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  • Author: Cecilia Shing x
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Matthew W. Driller, Christos K. Argus and Cecilia M. Shing

Purpose:

To determine the reliability of a 30-s sprint cycle test on the Wattbike cycle ergometer.

Methods:

Over 3 consecutive weeks, 11 highly trained cyclists (mean ± SD; age 31 ± 6 y, mass 74.6 ± 10.6 kg, height 180.5 ± 8.1cm) completed four 30-s maximal sprints on a Wattbike ergometer after a standardized warmup. The sprint test implemented a “rolling start” that consisted of a 60-s preload (at an intensity of 4.5 W/kg) before the 30-s maximal sprint. Variables determined across the duration of the sprint were peak power (Wpeak), mean power (Wmean), W/kg, mean cadence (rpm), maximum heart rate (n = 10), and postexercise blood lactate.

Results:

The average intraclass correlation coefficients between trials (2v1, 3v2, 4v3, 4v1) were Wpeak .97 (90%CI .94–.99), Wmean .99 (90%CI .97–1.00), W/kg .96 (90%CI .91–.98), mean cadence .96 (90%CI .92–.99), maximum heart rate .99 (90%CI .97–.99), and postexercise blood lactate .94 (90%CI .87–.98). The average typical error of measurement (expressed as a CV% and absolute value between trials—2v1, 3v2, 4v3, 4v1) was Wpeak 4.9%, 52.7 W; Wmean 2.4%, 19.2 W; W/kg 2.3%, 0.18 W/kg; mean cadence 1.4%, 1.6 rpm; maximum heart rate 0.9%, 1.6 beats/min; and postexercise blood lactate 4.6%, 0.48 mmol/L.

Conclusion:

A 30-s sprint test on the Wattbike cycle ergometer is highly reproducible in trained cyclists.

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Dana M. Lis, Trent Stellingwerff, Cecilia M. Shing, Kiran D.K. Ahuja and James W. Fell

Adherence to a gluten-free diet (GFD) for nonceliac athletes (NCA) has become increasingly popular despite a paucity of supportive medical or ergogenic evidence. This study aimed to quantify the demographics of NCA and determine associated experiences, perceptions, and sources of information related to GFD. Athletes (n = 910, female = 528, no gender selected = 5) completed a 17-question online survey. Forty-one percent of NCA respondents, including 18-world and/or Olympic medalists, follow a GFD 50–100% of the time (GFD > 50): only 13% for treatment of reported medical conditions with 57% self-diagnosing their gluten sensitivity. The GFD > 50 group characteristics included predominantly endurance sport athletes (70.0%) at the recreationally competitive level (32.3%), between 31 and 40 years of age (29.1%). Those who follow a GFD > 50 reported experiencing, abdominal/gastrointestinal (GI) symptoms alone (16.7%) or in conjunction with two (30.7%) or three (35.7%) additional symptoms (e.g., fatigue) believed to be triggered by gluten. Eighty-four percent of GFD > 50 indicated symptom improvement with gluten-removal. Symptom-based and non-symptom-based self-diagnosed gluten-sensitivity (56.7%) was the primary reason for adopting a GFD. Leading sources of GFD information were online (28.7%), trainer/coach (26.2%) and other athletes (17.4%). Although 5–10% of the general population is estimated to benefit clinically from a GFD a higher prevalence of GFD adherence was found in NCA (41.2%). Prescription of a GFD among many athletes does not result from evidence-based practice suggesting that adoption of a GFD in the majority of cases was not based on medical rationale and may be driven by perception that gluten removal provides health benefits and an ergogenic edge in NCA.

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Samuel T. Howe, Phillip M. Bellinger, Matthew W. Driller, Cecilia M. Shing and James W. Fell

Beta-alanine may benefit short-duration, high-intensity exercise performance. The aim of this randomized double-blind placebo-controlled study was to examine the effects of beta-alanine supplementation on aspects of muscular performance in highly trained cyclists. Sixteen highly trained cyclists (mean ± SD; age = 24 ± 7 yr; mass = 70 ± 7kg; VO2max = 67 ± 4ml·kg−1·min–1) supplemented with either beta-alanine (n = 8, 65 mg·kg−1BM) or a placebo (n = 8; dextrose monohydrate) over 4 weeks. Pre- and postsupplementation cyclists performed a 4-minute maximal cycling test to measure average power and 30 reciprocal maximal isokinetic knee contractions at a fixed angular velocity of 180°·sec−1 to measure average power/repetition, total work done (TWD), and fatigue index (%). Blood pH, lactate (La) and bicarbonate (HCO3 -) concentrations were measured preand postisokinetic testing at baseline and following the supplementation period. Beta-alanine supplementation was 44% likely to increase average power output during the 4-minute cycling time trial when compared with the placebo, although this was not statistically significant (p = .25). Isokinetic average power/repetition was significantly increased post beta-alanine supplementation compared with placebo (beta-alanine: 6.8 ± 9.9W, placebo: –4.3 ± 9.5 W, p = .04, 85% likely benefit), while fatigue index was significantly reduced (p = .03, 95% likely benefit). TWD was 89% likely to be improved following beta-alanine supplementation; however, this was not statistically significant (p = .09). There were no significant differences in blood pH, lactate, and HCO3 between groups (p > .05). Four weeks of beta-alanine supplementation resulted in worthwhile changes in time-trial performance and short-duration muscular force production in highly trained cyclists.

