Hip adduction and abduction strength in different test positions and their relationship

Key points

1. 01Hip adductor and abductor strength were significantly higher at 45 degrees of hip flexion compared to 0 degrees (hip extended) in elite women footballers.
2. 02The abductor-to-adductor ratio is lower in the flexed position and higher in the extended position, meaning test position changes the ratio direction.
3. 03Only the abductor/adductor ratio at 0 degrees (hip extended) could distinguish players with a history of groin pain from those without (AUC = 0.734).
4. 04A cut-off ratio of 1.01 or below at 0 degrees had 77.8% sensitivity and 77.0% specificity for identifying previous groin pain.
5. 05Absolute adductor or abductor strength alone, at either angle, did not significantly differentiate previously injured from uninjured players.

How it was conducted

Design

Cross-sectional study with ROC analysis

Participants

101 elite women footballers from the Slovenian Women's Football League; 96 analysed after exclusions (mean age 19.2 years, 8.7 years training experience)

Measurement

Isometric hip adduction and abduction strength using a custom frame-stabilized dynamometer at two positions: 0 degrees (hip extended, supine) and 45 degrees (hip flexed, supine)

Injury history

Self-reported via OSTRC-O questionnaire; 10/96 players (9.9%) reported hip or groin pain in the past 12 months

Primary outcomes

Normalized peak torque (Nm/kg), abductor/adductor strength ratio at both positions, and ROC-derived cut-off values for distinguishing injured from uninjured players

What they found

• Adduction strength was significantly higher at 45 degrees (mean 2.53 Nm/kg) than at 0 degrees (mean 1.06 Nm/kg); difference 1.47 Nm/kg (95% CI 1.42 to 1.53), t = 51.57, p < 0.001, Cohen's d = 5.26.
• Abduction strength was significantly higher at 45 degrees (mean 2.38 Nm/kg) than at 0 degrees (mean 1.15 Nm/kg); difference 1.23 Nm/kg (95% CI 1.18 to 1.28), t = 52.907, p < 0.001, Cohen's d = 5.40.
• The abductor/adductor ratio was lower at 45 degrees (mean 0.95) than at 0 degrees (mean 1.11); difference -0.15 (95% CI -0.18 to -0.12), t = -9.971, p < 0.001, Cohen's d = 1.02.
• Correlations between test positions were statistically significant: r = 0.799 for adduction, r = 0.761 for abduction, and r = 0.510 for the ratio (all p < 0.001).
• Only the abductor/adductor ratio at 0 degrees differentiated previously injured from uninjured players: AUC = 0.734 (SE 0.091), p = 0.021.
• Optimal cut-off for the 0-degree ratio was 1.01; sensitivity 77.8%, specificity 77.0%.
• No other variable (adduction or abduction strength at either angle, or the ratio at 45 degrees) had an AUC significantly different from 0.5 (all p > 0.05).
• All 10 reported groin injuries were classified as overuse injuries; 3/10 players missed at least one training session or match due to groin pain.

Limitations

• Injury history was self-reported without imaging confirmation, which may have led to misclassification of injured players.
• Isometric strength testing may not reflect dynamic performance and has limited external validity for sport-specific movements.
• Duration of groin symptoms was not recorded, which may have influenced adductor strength and recovery status.
• The cross-sectional design prevents determining whether a lower abductor/adductor ratio caused injuries or resulted from them.

Why it matters

For patients

Women footballers with a history of groin pain are more likely to have a lower hip abductor-to-adductor strength ratio at a straight-leg position, which may help guide targeted rehab exercises.

For clinicians

Testing the abductor/adductor isometric strength ratio with the hip extended (0 degrees) is more clinically informative than the 45-degree position for identifying groin injury history; a ratio at or below 1.01 warrants attention.

For readers

Hip test position fundamentally changes strength values and the abductor/adductor ratio, so results from different positions are not interchangeable when assessing groin injury risk in women footballers.