Can the Functional Movement Screen™ be used to capture changes in spine and knee motion control following 12 weeks of training?

OBJECTIVE: To examine whether objective measures of spine and frontal plane knee motion exhibited during Functional Movement Screen™ (FMS) task performance changed following a movement-guided fitness (MOV) and conventional fitness (FIT) exercise intervention. DESIGN: Secondary analysis of a randomized controlled experiment. Before and after 12 weeks of exercise, participants' kinematics were quantified while performing the FMS and a series of general whole-body movement tasks. SETTING: Biomechanics laboratory. PARTICIPANTS: Fifty-two firefighters were assigned to MOV, FIT, or a control (CON) group. OUTCOME MEASURES: Peak lumbar spine flexion/extension, lateral bend and axial twist, and frontal plane knee motion. RESULTS: The post-training kinematic changes exhibited by trainees while performing the FMS tasks were similar in magnitude (effect size < 0.8) to those exhibited by CON. However, when performing the battery of general whole-body movement tasks, only MOV showed significant improvements in spine and frontal plane knee motion control (effect size > 0.5). CONCLUSIONS: Whether graded qualitatively, or quantitatively via kinematic analyses, the FMS may not be a viable tool to detect movement-based exercise adaptations. Amendments to the FMS tasks and/or scoring method are needed before it can be used for reasons beyond appraising the ability to move freely, symmetrically, and without pain.