Fig 1.
The laboratory setup for the repetitive movement task machine is showed from the front-right (A) and top (B) views.
Fig 2.
Flowchart illustrating the steps involved in the pre-processing and analysis of EMG data.
Table 1.
Participant demographics.
Table 2.
Mean ± SD values of variance accounted for (VAF) relative to the original extraction iteration of muscle synergies for the Control Group (CON) and Subacromial Impingement Syndrome Group (SIS) for the repetitive reaching task (RRT).
Table 3.
Mean ± SD values of variance accounted for each muscle (VAF muscle) regarding a three-synergy model for the repetitive reaching task (RRT).
Fig 3.
Averaged Inter-individual variability of Synergy activation coefficients for all the subjects of Control Group (CON) and Subacromial Impingement Syndrome Group (SIS) (UA—arbitrary units).
Top panel: corresponds to SIS while Bottom panel: regards to CON. The thick black line represents the group mean, while the thin lines represent individual synergy activation coefficients. (#1: synergy 1, #2: synergy 2, #3: synergy 3).
Fig 4.
Averaged synergy activation coefficients of Control Group (CON) and Subacromial Impingement Syndrome Group (SIS).
The left panel refers to Synergy #1, the central panel to Synergy #2, and the right panel to Synergy #3. The upper hemisphere of the graphs corresponds to the Forward phase (0–100% of the RRT cycle), while the lower hemisphere corresponds to the Reverse phase (100–0% of the RRT).
Table 4.
Intra-group and inter-group similarity values (r) of muscle synergy vectors of the Control Group (CON) and Subacromial Impingement Syndrome Group (SIS).
Fig 5.
Averaged muscle synergy vectors and muscle synergy vectors for all the subjects of the Control Group (CON) and Subacromial Impingement Syndrome Group (SIS) (UA–arbitrary units).
Top panel: averaged muscle synergy vectors between SIS and CON groups in the left panel refer to Synergy #1, the central panel to Synergy #2, and the right panel to Synergy #3. Central and bottom panel: muscle synergy vectors for all the subjects. Individual muscle weightings are depicted for each muscle within each synergy. The muscle synergy vectors have been normalized by their maximum under the synergy to which they belong. central panel refers to SIS, and the bottom panel to CON.
Table 5.
Intra-group and inter-group similarity values (r max) and lag times (%) of synergy activation coefficients and individual EMG profiles of Control Group (CON); Subacromial Impingement Syndrome Group (SIS).
Fig 6.
Averaged EMG envelopes (UA—arbitrary units) from 8 muscles obtained in Subacromial Impingement Syndrome Group (SIS) and Control Group (CON) participants during the RRT (200-time points).