The goal of this clinical trial is to determine the association between near-infrared spectroscopy (NIRS)-derived mitochondrial oxidative phosphorylation (OXPHOS) capacity of the vastus lateralis muscles, and both local muscular endurance capacity and local muscular fatigability of the thigh muscles in young adults. Additionally, this trial aims to determine the effect of acute taurine supplementation on local muscular endurance capacity and local muscular fatigability when compared to a placebo condition. The main questions it aims to answer are:
1. Will there be a positive correlation between NIRS rate constant (a marker of mitochondrial function) and local muscular endurance capacity, along with a negative correlation between NIRS rate constant and local muscular fatigability? 2. Will acute taurine supplementation lead to improvements in local muscular endurance capacity and local muscular fatigability when compared to a placebo condition?
Participants will:
1. Complete a NIRS assessment to non-invasively assess the mitochondrial capacity of both vastus lateralis muscles 2. Complete two acute supplementation assessment visits (separated by 7-10 days) which involve small blood collections before and after taurine or placebo supplementation 3. Perform a single-leg extension time-to-exhaustion test to measure local muscular endurance capacity on one leg, along with a repeated maximal voluntary isometric contraction fatigue index test to measure local muscular fatigability on the opposite leg, during each acute supplementation assessment visit.
Capable and willing to give written informed consent
Capable of understanding inclusion and
No medical condition that would limit participation in supervised exercise
No current prescription medications known to impact mitochondrial function
Sedentary or recreationally active (self-report average MVPA < 300 mins/week)
Willing to allow researchers to use data for research purposes
Crossover
Acute Taurine Supplementation
Dietary supplementParticipants will ingest six taurine capsules (6 grams of taurine) following a baseline blood collection to determine baseline plasma taurine levels. 60 minutes following ingestion, there will be an additional blood collection to determine post-supplementation plasma taurine levels. Participants will then perform exercise assessments. The order of taurine supplementation relative to placebo supplementation will be randomized in a double-blind crossover with 7-10 days separating each condition.
Acute Placebo Supplementation
Dietary supplementParticipants will ingest six placebo capsules (1.2 grams of microcrystalline cellulose) following a baseline blood collection to determine baseline plasma taurine levels. 60 minutes following ingestion, there will be an additional blood collection to determine post-supplementation plasma taurine levels. Participants will then perform exercise assessments. The order of placebo supplementation relative to taurine supplementation will be randomized in a double-blind crossover with 7-10 days separating each condition.
Single Leg Extension Time-to-Exhaustion
Within-participant comparison of single-leg extension time-to-exhaustion (a measure of local quadriceps muscular endurance capacity) when comparing the acute taurine supplementation and acute placebo supplementation conditions
Single-Leg Muscular Fatigue Index
Within-participant comparison of fatigue index during 24 repeated maximal voluntary isometric contractions (a marker of local quadriceps muscular fatigability) when comparing the acute taurine supplementation and acute placebo supplementation conditions
Correlation Between Vastus Lateralis NIRS Rate Constant and Single-Leg Extension Time-to-Exhaustion
The correlation between the rate constant of the vastus lateralis derived from the NIRS occlusion-based recovery kinetics assessment (a marker of mitochondrial OXPHOS capacity) and single-leg extension time-to-exhaustion (a maker of local quadriceps muscular endurance capacity).
Correlation Between Vastus Lateralis NIRS Rate Constant and Single-Leg Muscular Fatigue Index
The correlation between the rate constant of the vastus lateralis derived from the NIRS occlusion-based recovery kinetics assessment (a marker of mitochondrial OXPHOS capacity) and single-leg muscular fatigue index (a maker of local quadriceps muscular fatigability).
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