Computational protocol: Altered movement patterns and muscular activity during single and double leg squats in individuals with anterior cruciate ligament injury

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Protocol publication

[…] One examiner visually inspected the video according to a protocol defined in advance so that the trial with the most obvious altered movements was chosen for analysis. To analyze SEMG activity during the chosen trial, the Mega Win software was used to visualize SEMG amplitudes (microvolts, μV) on a time-axis (milliseconds, ms). The same examiner processed the SEMG recordings and identified the start and end of the trial by simultaneous inspection of the video and electrogoniometer recordings: the instance that the goniometer signal changed +2° during 0.1 s was defined as the start and the instance when the goniometer signal resumed starting-level was defined as the end of the test-movement. The mean durations of the SLS were 2.5 s (SD 0.5) and 2.4 s (SD 0.5) for the injured and non-injured sides, respectively and 2.6 s (SD 0.4) for the DLS.For analysis, the SEMG-recording during test-movements was divided into 10 time epochs (bins). The time bins were evenly distributed over the duration of the test-movement, within the limits of the time resolution of the Mega Win software (0.1 sec). A “pre-bin”, bin 1, was added for the inclusion of anticipatory muscular activation just prior to the defined beginning of the test-movement, corresponding to 10% of the duration of the test-movement. Hence, 11 time bins, evenly distributed and starting slightly before the test-movement were used in the SEMG analysis.The average amplitude for each of the 11 time bins was calculated by the Mega Win Software. However, comparisons and correlation calculations focused on preparatory muscular activity (time bin 1), the transition from flexion to extension (for individual participants either time bin 6 or 7) and the decline or cessation of muscular activity (time bin 11), given the crucial importance of these phases for the movement as a whole.To obtain a measure of SEMG deviation – for each muscle, for each participant, for both SLS and DLS – that could be quantitatively compared to TSP scores, the ratio of average amplitude for each of the 11 time bins between injured and non-injured sides, SEMGratio, was calculated in accordance with previous studies [,], so that equal activity of injured and non-injured sides would correspond to 1.0 []. To quantitatively characterize the activity in antagonistic muscles, a ratio of SEMG activity of quadriceps/hamstrings and tibialis anterior/gastrocnemius was calculated for bin 1, 6/7 and 11. Ratios were then compared between injured and non-injured sides. [...] The Wilcoxon Signed Ranks Test was used to test for differences between the injured and non-injured sides with respect to TSP scores, SEMGratio and for the antagonistic activity ratio within the injured side in bins 1, 6/7 and 11. Differences p ≤0.05 were considered statistically significant. Non-parametric confidence intervals (95%) were calculated for the median of the paired differences []. For the correlation calculations between the SEMGratio and the results of the TSP, the Spearman’s correlation coefficients (rs) were used, and correlations rs < −0.5 or rs ≥ 0.5 are presented. All calculations and statistical analyses were carried out using SPSS version 11.5 and IBM SPSS Statistics version 20.0.Data for the dominant/non-dominant leg were pooled in accordance with previous studies, in which subjects conducting movements similar to SLS and DLS were found to have a fairly symmetrical SEMG when comparing dominant and non-dominant sides []. […]

Pipeline specifications

Software tools MEGA, MUSCLE, SPSS
Applications Miscellaneous, Nucleotide sequence alignment
Organisms Homo sapiens
Diseases Muscular Diseases, Wounds and Injuries, Anterior Capsular Rupture, Ocular