Increase in Maximal Cycling Power With Acute Dietary Nitrate Supplementation

Muscle-shortening velocity and hence power have been shown to increase in the presence of nitric oxide (NO). NO availability increases after consuming nitrate (NO3-). Ingestion of NO3-rich beetroot juice (BRJ) has increased muscle power in untrained adults.Purpose:This study determined whether NO3- supplementation could acutely enhance maximal power in trained athletes.Methods:In this double-blind, crossover study, 13 trained athletes performed maximal inertial-load cycling trials (3–4 s) immediately before (PRE) and after (POST) consuming either NO3-rich (NO3) or NO3-depleted (PLA) BRJ to assess acute changes (ie, within the same day) in maximal power (PMAX) and optimal pedaling rate (RPMopt). Participants also performed maximal isokinetic cycling (30 s) to assess performance differences after supplementation.Results:2 x 2 repeated-measures ANOVA indicated a greater increase in PMAX from PRE to POST NO3 (PRE 1160 ± 301 W to POST 1229 ± 317 W) than with PLA (PRE 1191 ± 298 W to POST 1213 ± 300 W) (P = .009; ηp2 = 0.45). A paired t-test verified a greater relative change in PMAX after NO3 (6.0% ± 2.6%) than with PLA (2.0% ± 3.8%) (P = .014; d = 1.21). RPMopt remained unchanged from PRE (123 ± 14 rpm) to POST PLA (122 ± 14 rpm) but increased from PRE (120 ± 14 rpm) to POST NO3 (127 ± 13 rpm) (P = .043; ηp2 = 0.30). There was no relative change in RPMopt after PLA (–0.3% ± 4.1%), but there was an increase after NO3 (6.5% ± 11.4%) (P = .049; d = 0.79). No differences were observed between the 30-s isokinetic trials.Conclusions:Acute NO3- supplementation can enhance maximal muscle power in trained athletes. These findings may particularly benefit power-sport athletes who perform brief explosive actions.

Download Full-text

Effect of Dietary Nitrate Supplementation on Swimming Performance in Trained Swimmers

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.2016-0251 ◽

2017 ◽

Vol 27 (4) ◽

pp. 377-384 ◽

Cited By ~ 13

Author(s):

Sam Lowings ◽

Oliver Michael Shannon ◽

Kevin Deighton ◽

Jamie Matu ◽

Matthew John Barlow

Keyword(s):

Nitric Oxide ◽

Repeated Measures ◽

Swimming Performance ◽

Time Trial ◽

Mean Difference ◽

Breath Hold ◽

Double Blind ◽

Nitric Oxide Concentration ◽

Nitrate Supplementation ◽

Maximal Effort

Nitrate supplementation appears to be most ergogenic when oxygen availability is restricted and subsequently may be particularly beneficial for swimming performance due to the breath-hold element of this sport. This represents the first investigation of nitrate supplementation and swimming time-trial (TT) performance. In a randomized double-blind repeated-measures crossover study, ten (5 male, 5 female) trained swimmers ingested 140ml nitrate-rich (~12.5mmol nitrate) or nitrate-depleted (~0.01mmol nitrate) beetroot juice. Three hours later, subjects completed a maximal effort swim TT comprising 168m (8 × 21m lengths) backstroke. Preexercise fractional exhaled nitric oxide concentration was significantly elevated with nitrate compared with placebo, Mean (SD): 17 (9) vs. 7 (3)p.p.b., p = .008. Nitrate supplementation had a likely trivial effect on overall swim TT performance (mean difference 1.22s; 90% CI -0.18–2.6s; 0.93%; p = .144; d = 0.13; unlikely beneficial (22.6%), likely trivial (77.2%), most unlikely negative (0.2%)). The effects of nitrate supplementation during the first half of the TT were trivial (mean difference 0.29s; 90% CI -0.94–1.5s; 0.46%; p = .678; d = 0.05), but there was a possible beneficial effect of nitrate supplementation during the second half of the TT (mean difference 0.93s; 90% CI 0.13–1.70s; 1.36%; p = .062; d = 0.24; possibly beneficial (63.5%), possibly trivial (36.3%), most unlikely negative (0.2%)). The duration and speed of underwater swimming within the performance did not differ between nitrate and placebo (both p > .30). Nitrate supplementation increased nitric oxide bioavailability but did not benefit short-distance swimming performance or the underwater phases of the TT. Further investigation into the effects of nitrate supplementation during the second half of performance tests may be warranted.

