Search Results

You are looking at 21 - 30 of 1,065 items for :

  • "supplements" x
Clear All
Open access

Peter Peeling, Linda M. Castell, Wim Derave, Olivier de Hon and Louise M. Burke

Numerous nutritional products are marketed with claims of optimizing athlete health and function and/or enhancing performance. Products that fall under the banner of “Sports Foods” or “Dietary Supplements,” may be used to support performance during training and competition or for enhancing aspects

Restricted access

Andrew E. Kilding, Claire Overton and Jonathan Gleave

Purpose:

To determine the effects of ingesting caffeine (CAFF) and sodium bicarbonate (SB), taken individually and simultaneously, on 3-km cycling time-trial (TT) performance.

Method:

Ten well-trained cyclists, age 24.2 ± 5.4 yr, participated in this acute-treatment, double-blind, crossover study that involved four 3-km cycling TTs performed on separate days. Before each TT, participants ingested either 3 mg/kg body mass (BM) of CAFF, 0.3 g · kg−1 · BM−1 of SB, a combination of the two (CAFF+SB), or a placebo (PLAC). They completed each 3-km TT on a laboratory-based cycle ergometer, during which physiological, perceptual, and performance measurements were determined. For statistical analysis, the minimal worthwhile difference was considered ~1% based on previous research.

Results:

Pretrial pH and HCO3 were higher in SB and CAFF+SB than in the CAFF and PLAC trials. Differences across treatments for perceived exertion and gastric discomfort were mostly unclear. Compared with PLAC, mean power output during the 3-km TT was higher in CAFF, SB, and CAFF+SB trials (2.4%, 2.6%, 2.7% respectively), resulting in faster performance times (–0.9, –1.2, –1.2% respectively). Effect sizes for all trials were small (0.21–0.24).

Conclusions:

When ingested individually, both CAFF and SB enhance high-intensity cycling TT performance in trained cyclists. However, the ergogenic effect of these 2 popular supplements was not additive, bringing into question the efficacy of coingesting the 2 supplements before short-duration high-intensity exercise. In this study there were no negative effects of combining CAFF and SB, 2 relatively inexpensive and safe supplements.

Restricted access

Michelle Smith Rockwell, Sharon M. Nickols-Richardson and Forrest W. Thye

The purpose of this investigation was to assess nutrition knowledge, opinions, and practices of coaches and trainers at a Division I university. Participants (n = 53) completed questionnaires regarding nutrition knowledge, opinions, and practices. Descriptive statistics and analysis of variance were used to analyze data. Overall, participants responded correctly to 67% of nutrition knowledge questions. Participants who coached/trained female athletes tended to score better than respondents who coached/trained male athletes. Strength and conditioning coaches and participants with greater than 15 years of experience scored higher than other participants. Nutrition opinions/practices responses revealed that nutritional supplements were provided for all but 6% of participants’ athletes. Participants rated body weight as more important than body composition to athletes’ performances. Over 30% of participants perceived at least one case of disordered eating within the past year. Some participants (53%) felt that athletes may consume more nutritious meals on team-sponsored trips if given larger food allowances. Thirty percent of participants reported dietitians were available to them; the same percentage reported utilizing dietitians. Coaches and trainers are knowledgeable about some appropriate nutritional recommendations, but registered dietitians or qualified sports nutrition professionals may complement the nutrition-related education and counseling of athletes (23).

Restricted access

Wim Derave and Kevin D. Tipton

Many athletes use dietary supplements, with use more prevalent among those competing at the highest level. Supplements are often self-prescribed, and their use is likely to be based on an inadequate understanding of the issues at stake. Supplementation with essential micronutrients may be useful when a diagnosed deficiency cannot be promptly and effectively corrected with food-based dietary solutions. When used in high doses, some supplements may do more harm than good: Iron supplementation, for example, is potentially harmful. There is good evidence from laboratory studies and some evidence from field studies to support health or performance benefits from appropriate use of a few supplements. The available evidence from studies of aquatic sports is small and is often contradictory. Evidence from elite performers is almost entirely absent, but some athletes may benefit from informed use of creatine, caffeine, and buffering agents. Poor quality assurance in some parts of the dietary supplements industry raises concerns about the safety of some products. Some do not contain the active ingredients listed on the label, and some contain toxic substances, including prescription drugs, that can cause health problems. Some supplements contain compounds that will cause an athlete to fail a doping test. Supplement quality assurance programs can reduce, but not entirely eliminate, this risk.

Restricted access

Terri Graham-Paulson, Claudio Perret and Victoria Goosey-Tolfrey

PT1 paratriathlete, the authors explored the use of CAF as a supplement. The handcycle section of a paratriathlon comprises more than half the total time (∼00:36 in a ∼01:02 hr:min performance); hence, this section was chosen as part of a controlled laboratory testing protocol. The aim of the current

Restricted access

Andreas Apostolidis, Vassilis Mougios, Ilias Smilios, Johanna Rodosthenous and Marios Hadjicharalambous

-intensity actions, with oxygen uptake averaging approximately 70% of VO 2 max. 13 However, anaerobic performance and neuromuscular performance, both of which may increase with caffeine supplementation (as discussed above), are also important determinants of soccer performance. Thus, soccer games and controlled

Restricted access

Ozcan Esen, Ceri Nicholas, Mike Morris and Stephen J. Bailey

Dietary supplementation with inorganic nitrate (NO 3 − ) has emerged as a popular nutritional intervention to enhance exercise performance. After ingestion, NO 3 − is chemically reduced to nitrite (NO 2 − ), via anaerobic bacteria that populate the oral cavity, and subsequently to nitric oxide (NO

Restricted access

Austin T. Robinson, Adriana Mazzuco, Ahmad S. Sabbahi, Audrey Borghi-Silva and Shane A. Phillips

Preworkout supplements appeal to physically active individuals as a presumably safe method to improve athletic performance ( Hoffman et al., 2009 ; Ormsbee et al., 2012 ; Outlaw et al., 2014 ). In support of this notion, some multi-ingredient preworkout supplements have been shown to augment the

Open access

D. Enette Larson-Meyer, Kathleen Woolf and Louise Burke

, or assistance with sport-specific nutrition strategies, advice on supplement use is also commonly desired. The use of dietary supplements, however, should not compensate for poor food choices and an inadequate diet, except as a short-term strategy when dietary changes are not possible ( Maughan

Restricted access

Gabriella Berwig Möller, Maria Júlia Vieira da Cunha Goulart, Bruna Bellincanta Nicoletto, Fernanda Donner Alves and Cláudia Dornelles Schneider

Probiotics are live microorganisms, usually lactic acid bacteria, that when administered in adequate amounts, bring health benefits to the host ( Rijkers et al., 2011 ). Their usage has widely increased, mainly as dietary supplements in capsules, powder or fermented milk ( Pyne et al., 2015