Eccentric hip muscle function in females with and without patellofemoral pain syndrome.
BACKGROUND
Patellofemoral pain syndrome (PFPS) is a common knee condition in athletes. Recently, researchers have indicated that factors proximal to the knee, including hip muscle weakness and motor control impairment, contribute to the development of PFPS. However, no investigators have evaluated eccentric hip muscle function in people with PFPS.


OBJECTIVE
To compare the eccentric hip muscle function between females with PFPS and a female control group.


METHODS
Cross-sectional study.


METHODS
Musculoskeletal laboratory.


METHODS
two groups of females were studied: a group with PFPS (n = 10) and a group with no history of lower extremity injury or surgery (n = 10).


METHODS
Eccentric torque of the hip musculature was evaluated on an isokinetic dynamometer.


METHODS
Eccentric hip abduction, adduction, and external and internal rotation peak torque were measured and expressed as a percentage of body mass (Nm/kg x 100). We also evaluated eccentric hip adduction to abduction and internal to external rotation torque ratios. The peak torque value of 5 maximal eccentric contractions was used for calculation. Two-tailed, independent-samples t tests were used to compare torque results between groups.


RESULTS
Participants with PFPS exhibited much lower eccentric hip abduction (t(18) = -2.917, P = .008) and adduction (t(18) = -2.764, P = .009) peak torque values than did their healthy counterparts. No differences in eccentric hip external (t(18) = 0.45, P = .96) or internal (t(18) = -0.742, P = .47) rotation peak torque values were detected between the groups. The eccentric hip adduction to abduction torque ratio was much higher in the PFPS group than in the control group (t(18) = 2.113, P = .04), but we found no difference in the eccentric hip internal to external rotation torque ratios between the 2 groups (t(18) = -0.932, P = .36).


CONCLUSIONS
Participants with PFPS demonstrated lower eccentric hip abduction and adduction peak torque and higher eccentric adduction to abduction torque ratios when compared with control participants. Thus, clinicians should consider eccentric hip abduction strengthening exercises when developing rehabilitation programs for females with PFPS.
Baldon
Rodrigo de Marche
Rde M
São Carlos Federal University, São Paulo, Brazil.
Nakagawa
Theresa Helissa
TH
Muniz
Thiago Batista
TB
Amorim
César Ferreira
CF
Maciel
Carlos Dias
CD
Serrão
Fábio Viadanna
FV
D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D006615:Hip / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010147:Pain Measurement; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology*; D012399:Rotation; D019415:Torque