TY - JOUR
T1 - The differential effects of gender, anthropometry, and prior hormonal state on frontal plane knee joint stiffness
AU - Cammarata, Martha L.
AU - Dhaher, Yasin Y.
N1 - Funding Information:
This work was supported by grants from the National Institutes of Health: NIAMS RO1 AR049837 and NICHD T32 HD07418. The authors would like to thank Tobey DeMott, MSPT, Jennifer Moore, MPT, and Anastasios Tsoumanis, MS, for their help with data collection and analysis.
PY - 2008/8
Y1 - 2008/8
N2 - Background: Gender differences in passive frontal plane knee stiffness may contribute to the increased anterior cruciate ligament injury rate in females. Gender-based stiffness differences have been attributed to anthropometric variations, but little data exist describing this relationship. Furthermore, sex hormone levels appear to influence joint stiffness, but the differential effects of instantaneous and prior hormonal concentrations remain unknown. This study sought to explore the effect of gender, prior hormonal status, and anthropometry on passive frontal plane knee joint stiffness. Methods: Twelve males and 31 females participated. Females were grouped by hormonal contraceptive use (non users [n = 11], monophasic contraceptive users [n = 11], and triphasic contraceptive users [n = 9]) and tested at the same point in the menstrual cycle. Subjects' right knee was passively stretched ±7° in the frontal plane at 3°/s. Stiffness was estimated at three loading levels and normalized by body size to minimize anthropometric biases. A 4 (group) × 3 (load) repeated measures analysis of variance was performed for both raw and normalized stiffness. Linear regression analyses were preformed between stiffness estimates and knee diameter and quadriceps femoris angle. Findings: Males displayed significantly greater (P < 0.05) frontal plane stiffness than females. When normalized, males displayed significantly greater stiffness in valgus (P < 0.05), but not varus (P > 0.05) than females. No significant effect (P > 0.05) of prior hormonal state was found; however, when normalized, varus stiffness was significantly less for triphasic contraceptive users than the other female groups (P < 0.05). Quadriceps femoris angle was negatively correlated and knee diameter was positively correlated to knee stiffness. Interpretation: Consistent with earlier in vitro findings, our data may indicate that ligament material properties are gender specific. A deficit in passive knee joint stiffness may place a larger burden on the neuromuscular system to resist frontal plane loading in females.
AB - Background: Gender differences in passive frontal plane knee stiffness may contribute to the increased anterior cruciate ligament injury rate in females. Gender-based stiffness differences have been attributed to anthropometric variations, but little data exist describing this relationship. Furthermore, sex hormone levels appear to influence joint stiffness, but the differential effects of instantaneous and prior hormonal concentrations remain unknown. This study sought to explore the effect of gender, prior hormonal status, and anthropometry on passive frontal plane knee joint stiffness. Methods: Twelve males and 31 females participated. Females were grouped by hormonal contraceptive use (non users [n = 11], monophasic contraceptive users [n = 11], and triphasic contraceptive users [n = 9]) and tested at the same point in the menstrual cycle. Subjects' right knee was passively stretched ±7° in the frontal plane at 3°/s. Stiffness was estimated at three loading levels and normalized by body size to minimize anthropometric biases. A 4 (group) × 3 (load) repeated measures analysis of variance was performed for both raw and normalized stiffness. Linear regression analyses were preformed between stiffness estimates and knee diameter and quadriceps femoris angle. Findings: Males displayed significantly greater (P < 0.05) frontal plane stiffness than females. When normalized, males displayed significantly greater stiffness in valgus (P < 0.05), but not varus (P > 0.05) than females. No significant effect (P > 0.05) of prior hormonal state was found; however, when normalized, varus stiffness was significantly less for triphasic contraceptive users than the other female groups (P < 0.05). Quadriceps femoris angle was negatively correlated and knee diameter was positively correlated to knee stiffness. Interpretation: Consistent with earlier in vitro findings, our data may indicate that ligament material properties are gender specific. A deficit in passive knee joint stiffness may place a larger burden on the neuromuscular system to resist frontal plane loading in females.
KW - Contraceptives
KW - Frontal plane
KW - Gender
KW - Hormones
KW - Knee stiffness
UR - http://www.scopus.com/inward/record.url?scp=46749139008&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=46749139008&partnerID=8YFLogxK
U2 - 10.1016/j.clinbiomech.2008.03.071
DO - 10.1016/j.clinbiomech.2008.03.071
M3 - Article
C2 - 18479791
AN - SCOPUS:46749139008
SN - 0268-0033
VL - 23
SP - 937
EP - 945
JO - Clinical Biomechanics
JF - Clinical Biomechanics
IS - 7
ER -