BACKGROUND & OBJECTIVE
One suggested purpose of movement screening is to identify "movement dysfunction," or a physical inability to execute a movement based on deviations from pre-established performance criteria. To standardize screening procedures, testers recite scripted verbal instructions, and â€“ in an effort to elicit "instinctual" movement patterns - don't provide any visual demonstration, practice, or feedback. The trouble is, these conventions may inadvertently disadvantage those with limited experience at the movements.
Suppose a patient performs poorly on a movement screen, but their deficits resolve quickly with practice and feedback. Should the movement screen label them as dysfunctional when in reality they merely lacked skill at a novel task? Under the standard testing conditions, practitioners may not be able to differentiate between skill and dysfunction. Therefore, the purpose of this study was to determine whether individuals perform differently on a common movement screen test - the overhead squat - under three conditions: (1) minimal instruction; (2) scripted verbal instructions, and (3) scripted verbal instructions, visual demonstration, and practice with feedback.
Fourteen recreationally active college students (7 females, age = 22±1 years) with no previous movement screen experience participated in the study. To track their three-dimensional biomechanics, the participants were outfitted with retroreflective markers and stood atop force plates. They were graded on three repetitions of a barefoot dowel rod overhead squat under three conditions:
Condition 1) They were told only to keep the dowel overhead as they squatted. Condition 2) They were read a modified version of the instructions from the Functional Movement Screen (FMS). Condition 3) They were read instructions that defined an external attentional focus ("stay tall," "big butt," "big chest"), shown a visual demonstration, and given three practice repetitions with corrective feedback.
Condition 1 was first, followed by Conditions 2 and 3 in a counterbalanced order.
The researchers used one-way repeated measures ANOVAs to analyze six biomechanical variables: (1) weight distribution symmetry, (2) center of mass (COM) vertical displacement, (3) horizontal distance between COM and dowel rod at the bottom of the squat, (4) difference between trunk and shank angles at the bottom of the squat, (5) peak forward trunk lean, and (6) peak ankle, knee, and hip angles.
There were no significant differences between conditions in weight distribution symmetry, horizontal distance between COM and dowel, peak forward trunk lean, or peak ankle angle (p > 0.05). Compared to Conditions 1 and 2, Condition 3 did elicit significantly greater