Optogait system

Before and after training, jump performance was assessed in four different jump types: (a) CMJ with the hands akimbo, (b) CMJ with arm swing (which is similar to a block jump in volleyball), (c) CMJ with run-up and arm swing (identical to an attack jump in volleyball), and (d) DJ with arm swing with a drop height of 37 cm. Jump heights were calculated from flight times, which we measured with an OptoGait system (Microgate Srl, Bolzano, Italy). A very high degree of validity and reliability has been demonstrated for both the tested jump types and the measuring instrument used (Carroll et al., 2019 (link); Glatthorn et al., 2011 (link); Sattler et al., 2012 (link)). In addition, ground contact times were recorded for the DJs. Five jumps were recorded in each jump type, resulting in a total number of 20 jumps. The low number of jumps should prevent effects of fatigue. The order of the jump types was randomized between participants. For all jumps, the participants were instructed to jump as high as possible. No instructions were given regarding the range of motion or ground contact time. They received feedback about their jump height after each jump. Before each measurement session, the participants performed a standardized specific warm-up, which also included the four jump types assessed during the measurements.

To ensure the recording of a higher number of steps, DT gait assessments were performed on a treadmill (Gait Trainer 3, Biodex Medical System, NY, USA) (Fig 4). Spatiotemporal gait parameters were recorded using an OptoGait system (Microgate). Following a 10-minute period of habituation to the treadmill [28 (link)], each participant’s preferred walking speed was determined according to a standardized protocol [29 (link)]. In OSA participants, the preferred walking speed determined before CPAP treatment was used for post-CPAP evaluations. To evaluate the influence of speed on OSA patients’ ability to walk under DT condition, gait assessments were performed in two conditions of speed (preferred walking speed and preferred walking speed+30%), alternatively in SiT (gait only) and in DT (gait and Stroop test). Each trial lasted 30 s with 4 trials per condition (2 gait*2 task paradigms, 16 trials in total). Participants walked continuously during 30 s between each trial. In SIT, participants were instructed to walk according to their natural pattern, arms moving freely by their sides, while looking straight-ahead at a fixed red target displayed on the screen. In DT, subjects were asked to walk as naturally as possible and to perform the Stroop test at the best of their capacity without any task prioritization. STV was calculated.