Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (M.S.)--University of North Texas, 2001. / Includes bibliographical references (leaves 44-46). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

There were two primary goals in this investigation. The first goal was to determine if results from field tests (time-trials and a Conconi incremental test) are related to performance in mass-start long-distance bicycle races. The second goal was to investigate inter-relationships among field test variables. The testing variables measured were critical velocity (CV), Conconi anaerobic threshold (AT) velocity, 4mM AT velocity, fatigue index, peak blood lactate, and anaerobic work capacity. Participants were USCF 30 category 1 through 5 cyclists. Participants performed one 20.75 km and two 10.37 km all-out tests in the field. They also performed an incremental test. The tests were performed at one-week intervals. Results from the field tests were compared to recent mass-start racing performance. Results indicated that Conconi AT velocity was related to performance in a 161-km race. There was also a relationship between 4mM AT velocity and CV and between Conconi AT velocity and 4mM AT velocity. It was concluded that field tests might provide information about performance ability in mass-start long-distance bicycle races.

Graduation date: 1992

The purpose of this study was to determine the effect of cadence on time trial performance in novice female cyclists. Ten novice female cyclists volunteered to participate in this study. Participants performed 3 sessions: one VO2 peak and two time trials (TT). Cadence was randomly selected and fixed for each TT (60 or 100 rpm) while power output (PO) was adjusted by the participant, as tolerated. Finish time, HR, blood lactate, PO, VO2, and RPE were measured throughout the time trials. The major finding of this study was the significantly faster (p<0.05) finish time (minutes) during the 60 rpm condition (34:23) versus the 100 rpm condition (37:34). Also the 60 rpm TT resulted in significant (p<0.05) differences for HR (155.9 vs 161.2 bpm), gross efficiency (21.1% vs 17.7%), and PO (147 vs 129 watts). These results indicate that novice female cyclists benefit from adopting a low cadence during an 8k TT. / by Patricia Graham. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Aim: The primary purpose of this study was to examine effects of a fan-induced airflow at standard room temperature (20-23°C) on 20-km cycling time trial performance. A secondary purpose was to investigate two fan speeds and whether a difference in performance existed with increased fan speed in intermediate duration indoor cycling tests. Methods: Seven trained cyclists completed three 20-km cycling time trials under three conditions in a randomized crossover design. The 3 conditions were: 1) control (no fan), 2) low speed fan, and 3) high speed fan. Results: A tendency for modest decreases in time to completion (TTC) were noted in the two experimental conditions compared to the control condition (-2.06% low speed fan; -3.29% high speed fan). There was also a tendency for small increases in power output during the experimental conditions, although neither time nor power output differences were statistically significant. No differences in mean heart rate and rating of perceived exertion were observed among the three conditions. Conclusion: These results suggest a relationship between fan use and 20-km indoor cycling time trial performance, specifically TTC and mean power output, but larger samples are needed to provide adequate statistical power. Further investigation into the effects of fan use in standard testing environments is recommended. No additional benefit was observed from increased fan speeds. Differences in the experimental conditions on average resulted in non-significant 1.2% improvement.

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Aerobic and anaerobic correlates of multiple sprint cycling performance. J. Strength Cond. Res. 20(4):792-798. 2006.--The aims of this study were to examine (a) the relationship between maximal oxygen uptake (O2max) and several performance indices of multiple sprint cycling; (b) the relationship between maximal accumulated oxygen deficit (MAOD) and those same performance indices; and (c) the influence of recovery duration on the magnitude of those relationships. Twenty-five physically active men completed a O2max test, a MAOD test, and 2 maximal intermittent (20 x 5 seconds) sprint cycling tests with contrasting recovery periods (10 seconds or 30 seconds). Mean +/- SD for age, height, and body mass were 20.6 +/- 1.5 years, 177.2 +/- 5.4 cm, and 78.2 +/- 8.2 kg, respectively. All tests were conducted on a friction-braked cycle ergometer with subsequent data normalized for body mass. Moderate (0.3 r < 0.5) positive correlations were observed between power output data and MAOD (range, 0.31-0.46; 95% confidence limits, -0.10 to 0.72). Moderate to large positive correlations also were observed between power output data and O2max, the magnitude of which increased as values were averaged across all sprints (range, 0.45-0.67; 95% confidence limits 0.07-0.84). Correlations between fatigue and O2max were greater in the intermittent protocol with 30-second recovery periods (r = -0.34; 95% confidence limits, 0.06 to -0.65). The results of this study reflect the complex energetics associated with multiple sprint work. Though the findings add support to the idea that multiple sprint sports demand a combination of speed and endurance, further longitudinal research is required to confirm the relative importance of these parameters.

