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Robert P. Lamberts

In high-performance cycling, it is important to maintain a healthy balance between training load and recovery. Recently a new submaximal cycle test, known as the Lamberts and Lambert Submaximal Cycle Test (LSCT), has been shown to be able to accurately predict cycling performance in 15 well-trained cyclists. The aim of this study was to determine the predictive value of the LSCT in 102 trained to elite cyclists (82 men and 20 women). All cyclists performed an LSCT test followed by a peak-power-output (PPO) test, which included respiratory-gas analysis for the determination of maximal oxygen consumption (VO2max). They then performed the LSCT test followed by a 40-km time trial (TT) 72 h later. Average power output during the 3 stages of the LSCT increased from 31%, 60%, and 79% of PPO, while the ratings of perceived exertion increased from 8 to 13 to 16. Very good relationships were found between actual and LSCT-predicted PPO (r = .98, 95%CI: .97–.98, P < .0001), VO2max (r = .96, 95%CI: .97–.99, P < .0001) and 40-km-TT time (r = .98, 95%CI: .94–.97, P < .0001). No gender differences were found when predicting cycling performance from the LSCT (P = .95). The findings of this study show that the LSCT is able to accurately predict cycling performance in trained to elite male and female cyclists and potentially can be used to prescribe and fine-tune training prescription in cycling.

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Edwin Chong, Kym J. Guelfi and Paul A. Fournier

This study investigated whether combined ingestion and mouth rinsing with a carbohydrate solution could improve maximal sprint cycling performance. Twelve competitive male cyclists ingested 100 ml of one of the following solutions 20 min before exercise in a randomized double-blinded counterbalanced order (a) 10% glucose solution, (b) 0.05% aspartame solution, (c) 9.0% maltodextrin solution, or (d) water as a control. Fifteen min after ingestion, repeated mouth rinsing was carried out with 11 × 15 ml bolus doses of the same solution at 30-s intervals. Each participant then performed a 45-s maximal sprint effort on a cycle ergometer. Peak power output was significantly higher in response to the glucose trial (1188 ± 166 W) compared with the water (1036 ± 177 W), aspartame (1088 ± 128 W) and maltodextrin (1024 ± 202W) trials by 14.7 ± 10.6, 9.2 ± 4.6 and 16.0 ± 6.0% respectively (p < .05). Mean power output during the sprint was significantly higher in the glucose trial compared with maltodextrin (p < .05) and also tended to be higher than the water trial (p = .075). Glucose and maltodextrin resulted in a similar increase in blood glucose, and the responses of blood lactate and pH to sprinting did not differ significantly between treatments (p > .05). These findings suggest that combining the ingestion of glucose with glucose mouth rinsing improves maximal sprint performance. This ergogenic effect is unlikely to be related to changes in blood glucose, sweetness, or energy sensing mechanisms in the gastrointestinal tract.

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David Montero and Carsten Lundby

Context:

Few recent studies indicate that short-term repeated-sprint (RS) training in hypoxia (RSH) improves RS performance compared with identical training under normoxic conditions (RSN) in endurance-trained subjects.

Purpose:

To determine the effects of RSH against RSN on RS performance under normoxic and moderate hypoxic conditions, using a randomized, doubleblind, crossover experimental design.

Methods:

Fifteen endurance-trained male subjects (age 25 ± 4 y) performed 4 wk of RS training (3 sessions/wk) in normobaric hypoxia (RSH, FiO2 = 13.8%) and normoxia (RSN, FiO2 = 20.9%) in a crossover manner. Before and after completion of training, RS tests were performed on a cycle ergometer with no prior exercise (RSNE), after an incremental exercise test (RSIE), and after a time-trial test (RSTT) in normoxia and hypoxia.

Results:

Peak power outputs at the incremental exercise test and time-trial performance were unaltered by RSH in normoxia and hypoxia. RS performance was generally enhanced by RSH, as well as RSN, but there were no additional effects of RSH over RSN on peak and mean sprint power output and the number of repeated sprints performed in the RSNE, RSIE, and RSTT trials under normoxic and hypoxic conditions.

Conclusions:

The present double-blind crossover study indicates that RSH does not improve RS performance compared with RSN in normoxic and hypoxic conditions in endurance-trained subjects. Therefore, caution should be exercised when proposing RSH as an advantageous method to improve exercise performance.

