A Maximal Rowing Ergometer Protocol to Predict Maximal Oxygen Uptake.

PURPOSE: To examine the relationship between the maximal power output (MPO) in an individualized 7 × 2-minute incremental (INCR) test, average power in a 2k (W2k) rowing ergometer test, and maximal oxygen uptake (V˙O2max) and to develop a regression equation to predict V˙O2max. METHODS: A total of 34 male club rowers (age 18-30 y) performed a 2k and an INCR test in a Concept2 rowing ergometer to determine and compare MPO, W2k, and V˙O2max. RESULTS: No significant difference was found between V˙O2max measured during INCR or 2k test (P = .73). A very high correlation coefficient (r = .96) was found between MPO and V˙O2max and between W2k and V˙O2max (r = .93). Linear regression analyses were developed for predicting V˙O2max from MPO: (1) V˙O2max (mL·min-1) = 11.49 × MPO + 810 and V˙O2max from W2k: (2) V˙O2max = 10.96 × W2k + 1168. Cross-validation analyses were performed using an independent sample of 14 rowers. There was no difference between the mean predicted V˙O2max in the INCR test (4.41 L·min-1) or the 2k test (4.39 L·min-1) and the observed V˙O2max (4.40 L·min-1). Technical error of measurement was 3.1% and 3.6%, standard error of estimate was 0.136 and 0.157 mL·min-1, and validation coefficients (r) were .95 and .94 using Equation (1) and (2), respectively. CONCLUSION: A prediction model only including MPO or W2k explains 88% to 90% of the variability in V˙O2max and is suggested for practical use in male club rowers.

Impact of intermittent feeding on polishing of micropollutants by moving bed biofilm reactors (MBBR).

Moving bed biofilm reactors (MBBRs) were placed at two wastewater treatment plants, where they were constantly fed with effluent and intermittently fed with primary wastewater. Each reactor was subjected to different feast/famine periods and flow rates of primary wastewater, thus the different organic and nutrient loads (chemical oxygen demand(COD), ammonium(NH4-N)) resulted in different feast-famine conditions applied to the biomass. In batch experiments, this study investigated the effects of various feast-famine conditions on the biodegradation of micropollutants by MBBRs applied as an effluent polishing step. Rate constants of micropollutant removals were found to be positively correlated to the load of the total COD and NH4-N, indicating that higher organic loads were favourable for the growth of micropollutant degraders in these MBBRs. Rate constant of atenolol was five times higher when the biomass was fed with the highest COD and NH4-N load than it was fed with the lowest COD and NH4-N load. For diclofenac, mycophenolic acid and iohexol, their maximum rate constants were obtained with feeding of COD and NH4-N of approximately 570 mgCOD/d and 40∼60 mgNH4-N/d respectively. This also supports the concept that co-metabolism (rather competition inhibition or catabolic repression) plays an important role in micropollutants biodegradation in wastewater.