Acute effect of a multi-ingredient pre-workout supplement on pacing and kinetic expression during shorter and longer bouts of high intensity functional training.

Abstract

Background: High-intensity functional training (HIFT) varies daily workout programming, and trainees are often tasked with completing "as many repetitions as possible" (AMRAP) within a set time. Successful performance depends on fatigue management skills and maintaining a consistent expression of force and velocity when performing and transitioning between exercises over the duration of the workout. Multi-ingredient pre-workout (MIPS) supplement formulations often contain ingredients shown to facilitate energy availability and mitigate fatigue, and therefore, might positively affect HIFT performance. This study aimed to assess a multi-ingredient pre-workout supplement's acute effect on pacing and the expression of kinetics throughout a 5- and 15-minute HIFT-style AMRAP.

Methods: Twelve men and 10 women (29.3 ± 7.1 years, 171 ± 7 cm, 80.5 ± 15.6 kg) with HIFT experience ( > 2 years) completed four weekly visits, consuming either the supplement (S) or placebo (P) before a 5- or 15-minute AMRAP of rowing (9 or 7 Calories for men and women), six barbell thrusters (43.1 kg and 29.5 kg), and three jumps onto a box (0.61 m and 0.51 m). Video recordings of each workout were analyzed to quantify repetitions completed, volume load (kg), and pace (i.e. time spent on each workout component, repetition completion rate). The expression of kinetics and related factors were quantified during rowing via the ergometer microcomputer (Calories per stroke, power [W], and strokes per minute), during barbell thrusters by a 3D motion tracking system (barbell velocity [m · sec^-1] and power [W]), and by in-ground force plates during box jumps (peak and mean force [N], time-to-peak force [ms], rate of force development [RFD; N·sec^-1], and impulse [N·sec]). The averages, standard deviation, and slope across rounds were calculated for all pacing and kinetic variables for separate 3-way (sex × workout durations × supplement conditions) repeated measures analysis of variance comparisons.

Results: Men and women completed a greater total volume load (~4.4%, p = 0.009) and repetitions at a faster rate (~2.2%, p = 0.043) during S compared to P and regardless of workout duration. These were best explained by participants completing a greater rowing volume load (~8.1%, p = 0.009) by averaging more powerful strokes (~7.0%, p = 0.005), more consistent transitions to rowing (~11.0%, p = 0.020), and a trend for faster barbell thruster repetition completion rate (~2.3%, p = 0.077). Interestingly, participants varied more across rounds during S (~16.8-29.4%, p < 0.05) in box jump force expression (peak force, mean force, time-to-peak force, and RFD). No other differences were seen between supplement conditions, only expected differences were seen between men and women and between workout durations.

Conclusions: Although it did not affect repetitions completed, the multi-ingredient pre-workout supplement led to a greater volume load and faster overall repetition completion rate. These were primarily due to improvements surrounding rowing performance and evidence of an effect on thruster pacing and box jump force expression. The effects were similar in both sexes and workout durations. Athletes might consider this MIPS formulation to improve HIFT performance, particularly when a workout contains a component that requires sustained, continuous effort.