Search

Research suggests that beet juice is beneficial during aerobic exercise. However, the impact of beet juice during primarily anaerobic exercise is equivocal. The purpose of this study was to determine the effects of acute beet juice supplementation on maximal intensity performance during 30-s and 60-s maximal-intensity cycling sprints. Using a double-blind, crossover-study design, 14 anaerobically trained male hockey players completed six Wingate cycling tests: familiarization trials of a 30-s and 60-s Wingate test, followed by 30-s Wingate placebo/beet juice trials, and 60-s Wingate placebo/beet juice trials. Repeated measures ANOVAs were used to compare the change in power between conditions over the duration of each trial. Paired t-tests were run to compare performance between conditions of various work and power variables. One-way ANOVAs were utilized to compare the change between conditions of the 30-s test to the change between conditions of the 60-s test. Beet juice supplementation yielded no statistical differences from placebo in any of the measured variables during the 30-s or 60-s tests (p > 0.05). The percent change for fatigue index was significantly different between the 30-s and 60-s tests (p = 0.032) suggesting less fatigue with beet juice supplementation. Overall, beet juice did not improve maximal intensity performance during 30-s or 60-s cycling sprint tests. Performance during the 60-s bout was not impacted to a greater extent than the 30-s bout after beet juice supplementation. These results suggest that beet juice supplementation does not improve short-duration exercise performance in anaerobically trained athletes. [ABSTRACT FROM AUTHOR]

Consumption of macronutrients, particularly carbohydrate (CHO) and possibly a small amount of protein, in the early recovery phase after endurance exercise can enhance muscle glycogen resynthesis rates. A target of at least 1 .2 gkg body weight-1· h-1 CHO (over several hours) is suggested. This rate of CHO intake could be sustained with liquid, gel, or solid food rich in CHO for maximizing muscle glycogen. Whether the coingestion of protein with CHO compared with isocaloric CHO results in meaningful differences in glycogen replenishment that translate into subsequent performance enhancement is equivocal. Advantages of added protein with CHO in reducing true muscle damage from endurance exercise remain to be verified. There are, however, no apparent contraindications for using milk or specialty CHO/protein/amino acid products either. Future investigations that examine signaling mechanisms within muscle should be conducted in parallel with translational evidence in humans. [ABSTRACT FROM AUTHOR]

Many tactical athletes (military and emergency personnel) have fixed load carriage occupational requirements. Understanding the effects of running with common military "fighting loads" (no load to approximately 18 kg) on heart rate (HR), perceived exertion (RPE), and measuring it with accelerometers has implications for training and ensuring physical readiness of recruits. Eleven (7 male and 4 female) civilians (21.5±2.3 years, 1.83±0.09 m, and 80.7±18.5 kg) completed four, 5- minute running (8.05 kph) conditions: no external load, rifle carriage (3.5 kg), pack carriage (13.6 kg), and rifle/pack carriage (17.1 kg) in random order, while HR, RPE, and hip worn ActiGraph accelerometer step cadence, and activity counts per minute (CPM) were collected. One way 4-level analysis of variance or Friedman test explored the condition main effect on HR, RPE, step cadence, and CPM. Pairwise comparisons with Bonferroni correction determined which conditions differed from each other. HR and RPE significantly differed (p < 0.001) by load condition. No external load had the lowest HR and RPE (HR=141.8 bpm, RPE=9.4), while rifle/pack carriage had the highest (HR=160 bpm, RPE=14.8). However, rifle carriage (HR=153.7 bpm, RPE=12.3) elicited similar physiological responses as pack carriage (HR=155.0 bpm, RPE=13.6). Step cadence was equal across conditions, but CPM decreased as loads increased. Because a lighter load carried in the hands caused similar HR and RPE response to wearing a heavier pack, recruits should practice both in preparation for military or tactical occupations. Accelerometers may be used to assess step cadence, but not the increased physiological demands of external load conditions.