Neuromuscular training programs predominantly include instructions that promote an internal focus.

Neuromuscular training programs that include movement pattern retraining and strengthening, plyometric, and balance exercises are recommended for anterior cruciate ligament injury prevention. Recent evidence suggests that the effectiveness of these programs may be enhanced when athletes train with an external focus; however, clinicians typically rely predominantly on instructions encouraging an internal focus. The aim of this study was to examine the types of instructions provided as part of popular neuromuscular training programs used for anterior cruciate ligament injury prevention. The technique-related instructions provided as part of the FIFA 11+, HarmoKnee, Knakontroll, and Prevent Injury and Enhance Performance programs were categorized as either promoting an internal focus or an external focus. Instructions provided during movement pattern retraining tasks and strengthening, plyometric, and balance training exercises were specifically examined. Next, the percentage of technique-related instructions that promoted an internal focus, versus the percentage that promoted an external focus, were compared for the various program components. Across all programs examined, the vast majority of technique-related instructions for the movement pattern re-training tasks (≥83.3%) and the strengthening, balance, and plyometric exercises (≥75.0%) appeared to promote an internal focus. Despite evidence suggesting that the effectiveness of neuromuscular training programs may be enhanced by encouraging an external focus, most technique-related instructions provided as part of popular neuromuscular training programs appear to promote an internal focus. Modifying neuromuscular training programs to promote a more external focus could help to improve the effectiveness of these programs for anterior cruciate ligament injury prevention.

Dopaminergic toxicity of the herbicide atrazine in rat striatal slices.

A possible link between Parkinson's disease and pesticide exposure has been suggested, and recently it was shown that the herbicide atrazine (ATR) modulates catecholamine metabolism in PC12 cells and affects basal ganglia function in vivo. Hence, the objectives of this study were to: (i) determine if ATR is capable of modulating dopamine (DA) metabolism in striatal tissue slices in vitro and (ii) explore possible mechanisms of its effects. Striatal tissues from adult male Sprague-Dawley rats were incubated with up to 500 microM ATR in a metabolic shaker bath at 37 degrees C and an atmosphere of 95% O(2) and 5% CO(2) for 4h. At the end of incubation, samples were collected for both tissue and media levels of DA and its metabolites (3,4-dihydroxyphenylacetic acid, DOPAC and homovanillic acid, HVA), which were determined by high-performance liquid chromatography with electrochemical detection (HPLC-ECD). To gain some mechanistic insight in to the way ATR affects DA metabolism, several pharmacological manipulations were performed. Striata exposed to ATR at concentrations of 100 microM and greater had a dose-dependent decrease of tissue levels of DA. At doses of ATR 50 microM and greater, the DOPAC+HVA/DA ratio was dose-dependently increased. Tyrosine hydroxylase (TH, the rate-limiting enzyme in DA synthesis) protein levels and activity were not affected by ATR treatment. However, high potassium-induced DA release into the medium was decreased, whereas the increase in media DA observed in the presence of the DA uptake inhibitor nomifensine was increased even further by ATR in a dose-dependent manner. All of these effects of ATR were observed at levels that were not toxic to the tissue, as LDH release into the medium (lactate dehydrogenase, an index of non-specific cytotoxicity) was not affected by ATR. Taken together, results from this study suggest that ATR decreases tissue DA levels not by affecting TH activity, but possibly by interfering with the vesicular storage and/or cellular uptake of DA.