Download Full-text

Nitrate Supplementation’s Improvement of 10-km Time-Trial Performance in Trained Cyclists

International Journal of Sport Nutrition and Exercise Metabolism ◽

10.1123/ijsnem.22.1.64 ◽

2012 ◽

Vol 22 (1) ◽

pp. 64-71 ◽

Cited By ~ 182

Author(s):

Naomi M. Cermak ◽

Martin J. Gibala ◽

Luc J.C. van Loon

Keyword(s):

Repeated Measures ◽

Time Trial ◽

Submaximal Exercise ◽

Beetroot Juice ◽

Limited Data ◽

Double Blind ◽

Time Trial Performance ◽

Ergogenic Effects ◽

Nitrate Supplementation ◽

Trial Performance

Six days of dietary nitrate supplementation in the form of beetroot juice (~0.5 L/d) has been reported to reduce pulmonary oxygen uptake (VO2) during submaximal exercise and increase tolerance of high-intensity work rates, suggesting that nitrate can be a potent ergogenic aid. Limited data are available regarding the effect of nitrate ingestion on athletic performance, and no study has investigated the potential ergogenic effects of a small-volume, concentrated dose of beetroot juice. The authors tested the hypothesis that 6 d of nitrate ingestion would improve time-trial performance in trained cyclists. Using a double-blind, repeated-measures crossover design, 12 male cyclists (31 ± 3 yr, VO2peak = 58 ± 2 ml · kg−1 · min−1, maximal power [Wmax] = 342 ± 10 W) ingested 140 ml/d of concentrated beetroot (~8 mmol/d nitrate) juice (BEET) or a placebo (nitrate-depleted beetroot juice; PLAC) for 6 d, separated by a 14-d washout. After supplementation on Day 6, subjects performed 60 min of submaximal cycling (2 × 30 min at 45% and 65% Wmax, respectively), followed by a 10-km time trial. Time-trial performance (953 ± 18 vs. 965 ± 18 s, p < .005) and power output (294 ± 12 vs. 288 ± 12 W, p < .05) improved after BEET compared with PLAC supplementation. Submaximal VO2 was lower after BEET (45% Wmax = 1.92 ± 0.06 vs. 2.02 ± 0.09 L/min, 65% Wmax 2.94 ± 0.12 vs. 3.11 ± 0.12 L/min) than with PLAC (main effect, p < .05). Wholebody fuel selection and plasma lactate, glucose, and insulin concentrations did not differ between treatments. Six days of nitrate supplementation reduced VO2 during submaximal exercise and improved time-trial performance in trained cyclists.

Download Full-text

A randomized double‐blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community

Indoor Air ◽

10.1111/ina.12019 ◽

2013 ◽

Vol 23 (3) ◽

pp. 175-184 ◽

Cited By ~ 48

Author(s):

S. Weichenthal ◽

G. Mallach ◽

R. Kulka ◽

A. Black ◽

A. Wheeler ◽

...

Keyword(s):

Crossover Study ◽

First Nations ◽

Indoor Air ◽

Air Filtration ◽

Double Blind ◽

Acute Changes ◽

Nations Community ◽

Blind Crossover Study ◽

Double Blind Crossover Study

Download Full-text

Built for rowing: frog muscle is tuned to limb morphology to power swimming

Journal of The Royal Society Interface ◽

10.1098/rsif.2013.0236 ◽

2013 ◽

Vol 10 (84) ◽

pp. 20130236 ◽

Cited By ~ 13

Author(s):

Christopher T. Richards ◽

Christofer J. Clemente

Keyword(s):

