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Methods - exercise part 2

Here is the second section of the methods of the same article by Wiles, J. D., Coleman, D., Tegerdine, M. and Swaine, I. L. (2006) The effects of caffeine ingestion on performance time, speed and power during a laboratory-based 1 km cycling time-trial, Journal of Sports Sciences, 24 (11):1165 -1171.

Select the appropriate response to the critical questions to determine whether the experimental procedure is justified and whether it shows that the study is capable of achieving its aims. When you have finished click Submit for your feedback.

Methods: Participants Critical questions Your response

All participants underwent a familiarization test on the SRM Ergo bike (Schoberer Rad Meßtechnik, Jülich, Germany). The electronic-braking “cadence gearing” was set to number 6 throughout the study. The ergometer loading is based upon the power output required for an 80 kg rider (on a bicycle weighing 10 kg) to cycle outdoors. Gear 6 requires 90 revmin-1 to achieve a speed of 40kmh-1. The visual display panel was masked so that only distance was visible, thus mimicking track conditions as closely as possible in the protocol. The participants’ individualized SRM ergo bike measurements were scaled and recorded for replication in subsequent testing. Throughout the study, all participants were requested to maintain consistent dietary habits and were required to abstain from all foods and liquids containing caffeine in the 72 h before the experimental trials. The participants were also asked to abstain from any products containing alcohol and to rest for a period of at least 24 h before their test sessions. Adherence to these requests was confirmed by each participant verbally before each trial. Before the onset of data collection, within-participant variation calculated using repeated trials gave coefficients of variation of 1.24% (performance time), 0.75% (mean power) and 2.19% (peak power).

Caffeine derived from dissolved Pro-plus tablets was used in this investigation. The experimental dose consisted of 5mgkg-1 of dissolved caffeine (Proplus, Herts, UK), which had been individually prepared according to each participant’s body mass, mixed with 200 ml of lemon concentrate (Safeway, Hayes, Middlesex, UK) and 50 ml of water. This mixture has previously been shown to result in improvements in exercise performance while minimizing the side-effects of caffeine intake (Pasman, van Baak, Jeukendrup, & de Haan, 1995). The placebo consisted of 200ml of lemon concentrate mixed with 50 ml of water. Both were prepared in identical plastic bottles and labelled either “A” (caffeine) or “B” (placebo). On the day of testing, the participants reported to the laboratory and were then given either a treatment solution (A or B) or informed that their trial was a control (C) using a randomized order design. All treatments were administered in a double-blind fashion. The participants were then asked to rest for an hour, either after they had consumed all of their solution or, in the case of the controls, after they had drunk as much water as they wanted.

After one hour of rest, the participants’ height and body mass were measured using a stadiometer and SECA balance beam scales respectively (Birmingham, UK). They then performed a 15 min personalized warm-up using the SRM ergo bike, the content of which was recorded to ensure that it remained constant for all future trials. At the end of the warm-up, the participants were asked to stand down from the SRM ergo bike and perform pre-set stretches of their choice for approximately 90 s (during this time the calibration of the SRM ergo bike was carried out). As soon as the flywheel had come to a complete standstill, the participants mounted the SRM ergo bike and, once they had indicated that they were ready, testing was initiated using a 3 s countdown. The cyclists then performed an all-out maximal sprint for 1 km with a standardized verbal countdown to inform them of the distance covered during the test. On completion of the 1 km time-trial, the participants completed their own warm-down routine.

1. Is there a rationale/clear explanation provided for the experimental design?

2. Are the required dietary habits reliable?

3. Is the experimental dose justified?

4. Are the controls and treatments clearly stated?

5. Is the experimental procedure clear and could it be replicated?

1. Yes  No 
            no is correct       
However, on a more general level, the need for the research has been clearly established in the introduction.

2. Yes  No 
            yes is correct       
But only in so far as verbal confirmation can be reliable.

3. Yes  No 
            yes is correct       
Through reference to another study.

4. Yes  No 
            yes is correct       

5. Yes  No 
            yes is correct       

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