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Date of Graduation
5-14-2026
Semester of Graduation
Spring
Degree Name
Master of Science (MS)
Department
Department of Kinesiology
First Advisor
Michael Saunders
Second Advisor
Nicholas Luden
Third Advisor
Andrew D'Lugos
Abstract
Purpose: This study examined the effects of a sodium bicarbonate hydrogel (SBH) on mountain bike (MTB) performance and gastrointestinal symptoms (GIS) in comparison to a traditional sodium bicarbonate supplement (SB) and placebo (PL). Methods: 16 subjects completed a preliminary trial followed by 3 experimental trials. Each trial began with consumption of 0.3 g/kg of SB, SBH, or PL, each with 40 g of carbohydrates 90 min prior to exercise. The exercise protocol consisted of a 6-min warm up followed by six 60 s intervals on a stationary bike at 120% of Wmax separated by 90 s active recovery at 50% Wmax. Following the intervals, subjects completed two laps on an MTB time trial (TT) course at maximal effort. Blood lactate was measured prior to treatment supplementation (PRTR), 90 min post-treatment supplementation (POTR), immediately following the intervals (POINT), and following the TT (POTT). GIS were recorded at PRTR, POTR, mid-interval (MID), POINT, and POTT timepoints, and RPE was measured halfway through intervals (EARLY), at the end of intervals (LATE), and following the time trial (TT). Repeated-measures ANOVAs were used to assess the effects of treatment and time (where appropriate) on lactate, RPE and performance. Wilcoxon Signed Ranks tests were used to determine treatment and time effects on GIS. An alpha level of 0.05 was used to determine statistical significance. Results: There was a main effect of time on lactate concentrations, with significantly higher values at POINT and POTT timepoints compared to PRTR/POTR (p < 0.05). Additionally, peak lactate values at the POINT timepoint were higher with SB (11.8 ± 2.2 mmol/L) compared to PL (9.4 ± 1.2 mmol/L); with SBH values (11.5 ± 4.5 mmol/L) no different from SB. RPE values were not different between treatments. GIS were significantly higher at POTR (10.5 ± 0.8), POINT (13.4 ± 2.4), and POTT (10.4 ± 0.5) timepoints compared to PRTR (9.4 ± 0.2), with no significant differences between treatments. MTB performance times did not differ between treatments. However, under PL conditions, lap 2 times were significantly slower than lap 1 (11.7 ± 1.5 min; 11.4 ± 1.3 min; p < 0.05); an effect which was not present in either SB (11.5 ± 1.9 min; 11.4 ± 1.9 min) or SBH (11.4 ± 1.6 min; 11.4 ±1.7 min) conditions. Conclusions: Although overall TT performance did not differ between conditions, SB and SBH appeared to prevent the decline in lap performance observed in PL. SBH ingestion did not result in meaningful changes in blood lactate, RPE, GIS or performance in comparison to SB.
