Energy system contribution during 200- to 1500-m running in highly trained athletes

Purpose: The purpose of the present study was to profile the aerobic and anaerobic energy system contribution during high-speed treadmill exercise that simulated 200-, 400-, 800-, and 1500-m track running events.

Methods: Twenty highly trained athletes (Australian National Standard) participated in the study, specializing in either the 200-m (N = 3), 400-m (N = 6), 800-m (N = 5), or 1500-m (N = 6) event (mean O₂ peak [mL·kg^-1·min^-1] ± SD = 56 ± 2, 59 ± 1, 67 ± 1, and 72 ± 2, respectively). The relative aerobic and anaerobic energy system contribution was calculated using the accumulated oxygen deficit (AOD) method.

Results: The relative contribution of the aerobic energy system to the 200-, 400-, 800-, and 1500-m events was 29 ± 4, 43 ± 1, 66 ± 2, and 84 ± 1% ± SD, respectively. The size of the AOD increased with event duration during the 200-, 400-, and 800-m events (30.4 ± 2.3, 41.3 ± 1.0, and 48.1 ± 4.5 mL·kg^-1, respectively), but no further increase was seen in the 1500-m event (47.1 ± 3.8 mL·kg^-1). The crossover to predominantly aerobic energy system supply occurred between 15 and 30 s for the 400-, 800-, and 1500-m events.

Conclusions: These results suggest that the relative contribution of the aerobic energy system during track running events is considerable and greater than traditionally thought.

Cost-efficacy of surgically induced weight loss for the management of type 2 diabetes : a randomized controlled trial

OBJECTIVE -- To determine the within-trial cost-efficacy of surgical therapy relative to conventional therapy for achieving remission of recently diagnosed type 2 diabetes in class I and II obese patients.

RESEARCH DESIGN AND METHODS -- Efficacy results were derived from a 2-year randomized controlled trial. A health sector perspective was adopted, and within-trial intervention costs included gastric banding surgery, mitigation of complications, outpatient medical consultations, medical investigations, pathology, weight loss therapies, and medication. Resource use was measured based on data drawn from a trial database and patient medical records and valued based on private hospital costs and government schedules in 2006 Australian dollars (AUD). An incremental cost-effectiveness analysis was undertaken.

RESULTS -- Mean 2-year intervention costs per patient were 13,400 AUD for surgical therapy and 3,400 AUD for conventional therapy, with laparoscopic adjustable gastric band (LAGB) surgery accounting for 85% of the difference. Outpatient medical consultation costs were three times higher for surgical patients, whereas medication costs were 1.5 times higher for conventional patients. The cost differences were primarily in the first 6 months of the trial. Relative to conventional therapy, the incremental cost-effectiveness ratio for surgical therapy was 16,600 AUD per case of diabetes remitted (currency exchange: 1 AUD = 0.74 USD).

CONCLUSIONS -- Surgical therapy appears to be a cost-effective option for managing type 2 diabetes in class I and II obese patients.