BackgroundMulti-ingredient pre-workout supplements (MIPS) are popular among resistance trained individuals. Previous research has indicated that acute MIPS ingestion may increase muscular endurance when using a hypertrophy-based protocol but less is known in regard to their effects on strength performance and high intensity running capacity. Therefore, the purpose was to determine if short-term, MIPS ingestion influences strength performance and anaerobic running capacity.MethodsIn a double-blind, randomized, placebo controlled, crossover design; 12 males (19 ± 1 yrs.; 180 ± 12 cm; 89.3 ± 11 kg; 13.6 ± 4.9 %BF) had their body composition assessed followed by 5-repetition maximum (5RM) determination of back squat (BS; 119.3 ± 17.7 kg) and bench press (BP; 92.1 ± 17.8 kg) exercises. On two separate occasions subjects ingested a MIPS or a placebo (P) 30-minutes prior to performing a counter movement vertical jump test, 5 sets of 5 repetitions at 85 % of 5RM of BS and BP, followed by a single set to failure, and an anaerobic capacity sprint test to assess peak and mean power. Subjective markers of energy levels and fatigue were also assessed. Subjects returned one week later for a second testing session using counter treatment.ResultsMIPS resulted in a greater number of repetitions performed in the final set to failure in the BP (MIPS, 9.8 ± 1.7 repetitions; P, 9.1 ± 2; p = 0.03, d = 0.38), which led to a greater total volume load (set x repetitions x load) in the MIPS (753 ± 211 kg) compared to P (710 ± 226 kg; p =0.03, d = .20). MIPS ingestion improved subjective markers of fatigue (p = 0.01, d = 3.78) and alertness (p = 0.048, d = 2.72) following a bout of resistance training. An increase in mean power was observed in the MIPS condition (p = 0.03, d = 0.25) during the anaerobic sprint test.ConclusionResults suggest that acute ingestion of a MIPS study may increase upper body muscular endurance. In addition, acute MIPS ingestion improved mean power output during an anaerobic capacity sprint test. However, the practical significance of these performance related outcomes may be minimal due to the small effect sizes observed. MIPS ingestion does appear to positively influence subjective markers of fatigue and alertness during high-intensity exercise.

The purpose of the present experiment was to observe the performance of participants attempting to produce a 1:1 bimanual coordination pattern with 90 degrees relative phase between the arms when feedback concerning the movement of the two limbs was integrated within a Lissajous plot and when this information was withdrawn. One group was paced with an auditory metronome and the other was encouraged to increase frequency when they fell below the goal frequency. We predicted that providing a salient integrated feedback display without a metronome would allow participants to effectively tune-in the goal relative phase pattern within several minutes; instead of several days as typically found in the literature when the metronome was used. The data indicated remarkably effective performances after 5 min of practice when the metronome was not used, with motion of both limbs harmonic in nature, and continuous relative phase errors (approximately 10 degrees) and standard deviation of continuous relative phase (approximately 10 degrees) relatively small. This seems remarkable given that this coordination pattern has proven relatively difficult to perform under normal and Lissajous feedback conditions even after several days of practice. As predicted relative phase errors and variability increased substantially when the metronome was used. When the extrinsic feedback was withdrawn all participants tended to drift from the required 90 degrees relative phase, but the cycle duration variability in the two limbs remained stable and limb motion remained harmonic in nature. The current findings suggest that some of the difficulty typically associated with producing various relative phase patterns is due to the less than optimal perceptual information available in the various testing situations and the use of pacing metronomes.

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The present findings demonstrate that when participants are provided a Lissajous display with cursor indicating the position of the limbs and a template illustrating the desired movement pattern they can rapidly (10 min) and effectively (continuous relative phase errors and variability ~10 degrees ) tune in a difficult 5:3 bimanual coordination pattern and without additional practice re-tune their responding to an equally difficult 4:3 coordination pattern. The findings indicate the extreme difficulty associated with producing complex polyrhythms in previous experiments has been due to split attention when Lissajous feedback has been provided and inability of the participant to detect and correct coordination errors when only provided vision of the limbs. Effective transfer to the 4:3 polyrhythm without previous practice suggests that the perception-action system's capabilities are extensive. The present findings when viewed in the context of recent experiments using similar protocols suggest that much, but not all, of the difficulty associated with producing a variety of bimanual coordination tasks should be viewed in terms of perceptual constraints imposed by the testing environment.