Aquatic Insects ◽

Muscle Power ◽

Terminal Velocity ◽

Gear Ratio ◽

Morphological Properties ◽

Maximal Power ◽

Shortening Velocity ◽

Longus Muscle ◽

Human Powered

Rowing is demanding, in part, because drag on the oars increases as the square of their speed. Hence, as muscles shorten faster, their force capacity falls, whereas drag rises. How do frogs resolve this dilemma to swim rapidly? We predicted that shortening velocity cannot exceed a terminal velocity where muscle and fluid torques balance. This terminal velocity, which is below V max , depends on gear ratio (GR = outlever/inlever) and webbed foot area. Perhaps such properties of swimmers are ‘tuned’, enabling shortening speeds of approximately 0.3 V max for maximal power. Predictions were tested using a ‘musculo-robotic’ Xenopus laevis foot driven either by a living in vitro or computational in silico plantaris longus muscle. Experiments verified predictions. Our principle finding is that GR ranges from 11.5 to 20 near the predicted optimum for rowing (GR ≈ 11). However, gearing influences muscle power more strongly than foot area. No single morphology is optimal for producing muscle power. Rather, the ‘optimal’ GR decreases with foot size, implying that rowing ability need not compromise jumping (and vice versa ). Thus, despite our neglect of additional forces (e.g. added mass), our model predicts pairings of physiological and morphological properties to confer effective rowing. Beyond frogs, the model may apply across a range of size and complexity from aquatic insects to human-powered rowing.

Download Full-text

Faculty Opinions recommendation of A randomized double-blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718015679.793514687 ◽

2016 ◽

Author(s):

Nadia Hansel

Keyword(s):

Crossover Study ◽

First Nations ◽

Indoor Air ◽

Air Filtration ◽

Double Blind ◽

Acute Changes ◽

Nations Community ◽

Blind Crossover Study ◽

Double Blind Crossover Study

Download Full-text

Pharmacokinetics and Tolerability of Factor XIII Concentrates Prepared from Human Placenta or Plasma: a Crossover Randomised Study

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649787 ◽

1995 ◽

Vol 74 (02) ◽

pp. 622-625 ◽

Cited By ~ 29

Author(s):

H H Brackmann ◽

R Egbring ◽

A Ferster ◽

P Fondu ◽

J M Girardel ◽

...

Keyword(s):

Factor Xiii ◽

Bleeding Events ◽

Serious Adverse Events ◽

Double Blind ◽

Randomised Study ◽

The Mean ◽

Blind Crossover Study ◽

Double Blind Crossover Study ◽

Fxiii Activity ◽

Observation Period

SummaryThe pharmacokinetics and tolerability of factor XIII (FXIII) from plasma were compared with those of FXIII from placenta in a randomised, double-blind, crossover study involving 13 patients with congenital FXIII deficiency. Both FXIII activity and FXIII antigen were monitored. No difference was seen in the mean half-lives of the two preparations (9.3 days and 9.1 days for plasma and placenta FXIII activity, respectively). Response was similar for both preparations, but was slightly greater for FXIII from plasma.Similar results were found for recovery (65% vs 60%). The area under the data completed by extrapolation was significantly higher for FXIII from plasma. No differences between preparations in terms of efficacy or tolerability were observed. It can be concluded that treatment with FXIII concentrate from plasma is as efficient as with FXIII concentrate from placenta in terms of recovery and half-life. Both preparations were equivalent in terms of safety during the observation period. With the administration of monthly injections of approximately 30 U/kg serious bleeding events were prevented and no other serious adverse events occurred.

Download Full-text

Inhibition of Spontaneous Platelet Aggregation by Sulfinpyrazone

Thrombosis and Haemostasis ◽

10.1055/s-0038-1666900 ◽

1979 ◽

Vol 42 (02) ◽

pp. 621-625 ◽

Cited By ~ 1

Author(s):

G G Nenci ◽

G Agnelli ◽

M Berrettini ◽

P Parise ◽

E Ballatori

Keyword(s):

Platelet Aggregation ◽

Crossover Study ◽

Double Blind ◽

Platelet Aggregability ◽

Initiation Of Therapy ◽

Spontaneous Platelet Aggregation ◽

Blind Crossover Study ◽

Double Blind Crossover Study

SummaryIn a randomized double-blind crossover study in 16 patients with enhanced in vitro spontaneous platelet aggregation, sulfinpyrazone proved to be effective in normalizing platelet aggregability within 4 days after initiation of therapy.

Download Full-text