Validity of the 3-Minute All-Out Exercise Test on the CompuTrainer.

The 3-minute all-out exercise test (3MT) has emerged as a useful procedure for identifying critical power (CP) and the finite work capacity above CP (W') within a single visit. The CP concept enables for the prediction of exhaustive time limits (T(LIMs)) for a wide range of severe intensity power outputs and is a method for prescribing high-intensity interval training (HIIT). Road cyclists often use the CompuTrainer for indoor HIIT. The purpose of this study was to validate the 3MT for use on the CompuTrainer. On 4 separate visits, 10 competitive cyclists performed a 3MT, and three separate constant-load bouts projected to yield exhaustive T(LIMs) of 3, 6, and 9 minutes, respectively, using the Computrainer. Actual CP and W' were calculated using the linear work-time (W-t) and power-inverse time (1/t) models. The results for CP (W) from the 3MT (215 ± 40), the W-t model (212 ± 36), and the 1/t model (213 ± 36) did not differ (F = 2.96, p = 0.11, η2(p) = 0.43). Similarly, the results for W' (kJ) for the 3MT (11.2 ± 4.0), the W-t model (12.1 ± 6.5), and the 1/s model (11.7 ± 6.3) did not differ (F = 2.40, p = 0.15, η2(p) = 0.375). We conclude that use of the 3MT and the CP concept for performance assessment and HIIT prescription on the CompuTrainer is a valid procedure.

EPOXI at comet Hartley 2.

Understanding how comets work--what drives their activity--is crucial to the use of comets in studying the early solar system. EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation) flew past comet 103P/Hartley 2, one with an unusually small but very active nucleus, taking both images and spectra. Unlike large, relatively inactive nuclei, this nucleus is outgassing primarily because of CO(2), which drags chunks of ice out of the nucleus. It also shows substantial differences in the relative abundance of volatiles from various parts of the nucleus.