Rosendahl Mathews (pimpletime8)

INTRODUCTION The effects of long-duration (213.0 ± 30.5 d) stays aboard the orbital station Mir and short-term (∼10 d) spaceflights aboard the International Space Station (ISS) on the joint torques of various muscles and work capacity of knee extensors were studied in male cosmonauts.METHODS Joint torque and muscle endurance testing was performed 30 d before and 3-5 d after a spaceflight, using a LIDO® Multi-Joint Isokinetic Rehabilitation System (USA).RESULTS Greater postflight changes in maximal joint torque were observed for back, knee, and ankle extensors compared with flexors, and the difference was especially clearly seen after long-term spaceflights. The decrease in maximal joint torque of hip extensors substantially varied, being the greatest in voluntary concentric movements in a low-velocity high-force mode at angular velocities of 30 and 60° · s-1 (by 16 and 13%, respectively) and the lowest in high-velocity modes at velocities of 120 and 180° · s-1 (by 9 and 11%, respectively). Muscle work capacitternational Space Station missions. Aerosp Med Hum Perform. 2020; 91(5)422-431.OBJECTIVE The purpose of this study was to investigate the comfort of aircraft passengers during long flights and to determine the effects of the seatback angle and the seat pitch on passengers' upper body muscles (neck, shoulder, and lower back) and subjective comfort.METHODS All subjects sat on an aircraft seat for 2 h with different levels of seatback angle and seat pitch. Subjective discomfort scores and root mean square (RMS) and mean power frequency (MPF) values were used to evaluate muscle fatigue, and all data were calculated for every 15-min interval.RESULTS Significant increases of MPF for all three muscles were found at 30 min, along with significant increases in the perceived levels of discomfort (PLD) over 2 h. Besides, a 120° seatback angle and a 34˝ seat pitch resulted in lower PLD values for the lower back and hip areas than smaller ones (significant difference).DISCUSSION It took around 30 min before pronounced discomfort in the upper body regions occurred during flight. The larger parameters of seatback angle and seat pitch may significantly contribute to the easing of subjective discomfort. Moreover, a decrease in MPF coupled with a concomitant increase in RMS does not appear to be a reliable indicator of discomfort rate. The need for further development of discomfort indicators which are more directly related to muscular activation is recognized.Pei H, Yu S, Ding M, Bai Z. Aircraft passenger comfort based on muscle activation and perceived discomfort during long flights. Aerosp Med Hum Perform. 2020; 91(5)416-421.BACKGROUND Given the challenges of collecting reliable Psychomotor Vigilance Task (PVT) data in the field, this study compared a 3-min PVT on a hand-held device and wrist-worn device vs. a standardized laptop.METHODS The experiment utilized a randomized, repeated-measures design. Subjects (N = 36) performed the PVT on a touch-screen, hand-held device (HHD), a wrist-worn device (WWD), and a standardized laptop (L). Sleep was assessed using wrist-worn actigraphy.RESULTS Compared to the L, the HHD was slower on average (∼50% longer reaction times; ∼34% slower response speeds; ∼600% more lapses in attention combined with false starts) and introduced a proportional bias that decreased the range of response speeds by 60%. Compared to the L, the WWD with the backlight on was faster on average (reaction time ∼6%; response speed ∼13%), but equivalent in lapses combined with false starts, and introduced a proportional bias that increased the range of responses by 60%.DISCUSSION Compared to the L PVT, using a hand-held, touch screen interface to collect PVT data may introduce a large constant bias and a proportional bias that decreases the range of response speed. However, performance on the WWD closely mirrors performance on the L PVT and the proportional bias tends to be in favor of detecting individuals with slower respons