Fig 1.
Placement of reflective markers and calculated sagittal joint angles.
The markers shown in the image were used to calculate the marked joint angles during stance phases of each limb in take-off. 1 = dorsal border of scapula, 2 = greater tubercle of humerus, 3 = lateral humeral epicondyle, 4 = ulnar styloid process, 5 = distal end of fifth metacarpal, 6 = over the 11th rib at the level of the shoulder joint, 7 = cranial dorsal iliac spine, 8 = greater trochanter of femur, 9 = lateral femoral epicondyle, 10 = lateral malleolus of fibula, 11 = distal end of fifth metatarsal. SH = shoulder, E = elbow, C = carpus, H = hip, ST = stifle, T = tarsus. Dashed yellow line marks the line used for limb angle calculation.
Table 1.
Description of kinematic variables measured during take-off to a jump.
Fig 2.
Calculation of peak force and impulse values from force plate data.
Peak force and impulse values were calculated separately for fore- and hindlimbs. If trailing and leading limbs contacted separate force plates, force values from the two plates were summed. In this example of individual trial at 100% of wither height, the force curves from fore- and hindlimbs do not overlap, as there had been a suspension phase between fore- and hindlimbs. An example with overlap is presented in S1 Fig.
Table 2.
Linear mixed model results: Effect of bar height and approach stride number on kinetics at take-off to a jump in agility dogs.
Table 3.
Linear mixed model results: Effect of bar height and approach stride number on jump arch and limb coordination at take-off in agility dogs.
Table 4.
Linear mixed model results: Effect of bar height and approach stride number on sagittal joint kinematics at take-off to a jump in agility dogs.
Fig 3.
Craniocaudal impulses of fore- and hindlimbs at three bar heights during take-off.
Estimated marginal means are presented as white dots along with 95% confidence interval lines. Light blue dots represent the observed values and light gray lines the random effects. A-C: Decelerative, accelerative, and net craniocaudal impulses produced by forelimbs. D-F: Decelerative, accelerative, and net craniocaudal impulses produced by hindlimbs. In both fore- and hindlimbs, all bar heights differed significantly from each other in all craniocaudal impulses (p≤0.001), except for decelerative impulse (A), which did not significantly differ between 80% and 100% bar heights in forelimbs.
Fig 4.
Synchronicity in touch-down timings of trailing and leading forelimbs (A) and hindlimbs (B). Estimated marginal mean is presented as a white dot along with the 95% confidence interval line. Light blue dots represent the observed values and light gray lines the random effects. Synchronicity is presented as the percentage of trailing limb stance time at which leading limb touch-down occurs. Lower value indicates more synchronous touch-down of trailing and leading limbs. In both fore- and hindlimbs, values differed significantly between all bar heights (80% vs. 100%, p = 0.048 in forelimbs and p = 0.006 in hindlimbs, p<0.001 for other pairwise comparisons). TrFL = trailing forelimb, TrHL = trailing hindlimb.
Fig 5.
Sagittal joint angles during stance phase at take-off to a jump.
Joint angles of trailing forelimb shoulder, elbow, and carpus and trailing hindlimb hip, stifle, and tarsus are presented. Mean curves ± standard error of mean from all trials at three bar heights are shown: 80% (blue), 100% (orange), and 120% (green) of wither height. Figures for leading fore- and hindlimb joints are presented in S2 Fig. Please note that the effect of stride number is not controlled in this figure, and the number of trials per dog per bar height varied from 0 to 7.