This study investigates whether 8 weeks of post-training whey protein supplementation (30 g/day) affects serum mineral concentrations (calcium, phosphorus, magnesium, and iron) in elite endurance and power athletes during structured training.

This is a 10-week non-randomized, open-label intervention study involving elite male track-and-field athletes aged 18-26 years. Participants are allocated into a whey protein supplementation group or a control group based on convenience allocation. The intervention consists of daily intake of 30 g whey protein following training sessions over 8 weeks. Blood samples are collected at baseline and post-intervention to assess serum calcium, phosphorus, magnesium, and iron levels. The study aims to differentiate supplementation effects from training-induced physiological changes.

Inclusion Criteria:

• Male elite track-and-field athletes
• Age 18-30 years
• Engaged in structured training program
• No supplement use in past 3 months

Exclusion Criteria:

• Use of nutritional or mineral supplements
• Metabolic or musculoskeletal disorders
• Acute injury affecting performance
• Use of ergogenic aids (e.g., creatine, anabolic agents)