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Rating of perceived exertion (RPE) is a reliable method of assessing exercise intensity during isolated arm and leg cycling. The aim of this study was to assess the validity and reproducibility of perceptually regulated exercise responses during combined arm + leg cycling. Twelve males (age; 24.6 ± 5.3 years, height; 1.81 ± 0.7 m, mass; 83.1 ± 8.4 kg) initially undertook incremental exercise tests to volitional exhaustion for arm cycling (133 ± 14 W) and leg cycling (253 ± 32 W). On three subsequent occasions, participants undertook combined arm + leg cycling trials using two modified Monark ergometers involving three bouts of exercise at RPE 9, 13 and 17, in that order. Heart rate (HR), oxygen uptake ( $$\dot{V}{\text{O}}_{{2}}$$ ) and pulmonary ventilation ( $$\dot{V}_{{\text{E}}}$$ ) were recorded continuously. No significant differences were observed for HR (P = 0.086), $$\dot{V}{\text{O}}_{{2}}$$ (P = 0.525) and $$\dot{V}_{{\text{E}}}$$ (P = 0.899) between trials, whilst significant differences were observed between each level of RPE (all P

Published reports have shown large apparent inter-individual differences of gains in maximal oxygen intake (VO(2max)) in response to a standard 20-week programme of aerobic conditioning that progressed to 75% of the individual's initial VO(2max). The observed gains of VO(2max) ranged from 0 to 1,000 ml min(-1), with a coefficient of variation (CV) of 8.4%. The present analysis evaluates the potential contribution of test-retest errors to these apparent large inter-individual differences in training response. The 2-day test-retest CV for VO(2max) readings in 742 healthy adults was initially 5.0%, dropping to 4.1% after training. Published training responses were estimated from the mean of paired measurements obtained before and after training if readings agreed by5%, but from the highest of paired values if these differed by5%. Taking account of the relative proportions of single and paired observations, the weighted VO(2max) data for the entire sample had an effective 2-day CV of 4.3% before and 3.4% after training. Assumption 1: if the 20-week test-retest error remained similar to the 2-day figure, measurement error would contribute a CV of 5.5% to apparent training responses, or (for the stated initial mean VO(2max) of 2,409 ml min(-1)) an SD of 132 ml min(-1). Assumption 2: if the 20-week CV was similar to that in other long-term studies (~5%), measurement error would contribute a CV of 6.1%, or a SD of 146 ml min(-1). The published data show a total SD of 202 ml min(-1) for apparent inter-individual differences in training response, with age, gender, race and baseline VO(2max) accounting for only 11% of this variance. After estimating the likely effect of test-retest measurement errors, the SD due to inter-individual differences would decrease to 138 ml min VO(2max) (assumption 1) or 123 ml min(-1) (assumption 2). We conclude that when estimating the extent of inter-individual differences in training response, allowance must be made not only for the minor effects of recognized covariates (age, gender, race and initial fitness), but also for the larger influence of test-retest measurement errors. Nevertheless, substantial inter-individual differences persist after making such adjustments. The most likely explanation of these differences is a familial aggregation of training responses.

The aim of the present study was to examine the effect of an 8-week endurance training program on repeated-sprint (RS) performance and post-sprints muscle reoxygenation rate in 18 moderately trained males (34 ± 5 years). Maximal aerobic speed (MAS), 10 km running and RS (2 × 15-s shuttle-sprints, interspersed with 15 s of passive recovery) performance were assessed before and after the training intervention. Total distance covered (TD) and the percentage of distance decrement (%Dec) were calculated for RS. Between-sprints muscle reoxygenation rate (Reoxy rate) was assessed with near-infrared spectroscopy during RS before and after training. After training, MAS (+9.8 ± 5.8%, with 100% chances to observe a substantial improvement), 10 km time (−6.2 ± 5.3%, 99%), TD (+9.6 ± 7.7%, 98%), %Dec (−25.6 ± 73.6%, 93%) and Reoxy rate (+152.4 ± 308.1%, 95%) were improved. The improvement of Reoxy rate was largely correlated with improvements in MAS [r = 0.63 (90% CL, 0.31;−0.82)] and %Dec [r = −0.52 (−0.15;−0.76)]. Present findings confirm the beneficial effect of endurance training on post-sprint muscle reoxygenation rate, which is likely to participate in the improvement of repeated-sprint ability after training. These data also confirm the importance of aerobic conditioning in sports, where repeating high-intensity/maximal efforts within a short time-period are required.

Dr. Roy Shephard recently commented on our article examining the age-attenuated response of aerobic power in women participating in a monitored exercise program (Earnest et al. 2010). While we do not totally disagree with his comments, we feel that Dr. Shephard has missed several key points regarding our investigation. Critical to this discussion is that our paper should be taken in the context of its main hypothesis. Our current article is an ancillary report to a parent NIH trial known as the Dose Response of Exercising Women (DREW) trial. Women participating in DREW were recruited based on age, body mass (overweight and obese), elevated blood pressure, and being sedentary. As previously reported in a Methods paper, followed by our primary outcomes paper, the principal aim of DREW was to examine the a priori question of whether there is ‘‘minimal,’’ ‘‘threshold,’’ or ‘‘optimal’’ dose of exercise needed to improve fitness and health by examining the effects of exercise at 50, 100, and 150% of the NIH Consensus Panel physical activity recommendation on cardiorespiratory fitness (NIH Consensus Development Panel on Physical Activity and Cardiovascular Health 1996; Church et al. 2007; Morss et al. 2004). As Dr. Shephard did not cite these papers he may not have read these prior to his critique. Unfortunately, in the era of large clinical trials examining exercise training with multiple outcomes of potential interest the ability to report on the findings of these trials is a two-edged sword that is blunted by the inability to list every methodological detail within every paper given page and/or word count restrictions for most journals. Admittedly, while Methods papers help by providing greater detail than one might have room for in future publications, it is conceivable that some of these details are lost should a reader take each ancillary paper onto itself. For this inconvenience, we apologize and hope that future critiques will consider the body of work surrounding the DREW study; specifically, the design, intent, and primary outcomes for the study. With regard to exercise testing, we used a standardized testing protocol based on three criteria following in the following order of importance: (a) a plateau of VO2 (\100 ml/ min) accompanying a 2 min stage protocol—not a ramp as Dr. Shephard asserts—that increased in small increments (i.e., 20 W/2 min) (b) an RER exceeding 1.10, and (c) and the attainment of a max heart rate within 10 beats of 220— age. An issue within Dr. Shephard’s critique extends to the heart rate response of our older age group. Yet, when one examines the heart rate response of this group (mean age 64.9 years) and our stated criteria, their heart response puts them pretty much spot on for our third criteria. Moreover, Gulati et al. (2010) have recently reported the potential error in using the 220-age equation, thus advocating the prediction of maximal heart rate using 206-0.88 (age), which better estimates the actual maximal heart associated with exercise testing in asymptomatic women (Gulati et al. 2010). Following the latter criteria, our expected maximal heart rate for the[60 years group would be 149 b/min. Given our 10 b/ min allowance for the statistical error surrounding prediction equations, our current report not only matches nicely with this revised equation, but also lies well within the 95% confidence limits also proposed by (Gulati et al. 2010). Communicated by Susan Ward.