The purpose of this study is to evaluate the effectiveness of aerobic endurance (E), strength (R), and combined endurance and strength (CB) training for improving performance of tactical occupational tasks and determine if combined training interferes with performance enhancements of E or R alone. A total of 56 recreationally active women were randomly placed into four groups: R (n = 18), E (n = 13), CB (n = 15), Control (n = 10). Subjects trained three non-consecutive days per week for 8 weeks. Performance was measured pre-, mid-, and post-training for bench press one-repetition maximum (1-RM), squat 1-RM, bench press throw and squat jump peak power, VO2peak, 3.2 km load carriage (LC), 3.2 km run (run), and repetitive lift and carry (RLC). R and E demonstrated improvements which were generally specific to their training. R improved squat (48.3%) and bench press 1-RM (23.8%), bench press throw (41.9%), RLC (31.3%), and LC (11.5%). E improved run (14.7%), VO2peak (6.2%), squat 1-RM (15.3%), LC (12.9%), and RLC (22.5%). CB improved squat (37.6%) and bench press 1-RM (20.9%), bench press throw (39.6%), VO2peak (7.6%), run (10.4%), LC (13.1%), and RLC (45.5%). Post-training 1-RM squat was greater in R and CB than E, while E completed the 3.2 km load carriage task faster than C. In conclusion, 8 weeks of combined training improved performance in all tactical occupational tasks measured and did not interfere with improvements in strength, power and endurance measures compared to R or E alone.

No abstract

We tested whether inhibiting mechanically-responsive articular chondrocyte mitochondria after severe traumatic injury and preventing oxidative damage represent a viable paradigm for posttraumatic osteoarthritis (PTOA) prevention. We used a porcine hock intra-articular fracture (IAF) model well suited to human-like surgical techniques and with excellent anatomic similarities to human ankles. After IAF, amobarbital or N-acetylcysteine (NAC) was injected to inhibit chondrocyte electron transport or downstream oxidative stress, respectively. Effects were confirmed via spectrophotometric enzyme assays or glutathione/glutathione disulfide assays and immunohistochemical measures of oxidative stress. Amobarbital or NAC delivered after IAF provided substantial protection against PTOA at 6 months, including maintenance of proteoglycan content, decreased histological disease scores, and normalized chondrocyte metabolic function. These data support the therapeutic potential of targeting chondrocyte metabolism after injury and suggest a strong role for mitochondria in mediating PTOA.

Traffic-related air pollution in urban areas contributes significantly to commuters’ daily PM2.5 exposures, but varies widely depending on mode of commuting. To date, studies show conflicting results for PM2.5 exposures based on mode of commuting, and few studies compare multiple modes of transportation simultaneously along a common route, making inter-modal comparisons difficult. In this study, we examined breathing zone PM2.5 exposures for six different modes of commuting (bicycle, walking, driving with windows open and closed, bus, and light-rail train) simultaneously on a single 2.7 km (1.68 mile) arterial urban route in Salt Lake City, Utah (USA) during peak “rush hour” times. Using previously published minute ventilation rates, we estimated the inhaled dose and exposure rate for each mode of commuting. Mean PM2.5 concentrations ranged from 5.20 μg/m3 for driving with windows closed to 15.21 μg/m3 for driving with windows open. The estimated inhaled doses over the 2.7 km route were 6.83 μg for walking, 2.78 μg for cycling, 1.28 μg for light-rail train, 1.24 μg for driving with windows open, 1.23 μg for bus, and 0.32 μg for driving with windows closed. Similarly, the exposure rates were highest for cycling (18.0 μg/hr) and walking (16.8 μg/hr), and lowest for driving with windows closed (3.7 μg/hr). Our findings support previous studies showing that active commuters receive a greater PM2.5 dose and have higher rates of exposure than commuters using automobiles or public transportation. Our findings also support previous studies showing that driving with windows closed is protective against traffic-related PM2.5 exposure.

The purpose of this study was to determine the reliability of military-relevant tests designed to assess soldier readiness. Forty-seven soldiers (46 men, 1 woman; 22 +/- 3 years; 80.4 +/- 11.7 kg) performed each of seven soldier readiness tests on four different occasions over the course of 8 weeks. The soldier readiness tests were: (1) 3.2-km load carriage (LC) time-trial, (2) running long jump (RLJ), (3) one-repetition maximum box lift (1RMBL), (4) 10-minute repetitive box lift and carry (RBLC), (5) simulated victim rescue (VR), (6) mock grenade throw (GT) for accuracy, and (7) simulated combat rushes (CR). Repeated measures analysis of variance revealed significant learning effects for 1RMBL, RBLC, and GT; these tests required two (1RMBL and RBLC) or three (GT) trials to obtain statistically stable values. The intraclass correlation coefficient was 0.78 to 0.89 for all tests. LC, 1RMBL, RBLC, CR, and RLJ all demonstrated standard error of measurement values that were 3% to 5%, whereas VR and GT were 9% and 36%, respectively. In conclusion, the 1RMBL, RBLC, and GT tests required familiarization before a stable value was obtained. The LC, 1RMBL, RBLC, CR, and RLJ tests (and, to a lesser degree, the VR test) demonstrated reasonably acceptable levels of reliability and measurement error, whereas the GT test did not.