Phenylcapsaicin for physical performance in resistance-trained men Original paper

In this randomized controlled crossover study, phenylcapsaicin improved some metrics of physical performance in men with 2 to 5 years of resistance training experience.

This Study Summary was published on February 12, 2024.

Quick Summary

In this randomized controlled crossover study, phenylcapsaicin improved some metrics of physical performance in men with 2 to 5 years of resistance training experience.

What was studied?

The effect of phenylcapsaicin (PC; an analogue of capsaicin) on physical performance measurements.

Who was studied?

25 men (average age of 22) with 2 to 5 years of resistance training.

The participants had an average height of 177 centimeters or 5 feet 10 inches, average body mass of 77 kilograms or 169 pounds, and an average squat 1-repetition maximum (1RM) of 126 kilograms or 277 pounds.

How was it studied?

In this randomized controlled crossover study, the participants’ 1RM on the squat was tested at baseline. During each of 3 weeks, the participants took 1 of 3 different interventions — low-dose (0.625 mg) PC, high-dose (2.5 mg) PC, or a placebo (maltodextrin with a red dye) — 45 minutes before undergoing an exercise test consisting of 1 of 2 sessions.

In session 1, the participants performed a battery of tests with electromyography (EMG) pads applied to their thigh muscles to measure neural activity. The main test during session 1 was squat velocity and load during 8 squats of 70% of 1RM, repeated for a total of 3 sets. Before and immediately after the squats at 70% of 1RM, vertical jump height, squat velocity (maximum velocity during a squat at 60% of 1RM and at 70% of 1RM), and isometric squat power (the maximal power exerted in a squat at 90° of knee flexion against a machine) were tested.

Session 2 was conducted 24 hours after session 1 and consisted of testing the same outcomes again, but without the squats at 70% of 1RM from session 1.

Sessions 1 and 2 were repeated for each of the interventions.

What were the results?

Vertical jump height differed among the 3 interventions, with high-dose PC outperforming low-dose PC and placebo.

There were no differences in EMG readings, isometric squat power, or squat load during the 70% 1RM squat sets.

This Study Summary was published on February 12, 2024.