J. Ocel

Effect of weight loss and refeeding diet composition on anaerobic performance in wrestlers

Collegiate wrestlers (N = 12) consumed a formula, hypoenergy diet (18 kcal.kg-1, 60% carbohydrate) without dehydration for 72 h. For the next 5 h, the athletes were fed either a 75% (HC) or a 47% (MC) carbohydrate formula diet of 21 kcal.kg-1. Each wrestler performed three anaerobic arm ergometer performance tests (TEST1, before weight loss; TEST2, after weight loss; TEST3, after refeeding). Blood withdrawn just before and after each test was analyzed for pH, bicarbonate, base excess, glucose, and lactate. Both groups had a similar significant reduction in total work done during TEST2 (92.4% of TEST1). Work done in TEST3 by HC was 99.1% of TEST1 while MC did 91.5% of their initial work (P = 0.1). Peak power was unaffected by the treatment. Plasma lactate significantly increased during the performance test from 1.72 to 21.91 mmol.l-1 as did plasma glucose from 4.88 to 5.25 mmol.l-1 when groups and trials were collapsed. Lactate accumulation was diminished during TEST2 compared with the other tests. Although the exercise bout reduced pH, bicarbonate, and base excess, there was no difference in the effect by group. In conclusion, weight loss by energy restriction significantly reduced anaerobic performance of wrestlers. Those on a high carbohydrate refeeding diet tended to recover their performance while those on a moderate carbohydrate diet did not. The changes in performance were not explained by the acid/base parameters measured.

Effect of oral sodium loading on high-intensity arm ergometry in college wrestlers.

PURPOSE The aim of this study was to examine the effect of 0.3 g x kg(-1) of NaHCO3, 0.21 g x kg(-1) of NaCl, and a low-calorie placebo control (PC) on high-intensity arm ergometry in eight college wrestlers (aged 20.6 +/- 0.8 yr, body mass 70.4 +/- 2.1 kg). METHODS Subjects performed eight 15-s intervals of maximal effort arm ergometry separated by 20 s of recovery cranking. Treatments were administered in a randomized, double-blind manner in two equal doses at 90 and 60 min before testing. Venous blood samples were withdrawn at baseline, preexercise, and postexercise intervals. RESULTS Preexercise pH (7.33 +/- 0.01, 7.31 +/- 0.01, and 7.40 +/- 0.01) and base excess (2.41 +/- 0.35, 0.93 +/- 0.39, and 8.45 +/- 0.51) after PC and NaCl ingestion, respectively, were similar, whereas ingestion of NaHCO3 resulted in significantly higher values (P < or = 0.05). Postexercise pH (7.02 +/- 0.01, 7.02 +/- 0.03, and 7.09 +/- 0.03) and base excess (-13.29 +/- 0.96, -14.49 +/- 1.01, and -8.83 +/- 1.38) were significantly lower after both PC and NaCl ingestion compared with NaHCO3 ingestion. Postexercise plasma [lactate] was also greater in both PC and NaHCO3 trials (21.42 +/- 1.52, 20.07 +/- 1.39, and 22.65 +/- 1.77 mmol x L(-1)). However, peak power (370.7 +/- 26.0, 346.3 +/- 13.6, and 354.3 +/- 18.9 W) and total work accomplished in eight intervals (30.2 +/- 1.5, 29.6 +/- 1.1, and 29.9 +/- 1.1 kJ), and percent fatigue (31.0 +/- 2.7, 29.0 +/- 3.2, and 29.2 +/- 4.0%) were similar. CONCLUSIONS These data contradict previous reports of ergogenic benefits NaHCO3 and NaCl administration before exercise and further suggest that performance in this type of activity may not be enhanced by exogenously induced metabolic alkalosis or sodium ingestion.

Small RNA-seq during acute maximal exercise reveal RNAs involved in vascular inflammation and cardiometabolic health: brief report

Exercise improves cardiometabolic and vascular function, although the mechanisms remain unclear. Our objective was to demonstrate the diversity of circulating extracellular RNA (ex-RNA) release during acute exercise in humans and its relevance to exercise-mediated benefits on vascular inflammation. We performed plasma small RNA sequencing in 26 individuals undergoing symptom-limited maximal treadmill exercise, with replication of our top candidate miRNA in a separate cohort of 59 individuals undergoing bicycle ergometry. We found changes in miRNAs and other ex-RNAs with exercise (e.g., Y RNAs and tRNAs) implicated in cardiovascular disease. In two independent cohorts of acute maximal exercise, we identified miR-181b-5p as a key ex-RNA increased in plasma after exercise, with validation in a separate cohort. In a mouse model of acute exercise, we found significant increases in miR-181b-5p expression in skeletal muscle after acute exercise in young (but not older) mice. Previous work revealed a strong role for miR-181b-5p in vascular inflammation in obesity, insulin resistance, sepsis, and cardiovascular disease. We conclude that circulating ex-RNAs were altered in plasma after acute exercise target pathways involved in inflammation, including miR-181b-5p. Further investigation into the role of known (e.g., miRNA) and novel (e.g., Y RNAs) RNAs is warranted to uncover new mechanisms of vascular inflammation on exercise-mediated benefits on health.NEW & NOTEWORTHY How exercise provides benefits to cardiometabolic health remains unclear. We performed RNA sequencing in plasma during exercise to identify the landscape of small noncoding circulating transcriptional changes. Our results suggest a link between inflammation and exercise, providing rich data on circulating noncoding RNAs for future studies by the scientific community.

ADAPTATION OF THE SLOW COMPONENT OF ??VO2 (SC) FOLLOWING 6 WEEKS OF HIGH OR LOW INTENSITY EXERCISE TRAINING

Eighteen untrained males [age: 23 + 0.6 yr (SEM)] were randomized into high intensity (HIT: above lactate threshold, LT), moderate intensity (LIT: below the LT) or no training (NT) groups. Subjects trained on a cycle ergometer 4 days wk for 6 wk with the power output held constant. Maximal cycle ergometry was performed before and after the training period to determine changes in power output and oxygen consumption (VO 2) at the LT and peak exertion. Before training and after 1, 2, 4, and 6 wk, subjects performed high constant-load (HCL) cycling bouts to quantify training adaptations in the SC. Training was designed to keep total work equivalent between the HIT and LIT groups. Increases in power output and VO 2 at LT and peak exercise after 6 wk were noted in the HIT and LIT groups in comparison to NT group (p<0.05). No differences were noted between HIT and LIT. Two-way repeated measures ANOVA revealed a significant trial *group interaction for adaptation in the SC (p<0.001). After 1wk of training, a significant reduction in the SC was noted for HIT [mean+SEM]: (pre-training (PT): 703 + 61 mlmin; 1 wk: 396 + 60 ml min) (44% from PT). Further adaptation for the HIT was also noted at 4 wk: 202 + 45 ml . in (-71% from PT). For LIT, a significant reduction was noted at 2 wk (PT: 588+76 ml min; 2 wk: 374 + 50mlmin) (-36% from PT). Further adaptation for LIT group was noted at 6 wk (252 + 38 ml . in) (57% from PT). Adaptation in SC was not noted at any interval for NT. Temporal changes in blood lactate (r = 0.40) and ventilation (r = 0.72) were significantly correlated with the changes for SC over the 6 wk training period (p<0.05). In conclusion, it was demonstrated that training at supra-LT and sub-LT intensities produces similar improvement in VO2 and power output at peak exercise and in the LT, when total work output is controlled. However, training at supra-LT intensity promotes larger and faster adaptations in the SC than training at the sub-LT levels.