Core Strength Training, Anthropometry, and Postural Control in Youth Optimist Sailors

During upwind sailing ("hiking"), Optimist sailors suspend their torso over the windward gunwale, secured only by foot straps over their feet and ankles. This exertion demands sustained isometric contractions of the anterior core, rectus abdominis, quadriceps, and pelvic stabilisers. Inadequate core muscle endurance and deficient postural control compromise boat handling efficiency, accelerate central and peripheral fatigue, and elevate the risk of chronic lower back disorders in young athletes.

Participants will be randomly assigned (1:1 ratio) to either:

Experimental Group (CST+TST): Participating in a 12-week standardized CST program (3 sessions per week) in addition to regular Technical Sailing Training (TST).

Active Control Group (TST Alone): Participating exclusively in the standardized Technical Sailing Training (TST) program (3-4 hours per session, 3 sessions per week).

The CST program progresses systematically across four 2-week meso-blocks, transitioning from foundational bodyweight stability (Weeks 1-6) to advanced dynamic overload and multi-planar surface instability using small fitness tools (Weeks 7-12), such as fit balls, dumbbells, weight discs, resistance bands, Bosu balance trainers, TRX suspension straps, kettlebells, and ankle/wrist weights.

Inclusion criteria

• Active competitive youth Optimist class dinghy sailors aged between 8 and 15 years.
• Minimum of 2 consecutive years of continuous competitive sailing experience registered with a recognized national sailing federation or licensed sailing club.
• Regular participation in a minimum of 3 technical sailing sessions per week.
• Valid sports medical clearance certificate authorizing participation in competitive athletic training.
• Signed written informed consent provided by parent(s) or legal guardian(s), accompanied by written informed assent from the participant.

Exclusion criteria

• Acute or chronic musculoskeletal injuries affecting the spine, abdominal wall, lower limbs, or upper extremities within the preceding 6 months.
• Concurrent participation in structured external core or strength training programs outside the trial protocol during the preceding 3 months.
• Neurological, vestibular, or uncorrected visual impairments affecting balance, posturography, or postural control.
• Training adherence rate below 85% of total prescribed sessions over the 12-week interventional period.