Original paper
Normative values of hip strength in adult male association football players assessed by handheld dynamometry

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Abstract

Chronic groin pain is a common problem in association football players. Normative values for the strength of hip muscles, measured in an accurate and accessible manner, are needed to gauge strength and inform return to play decisions in this group. The purpose of this study was to define normative values of hip muscle strength using handheld dynamometry. A series of reliable clinical tests that are commonly used when making return to sport decisions in athletes with chronic adductor related groin pain have been selected. One hundred and twenty adult male association football players, free from injury, were recruited. Isometric strength of the hip flexors and adductor muscles was measured using a handheld dynamometer. Mean age was 24.9 years (SD 5.9). Eighty participants (67%) had experienced groin pain in the past. Mean strength for dominant leg hip flexion was 47.3 kg (95% confidence interval 45.6–49.0), non-dominant leg hip flexion was 42.5 kg (41.1–43.9), adduction at 0° hip flexion was 35.6 kg (34.1–37.1), adduction at 45° was 32.0 kg (30.9–33.1), and adduction at 90° was 25.5 kg (24.4–26.5). This study establishes reference ranges and predictive equations for maximal isometric contraction strength of the hip muscles in non-injured adult male association football players. This information will assist assessment and management of an athlete's return to play following injury.

Introduction

Groin pain is a common problem in association football (soccer) players. Groin injuries account for up to 22% of injuries requiring time off training and out of competition.1 Acute strains of the groin may resolve in a short period of time but once the injury becomes chronic, it is often more difficult to manage.1 Symptoms may change with time, and more than one problem can develop.2 There is debate about the aetiology of adductor related groin pain with different authors suggesting a bone stress injury,3 an adductor enthesopathy, enthesitis,2 partial avulsion,4 or some form of inguinal fascial defect.5

With the aetiology unclear, there remains a need to manage athletes with chronic groin pain in order to help them to return to sport. Holmich et al. have shown that a structured strengthening programme is better at returning athletes with adductor related groin pain to their sports than physiotherapy without strengthening.6 Tyler et al. have shown that both absolute and weight-corrected weakness of the hip adductors are associated with an increased risk of groin injury in ice hockey players,7 and that strengthening of the adductors reduces this risk.8 Currently the normative strength values in association football players, and therefore the goals for rehabilitation are unknown.

Various authors have reported using simultaneous adductor activation tests to stress the adductors and the symphysis pubis in athletes who have adductor related groin pain. Holmich et al.9 evaluated a number of tests for assessing groin pain and showed that resisted hip adduction with hips and knees extended was reproducible and had minimal variability (Fig. 1A). Verrall et al.10 described the “Squeeze test” which is performed with the patient supine, hips flexed to 45° and knees at 90°, and squeezing on the examiner's fist (Fig. 1B). Rodriguez et al.11 described the “Pubic Symphysis Gap Test” which is performed with the patient supine, hips and knees flexed to 90°, feet off the plinth and again, squeezing the examiner's fist between the knees (Fig. 1C).

Other authors have used resisted hip flexion to stress the joints of the pelvic ring. Holmich et al.9 assessed the reliability of testing resisted hip flexion with the hip flexed to 90° and found that the greater strength of this muscle made this testing position less reliable than other tests. Tyler et al.7, 8 tested the strength of resisted hip flexion over the end of an examination couch (Fig. 1D). In this position, the hip is extended.

In a study that considered 24 different criteria that could be used to assess clinical improvement in athletes recovering from osteitis pubis, Hogan and Lovell12 reported that only five criteria were statistically significant. They included the absence of pain with isometric hip adduction in various degrees of hip flexion, and the absence of pain during the Modified Thomas Test. They recommend the use of these criteria in determining the appropriate time to progress load in athletes who are recovering from osteitis pubis.

Bohannon has stated that normative values of strength are essential in order for therapists to be able to correctly identify patients with physical limitations.13 He has shown that manual muscle testing does not have the sensitivity of handheld dynamometry for detecting deficits in strength relative to normal values.14

The aim of this study was to record the normative strength values in association football players, of the muscle groups commonly tested in the clinical assessment of athletes with groin pain, using handheld dynamometry in recommended test positions.

Section snippets

Methods

Adult male players from seven association football teams participating in the New Zealand Football Championship and Northern Premier League competitions within the Auckland region of New Zealand were invited to participate in this study. All players attending training sessions while testing was being conducted were included. Players were excluded if they were unable to fully participate in training as a result of injury at the time of testing. Written informed consent was obtained from club

Results

One hundred and twenty-one players from seven football teams were invited to participate in this study. All invited players agreed to participate (100%). One player withdrew due to the development of groin pain during testing. Therefore 120 (99%) participants completed the study. The age of participants ranged from 15 to 45 years (mean 24.9 years, SD 5.9), with the number of previous seasons played at this level ranging from 1 to 27 (mean 8.8, SD 6.3). Eighty participants (66.9%) had

Discussion

This study assessed the strength of adult male association football players. We present normative ranges of strength for hip muscle groups in testing positions commonly used in the assessment of adductor related groin pain. Regression equations have been provided to allow for the calculation of individual-specific strength of these muscle groups. This information can be used to assess the degree of an athlete's weakness at presentation relative to predicted normal. This information may be used

Conclusion

This study establishes reference ranges for strength of the hip muscles in adult male association football players. We have also shown that weight, playing position and employment type are associated with hip muscle strength and have provided predictive equations for hip muscle strength. This information can be used to monitor recovery from injury, and with further research may be useful in identifying athletes at risk of injury, and in the development of injury prevention strengthening

Practical implications

  • The predictive equations calculated can be used to estimate normal hip flexor and adductor strength for association football players using information about their leg dominance, height, weight, playing position and work type.

  • The predictive equations for hip muscle strength of adult male association football players may prove useful in return to play decisions following groin injury, identifying those at risk of injury and injury prevention programmes.

  • There is a significant difference in hip

Acknowledgements

The authors would like to thank the players and clubs who participated in this study. There has been no financial assistance for this research project.

References (18)

  • P. Holmich et al.

    Effectiveness of active physical training as treatment for long-standing adductor-related groin pain in athletes: randomised trial

    Lancet

    (1999)
  • A.B. Nielsen et al.

    Epidemiology and traumatology of injuries in soccer

    Am J Sports Med

    (1989)
  • P. Holmich

    Long-standing groin pain in sportspeople falls into three primary patterns, a “clinical entity” approach: a prospective study of 207 patients

    Br J Sports Med

    (2007)
  • G. Verrall et al.

    Osteitis pubis: a stress injury to the pubic bone

  • D. Brennan et al.

    Secondary cleft sign as a marker of injury in athletes with groin pain: MR image appearance and interpretation

    Radiology

    (2005)
  • D.C. Taylor et al.

    Abdominal musculature abnormalities as a cause of groin pain in athletes. Inguinal hernias and pubalgia

    Am J Sports Med

    (1991)
  • T.F. Tyler et al.

    The association of hip strength and flexibility with the incidence of adductor muscle strains in professional ice hockey players

    Am J Sports Med

    (2001)
  • T.F. Tyler et al.

    The effectiveness of a preseason exercise program to prevent adductor muscle strains in professional ice hockey players

    Am J Sports Med

    (2002)
  • P. Holmich et al.

    Clinical examination of athletes with groin pain: an intraobserver and interobserver reliability study

    Br J Sports Med

    (2004)
There are more references available in the full text version of this article.

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