Testing at a speed of 120 degrees s-1 yielded better reliability scores for all measured variables, indicating that this dynamometer is effective for both concentric and eccentric muscle performance assessments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Eccentric and concentric isokinetic knee flexion and extension: a reliability study using the Cybex 6000 dynamometer. Li, RC., Wu, Y., Maffulli, N., et al.[2022]

A novel eccentric (ECC) overload flywheel resistance exercise program significantly improved muscle power and function in chronic stroke patients, with peak power increasing by 34% in the affected leg after 8 weeks of training.

Participants also showed improvements in balance, gait, and overall functional performance, as evidenced by better scores on tests like the Berg Balance Scale and Timed-Up-and-Go, indicating that this exercise method is both effective and safe for stroke rehabilitation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Chronic stroke patients show early and robust improvements in muscle and functional performance in response to eccentric-overload flywheel resistance training: a pilot study. Fernandez-Gonzalo, R., Nissemark, C., Åslund, B., et al.[2018]

In a 9-week study involving 31 healthy subjects, isoload (IL) eccentric resistance training significantly improved quadriceps strength and muscle structure compared to isokinetic (IK) training, with increases in eccentric strength at short muscle lengths by 20% and muscle thickness by 10%.

The study suggests that the greater torque and angular velocities achieved during IL training are key factors driving these neuromuscular adaptations, highlighting the potential of IL training for optimizing resistance training and rehabilitation programs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Neuromuscular adaptations to isoload versus isokinetic eccentric resistance training. Guilhem, G., Cornu, C., Maffiuletti, NA., et al.[2016]

A study involving 22 institutionalized elders showed that high-intensity resistance training (80% of 1-repetition maximum) significantly improved knee extensor strength, endurance, and functional performance compared to low-moderate intensity training (40%) and a placebo group.

High-intensity training not only led to greater strength gains but also resulted in significant improvements in functional activities like stair climbing and walking distance, indicating that higher intensity training is both safe and more effective for enhancing physical function in frail older adults.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Physiological and functional responses to low-moderate versus high-intensity progressive resistance training in frail elders. Seynnes, O., Fiatarone Singh, MA., Hue, O., et al.[2022]

Citations

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Eccentric Resistance Exercise for Skeletal Muscle Response

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Eccentric strength training for the shoulder shows significant improvements in muscle strength and muscle architecture, without decreasing the shoulder ...

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Eccentric exercise is effective for improving strength and some markers of cardiovascular health compared to traditional exercise modalities.

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sportsmedicine-open.springeropen.com/articles/10.1186/s40798-025-00887-w

Eccentric-Only Versus Concentric-Only Isokinetic Strength ...

A meta-analysis of 11 studies with 20 comparisons did not show statistically significantly different effects between eccentric and concentric ...

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mdpi.com/2076-3417/13/13/7969

Eccentric Resistance Training: A Methodological Proposal ...

This review presents a methodological proposal for classifying eccentric exercises based on complexity, objectives, methods, and intensity.

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Effects of once- versus twice-weekly eccentric resistance ...

One weekly submaximal eccentric resistance training session over 12 weeks elicits similar improvements in neuromuscular function compared to the currently ...

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Symptomatic and Functional Responses to Concentric- ...

Our results indicated more pronounced functional deficits occurred after a single bout of ECC isotonic exercise than with a CON-ECC isokinetic exercise protocol ...