Single- Versus Dual-Task Functional Movement Paradigms: A Biomechanical Analysis

Abstract

Context: Laboratory-based movement assessments are commonly performed without cognitive stimuli (ie, single-task) despite the simultaneous cognitive processing and movement (ie, dual task) demands required during sport. Cognitive loading may critically alter human movement and be an important consideration for truly assessing functional movement and understanding injury risk in the laboratory, but limited investigations exist. Objective: To comprehensively examine and compare kinematics and kinetics between single- and dual-task functional movement among healthy participants while controlling for sex. Design: Cross-sectional study. Setting: Laboratory. Patients (or Other Participants): Forty-one healthy, physically active participants (49% female; 22.5 ± 2.1 y; 172.5 ± 11.9 cm; 71.0 ± 13.7 kg) enrolled in and completed the study. Intervention(s): All participants completed the functional movement protocol under single- and dual-task (subtracting by 6s or 7s) conditions in a randomized order. Participants jumped forward from a 30-cm tall box and performed (1) maximum vertical jump landings and (2) dominant and (3) nondominant leg, single-leg 45° cuts after landing. Main Outcome Measures: The authors used mixed-model analysis of variances (α = .05) to compare peak hip, knee, and ankle joint angles (degrees) and moments (N·m/BW) in the sagittal and frontal planes, and peak vertical ground reaction force (N/BW) and vertical impulse (Ns/BW) between cognitive conditions and sex. Results: Dual-task resulted in greater peak vertical ground reaction force compared with single-task during jump landing (mean difference = 0.06 N/BW; 95% confidence interval [CI], 0.01 to 0.12; P = .025) but less force during dominant leg cutting (mean difference = −0.08 N/BW; 95% CI, −0.14 to −0.02; P = .015). Less hip-flexion torque occurred during dual task than single task (mean difference = −0.09 N/BW; 95% CI, −0.17 to −0.02). No other outcomes were different between single and dual task (P ≥ .053). Conclusions: Slight, but potentially important, kinematic and kinetic differences were observed between single- and dual-task that may have implications for functional movement assessments and injury risk research. More research examining how various cognitive and movement tasks interact to alter functional movement among pathological populations is warranted before clinical implementation.

Cognitive Demands Influence Drop Jump Performance and Relationships With Leg Stiffness in Healthy Young Adults

“…The cognitive resources needed to plan movements during cognitively loaded drop jumps also have implications for injuries (22). Noncontact injuries, such as ACL injuries, have been associated with drop jump mechanics, including stiffness, peak vGRF, leg deformation, RSI, and GCT, and cognition, such as reaction time, visual processing speed, and memory (23,25,32,53). Noncontact injuries predominantly also occur during fast-paced moments of distraction and dual focus (7,38,47,48,53).…”

“…Associating kinetics, such as lower extremity stiffness and vertical ground reaction forces (vGRFs), with accessible measures, such as ground contact time and leg deformation, can enhance practical applications in the daily training environment (8,30,33). Increased lower extremity stiffness and vGRF have long been associated with decreased ground contact times (GCTs) and leg deformation in various athletic movements, including drop jumps (2,8,17,32). Drop jumps are a common and accessible exercise in training the stretch-shortening cycle and have been successfully used to research mechanics under different physical and cognitive demands (3,4,22,33,51).…”

Think outside the box: Incorporating secondary cognitive tasks into return to sport testing after ACL reconstruction

“…Cognitive dual-tasks have also been incorporated with cutting maneuvers. One study found that when a serial subtraction task (by 6 s or 7 s) was added to a 45-degree cutting task, healthy individuals demonstrated less peak vGRF and less hip flexion torque ( 84 ). Many studies have also introduced decision-making to cutting tasks.…”

An Exemplar Frontal Plane Visual Kinematic Stimulus Elicits Sex-Specific Learned Behavior: An Exploratory Report

“…For instance, using a gait assessment, sex differences were magnified under dual-task conditions when compared with single-task conditions, such that female subjects were more susceptible to movement decrements during dual tasking (28). Conversely, maximum vertical jump landings and single-leg cutting maneuvers did not elicit sex effects during dual-task conditions (33). One reason for the mixed findings may be the result of differences in task constraints, but nevertheless, they indicate a need to also consider sex effects on outcome measures.…”