Supplementary Table S7. Temporal-window perturbation analysis of sEMG contrasts.
Muscle / contrast -500 ms -250 ms 0 ms +250 ms +500 ms
PD: RP - CB 6.77 [4.27, 9.27] 5.82 [3.40, 8.24] 4.30 [1.26, 7.33] 4.01 [0.62, 7.40] 5.91 [2.28, 9.53]
BB: WVS - SB, lifting 12.08 [6.71, 17.46] 11.41 [5.99, 16.83] 7.61 [1.74, 13.49] 4.70 [-1.07, 10.47] 4.45 [-1.55, 10.44]
BB: WVS - CB, lifting 12.75 [7.40, 18.10] 11.56 [6.17, 16.96] 9.40 [3.55, 15.24] 5.71 [-0.04, 11.45] 4.65 [-1.32, 10.61]
BB: WVS - RP, lifting 14.18 [9.07, 19.29] 14.26 [9.11, 19.42] 12.36 [6.78, 17.95] 9.33 [3.84, 14.81] 8.56 [2.87, 14.26]
MT: lowering - lifting 10.47 [6.41, 14.54] 12.80 [9.04, 16.57] 13.91 [10.37, 17.44] 13.44 [9.61, 17.27] 9.67 [5.35, 13.99]
TB: WVS - CB 6.70 [1.97, 11.44] 6.28 [1.50, 11.06] 5.32 [0.44, 10.19] 4.76 [-0.47, 9.99] 5.15 [-0.60, 10.91]
TB: WVS - RP 7.43 [2.80, 12.06] 6.96 [2.29, 11.64] 5.58 [0.82, 10.35] 4.32 [-0.81, 9.45] 2.35 [-3.27, 7.97]
LD: SB - RP, lowering 4.75 [-1.35, 10.85] 5.00 [-1.27, 11.26] 5.27 [-0.99, 11.53] 2.88 [-3.15, 8.92] 6.41 [0.08, 12.75]
LD: lifting - lowering within CB 10.39 [4.64, 16.15] 14.56 [8.65, 20.48] 14.82 [8.91, 20.73] 13.59 [7.89, 19.28] 11.65 [5.67, 17.63]
LD: lifting - lowering within RP 3.63 [-2.01, 9.27] 6.77 [0.97, 12.57] 8.20 [2.41, 13.99] 9.73 [4.15, 15.31] 10.80 [4.94, 16.66]
Values are model-estimated contrasts [95% CI] using the participant-specific fixed 20% right-LD EMG-defined activity-onset criterion (50-ms moving RMS envelope; at least 50-ms threshold persistence) and 1-second lifting/lowering analytical windows shifted by the indicated amount. The 0-ms condition represents the reference placement of the 1-second sensitivity window, not the primary full 2-second analytical interval; therefore, the 0-ms estimates are not expected to reproduce the primary-model estimates. The ±250- and ±500-ms conditions shift this same 1-second window earlier or later. For LD, attachment × phase interaction p values were 0.305, 0.162, 0.143, 0.480, and 0.269 at -500, -250, 0, +250, and +500 ms, respectively. PD = posterior deltoid; BB = biceps brachii; MT = middle trapezius; TB = triceps brachii; LD = latissimus dorsi.