Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Master of Science (MS)

Document Type

Master's Thesis




Kinesiology and Health Promotion

First Advisor

Dr. Haley Bergstrom


Curcumin, a polyphenol, has been suggested to improve metabolic byproduct clearance and increase nitric oxide production in working muscle. These purported effects may delay neuromuscular fatigue. Therefore, the purpose of this study was to examine the effects of curcumin in combination with fenugreek (CUR) or fenugreek soluble fiber alone (FEN) on the neuromuscular fatigue threshold (PWCFT), time to exhaustion (Tlim) on a graded exercise test (GXT), and O2peak in untrained subjects.Forty-seven,college-aged, aerobically untrained individuals were randomly assigned to one of three supplementation groups; placebo (PLA, n=15),curcumin + fenugreek, CurQfen® (CUR, n=18), or fenugreek soluble fiber (FEN, n=14). All subjects performed a maximal GXT on a cycle ergometer to determine the PWCFT, Tlim, and O2peak before (PRE-test) and after (POST-test) 28 days of daily supplementation. Statistical analyses included 3 separate, one-way ANCOVAs to determine if there were any differences among the groups (PLA, CUR, FEN) for adjusted post-test scores for the PWCFT, O2peak, and Tlim. The respective pre-test score was used as the covariate. In addition, reliability analyses (PRE- to POST-test) for the PLA group were used to calculate the minimal difference needed to be real (MD). The adjusted POST PWCFTvalues showed no statistical differences between groups (F= 3.141p= 0.053); however pairwise LSD comparisons indicated a significant difference between the CUR and PLA groups (p= 0.016), but not between the CUR and FEN groups. Therefore, separate one-way ANCOVAs were used to examine the adjusted PWCFTmeans for the PLA vs. CUR (F = 4.906, p =0.035) and the PLA vs. FEN (F = 2.969, p = 0.097). The one- way ANCOVA for O2peak (F= 0.612 p= 0.547) and Tlim(F = 0.688, p = 0.508) values showed no statistical difference among the groups. Individual responses in each group showed ~ 20% of subjects in the CUR group, ~ 7% in the FEN group, and ~6% in the PLA group had values greater than the MD for the PWCFT, but none of the subjects in the PLA, FEN, or CUR groups exceeded the MD for O2peak or Tlim. These findings indicatedCurQfen® supplementation increased the PWCFTcompared to a placebo, but not compared to fenugreek soluble fiber alone. However, there were no effects of CurQfen® on O2 peak or Tlim. The mechanisms responsible for delaying time to neuromuscular fatigue may include increased NO production and increased blood flow to remove metabolic byproducts; however, the cellular changes which could lead to increases in Tlim andO2peak may not have been sensitive to the GXT protocol or the given dosage of curcumin supplementation. Considering individual responses, CurQfen® supplementation resulted in a real change in the PWCFTfor a small portion of the subjects (~20%). These findings suggested that CurQfen® supplementation without exercise training may help to improve time to neuromuscular fatigue in certain individuals, but the group mean analyses were not necessarily reflective of the responses for a majority of the subjects.

Digital Object Identifier (DOI)