The purpose of this study was to validate an existing V̇O2max prediction equation for a graded cycle ergometer test, using adolescents as subjects (14). Healthy, active males (n = 19) and females (n = 19), ages 13–18 years old, pedaled at a rate of 60 rpm until exhaustion, with resistance increasing 15 W every minute. Oxygen uptake, ventilation, and respiratory exchange ratio were measured continuously. A significant correlation was found between predicted and actual V̇O2max for both male (r = 0.90, p < .001) and female (r = 0.91, p < .001) adolescents. For all subjects combined the correlation was r = 0.96, p < .001 with an SEE = 198 ml · min−1. Mean differences between actual and predicted V̇O2max values were 1.0 ± 0.7 ml · kg−1 · min−1 and 2.0 ± 0.7 ml · kg−1 · min−1 for the males and females, respectively (2.1% and 5.2% difference). The data indicate these cycle ergometry equations are valid for prediction of V̇O2max in male and female adolescents.
Alan P. Jung, David C. Nieman and Michael W. Kernodle
David Michael Morris and Rebecca Susan Shafer
The authors sought to compare power output at blood lactate threshold, maximal lactate steady state, and pH threshold with the average power output during a simulated 20-km time trial assessed during cycle ergometry. Participants (N = 13) were trained male and female cyclists and triathletes, all permanent residents at moderate altitude (1,525–2,225 m). Testing was performed at 1,525 or 1,860 m altitude. Power outputs were determined during a simulated 20-km time trial (PTT), at blood pH threshold (PpHT), at maximal lactate steady state (PMLSS), and at blood lactate threshold determined by 2 methods: the highest power output that did not result in consecutive and continued increases in blood lactate concentrations from exercising baseline (PLT) and the highest power output that did not result in consecutive and continued increases of ≥1 mmol/L in blood lactate concentrations from exercising baseline (PLT1). PLT, PLT1, and PMLSS were all significantly lower than PpHT (p < .05) and PTT (p < .05). No significant difference was observed between PpHT and PTT (p > .05). Significant correlations were observed between each of the metabolic variables, PLT, PLT1, PMLSS, and PpHT, compared with PTT (p < .05). The authors conclude that, of the 4 metabolic variables, only PpHT offered an accurate reflection of PTT.
Gregory B. Dwyer and Anthony D. Mahon
Little is known about the responses to graded exercise in athletes with cerebral palsy (CP). This study compared the ventilatory threshold (VT) and peak VO2 among athletes with CP during treadmill and cycle ergometry exercise. Six (4 men, 2 women) track athletes with CP volunteered to participate in the study. Graded exercise tests on a treadmill and cycle ergometer were performed on separate days to assess VT and peak VO2. Paired t tests were used to compare the two exercise modes. The VT, expressed as a percentage of peak VO2, was significantly higher on the cycle ergometer than on the treadmill. The absolute VO2 at the VT was similar during both testing modes, and peak VO2 was significantly higher on the treadmill than on the cycle ergometer. Similar to responses seen in able-bodied individuals, the VO2 at VT was similar during both modes of exercise, while the peak VO2 was 10% lower on the cycle than on the treadmill. Cycle ergometer peak VO2 in these athletes was higher than previous reports of individuals with CP for the cycle ergometer.
Nathan D. Dicks, Nicholas A. Jamnick, Steven R. Murray and Robert W. Pettitt
To investigate a new power-to-body-mass (BM) ratio 3-min all-out cycling test (3MT%BM) for determining critical power (CP) and finite work capacity above CP (W ′).
The gas-exchange threshold (GET), maximal oxygen uptake (VO2max), and power output evoking VO2max (W peak) and GET (W GET) for cycle ergometry were determined in 12 participants. CP and W′ were determined using the original “linear factor” 3MT (3MTrpm^2) and compared with CP and W′ derived from a procedure, the 3MT%BM, using the subject’s body mass and self-reported physical activity rating (PA-R), with values derived from linear regression of the work–time model and power–inverse-time model (1/time) data from 3 separate exhaustive squarewave bouts.
