Context: Jump landing is a common activity in collegiate activities, such as women's basketball, volleyball, and soccer, and is a common mechanism for anterior cruciate ligament (ACL) injury. It is important to better understand how athletes returning to competition after ACL reconstruction are able to maintain dynamic postural control during a jump landing.Objective: To use time to stabilization (TTS) to measure differences in dynamic postural control during jump landing in ACL-reconstructed (ACLR) knees compared with healthy knees among National Collegiate Athletic Association Division I female athletes.Design: Case-control study. Setting: University athletic training research laboratory.Patients or Other Participants: Twenty-four Division I female basketball, volleyball, and soccer players volunteered and were assigned to the healthy control group (n 5 12) or the ACLR knee group (n 5 12). Participants with ACLR knees were matched to participants with healthy knees by sport and by similar age, height, and mass.Intervention(s): At 1 session, participants performed a single-leg landing task for both limbs. They were instructed to stabilize as quickly as possible in a single-limb stance and remain as motionless as possible for 10 seconds.Main Outcome Measure(s): The anterior-posterior TTS and medial-lateral TTS ground reaction force data were used to calculate resultant vector of the TTS (RVTTS) during a jump landing. A 1-way analysis of variance was used to determine group differences on RVTTS. The means and SDs from the participants' 10 trials in each leg were used for the analyses.Results: The ACLR group (2.01 6 0.15 seconds, 95% confidence interval [CI] 5 1.91, 2.10) took longer to stabilize than the control group (1.90 6 0.07 seconds, 95% CI 5 1.86, 1.95) (F 1,22 5 4.28, P 5 .05). This result was associated with a large effect size and a 95% CI that did not cross zero (Cohen d 5 1.0, 95% CI 5 0.91, 1.09).Conclusions: Although they were Division I female athletes at an average of 2.5 years after ACL reconstruction, participants with ACLR knees demonstrated dynamic postural-control deficits as evidenced by their difficulty in controlling ground reaction forces. This increased TTS measurement might contribute to the established literature reflecting differences in single-limb dynamic control. Clinicians might need to focus rehabilitation efforts on stabilization after jump landing. Further research is needed to determine if TTS is a contributing factor in future injury.Key Words: postural control, jump landings, dynamic stability
Key PointsN The resultant vector time to stabilization demonstrated that participants with anterior cruciate ligament-reconstructed knees took longer to stabilize during a single-leg jump-landing task than participants in the control group.N Dynamic postural-control deficits and difficulties in controlling ground reaction forces during landing might be present in women with anterior cruciate ligament-reconstructed knees even after clearance by a physician and return to play.N Clinician...