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Thomas M. Doering, James W. Fell, Michael D. Leveritt, Ben Desbrow and Cecilia M. Shing

The purpose of this study was to investigate if acute caffeine exposure via mouth-rinse improved endurance cycling time-trial performance in well-trained cyclists. It was hypothesized that caffeine exposure at the mouth would enhance endurance cycling time-trial performance. Ten well-trained male cyclists (mean± SD: 32.9 ± 7.5 years, 74.7 ± 5.3kg, 176.8 ± 5.1cm, VO2peak = 59.8 ± 3.5ml·kg–1·min–1) completed two experimental timetrials following 24 hr of dietary and exercise standardization. A randomized, double-blind, placebo-controlled, cross-over design was employed whereby cyclists completed a time-trial in the fastest time possible, which was equivalent work to cycling at 75% of peak aerobic power output for 60 min. Cyclists were administered 25ml mouth-rinses for 10 s containing either placebo or 35mg of anhydrous caffeine eight times throughout the time-trial. Perceptual and physiological variables were recorded throughout. No significant improvement in time-trial performance was observed with caffeine (3918 ± 243s) compared with placebo mouth-rinse (3940 ± 227s). No elevation in plasma caffeine was detected due to the mouth-rinse conditions. Caffeine mouth-rinse had no significant effect on rating of perceived exertion, heart rate, rate of oxygen consumption or blood lactate concentration. Eight exposures of a 35 mg dose of caffeine at the buccal cavity for 10s does not significantly enhance endurance cycling time-trial performance, nor does it elevate plasma caffeine concentration.

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Marie-Louise Bird, Cecilia Shing, Casey Mainsbridge, Dean Cooley and Scott Pedersen

Background:

Sedentary behavior is related to metabolic syndrome and might have implications for the long-term health of workers in a low activity environment. The primary aim of this pilot study was to determine activity levels of adults working at a University during work hours. A secondary aim was to determine the relationship between actual and perceived activity levels.

Methods:

Activity levels of university staff (n = 15, male = 7, age = 53 ± 7 years, BMI = 26.5 ± 2.5kg·m2) were monitored over 5 consecutive workdays using SenseWear accelerometers, then participants completed a questionnaire of their perception of workplace sedentary time.

Results:

Each participant spent 71.5 ± 13.1% (358 ± 78 min) of their workday being sedentary (< 1.5 METs), 15.6 ± 9.0% involved in light activity (1.5–3 METs), 11.7 ± 10.0% in moderate activity (3–5 METs), and 1.1 ± 1.3% in vigorous activity (> 5 METs) (P < .0001). The mean difference between actual (SenseWear < 1.5 METs) and perceived sitting time was –2 ± 32%; however, perceived sedentary time was reported with a range of under-to-over estimation of –75% to 51%.

Conclusion:

This pilot study identifies long periods of low metabolic activity during the workday and poor perception of individual sedentary time. Interventions to reduce sedentary time in the workplace may be necessary to ensure that the work environment does not adversely affect long-term health.

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Matthew W. Driller, James W. Fell, John R. Gregory, Cecilia M. Shing and Andrew D. Williams

Purpose:

Several recent studies have reported substantial performance and physiological gains in well-trained endurance runners, swimmers, and cyclists following a period of high-intensity interval training (HIT). The aim of the current study was to compare traditional rowing training (CT) to HIT in well-trained rowers.

Methods:

Subjects included 5 male and 5 female rowers (mean ± SD; age = 19 ± 2 y; height = 176 ± 8 cm; mass = 73.7 ± 9.8 kg; Vo2peak = 4.37 ± 1.08 L·min−1). Baseline testing included a 2000-m time trial and a maximal exercise test to determine Vo2peak, 4-min all-out power, and 4 mmol·L−1 blood lactate threshold. Following baseline testing, rowers were randomly allocated to HIT or CT, which they performed seven times over a 4-wk period. The HIT involved 8 × 2.5-min intervals at 90% of the velocity maintained at Vo2peak, with individual recoveries returning to 70% of the subjects’ maximal heart rate between intervals. The CT intensity consisted of workloads corresponding to 2 and 3 mmol·L−1 blood lactate concentrations. On completion of HIT or CT, rowers repeated the testing performed at baseline and were then allocated to the alternative training program and completed a crossover trial.

Results:

HIT produced greater improvements in 2000-m time (1.9 ± 0.9%; mean ± SD), 2000-m power (5.8 ± 3.0%), and relative Vo2peak (7.0 ± 6.4%) than CT.

Conclusion:

Four weeks of HIT improves 2000-m time-trial performance and relative Vo2peak in competitive rowers, more than a traditional approach.