The VO2max, VO2GET, W peak, and W GET values estimated from PA-R and a non-exercise-regression equation did not differ (P > .05) from actual measurements. Estimates of CP derived from the 3MT%BM (235 ± 56 W), 3MTrpm^2 (234 ± 62 W), work–time (231 ± 57 W), and 1/time models (230 ± 57 W) did not differ (F = 0.46, P = .72). Similarly, estimates of W′ between all methods did not differ (F = 3.58, P = .07). There were strong comparisons of the 3MT%BM to 1/time and work–time models with the average correlation, standard error of the measurement, and CV% for critical power being .96, 8.74 W, and 4.64%, respectively.
The 3MT%BM is a valid, single-visit protocol for determining CP and W′.
Rachel L. Wright, Dan M. Wood and David V.B. James
The aims of the study were to investigate whether starting cadence had an effect on 10-s sprint-performance indices in friction-loaded cycle ergometry and to investigate the influence of method of power determination. In a counterbalanced order, 12 men and 12 women performed three 10-s sprints using a stationary (0 rev/min), moderate (60 rev/min), and high (120 rev/min) starting cadence Calculated performance indices were peak power, cadence at peak power, time to peak power, and work to peak power. When the uncorrected method of power determination was applied, there was a main effect for starting cadence in female participants for peak power (stationary 635 ± 183.7 W, moderate 615.4 ± 168.9 W and high 798.4 ± 120.1 W) and cadence at peak power (89.8 ± 2.3 rev/min, 87.9 ± 21.5 rev/min, and 113.1 ± 12.5 rev/min). For both the uncorrected and directly measured methods of power determination in men and women, there was a main effect for starting cadence for time to peak power and work to peak power. In women, for an uncorrected method of power determination, it can be concluded that starting cadence does affect peak power and cadence at peak power. This effect is, however, negated by a direct-measurement method of power determination. In men and women, for both uncorrected and directly measured methods o power determination, time to peak power and work to peak power were affected by starting cadence. Therefore, a higher-cadence start is unsuitable, particularly when sprint-performance indices are determined from an uncorrected method.
Kevin L. Lamb
This study examined the validity and reliability of the Rating of Perceived Exertion (RPE) scale and the Children’s Effort Rating Table (CERT) as methods of regulating exercise intensity during discontinuous cycle ergometry. Sixty-four school children (ages 9–10) were randomly assigned to one of two groups, RPE or CERT, and received two trials 7 days apart. On both occasions, subjects produced 4 × 4-min scale-specific exercise intensities—3, 5, 7, and 9 (CERT) or 8, 12, 15, and 18 (RPE)—interspersed with 2-min rest periods. Analyses yielded significant (p < .01) correlations between perceived effort levels and objective measures: r = .47 to .61 (heart rate) and r = .59 to .75 (power output). Intraclass correlations indicated satisfactory overall repeatability of the produced exercise intensities (R > .70), but some notable inconsistencies were observed. The usefulness of effort perception scales among preadolescent children is presently rather limited, probably due to a number of confounding factors that need to be systematically addressed.
Kevin L. Lamb
This study assessed and compared the validity of children’s effort ratings using the established Borg 6–20 Rating of Perceived Exertion (RPE) scale and a recently devised Children’s Effort Rating Table (CERT) during continuous cycle ergometry. Seventy school children were randomly assigned to one of two groups: Group 1 (RPE) and Group 2 (CERT). Both groups received two incremental exercise trials (Trial 1 and Trial 2) 7 days apart. For both scales, data analysis yielded significant (p < .01) Pearson correlations between perceived effort ratings and heart rate (HR) (rs ≥ .50) and perceived effort and absolute power outputs (rs ≥ .59). Moreover, correlations for CERT were consistently higher than for RPE. Test-retest intraclass correlations of R = .91 (CERT) and R = .90 (RPE) revealed that both scales were reliable. These data suggest that among preadolescent children the traditional scale (RPE) is not the only, nor indeed the best, option for monitoring perceived exertion during controlled exercise.
