Comparison of Eccentric Exercise and Static Stretching on Muscle Flexibility

Background: Muscle flexibility is a fundamental physical quality for body development, daily life and sports activities, and also for maintaining muscle quality during aging. Limited flexibility leads to an increased prevalence of musculoskeletal injury in general population and longer return to sports activities. Among the existent strategies to increase muscle flexibility in sports training and physical rehabilitation, static stretching is commonly used by health and physical activity professionals. Its effectiveness in increasing flexibility has been widely demonstrated; however its effects on muscle strength and power remains controversial. Therefore, eccentric resistance exercise has been proposed as an effective intervention for increasing muscle flexibility through structural changes on muscle architecture (pennation angle and fascicle length) with the additional benefit of resistance training on muscle strength and power. Nonetheless, its unknown if the increase in muscle flexibility through eccentric resistance exercise could be similar to what has been previously demonstrated with static stretching.

NCT Number	NCT06469346
Lead Sponsor	Universidad de La Frontera
Conditions	Muscle Stretching Exercise, Range of Motion, Articular
Enrollment	42 participants
Start Date	2025-03-03
Primary Completion	2025-12-30 (estimated)
Study Completion	2026-09-30 (estimated)
Updated on ClinicalTrials.gov	2026-06-12