Effects of a short-term carbohydrate-restricted diet on strength and power performance.

The purpose of the study was to examine the effects of switching from a habitual diet to a carbohydrate-restricted diet (CRD) on strength and power performance in trained men (n = 16) and women (n = 15). Subjects performed handgrip dynamometry, vertical jump, 1RM bench press and back squat, maximum-repetition bench press, and a 30-second Wingate anaerobic cycling test after consuming a habitual diet (40.7% carbohydrate, 22.2% protein, and 34.4% fat) for 7 days and again after following a CRD (5.4% carbohydrate, 35.1% protein, and 53.6% fat) for 7 days. Before both testing sessions, body weight and composition were examined using bioelectrical impedance analysis. Three 2 × 2 multiple analyses of variance were used to compare performance variables between the habitual diet and CRD. Subjects consumed significantly fewer (p < 0.05) total kilocalories during the CRD (2,156.55 ± 126.7) compared with the habitual diet (2,537.43 ± 99.5). Body mass decreased significantly (p < 0.05). Despite a reduction in body mass, strength and power outputs were maintained for men and women during the CRD. These findings may have implications for sports that use weight classes, and in which strength and power are determinants of success. A CRD may be an alternative method for short-term weight loss without compromising strength and power outputs. The use of a 7-day CRD could replace weight loss methods employing severe dehydration before competition.

Comparison of drug detection by three quadrupole time-of-flight mass spectrometry platforms.

Urine and plasma specimens fortified with 82 drugs and metabolites were prepared and analyzed by liquid chromatography quadrupole time-of-flight mass spectrometry (QTOF) instrumentation from three different vendors using the instrument manufacturers' methods and workflows for drug screening. No prior knowledge about the compounds included or their concentrations were provided. Samples were prepared and sent for analysis on a TripleTOF(®) 5600 system, a 6530 QTOF and a Xevo(®) G2-S QTof. All three platforms performed well with >90% of compounds detected in one set of spiked plasma samples, and 79-88% for a second set of spiked plasma and two sets of spiked urine samples.