DYNAMIC HIP ADDUCTION, ABDUCTION AND ABDOMINAL EXERCISES FROM THE HOLMICH GROIN-INJURY PREVENTION PROGRAM ARE INTENSE ENOUGH TO BE CONSIDERED STRENGTHENING EXERCISES - A CROSS-SECTIONAL STUDY

Kasper Krommes; Thomas Bandholm; Markus D Jakobsen; Lars L Andersen; Andreas Serner; Per Hölmich; Kristian Thorborg

DYNAMIC HIP ADDUCTION, ABDUCTION AND ABDOMINAL EXERCISES FROM THE HOLMICH GROIN-INJURY PREVENTION PROGRAM ARE INTENSE ENOUGH TO BE CONSIDERED STRENGTHENING EXERCISES - A CROSS-SECTIONAL STUDY

Int J Sports Phys Ther. 2017 Jun;12(3):371-380.

Authors

Kasper Krommes¹, Thomas Bandholm², Markus D Jakobsen³, Lars L Andersen, Andreas Serner, Per Hölmich¹, Kristian Thorborg¹

Affiliations

¹ Sports Orthopedic Research Centre-Copenhagen (SORC-C), Department of Orthopaedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Denmark.
² Physical Medicine & Rehabilitation Research - Copenhagen (PMR-C), Department of Physical and Occupational Therapy, Department of Orthopaedic Surgery, Clinical Research Center, Amager-Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark.
³ National Research Centre for the Working Environment, Copenhagen, Denmark.

PMID: 28593090
PMCID: PMC5455186

Abstract

Background: Training intensity is an important variable in strength training and above 80% of one repetition maximum is recommended for promoting strength for athletes. Four dynamic and two isometric on-field exercises are included in the Hölmich groin-injury prevention study that initially failed to show a reduction in groin injuries in soccer players. It has been speculated that exercise-intensity in this groin-injury prevention program was too low to induce the strength gains necessary to protect against groin-related injuries.

Purpose: To estimate the intensity of the six exercises from the Hölmich program using electromyography (EMG) and possibly categorize them as strength-training exercises.

Study design: Cross-sectional study.

Methods: 21 adult male soccer players training >5 hours weekly were included. Surface-EMG was recorded from adductor longus, gluteus medius, rectus abdominis and external obliques during isometric adduction against a football placed between the ankles (IBA), isometric adduction against a football placed between the knees (IBK), folding knife (FK), cross-country skiing on one leg (CCS), adduction partner (ADP) and abduction partner (ABP). The EMG-signals were normalized (nEMG) to an isometric maximal voluntary contraction for each tested muscle.

Results: Adductor longus activity during IBA was 84% nEMG (95% CI: 70-98) and during IBK it was 118% nEMG (95% CI 106-130). For the dynamic exercises, ADP evoked 87% nEMG (95% CI 69-105) in adductor longus, ABP evoked 88% nEMG (95% CI 76-100) in gluteus medius, FK evoked 82% nEMG (95% CI 68-96) rectus abdominis, and 101% nEMG (95% CI 85-118) in external obliques. During CSS < 37% nEMG was evoked from all muscles.

Conclusion: These data suggest that exercise-intensity of all the six investigated exercises in the Hölmich groin injury prevention program, except cross-county skiing, is sufficient to be considered strength-training for specific muscle groups in and around the groin region.

Level of evidence: 3.

Keywords: Abdominals; adductor longus; electromyography; gluteus medius; soccer.