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André X. Bigard, Pierre Lavier, Lionel Ullmann, Hélène Legrand, Philippe Douce and Charles Y. Guezennec

This study was conducted to test the hypothesis that a branched-chain amino acid (BCAA) supplementation would minimize changes in body composition and alterations in plasma amino acid profile induced by prolonged exercises at altitude. Twenty-four highly trained subjects participated in six successive sessions of ski mountaineering (6-8 hr duration, altitude 2,500-4,100 m). Twelve subjects took a dietary supplement of BCAA (BCAA group) and 12 took a dietary supplement that was 98% carbohydrate (C group). Body weight decreased in C subjects (-2.1%,p < .01), while the body weight loss recorded in the BCAA group was not statistically significant (-1.2%, NS). Changes in body composition that resulted from repeated skiing exercise at altitude were not significantly minimized by BCAA administration. Peak power output recorded during an incremental bicycle exercise decreased in C subjects but did not change significantly in BCAA subjects. Results of this study demonstrate that neither changes in body composition related to the ski mountaineering program nor muscular performance during isometric contraction was significantly affected by BCAA administration.

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Mark Hayes, Paul C. Castle, Emma Z. Ross and Neil S. Maxwell

Purpose:

To examine the effect of a hot humid (HH) compared with a hot dry (HD) environment, matched for heat stress, on intermittent-sprint performance. In comparison with HD, HH environments compromise evaporative heat loss and decrease exercise tolerance. It was hypothesized that HH would produce greater physiological strain and reduce intermittent-sprint exercise performance compared with HD.

Method:

Eleven male team-sport players completed the cycling intermittent-sprint protocol (CISP) in 3 conditions, temperate (TEMP; 21.2°C ± 1.3°C, 48.6% ± 8.4% relative humidity [rh]), HH (33.7°C ± 0.5°C, 78.2% ± 2.3% rh), and HD (40.2°C ± 0.2°C, 33.1% ± 4.9% rh), with both heat conditions matched for heat stress.

Results:

All participants completed the CISP in TEMP, but 3 failed to completed the full protocol of 20 sprints in HH and HD. Peak power output declined in all conditions (P < .05) but was not different between any condition (sprints 1–14 [N = 11]: HH 1073 ± 150 W, HD 1104 ± 127 W, TEMP, 1074 ± 134; sprints 15–20 [N = 8]: HH 954 ± 114 W, HD 997 ± 115 W, TEMP 993 ± 94; P > .05). Physiological strain was not significantly different in HH compared with HD, but HH was higher than TEMP (P < .05).

Conclusion:

Intermittent-sprint exercise performance of 40 min duration is impaired, but it is not different in HH and HD environments matched for heat stress despite evidence of a trend toward greater physiological strain in an HH environment.

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Prue Cormie, Jeffrey M. McBride and Grant O. McCaulley

The purpose of this investigation was to examine the impact of load on the power-, force- and velocity-time curves during the jump squat. The analysis of these curves for the entire movement at a sampling frequency of 200–500 Hz averaged across 18 untrained male subjects is the most novel aspect of this study. Jump squat performance was assessed in a randomized fashion across five different external loads: 0, 20, 40, 60, and 80 kg (equivalent to 0 ± 0, 18 ± 4, 37 ± 8, 55 ± 12, 74 ± 15% of 1RM, respectively). The 0-kg loading condition (i.e., body mass only) was the load that maximized peak power output, displaying a significantly (p ≤ .05) greater value than the 40, 60, and 80 kg loads. The shape of the force-, power-, and velocity-time curves changed significantly as the load applied to the jump squat increased. There was a significantly greater rate of power development in the 0 kg load in comparison with all other loads examined. As the first comprehensive illustration of how the entire power-, force-, and velocity-time curves change across various loading conditions, this study provides extensive evidence that a load equaling an individuals body mass (i.e., external load = 0 kg) maximizes power output in untrained individuals during the jump squat.

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Gregory T. Levin, Paul B. Laursen and Chris R. Abbiss

Purpose:

To assess the reliability of a 5-min-stage graded exercise test (GXT) and determine the association between physiological attributes and performance over stochastic cycling trials of varying distance.

Methods:

Twenty-eight well-trained male cyclists performed 2 GXTs and either a 30-km (n = 17) or a 100-km stochastic cycling time trial (n = 9). Stochastic cycling trials included periods of high-intensity efforts for durations of 250 m, 1 km, or 4 km depending on the test being performing.

Results:

Maximal physiological attributes were found to be extremely reliable (maximal oxygen uptake [VO2max]: coefficient of variation [CV] 3.0%, intraclass correlation coefficient [ICC] .911; peak power output [PPO]: CV 3.0%, ICC .913), but a greater variability was found in ventilatory thresholds and economy. All physiological variables measured during the GXT, except economy at 200 W, were correlated with 30-km cycling performance. Power output during the 250-m and 1-km efforts of the 30-km trial were correlated with VO2max, PPO, and the power output at the second ventilatory threshold (r = .58–.82). PPO was the only physiological attributed measured during the GXT to be correlated with performance during the 100-km cycling trial (r = .64).

