Influence of single-leg training on muscle metabolism and endurance during exercise with the trained limb and the untrained limb

We have previously shown that single-leg training results in improved endurance for exercise with the untrained leg (UTL) as well as for exercise with the trained leg (TL). The purpose of this study was to see whether the improved endurance of the untrained leg could be explained on the basis of changes in muscle metabolism. Exercise time to exhaustion at 80% of maximum oxygen uptake (VO2 max) was determined for each leg separately, pre- and post-training. Muscle metabolite concentrations were measured pre- and post-training in biopsy samples obtained immediately before this endurance test and at the pre-training point of exhaustion (END1). After six weeks of single-leg training endurance time was increased for both the UTL and the TL (UTL 34.0 +/- 16.4 min vs 97.9 +/- 26.3 min, P less than 0.01; TL 28.3 +/- 10.1 min vs 169.0 +/- 32.6 min, P less than 0.01). No changes in muscle metabolite concentrations were found in resting muscle. Training increased muscle ATP (P less than 0.05) and glycogen (P less than 0.01) concentrations and decreased muscle lactate concentration (P less than 0.05) in the TL at END1. No significant changes in muscle metabolite concentrations were found for the UTL. The improved endurance of the contralateral limb after single-leg training could not be explained on the basis of changes in muscle metabolism.     

Mobility and wage equilibration in the educator labor market

Using longitudinal data, this article examines mobility and wage equilibration patterns for instructional personnel for kindergarten through the twelfth grade. The study concludes that (1) contrary to popular belief, educators are at least as responsive as other workers to interoccupational wage differences in deciding to change occupations; (2) educators paid above (below) the wage they could expect in the economy at large experience less (greater) than average wage growth; (3) educators are responsive to wage differentials within teaching in deciding to change districts but not as strongly responsive as to wage differentials between teaching and other occupations; and (4) educators paid above (below) the average wage for educators with similar qualifications experience less (greater) than average wage growth from one school year to the next.“Frustrated teachers stew over working conditions, but most don't quit.”