Ashley A. Walter, Abbie E. Smith, Trent J. Herda, Eric D. Ryan, Jordan R. Moon, Joel T. Cramer and Jeffrey R. Stout
The purpose of this study was to examine the effects of 5 d of creatine (Cr) loading on the electromyographic fatigue threshold (EMG FT) in college-age men. Sixteen men (age 22.4 ± 2.6 yr, height 177.4 ± 6.8 cm, weight 79.5 ± 10.6 kg; M ± SD) participated in this double-blind study and were randomly placed into either placebo (Pl; 10 g of flavored fructose powder per packet; n = 8) or Cr (5 g dicreatine citrate plus 10 g of flavored fructose powder per packet; n = 8) loading groups. Each participant ingested 1 packet 4 times/d, totaling 20 g/d for 5 days (loading). Before and after loading, each participant performed a discontinuous cycle-ergometer test to determine his EMG FT, using bipolar surface electrodes placed on the vastus lateralis of the right thigh. Four 60-s work bouts (ranging from 200 to 400 W) were completed. Adequate rest was given between bouts to allow for the participants’ heart rate (HR) to drop within 10 beats of their resting HR. The EMG amplitude was averaged over 5-s intervals for each 60-s work bout. Resulting slopes from each successive work bout were used to calculate EMG FT. A 2-way ANOVA, Group (Cr vs. Pl) EETime (pre vs. post), resulted in a nonsignificant (p > .05) interaction for supplement and time. In addition, a significant increase (p = .009) in weight was observed in the Cr group. These data suggest that there was a minimal influence of Cr loading on EMG FT for the participants in this study.
James C. Martin, Steven J. Elmer, Robert D. Horscroft, Nicholas A.T. Brown and Barry B. Shultz
The purpose of this study was to develop and evaluate an alternative method for determining the position of the anterior superior iliac spine (ASIS) during cycling. The approach used in this study employed an instrumented spatial linkage (ISL) system to determine the position of the ASIS in the parasagittal plane. A two-segment ISL constructed using aluminum segments, bearings, and digital encoders was tested statically against a calibration plate and dynamically against a video-based motion capture system. Four well-trained cyclists provided data at three pedaling rates. Statically, the ISL had a mean horizontal error of 0.03 ± 0.21 mm and a mean vertical error of −0.13 ± 0.59 mm. Compared with the video-based motion capture system, the agreement of the location of the ASIS had a mean error of 0.30 ± 0.55 mm for the horizontal dimension and −0.27 ± 0.60 mm for the vertical dimension. The ISL system is a cost-effective, accurate, and valid measure for two-dimensional kinematic data within a range of motion typical for cycling.
Kenneth R. Turley, Danette M. Rogers, Kevin M. Harper, Kathleen I. Kujawa and Jack H. Wilmore
This study was designed to determine the differing cardiorespiratory responses between maximal treadmill (TM) and cycle (CY) ergometry, and the reliability and variability of these responses in 46 children 7 to 9 years old (23 boys and 23 girls). Two maximal TM and two maximal CY tests were administered, as well as a body composition assessment. The TM resulted in a 9.4%, 11,1%, and 10.2% higher maximal oxygen consumption values (V̇O2, ml·kg−1·min−1) than the CY in boys, girls, and the total population, respectively. Both the TM and the CY proved to be reliable measures of maximal V̇O2 (ml·kg−1·min−1) in both boys and girls, with intraclass correlations ranging from R = .63 to .90. Variability was significantly less (p ≤ .05) on the CY (V̇O2 in L·min−1) than the TM, 4.4% versus 6.2%, respectively.