Dynamic postural control is achieved by maintaining a stable base of support whilst undertaking upright tasks. For individuals with lower limb injury or pain, an inability to control balance may be a contributing factor to their condition. Nonetheless, clinicians tend to consider that poor movement patterns arising during functional movement tests are due to a lack of control (e.g. at the hip or knee), which undermines the contribution of global balance to observed movement patterns.

PURPOSE: To determine the contribution of postural control to performance on 3 common functional movement tests.

METHODS: Women with anterior knee pain (AKP) and age- and sex-matched uninjured controls were recruited. Dynamic postural control was examined using the Star Excursion Balance Test (SEBT) where participants stood on their most affected leg and reached for maximal distance with the other leg in 8 directions. SEBT scores were normalised to leg length, summed for an overall score, and also separated into scores for ‘away’ and ‘toward’ the affected leg. Participants also performed 3 common lower limb musculoskeletal screening tests, including a single leg squat (SLS), single leg hop (SLH) and drop vertical jump (DVJ). Each test was captured using 2D video and rated for movement quality using a validated global 10-point ordinal scale by 10 trained physical therapists. Mean ratings of performance for each participant and test were compared between groups using one-way ANOVA. Linear regression was used to determine the ability of SEBT scores to predict lower limb function.

RESULTS: Ten women with AKP (age: 23.2±2.8 years) and 10 women free from musculoskeletal impairment (age: 23.1±1.8 years) participated. Total SEBT score (345±32cm vs 377±19cm, p=0.015) and SEBT score ‘away’ from the affected leg (134±10cm vs 150±8cm, p=0.002) were lower for those with AKP compared to controls. There was no difference in SEBT score ‘toward’ the affected leg for the AKP group compared to the controls (121±15cm vs 131±9cm, p=0.114). Total SEBT score predicted variance in SLS performance (R2 = 0.525, p< 0.001); but not SLH (p=0.861) or DVJ performance (p=0.335).

CONCLUSION: Young adult women with AKP exhibit poorer lower limb dynamic postural control than healthy controls. Further, balance is positively related to single leg squat performance.