The efficacy of the use of an upper body compression garment (UBCG) as an ergogenic aid to reduce thermoregulatory strain in older adults remains unknown. The aim of this study was to evaluate the effects of UBCG on thermoregulatory, cardiorespiratory, and perceptual responses during cycling in a temperate environment (~25 °C, 66% rh) in trained older adults. Twelve cyclists aged 66 ± 2 years performed an intermittent 1-hr cycling trial at 50% of the peak power output followed by 10 min of passive recovery. Participants were provided with either commercially available UBCG or a control garment in a randomized order. UBCG increased thermoregulatory strain during exercise, as indicated by a significantly higher core temperature (38.1 ± 0.3 °C vs. 37.9 ± 0.3 °C; p = .04), body temperature (36.9 ± 0.2 °C vs. 36.7 ± 0.2 °C; p = .01), and thermal sensation (8.0 ± 0.4 vs. 7.5 ± 1.0; p = .02). These results suggest that the use of UBCG in trained older adults does not reduce the thermoregulatory strain during moderate exercise.
Iker Leoz-Abaurrea, Mikel Izquierdo, Miriam Gonzalez-Izal and Roberto Aguado-Jiménez
Andrew D. Williams, Isaac Selva Raj, Kristie L. Stucas, James W. Fell, Diana Dickenson and John R. Gregory
Uncoupled cycling cranks are designed to remove the ability of one leg to assist the other during the cycling action. It has been suggested that training with this type of crank can increase mechanical efficiency. However, whether these improvements can confer performance enhancement in already well-trained cyclists has not been reported.
Fourteen well-trained cyclists (13 males, 1 female; 32.4 ± 8.8 y; 74.5 ± 10.3 kg; Vo2max 60.6 ± 5.5 mL·kg−1·min−1; mean ± SD) participated in this study. Participants were randomized to training on a stationary bicycle using either an uncoupled (n = 7) or traditional crank (n = 7) system. Training involved 1-h sessions, 3 days per week for 6 weeks, and at a heart rate equivalent to 70% of peak power output (PPO) substituted into the training schedule in place of other training. Vo2max, lactate threshold, gross efficiency, and cycling performance were measured before and following the training intervention. Pre- and post testing was conducted using traditional cranks.
No differences were observed between the groups for changes in Vo2max, lactate threshold, gross efficiency, or average power maintained during a 30-minute time trial.
Our results indicate that 6 weeks (18 sessions) of training using an uncoupled crank system does not result in changes in any physiological or performance measures in well-trained cyclists.
Gregory T. Levin, Paul B. Laursen and Chris R. Abbiss
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.
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.
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).
Many physiological variables from a reliable GXT were associated with performance over shorter (30-km) but not longer (100-km) stochastic cycling trials.
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.
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.
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.
Darren G. Burke, Shawn Silver, Laurence E. Holt, Truis Smith-Palmer, Christopher J. Culligan and Philip D. Chilibeck
Dietary supplementation (SUP) has become a significant part of athletic training. Studies indicate that creatine (Cr) can enhance short-duration, high-intensity activities. This study examined the effect of 21 days of low dose Cr SUP (~7.7 g/day) and resistance training on force output, power output, duration of mean peak power output, and total work performed until fatigue. A double-blind protocol was used, where an individual, who was not part of any other aspect of the study, randomly assigned subjects to creatine and placebo groups. Forty-one male university athletes were randomly assigned to either Cr (n= 20) or placebo (n = 21) SUP. On the first and last day of the study, subjects were required to perform concentric bench press movements until exhaustion on an isokinetic dynamometer. The dynamometer was hard-wired to a personal computer, which provided force, velocity, and duration measures. Force and power output until fatigue, were used to determine total work, force-time, and power-time relationships. ANOVA results revealed that the Cr subjects performed more total work until fatigue, experienced significantly greater improvements in peak force and peak power, and maintained elevated mean peak power for a longer period of time. These results indicate that Cr SUP can significantly improve factors associated with short-duration, high-intensity activity.
Alannah Quinlivan, Christopher Irwin, Gary D. Grant, Sheilandra Anoopkumar-Dukie, Tina Skinner, Michael Leveritt and Ben Desbrow
This study investigated the ergogenic effects of a commercial energy drink (Red Bull) or an equivalent dose of anhydrous caffeine in comparison with a noncaffeinated control beverage on cycling performance. Eleven trained male cyclists (31.7 ± 5.9 y 82.3 ± 6.1 kg, V̇O2max = 60.3 ± 7.8 mL · kg–1 · min–1) participated in a double-blind, placebo-controlled, crossover-design study involving 3 experimental conditions. Participants were randomly administered Red Bull (9.4 mL/kg body mass [BM] containing 3 mg/kg BM caffeine), anhydrous caffeine (3 mg/kg BM given in capsule form), or a placebo 90 min before commencing a time trial equivalent to 1 h cycling at 75% peak power output. Carbohydrate and fluid volumes were matched across all trials. Performance improved by 109 ± 153 s (2.8%, P = .039) after Red Bull compared with placebo and by 120 ± 172 s (3.1%, P = .043) after caffeine compared with placebo. No significant difference (P > .05) in performance time was detected between Red Bull and caffeine treatments. There was no significant difference (P > .05) in mean heart rate or rating of perceived exertion among the 3 treatments. This study demonstrated that a moderate dose of caffeine consumed as either Red Bull or in anhydrous form enhanced cycling time-trial performance. The ergogenic benefits of Red Bull energy drink are therefore most likely due to the effects of caffeine, with the other ingredients not likely to offer additional benefit.
Jos J. de Koning, Dionne A. Noordhof, Tom P. Uitslag, Rianna E Galiart, Christopher Dodge and Carl Foster
Gross efficiency (GE) is coupling power production to propulsion and is an important performance-determining factor in endurance sports. Measuring GE normally requires measuring VO2 during submaximal exercise. In this study a method is proposed to estimating GE during high-intensity exercise.
Nineteen subjects completed a maximal incremental test and 2 GE tests (1 experimental and 1 control test). The GE test consisted of 10 min cycling at 50% peak power output (PPO), 2 min at 25 W, followed by 4 min 100% PPO, 1 min at 25 W, and another 10 min at 50% PPO. GE was determined for the 50%-PPO sections and was, for the second 50%-PPO section, back-extrapolated, using linear regression, to the end of the 100%-PPO bout.
Back-extrapolation of the GE data resulted in a calculated GE of 15.8% ± 1.7% at the end of the 100%-PPO bout, in contrast to 18.3% ± 1.3% during the final 2 min of the first 10-min 50%-PPO bout.
Back-extrapolation seems valuable in providing more insight in GE during high-intensity exercise.
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.