Texas Tech University

To Caffeinate or Not to Caffeinate? That's the Pre-workout Supplement Question.

Amanda Bowman

February 23, 2021

Grant Tinsley

Assistant professor Grant Tinsley is conducting a study to see if caffeine is the “it” factor for pre-workout supplements.

Working out is important to maintain a healthy lifestyle. According to the Centers for Disease Control and Prevention (CDC), regular physical activity can reduce your risk of depression and anxiety, help you sleep better, manage or maintain your weight and lower your risk of developing certain cancers like bladder, breast, kidney and lung.

While working out on its own can lead to numerous benefits, some people also use supplements to enhance their workouts. Such supplements include pre-workout powders or drinks that promote improved energy and stamina during intense workouts and come in caffeinated or noncaffeinated versions.

Tinsley's lab
Some of the workout equipment in Tinsley's lab.

Grant Tinsley, an assistant professor of kinesiology in Texas Tech University's College of Arts & Sciences, received a $20,000 grant from Legion Athletics to study the effects of the company's pre-workout products and whether caffeine is the driving force behind the improvement people feel from taking a pre-workout supplement.

"Pre-workout supplements are a category of sports nutrition products that are very popular among exercising individuals, as well as athletes, who want a little more energy to get through their workout," Tinsley said. "These types of supplements are often a little bit difficult to study because they contain a mixture of several different ingredients. So, at least from the scientific perspective, when we study these supplements, it's hard to isolate the effects of each individual ingredient.

"With that said, it's well known that that caffeine is an effective ergogenic aid, so it does enhance performance in lots of types of exercise. A big question with these pre-workout supplements is, 'Do all these other ingredients actually matter or is caffeine the only thing that matters? Is this just caffeine with a bunch of other stuff thrown in for marketing?' This study is comparing two versions of the same pre-workout supplement. One is caffeinated and one is noncaffeinated, and both will also be compared to a placebo supplement."

Tinsley and his research team will recruit 24 individuals, 12 males and 12 females, with current weight-training experience to participate in the study. These individuals will eat a standardized breakfast at Tinsley's lab, wait a period of time, ingest one of the three supplements (caffeinated, noncaffeinated or placebo), wait a bit more and then go through the exercise protocol.

More equipment in Tinsley's lab
More equipment in Tinsley's lab.

"We're largely looking at outcomes that relate to the types of workouts these individuals typically perform," he said. "Things like their maximal strength on the leg press exercise and the bench press exercise, as well as their muscular endurance, which is just how many repetitions they can perform until they can't complete anymore.

"We'll be testing those performance variables and assessing subjective factors, like their energy, focus, and fatigue throughout this exercise session. That's the big picture – after an individual completes one session, they'll enter a washout period of several days, then they'll return and complete the subsequent conditions."

One of the biggest implications of this study is answering the question of whether or not caffeine is necessary in a pre-workout supplement for optimal results.

"I think there's an increasing number of people who, even if they would be interested in taking a pre-workout supplement, may not consider them due to the caffeine content or adverse effects on sleep," Tinsley said. "Especially if we see that the noncaffeinated pre-workout still outperforms the placebo, this would be useful information to those who want a boost for an evening workout but aren't willing to sacrifice sleep quality. This could also be helpful information to those who are currently taking caffeinated pre-workouts later in the day, but experiencing adverse effects on sleep.

"If we see that a noncaffeinated alternative could yield similar benefits, I think that would have some nice, practical applications for those individuals so they can promote overall wellness through getting good sleep but also get a boost during their exercise sessions."

Tinsley wants to acknowledge the help he is receiving on this study from the 11 students in his lab: four undergraduate students, four master's students and three doctoral students.

"Even though I assembled this proposal and secured the funding, they were involved with important aspects of designing the study and will lead a lot of the day-to-day operations," he said. "Hopefully, it will be a valuable learning experience and produce research abstracts and publications for the students."