Hip adduction and abduction strength in youth male soccer and basketball players with and without groin pain in the past year

The objectives of this study were to 1) assess the differences between youth soccer and basketball players with and without past year groin pain (GP) in hip adduction and abduction strength and several training characteristics (age at the start of regular training, weekly training frequency, warm-up and training duration, use of stretching and/or stabilisation exercises during warm-up, use of resistance training); 2) present strength reference values for youth soccer and basketball players. 227 players participated (age 16.9 +/- 1.4 years; height 184.2 +/- 8.5 cm; mass 75.5 +/- 11.9 kg). Hip adduction and abduction strength was measured in supine position (hip, knee and ankle in neutral position) using a MuscleBoard dynamometer. Interlimb asymmetries and hip adduction:abduction ratios were calculated. Past year GP and training characteristics were assessed with a retrospective questionnaire. 11.9% of players reported past year GP (16.9% in soccer and 6.4% in basketball). The only significant difference between the past year GP and the control groups was found in the age of the players at the start of regular training (7.2 +/- 1.8 years for the GP group vs. 8.5 +/- 2.6 years for the control group). Additionally, soccer players without past year GP have significantly higher hip adduction strength (1.1 +/- 0.2 Nm/kg vs. 1.0 +/- 0.2 Nm/kg) and adduction:abduction strength ratio (1.10 +/- 0.18 vs. 1.03 +/- 0.16) compared to basketball players. Our results show that hip adduction and abduction strength, interlimb asymmetry and hip adduction:abduction ratio do not differentiate between players with and without past year GP (p = 0.29-0.90), which means that their adduction or abduction strength can be analysed regardless of the GP presence in the past year. Additionally, players with past year GP started regularly training at significantly lower age, which could indicate the problematic nature of early/premature sports specialisation.