Fig 1.
ABD: abduction. a: a participant performing the task with EMG sensors, IMUs and VivePro helmet and controllers; b: Participant view of its virtual hand while performing the task, left hand on home target; c: Top view of the positioning of the targets around the participant (right-handed). The Home target is positioned at 90° of shoulder flexion; Target 1 at 90° of shoulder abduction, elbow fully extended; Target 2 at 90° of shoulder abduction and 90° of shoulder external rotation, elbow flexed at 90°, Target at 120° of shoulder elevation in the scapular plan and Target 4 at 120° of shoulder flexion.
Fig 2.
Spatiotemporal data collection.
a. Example of spatiotemporal data collection while reaching target 3. iANG: initial angle of endpoint deviation, this angle was calculated using the shortest line between two targets [home and reaching targets] and the line corresponding to the initial peak of acceleration); fERR: final error, the shortest arc distance between the ideal arrival point into the sphere (target) and the actual arrival point. b. Example of a calculated 3D area under the curve for 1 reaching movement: the area under the curve is the summation of the rectangular trapezoids perpendicular to the ideal trajectory line and the actual trajectory line.
Table 1.
Participant’s baseline characteristics.
Table 2.
EMG signals of the two groups during baseline and experimental phase.
Table 3.
Mean total joint excursions during baseline and experimental phase of both groups.
Fig 3.
Inter-joint coordination at baseline and post-experimental phase.
Inter-joint coordination while reaching target 2 (120° scaption). a. Trunk lateral flexion (LF) vs sternoclavicular (SC) elevation and b. Glenohumeral (GH) flexion vs elbow flexion. Trunk lateral flexion: positive value represents a LF ipsilateral to the reaching arm. Significant difference (Time x Group effect: p < 0.05) for SC elevation, trunk LF, GH flexion and elbow flexion between the phases. a. Fatigue group showed a significant increase of SC elevation and trunk LF initial and final positions and total excursion during post-experimental phase (p < 0.05). b. Fatigue group showed a significant decrease of GH flexion initial and final positions and an increase of elbow flexion initial and final positions; total joint excursion during post-experimental phase was decreased for both joints (p < 0.05).
Fig 4.
Spatiotemporal data during baseline and post-experimental condition of both groups.
Data are presented as mean±SD of Baseline and Experimental condition for both groups. a: iANG, initial angle of endpoint deviation (°); b: Area, area under the curve (m2); c: Time, time taken to reach the targets (s); d: fERR, final error, arc sign (m). Significant Time effect and Time x Group effect, p<0.05, for iANG, Time and Area. No significant difference for fERR (Time effect: p = 0.226; and Time x Group effect: p = 0,33). *Significant increase of performance for controls compared to baseline, p < 0.05. †Significant decrease of performance compared to baseline, p < 0.05.
Table 4.
Spatiotemporal data mean difference between baseline and experimental condition of both groups.