Relationships between core strength, hip external rotator muscle strength, and star excursion balance test performance in female lacrosse players

Abstract

PURPOSEBACKGROUND: Female athletes have high rates of lower extremity (LE) injuries. Core strength (CS) and hip external rotator (HER) strength have been suggested to be factors that influence LE injury risk. Better balance has also been shown to decrease LE injury risk. Still, little research has examined whether core strength and hip muscle strength can influence LE balance. Therefore the purpose of the current study was to examine the relationships between core strength, hip ER strength and lower extremity balance as measured by the Star Excursion Balance Test (SEBT).

Methods: CS was examined via the bent knee lowering test (BKLT) (grades 1-5). Hip external rotator (HER) strength was measured singularly (HERL and HERR and combined (HERCOM) assessed via hand held dynamometry (reported in Newtons), and balance assessed via the SEBT expressed as % leg length, bilaterally in the postero-medial, postero-lateral, anterior directions and as a combined score (SEBTCOM). All outcomes were assessed in 45 female lacrosse players (16.0 ± 5.9 yrs, 65.1 ± 2.4 cm, 57.3 ± 7.4 kgs, experience=5.9 ± 2.9 yrs). Pearson product-moment correlations examined relationships between the BKLT, HER and SEBT. Linear regression analyses examined possible influences of CS and HER on balance (p ≤ .05).

Results: SEBTCOM was not correlated with BKLT [r(45)=-.20, p=.18] or HERCOM [r(45)=.20, p=.18]. There was no correlation between HER strength and CS (BKLT) [r(45)=.20, p=.20]. Overall scores on the BKLT were not correlated with any of the three balance SEBT scores. HERL [r(45)=.36, p=.02] and HERR [r(45)=.30, p=.05] were moderately positively correlated with left posteromedial SEBT direction. HERCOM and BKLT did not predict overall SEBTCOM balance scores (r(2)=.068, p=.23).

Conclusions: BKLT scores and combined HER strength did not correlate with LE balance, as measured by the SEBT, in female lacrosse players. However, HER strength of both the left and right LE's (singularly) was moderately correlated with scores on one reach direction (left posteromedial) but not with combined SEBT scores. Researchers should continue to examine whether core and hip muscles influence LE balance.

Level of evidence: 2b.

Keywords: Balance; bent knee lowering test; hand held dynamometry; transversus abdominis.

Figures

Figure 1.

(a) Initial Position of the Bent Knee Lowering Test (BKLT). (b) Abdominal Hollowing Position of the Bent Knee Lowering Test (BKLT).