(62) DURATION AFFECTS MULTIPLE PACING STRATEGY COMPONENTS DURING A HIGH-INTENSITY FUNCTIONAL TRAINING WORKOUT

Pacing (i.e., repetition completion rate [RCR]) is commonly auto regulated during high-intensity functional training (HIFT) workouts. Trainees are free to modify RCR differently for each programmed exercise, vary transition times between exercises, and break when necessary. In workouts that ask trainees to complete “as many repetitions as possible” (AMRAP), maximizing RCR and minimizing transition and break time will lead to the most repetitions being completed.Aside from more time being made available to complete repetitions and likely, more of a “sprint”-minded approach, little is known about the effect of workout duration on pacing strategy. Purpose: To compare pacing strategies employed during the same HIFT workout programmed at different total durations.

Methods: Seven men (28.8 ± 7.2 years, 172.9 ± 9.2 cm, 83.2 ± 17.0 kg) with ≥ 2 years of HIFT experience reported to the Biomechanics laboratory twice on the same day of the week over a 4-week period at a time consistent with their normal training schedule, and after having maintained a similar diet on the 3 days leading up to each visit. Following a standardized warm-up, participants randomly completed a 5- or 15-minute AMRAP of 9-calorie rowing, six barbell thrusters at 43.1 kg, and three .6-meter box jumps. All workouts were recorded and then videos were analyzed to quantify RCR for each exercise, transition and break time between exercises, and failed repetitions on each minute. Subsequently, the average, standard deviation (SD), and slope across each workout was calculated for all variables, and comparisons were made between workout durations via paired-samples t-tests.

Results: As expected, more repetitions (p < 0.001) completed during 15-min (182 ± 27 repetitions) compared to 5-min (80 ± 8 repetitions), with participants producing a faster RCR during 5-min (3.8 ± 1.5 reps/min, p < 0.001). Specifically, calories per second (+0.09 ± 0.04/sec, p < 0.001) and box jumps per second (+0.04 ± 0.02/sec, p = 0.002) were greater during 5-min. However, average rowing RCR (0.28 – 0.37 calories/sec) was slower than thruster RCR (0.43 – 0.44 repetitions/sec) and box jump RCR (0.40 – 0.43 repetitions/sec), and calories per stroke experienced a steeper decline during 5-min (slope = 0.03 ± 0.02/sec, p = 0.021). In contrast, longer and more variable transitions and total down time (transitions + breaks) were observed with all three exercises during 15-min (p < 0.05). No other differences were observed.

Conclusions: More repetitions were completed during the longer workout but at a slower rate overall and with each exercise. Longer and more variable transitions were seen between all exercises during 15-minute. A steadier pace was seen during 5-minutes, though a steeper decline in the strength of each rowing stroke (i.e., calories per stroke) was noted. PRACTICAL APPLICATION: Given the same prescription, a longer version of a HIFT AMRAP workout will impact overall and individual exercise pacing and down time. Coaches and athletes should aim to maintain an even pace throughout the workout and pay closest attention to slower-paced exercises appear more likely to experience a decline.

Acknowledgements: This study was funded by Shifted LLC, Eugene, OR, USA