Sequence-Dependent Performance Adaptations Following Myofascial Chain Training in Youth Football Players

Myofascial chains are interconnected lines of muscle and connective tissue that transmit force across body segments, contributing to movement efficiency, joint stability, and elastic energy storage. Among the chains described in fascial anatomy literature, the posterior chain is considered a primary contributor to explosive force production, while the spiral chain contributes to rotational control and dynamic balance. Despite growing interest in fascia-informed training approaches, no prior study has examined whether the sequence in which these chains are trained influences the magnitude, time-course, or persistence of performance adaptations in youth athletes.

To address this gap, the study employed a randomized crossover design. Participants were randomly allocated in a 1:1 ratio to one of two sequence groups: the Posterior Chain First Group (PCFG) or the Spiral Chain First Group (SCFG). Both groups continued their regular club training throughout the entire study period.

The intervention consisted of two consecutive six-week training blocks separated by a mid-test assessment. In the first block, each group performed their assigned myofascial chain protocol; following the crossover, groups switched protocols for the second block. Each training session lasted 30 minutes and was completed in addition to routine club practice. Outcomes were assessed at four time points - baseline, after the first block, after the second block, and at a four-week follow-up - to capture both the progression and persistence of adaptations.

The primary aim was to determine whether initiating training with the posterior chain versus the spiral chain produces differential adaptation trajectories, which may inform evidence-based sequencing decisions in youth athlete development programs.

IInclusion Criteria:

• Male, aged 15-16 years (U15-U16 category)
• Holding an active football player license and currently competing with a club team
• Regularly participating in routine club training sessions
• Free from any injury or musculoskeletal condition that could affect performance testing at the time of enrollment
• Parental/legal guardian consent and participant assent obtained

Exclusion criteria

• Presence of any musculoskeletal injury, recent surgery, or medical condition affecting lower-limb function within the past 6 months
• Inability to attend the required training sessions or assessment time points
• Unwillingness or inability of parents/legal guardians to provide informed consent