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Phases of jump used for comparison between sessions (A) and definition of angles used in this study (B).
Source publication
The purpose of this study was to determine the variability of lower limb range of motion (ROM) during vertical jumps using inertial-based systems. Ten participants attended three laboratory session to familiarise with the countermovement jump (session 1) and to perform three maximum countermovement jumps (session 2 and 3). Motion from the lower lim...
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Background:
Due to increased sedentary workstyles, active workstations have shown the ability to increase activity while only moderately affecting work ability. However, previous examinations have not examine fine motor mousing tasks on tripping descriptors.
Research question:
What affect do mousing tasks of varying target size have on tripping...
Citations
... These systems employ a combination of magnetometers, gyroscopes and accelerometers to track the 3D motion of body segments, allowing for the calculation of joint angles. However, the reproducibility of these sensors has been limited to exercise tasks such as walking, squatting, jumping and kicking (Al-Amri et al., 2018;Blair et al., 2018;Bini, Jayalath et al., 2018), which restricts the use of this information for cyclists. Moreover, to date, no study presented the reproducibility of body kinematics or kinetics taken from cyclists within a given session or between different sessions, which largely limits the use of derived metrics for interventions such as bike fitting. ...
In order to address gaps in the literature, this study assessed the reproducibility (i.e., difference between and within sessions) of joint and muscle forces using wearable sensors during stationary cycling. Seventeen male cyclists performed two sessions on a cycle ergometer cycling at a combination of three power outputs (1.5, 2.5 and 3.5 W/kg) and three pedalling cadences (60, 80 and 100 rpm) in two sessions (2–7 days apart). The first trial from each session was repeated at the end of the session for assessment of within-session reproducibility. Three-dimensional (3D) full-body motion and 3D bilateral pedal forces were collected using an inertial motion tracking system and a pair of instrumented pedals, respectively. Joint angles, muscle forces and knee joint forces were computed using OpenSim. Poor to excellent agreement (ICCs = 0.31–0.99) was observed and differences were trivial to small and non-significant between trials within-session. Poor to excellent agreement (ICCs = 0.05–0.97) was observed and differences were trivial to large between sessions. Variability can be attributed to changes in muscle recruitment strategies (within and between-sessions) and to repositioning of sensors (between-sessions).
... The motion tracking system used in this study provided generic instructions on how sensors should be positioned in relation to anatomical landmarks, which in our view increased the likelihood of differences in measurements whenever the sensors were repositioned. A prior study observed that this could be the case for vertical jumps [37], which conflicted with another study, looking at walking gait [38]. Further research is required to assess the extent of the variability in other measures, such as joint angles, moments, and forces, and to determine if the use of a baseline trial for data normalization could reduce the between-participant variability between sessions. ...
Purpose
The study assessed within- and between-session reliability of power output (PO) and pedal force effectiveness and compared PO from the pedals with the Lode Excalibur cycle ergometer.
Methods
Seventeen male cyclists performed 10 trials at 3 levels of PO (1.5, 2.5, and 3.5 W/kg) and 3 cadences (60, 80, and 100 rpm) in 2 sessions. Instrumented pedals and a portable motion tracking system were synchronized to collect pedal forces and 3D full body motion, respectively. PO and the index of effectiveness (IE) were compared within and between sessions for the pedals while PO was compared with the Lode Excalibur.
Results
Good agreement was observed for PO within sessions whilst right and left pedal IEs were moderate. Betweensession reliability ranged from poor to good for PO measured from the pedals, and reliability for IE ranged from poor to good. Significant differences in PO were observed between the pedals and the Lode Excalibur ergometer (17–50 W).
Conclusions
The customized system to measure pedal forces was reliable within a given session for measuring IE and PO but variability in data increased in the second session, potentially because of the repositioning of the motion tracking sensors. Validity in measuring PO from the pedals without the use of the crank encoder is questionable.
