1.Musculoskeletal profile of the hip rotators for the purpose of injury prevention and performance enhancement

Injury prevention/rehabilitation »

The hip rotators are mostly located at the posterior aspect of the hip (Table 1). The hip external rotators specifically are considered important for the execution of the instep and side-foot kicks (1, 2). It has been theorized that excess stress stemming from the execution of repetitive movements may result in muscle tightness (3). Given that instep and side-foot kick are fundamental activities in soccer practice, it may be concluded that these muscle groups may be susceptible to tightness. A less than optimal range of motion may affect quality of force production and application and will be associated with energy leaks (4). In addition poorly conditioned hip rotators may lead to abnormal lumbo-pelvic posture and lumbar spine motion during athletic movements (5).

External rotators	Internal rotators
Psoas	Gluteus medius (anterior fibers)
Illiacus	Gluteus minimus
Sartorius	Adductor magnus (anterior fibers)
Gluteus maximus	Adductor longus
Gluteus medius (posterior fibers)	Adductor brevis
Biceps femoris (long head)	TFL
Adductor magnus (posterior fibers)	ST/SM
Piriformis

Table 1. External and internal rotators of the hip joint.

Research indicates that the hips are affected in soccer players since hip-rotation ROM decreases over the years in soccer players (6) and both youth and senior footballers have significantly less internal rotation (and significantly higher abduction) than their respective age-matched controls (7). In addition higher decrease in hip range of motion (possibly due to internal rotation lessening) that is strongly associated with ACL ruptures has been reported in soccer players when compared with the general population (8), whilst soccer players with re-rupture of the ACL have significantly lower mean internal-external hip rotation when compared with healthy professional soccer players (9).

Tightness within the hip external rotators will limit hip internal rotation and tightness within the hip internal rotators will limit hip external rotation (3, 4). Given that all muscles listed in Table 1 are also implicated in the execution of other hip movements, profiles of hip extension/flexion and abduction/adduction along with external/internal rotation may provide to the strength and conditioning professional a starting point for interventions on an individual basis.

REFERENCES

1. Nunome H, Asai T, Ikegami Y, Sakurai S. Three-dimensional kinetic analysis of side-foot and instep soccer kicks. Med Sci Sports Exerc, 2002; 34:2028-2036.
2. Brophy RH, Backus SI, Pansy BS, Lyman S, Williams RJ. Lower extremity muscle activation and alignment during the soccer instep and side-foot kicks. J Orthop Sports Phys Ther, 2007; 37:260-268.
3. Ninos J. A chain reaction: the hip rotators. Strength Cond J, 2001; 23:26-27.
4. Kritz MF, Cronin J. Static Posture Assessment Screen of Athletes: Benefits and Considerations. Strength Cond J, 2008; 30:18-27.
5. Regan DP. Implications of hip rotators in lumbar spine injuries. Strength Cond J, 2000; 22:7-13.
6. de Castro JV, Machado KC, Scaramussa K, Gomes JL. Incidence of decreased hip range of motion in youth soccer players and response to a stretching program: a randomized clinical trial. J Sport Rehabil, 2013; 22:100-107.
7. Manning C, Hudson Z. Comparison of hip joint range of motion in professional youth and senior team footballers with age-matched controls: an indication of early degenerative change? Phys Ther Sport, 2009; 10:25-29.
8. Gomes JL, de Castro JV, Becker R. Decreased hip range of motion and noncontact injuries of the anterior cruciate ligament. Arthroscopy, 2008; 24:1034-1037.
9. Ellera Gomes JL, Palma HM, Ruthner R. Influence of hip restriction on noncontact ACL rerupture. Knee Surg Sports Traumatol Arthrosc, 2014; 22(1):188-91.