Acute, chronic, and detraining effects of dynamic stretching and tissue flossing on muscle function, sprint performance, balance, and proprioception, in soccer players with hamstring shortness: a three-arm parallel randomized controlled trial protocol.

OBJECTIVE: Hamstring shortness is prevalent among soccer players and is associated with an increased risk of muscle strain and performance deficits. Dynamic stretching and tissue flossing are two interventions used to address flexibility impairments; however, research has predominantly focused on their acute effects. A significant gap remains in understanding their isolated, individual chronic (≥2 weeks) and detraining effects on comprehensive athletic performance. Hence, this randomized controlled trial protocol aims to compare the acute, chronic, and detraining effects of dynamic stretching versus tissue flossing on muscle function, sprint performance, balance, and proprioception in soccer players with hamstring shortness.

METHODS: A three-arm, parallel randomized controlled trial will be conducted. A minimum of 57 male adolescent soccer players with clinically diagnosed hamstring shortness will be randomly assigned to a dynamic stretching group, a tissue flossing group, or a control group. The intervention groups will perform their respective protocols three times per week for six weeks. The outcomes include hamstring range of motion, muscle strength, and muscle power, 20-meter sprint time, dynamic balance, and knee joint proprioception. All outcomes will be assessed at four time points: baseline, immediately after the first session (acute), after six weeks of training (chronic), and after a three-week detraining period (9 weeks).

DISCUSSION: This trial will provide novel evidence on training- and detraining-related adaptations in response to two distinct intervention strategies. The findings are expected to clarify whether one modality offers superior immediate performance enhancement compared to chronic flexibility gains, and how well these effects are retained after detraining. The results will directly inform evidence-based recommendations for integrating these techniques into athletic training and injury prevention programs for soccer players.

CLINICAL TRIAL REGISTRATION: https://irct.ir/trial/87892, identifier: IRCT20251202068197N1.