Time-course changes in lower limb strength, vertical jump metrics and their relationship with patient reported outcomes following anterior cruciate ligament reconstruction

Benjamin Dutaillis; Tyler Collings; Philip Bellinger; Ryan G Timmins; Morgan D Williams; Mathew N Bourne

doi:10.1002/ksa.12694

Time-course changes in lower limb strength, vertical jump metrics and their relationship with patient reported outcomes following anterior cruciate ligament reconstruction

Knee Surg Sports Traumatol Arthrosc. 2025 May 12. doi: 10.1002/ksa.12694. Online ahead of print.

Authors

Benjamin Dutaillis^{1

2}, Tyler Collings^{1

2}, Philip Bellinger^{1

3}, Ryan G Timmins^{4

5}, Morgan D Williams¹, Mathew N Bourne^{1

2}

Affiliations

¹ School of Health Sciences and Social Work, Griffith University, Gold Coast, Australia.
² Australian Centre for Precision Health and Technology (PRECISE), Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia.
³ Griffith Sport Science, Griffith University, Gold Coast, Australia.
⁴ School of Behavioural and Health Sciences, Australian Catholic University, Brisbane, Australia.
⁵ The Sports Performance, Recovery, Injury and New Technologies (SPRINT) Research Centre, Brisbane, Australia.

PMID: 40351254
DOI: 10.1002/ksa.12694

Abstract

Purpose: To (1) investigate how lower limb strength, vertical jump metrics, and patient reported outcome measures (PROMs) change in the initial 3- to 12-months of recovery following ACLR; and (2) explore which strength and vertical jump metrics best differentiate between lower and higher Knee Osteoarthritis Outcome Score (KOOS) and Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) scores.

Methods: Thirty recreationally active athletes undergoing unilateral primary ACLR underwent field-based assessments of knee flexion and extension strength, hip adduction and abduction strength, and double and single leg countermovement (CMJ) and drop vertical jump (DVJ) kinetics at 3-, 6-, 9- and 12-months following surgery. The KOOS and ACL-RSI were also completed. Mixed models were used to investigate how measures of lower limb strength, vertical jump metrics and PROMs change across the first 12-months of rehabilitation. Mixed model decision trees were used to determine which strength and vertical jump measures best discriminated between lower and higher PROMs.

Results: Vertical jump height and reactive strength index (RSI) improved significantly over time (p < 0.001), with reductions in contraction and contact times (p < 0.05). Isometric knee extension and eccentric knee flexion strength increased significantly (p < 0.001), as did KOOS and ACL-RSI scores (p < 0.001). Surgically reconstructed limbs displayed deficits in most vertical jump and strength measures compared to the uninjured contralateral limb, although deficits reduced over time with between limb asymmetry deceasing in 70% of these variables (p range: 0.05 to <0.001). Single leg CMJ jump height < 8.4 cm best discriminated between lower and higher ACL-RSI scores (r² = 0.67, d = 0.8), whilst knee extension peak force asymmetry < 38.3% best discriminated between lower and higher KOOS scores (r² = -0.78, d = 0.9) across the time-course of rehabilitation.

Conclusion: Most measures of lower limb strength and vertical jump metrics change in both the ACLR and uninjured contralateral limbs across the first 12-months of recovery following primary ACLR. A strong relationship was found between measures of lower limb strength and vertical jump performance with PROMs.

Level of evidence: Level II, lower quality prospective cohort study.

Keywords: ACL; biomechanics; knee reconstruction; rehabilitation.