Author(s): LINARDATOS, J., GARDY, S., CROSBY, K., SCHEEDE-BERGDAHL, C., CHURCHWARD-VENNE, T.A., JOSSE, A.R., GIBBS, J.C., Institution: MCGILL UNIVERSITY, Country: CANADA, Abstract-ID: 1692

INTRODUCTION:
Introduction: Bone stress injuries are pervasive in endurance athletes due to their elevated training and nutritional demands. High impact loading (i.e., jumping) is considered most effective at inducing bone adaptive responses. Post-exercise feeding of dietary protein and carbohydrates has also been shown to support bone health. However, robust bone-targeted interventions in athletes are lacking, and few randomized controlled trials (RCT) have evaluated the efficacy of a combined exercise and nutrition intervention on bone mineral density (BMD) as a primary endpoint in endurance athletes. Purpose: This pilot RCT will assess the feasibility and acceptability of a high-impact loading and post-exercise dietary supplementation intervention (Nutri-Impact) in competitive endurance athletes. The primary feasibility objectives are to determine: 1) study recruitment rates; 2) study retention rates; and 3) adherence to Nutri-Impact.
METHODS:
Methods: Eligible 18–35-year-old competitive endurance athletes (n=36) will be randomized to either the Nutri-Impact intervention or a waitlist control. The experimental design is an assessor-blind parallel group pilot RCT of 18-weeks. The Nutri-Impact group will participate in 5x/week, 10-min home-based high-impact loading sessions and consume a whey protein isolate protein (0.5g/kg body mass) and carbohydrate (1.5g/kg body mass) beverage post-exercise. The waitlist control group will receive the condensed intervention at the end of the 18-weeks. The primary objectives will assess feasibility. Exploratory analyses of between-group differences in changes in BMD, bone metabolism, body composition, muscle strength, and cardiorespiratory fitness will be conducted. Prior to this a pre-pilot/user testing phase was conducted wherein participants completed a condensed version of the Nutri-Impact intervention (2 sessions with a kinesiologist) over 3 weeks. Feasibility was examined using descriptive statistics. Exit interviews were analyzed using a directed content analysis guided by the APEASE criteria.
RESULTS:
Preliminary results: 5 participants (F=3) completed the pre-pilot phase. Participants had a meanSD age of 264 years, body mass of 5612 kg, and running mileage of 5313 km/week. Adherence to the prescribed exercises and supplement doses was 95% each, and participant retention across the 3 weeks was 100%. Directed content analysis revealed themes pertaining to the acceptability and practicality of the intervention, including overall satisfaction, perceived bone-strength benefits, and fluctuating motivation levels. Limitations of the intervention included schedule challenges, high volume of prescribed sessions, and minor supplement-related gastrointestinal discomfort.
CONCLUSION:
Significance: The results of the pre-pilot phase suggest feasibility and acceptability of the Nutri-Impact intervention. Qualitative results indicated strengths of the intervention and informed revisions needed prior to the start of the full-scale pilot RCT.