Senior Honors Projects, 2010-2019

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Spring 2019

Document Type

Thesis

Degree Name

Bachelor of Science (BS)

Department

Department of Kinesiology

Advisor(s)

Michael J. Saunders

Abstract

PURPOSE:Muscle soreness levels and hydration status are important indicators of recovery from high intensity endurance exercise, and can be influenced by post-exercise nutrient intake. Chocolate milk has been reported to be an effective recovery beverage in adults, as it contains carbohydrate, protein, and water/electrolytes at levels that are appropriate for refueling, muscle repair, and rehydration. However, few studies have tested the efficacy of chocolate milk for post-exercise recovery in adolescents. METHODS:Eight competitive teenage cyclists (5 male, 3 female; 16.1 ±1.1 y; 174.0 ±10.7 cm; 138.4 ±5.6 lbs; 61.8 ±8.2 ml/kg/min) completed three experimental trials, in randomly counterbalanced order. Each trial consisted of a 90 min session of high-intensity cycling intervals, followed by the intake of two doses of a post exercise nutritional beverage. A different treatment beverage was consumed in each trial. Beverages were an artificially-flavored water placebo beverage (PL), a carbohydrate-electrolyte beverage (CHO), and chocolate milk (CM). Beverages were provided in double-blind fashion, and matched for fluid volume, and carbohydrate content (other than PL). Muscle soreness ratings were assessed (via a 100 mm visual analog scale) pre-exercise and 4 and 8 h post-exercise. Hydration status was measured via changes in body weight, assessed immediately after consuming the first beverage, and prior to consuming the second beverage (2 h later). Means and standard deviations were reported for each variable at each time-point. Changes in dependent measurements over time and between-treatments were assessed using magnitude-based inferences. RESULTS:Muscle soreness was generally increased 4 h post-exercise, and remained elevated 8 h post-exercise. Changes in soreness from pre-exercise to 4 h post-exercise were “likely” attenuated with CM versus CHO (89% likelihood of positive effect) and for CM versus PL (91% likelihood). Changes in soreness from pre-exercise to 8 h post-exercise were “likely” reduced with CM versus PL (87% likelihood), and also “likely” decreased for CHO versus PL (88% likelihood). Body weight “likely” decreased in the 2 h after beverage consumption, with no clear between-treatment effects. CONCLUSIONS:CM produced positive effects on muscle soreness in youth cyclists, in comparison to PL and CHO treatments. This supports prior findings in adults that CM is effective for post-exercise recovery. CM had similar effects on fluid retention (measured via changes in weight) versus PL and CHO beverages. Future studies of the effects of CM on post-exercise rehydration in adolescents should be conducted in which greater fluid losses from exercise are part of the methodology.

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