An examination of athletes' self-efficacy and strength training effort during an entire off-season.

Over the past 30-plus years in which self-efficacy (or confidence at a task) has been researched, findings have shown that in almost every domain of human functioning, self-efficacy positively relates to effort, persistence, and other adaptive behaviors. However, in the past decade, new research postulating that too much self-efficacy can lead to complacency and a subsequent downturn in behavior or performance has also experienced resurgence in the literature. Therefore, the purpose of this study was to test these opposing viewpoints regarding self-efficacy and effort for Division I athletes in a strength and conditioning domain over off-season training, a procedure yet to be undertaken. Subjects (N = 99), from 4 different sports (M(ag)e = 20.0 years, SD = 1.2 years), completed self-efficacy and effort measures at 4 distinct time points during off-season training. In addition, strength and conditioning coaches also rated each subject's effort--at each time point--so that a more valid measure of this construct could be attained. Results were analyzed using a multilevel approach and revealed that self-efficacy was positively, and significantly, related to the current effort that athletes exerted in strength training sessions. Consequently, practitioners are advised to structure strength and conditioning training sessions and the overall environment in ways that will positively impact the 4 proven sources of self-efficacy.

Effects of muscular strength, exercise order, and acute whole-body vibration exposure on bat swing speed.

The purposes for this study were to investigate effects of acute whole-body vibration (WBV) exposure and exercise order on bat speed and to examine relationship between muscular strength and bat speed. All participants were recreationally trained men (n = 16; 22 ± 2 years; 181.4 ± 7.4 cm; 84.7 ± 9 kg), with previous baseball experience and were tested for 1 repetitive maximum (1RM) strength in squat and bench press. Subjects then participated in 4 randomized sessions on separate days, each consisting of 3 sets of 5 bat swings. Exercises (upper and lower body dynamic and static movements related to bat swing) with or without WBV exposure were performed after sets 1 and 2. Trials were as follows: no-exercise Control (CTRL), upper body followed by lower body exercises without WBV (Arm-Leg NOVIB), upper body followed by lower body exercises with WBV (Arm-Leg VIB), and lower body followed by upper body exercises with WBV (Leg-Arm VIB). Bat speed was recorded during each swing and averaged across sets. Statistical analyses were performed to assess differences across sets and trials. Linear regressions analyzed relationship between strength and bat speed. A significant relationship existed between bat speed and lower body strength (r = 0.406, p = 0.008) but not for upper body strength. The exercise order of Arm-Leg VIB significantly increased bat speed by 2.6% (p = 0.02). Performing identical order of exercises without vibration (Arm-Leg NOVIB) significantly decreased bat speed by 2% (p = 0.039). It was concluded that adding vibration exposure to total-body exercises can provide acute enhancements in bat speed. Additionally, leg strength was shown to influence bat speed suggesting that increasing leg strength may enhance bat speed.

Acrylonitrile induces autolysis Bacillus subtilis.

Acrylonitrile (AN) is an industrial chemical used in the manufacture of plastics and other polymers. AN has been reported to be an acute toxin and is a known carcinogen in rodents. When AN was mixed with suspensions of Bacillus subtilis, the bacteria began autolysis. It was determined that AN is partially converted to cyanide, a strong protonophore in B. subtilis. Autolytic enzymes in B. subtilis become active when the protonmotive force is dissipated. The amount of cyanide produced from AN, however, was not enough to promote autolysis in exponential B. subtilis. This is the first report showing that AN may induce autolytic reactions in bacteria. It is suggested the autolysis of B. subtilis may be useful in the environmental monitoring of AN. In addition, the metabolism of AN by bacilli may be useful in bioremediation.