A dose response relationship between carbohydrate (CHO) ingestion and exercise performance has not been consistently reported. Additionally the underlying metabolic and neuromuscular explanations for an improvement in performance with increasing doses of CHO have not been fully explained. In Chapter 2 of this thesis 20 male cyclists completed 2 h of submaximal exercise followed by a time trial task (531 ± 48KJ). Three CHO electrolyte beverages, plus a control (water), were administered during a 2 h ride providing 0, 20, 39 or 64 g CHO·h-1 at a fluid intake rate of 1 L·h-1. Performance was assessed by time to complete the time trial task, mean power output sustained, and pacing strategy used. Mean task completion time (min:sec ± SD) for 39 g·h-1 (34:19.5 ± 03:07.1, p=0.006) and 64 g·h-1 (34:11.3 ± 03:08.5 p=0.004) of CHO were significantly faster than control (37:01.9 ± 05:35.0). The mean percentage improvement from control was -6.1% (95% CI: -11.3 to -1.0) and -6.5% (95% CI: -11.7 to -1.4) in the 39 and 64 g·h-1 trials respectively. The 20 g·h-1 (35:17.6 ± 04:16.3) treatment did not reach statistical significance compared to control (p = 0.126) despite a mean improvement of -3.7% (95% CI -8.8 to 1.5%). These data demonstrate that consuming CHO at a rate between 39 to 64 g·h-1 is likely to be optimal for most individuals looking to utilise a single source CHO as an ergogenic aid during endurance performances lasting less than 3 hrs. Attempts have been made to try and understand the acute metabolic regulation that occurs when ingesting increasing amounts of CHO. However, no one study has fully investigated the metabolic mechanisms underlying graded increments of CHO ingestion. In Chapter 3 we aimed to utilise stable isotopes and blood metabolite profiles to examine the integrated physiological responses to CHO ingestion when ingested at rates throughout the range where performance gains appear greatest. Twenty well-trained male cyclists completed 2 h constant load ride (95% lactate threshold, 185 ± 25W) where one of three CHO beverages, or a control (water), were administered every 15 min, providing participants with 0, 20, 39 or 64 g CHO·h-1 at a fixed fluid intake rate of 1L·h-1. Dual glucose tracer techniques (6,6,2H2 glucose and U13C labelled glucose) were used to determine glucose kinetics and exogenous carbohydrate oxidation (EXO) during exercise. Endogenous CHO contribution was suppressed in the second hour of exercise when consuming 39 and 64 g·h-1 in comparison to 0 g·h-1 (-7.3%, 95%CI: -13.1 to -1.6 and -11.2%, 95%CI: -16.9 to -5.5 respectively). Additionally, consuming 64 g·h-1 suppressed the endogenous CHO contribution by -7.2% (95%CI: -1.5 to -13.0) compared to the 20 g·h-1 treatment. Exogenous CHO oxidation rate increased by 0.13 g·min-1 (95%CI: 0.10 to 0.15) and 0.29 g·min-1 (95%CI: 0.27 to 0.31) when consuming 39 and 64 g·h-1 in comparison to 20 g·h-1 of CHO. Peak exogenous CHO oxidation rates were 0.34 (0.06), 0.54 (0.09) and 0.78 (0.19) g·min-1 for 20, 39 and 64 g·h-1 respectively. Plasma NEFA concentration was 0.10 (95%CI: 0.07 to 0.13), 0.12 (95%CI: 0.10 to 0.16) and 0.16 (95%CI: 0.13 to 0.19) mmol.L-1 higher when consuming 0 g·h-1 in comparison to 20, 39 and 64 g·h-1 respectively. Both 39 and 64 g·h-1 were effective at sparing endogenous CHO stores of which it is estimated that most of this is liver glycogen sparing, but the measured response was highly variable between individuals. Consuming 39 g·h-1 of CHO appears to be the minimum ingestion rate required to have a significant metabolic effect that results in an increase in performance. Recent research has indicated a key role of endogenous CHO sensing and oral glucose sensing in maintaining central drive and peripheral function during endurance exercise tasks. Consuming 39 and 64 g·h-1 of CHO elicits the greatest improvements in performance and also demonstrate a similar metabolic response. The improvement in subsequent time trial performance when consuming 39 and 64 g·h-1 coincided with significant alterations in whole body substrate usage that lead to endogenous CHO sparing at the same ingestion rates. In Chapter 4 we aimed to utilise gold standard neuromuscular function assessment techniques, alongside novel measures, to investigate the effect of consuming different rates of CHO on neuromuscular function during and following prolonged cycling exercise. In a double-blind, randomised cross-over design, well-trained male cyclists (n=20, mean±SD, age 34 ± 10 y, mass 75.8 ± 9 kg, peak power output 394 ± 36 W, V̇O2max 62 ± 9 ml·kg-1·min-1) completed 2 familiarisation trials then 4 experimental trials. Trials involved a 2 h submaximal ride followed by a high intensity time trial task lasting approx. 35 min with each of 0, 20, 39 and 64 g·h-1 CHO ingestion rates during submaximal exercise. Each trial involved pre and post exercise assessments (MVC, Mwave twitch potentiation and force, motor unit recruitment and firing rate assessment using high density EMG) and during exercise (gross EMG amplitude). MVC peak torque values were reduced post exercise by -20.4 nM (95%CI: -26.5 to -14.4) in comparison to pre value on all trials with no differences between trials. The firing rates of early recruited motor units significantly increased by 1.55 pps (95%CI: 0.51 to 2.59) following exercise in comparison to pre-exercise rates. Gross EMG during the 2 h cycling bout revealed a main effect of treatment (p<0.01) but post hoc comparisons provided no clarity and likely reflect methodological issues. Consuming CHO at ingestion rates between 20 and 64 g·h-1 had little to no impact on the neuromuscular function of well-trained cyclists when comparing pre and post fatiguing exercise values. Despite differences in time trial completion time between trials, following exercise to fatigue in an endurance task, no post exercise differences were detected.