Conclusions:

Many physiological variables from a reliable GXT were associated with performance over shorter (30-km) but not longer (100-km) stochastic cycling trials.

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Paul S.R. Goods, Brian T. Dawson, Grant J. Landers, Christopher J. Gore and Peter Peeling

Purpose:

This study aimed to assess the impact of 3 heights of simulated altitude exposure on repeat-sprint performance in teamsport athletes.

Methods:

Ten trained male team-sport athletes completed 3 sets of repeated sprints (9 × 4 s) on a nonmotorized treadmill at sea level and at simulated altitudes of 2000, 3000, and 4000 m. Participants completed 4 trials in a random order over 4 wk, with mean power output (MPO), peak power output (PPO), blood lactate concentration (Bla), and oxygen saturation (SaO2) recorded after each set.

Results:

Each increase in simulated altitude corresponded with a significant decrease in SaO2. Total work across all sets was highest at sea level and correspondingly lower at each successive altitude (P < .05; sea level < 2000 m < 3000 m < 4000 m). In the first set, MPO was reduced only at 4000 m, but for subsequent sets, decreases in MPO were observed at all altitudes (P < .05; 2000 m < 3000 m < 4000 m). PPO was maintained in all sets except for set 3 at 4000 m (P < .05; vs sea level and 2000 m). BLa levels were highest at 4000 m and significantly greater (P < .05) than at sea level after all sets.

Conclusions:

These results suggest that “higher may not be better,” as a simulated altitude of 4000 m may potentially blunt absolute training quality. Therefore, it is recommended that a moderate simulated altitude (2000–3000 m) be employed when implementing intermittent hypoxic repeat-sprint training for team-sport athletes.

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Joseph A. McQuillan, Deborah K. Dulson, Paul B. Laursen and Andrew E. Kilding

We aimed to compare the effects of two different dosing durations of dietary nitrate (NO3 -) supplementation on 1 and 4 km cycling time-trial performance in highly trained cyclists. In a double-blind crossover-design, nine highly trained cyclists ingested 140ml of NO3 --rich beetroot juice containing ~8.0mmol [NO3 -], or placebo, for seven days. Participants completed a range of laboratory-based trials to quantify physiological and perceptual responses and cycling performance: time-trials on day 3 and 6 (4km) and on day 4 and 7 (1km) of the supplementation period. Relative to placebo, effects following 3- and 4-days of NO3 - supplementation were unclear for 4 (-0.8; 95% CL, ± 2.8%, p = .54) and likely harmful for 1km (-1.9; ± 2.5% CL, p = .17) time-trial mean power. Effects following 6- and 7-days of NO3 - supplementation resulted in unclear effects for 4 (0.1; ± 2.2% CL, p = .93) and 1km (-0.9; ± 2.6%CL, p = .51) time-trial mean power. Relative to placebo, effects for 40, 50, and 60% peak power output were unclear for economy at days 3 and 6 of NO3 - supplementation (p > .05). Dietary NO3 - supplementation appears to be detrimental to 1km time-trial performance in highly trained cyclists after 4-days. While, extending NO3 - dosing to ≥ 6-days reduced the magnitude of harm in both distances, overall performance in short duration cycling time-trials did not improve relative to placebo.

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Julia H. Goedecke, Virginia R. Clark, Timothy D. Noakes and Estelle V. Lambert

The aims of the study were to determine if medium-chain triacylglycerol (MCT), ingested in combination with carbohydrate (CHO), would alter substrate metabolism and improve simulated competitive ultra-endurance cycling performance. Eight endurance-trained cyclists took part in this randomized, single-blind crossover study. On two separate occasions, subjects cycled for 270 min at 50% of peak power output, interspersed with four 75 kJ sprints at 60 min intervals, followed immediately by a 200 kJ time-trial. One hour prior to the exercise trials, subjects ingested either 75 g of CHO or 32 g of MCT, and then ingested 200 mL of a 10% CHO (wt/vol) solution or a 4.3% MCT + 10% CHO (wt/vol) solution every 20 min during the CHO and MCT trials, respectively. During the constant-load phases of the 270 min exercise trial, VO2, RER, and heart rate were measured at 30 min intervals and gastrointestinal (GI) symptoms were recorded. There was no difference in VO2 or RER between the MCT and CHO trials (P = 0.40). Hourly sprint (P = 0.03 for trial x time interaction) and time-trial times (14:30 ± 0.58 vs. 12:36 ± 1:6, respectively, P < 0.001) were slower in the MCT than the CHO trial. Half the subjects experienced GI symptoms with MCT ingestion. In conclusion, MCTs ingested prior to exercise and co-ingested with CHO during exercise did not alter substrate metabolism and significantly compromised sprint performance during prolonged ultra-endurance cycling exercise.