COMPARISON OF ISOKINETIC MUSCLE PERFORMANCE IN ACTIVE, HEALTHY MALES AND
FEMALES
Brett Wright, Halli Meyer, Rhonda Cross Beemer, PhD, ATC, (Mentor)
Pharmaceutical, Biomedical, & Administrative Sciences Department; College of Pharmacy & Health Sciences
Abstract
Methods
The purpose of this study was to examine lower extremity
muscle performance differences and relationships in active,
healthy males and females to determine attributes that increase
risk of developing knee injuries, such as patellofemoral pain
syndrome (PFPS). Previous research has shown that deficits in
certain muscle groups may lead to faulty kinematics that can
attribute to higher risk of developing knee pain and injury.
Gender differences have been observed that may lead to the
higher incidence of knee injuries in females. It was
hypothesized that peak torque values in all females will be less
when compared to males. Subjects were recruited in this IRB
approved study. Subjects (n=17) underwent a series of muscle
performance tests using the Biodex System 4 Isokinetic
Dynamometer. Actions performed in this study included knee
extension and flexion, hip external rotation, and hip abduction
in concentric and eccentric isokinetic testing mode. Results:
Independent sample T Tests indicated that males exhibited an
increase in peak torque for all testing conducted. Pearson
correlations indicate that there are positive relationships
between body weight, BMI, and concentric and eccentric peak
torques in both genders.
• This study was approved by Drake University IRB.
Recruitment of subjects was conducted using email, word-ofmouth, and printed flyers. All research took place in the Ellis
Disease Prevention Lab at Drake University
• Subjects completed the Anterior Knee Pain Scale, visual
analogue pain scales with activities known to cause knee
pain, and a visual analogue scale of current pain levels,
followed by a brief warm-up and stretching period (exclusion
criteria).
• Actions performed were knee extension, knee flexion, hip
external rotation, and hip abduction in both concentric and
eccentric isokinetic mode using the Biodex Isokinetic
Dynamometer System Pro. See Fig 1, 2, & 3 for example
actions. Torque limits were set at 25% of subjects’ body
weight.
• Pearson correlation coefficient was computed to
assess the relationship between body weight, height,
and BMI among genders.
Results
• Descriptive statistics were calculated for total
subjects’ height, weight, and BMI.
• 9 females (mean ±SD; height,66.89±2.89, body
wt,145.99±17.54, BMI22.73±2.09) and 8 males
(height 72.38±2.26, body wt. 213.22±55.01, BMI
28.4±5.62)
• There were significance differences across all 3 sets
found for concentric and eccentric peak torques
(p=.05) when comparing the genders.
Fig. 4: Peak torque concentric vs eccentric mean values for gender
Introduction
• Previous studies have shown that there are correlations
between hip and knee strength, functional ability, and
subjects with PFPS1. Weak hip abductors and lateral rotator
muscles have been associated with excessive femoral
adduction and femur medial rotation 2. Studies also suggest
that people with PFPS may have weaker knee extensors, hip
extensors, and hip rotator strength compared to subjects
without PFPS3.
Fig. 1: 30o of hip abduction
• Overall, in females set 3 if there was an increase in
height, there was in increase in PkTq Con Quad. An
increase in body weight showed an increase in PkTq Con
Hip Abduction.
• Overall, in males, an increase in BMI showed an increase
in PkTq for Con Hip ER and Ecc Ham. An increase in
height showed an increase in PkTq Con Hip ER. An
increase in weight showed an increase in PkTq Ecc Ham.
Conclusion
• Hypothesis: Peak torque values in females will be less
when compared to males.
• Based on that data analysis, it would appear that males do
have a greater peak torque in all actions when compared
to women both concentrically and eccentrically.
Furthermore, there seems to be positive correlations in
both male and female groups when among body weight,
height, and BMI and certain actions. The higher the
weight, height, and BMI the greater some values are in
gender.
• Limitation: All strength tests were done in an isokinetic
setting at 30o/s, which is not sport specific.
• This study identifies key muscle groups that should be
assessed when evaluating patients with knee pain.
References
• Women showed greater correlation coefficients between
eccentric hip abductor torque and coronal plane femur and
knee movements than men 4. Subjects with PFPS exhibit
greater hip adduction than controls. Women in general have
shown similar abnormal lower-extremity kinematics when
compared to male. Counterparts4.
• Studies have shown that females have lower eccentric
KF/KE peak torque ratios when compared to males4.
• Therefore, the purpose of this study was to evaluate peak
torques between males and females. It was hypothesized
that peak torque values in females will be less when
compared to males.
• Females: There were multiple positive correlations.
Most notable at p <0.01 were between height and
PkTq Con Quad (r-0.810, n=9, p<.01), body weight
and PkTq Con Hip ABD (r=.935, n=9, P<0.01)
Fig. 2: 70o of knee extension
Fig. 3: 20o of hip external rotation
•Statistical analyses were performed using SPSS statistical
software and Microsoft Excel
• Descriptive statics were calculated for total subjects’
height, weight, and BMI
• Independent Sample T Tests were completed for each
set to compare differences between genders in all
exercises (Fig. 4)
• Males: There were multiple positive correlations.
Most notable at p<0.01 were between BMI and
PkTq Con Hip ER (r=0.870, n=8, p<0.01), height
and PkTq Con Hip ER (r=0.852, n=8, p<0.01), body
weight and PkTq Con Hip ER (r=0.921, n=8,
p<0.01), BMI and PkTq Ecc Ham (r=0.934, n=8,
p<0.01) and body weight and PkTq Ecc Ham
(r=0.922, n=8, p<0.01).
1.
Nakagaw, T., Baldon, R., Muniz, T., Serrao, F., 2011. Relationship among eccentric
hip and knee torque, symptom severity and functional capacity in females with
patellofemoral pain syndrome. Physical therapy in sport. 12, 133-139.
2. Jacobs, C.A., Uhl, T.L., Mattacola, C.G., Shapiro, R., & Rayens, W.S. (2007). Hip
abductor function and lower extremity landing kinematics: Sex differences. Journal of
Athletic Training, 42, 76–83.
3. Souza, R.B., Powers, C.M., 2009b. Predictors of hip internal rotation during running:
an evaluation of hip strength and femoral structure in women with and without
patellofemoral pain. Am. J. Sports Med. 37, 579-587
4. Baldon, R.M., Lobato, D.F., Serrao, F.V., 2011. Differences between genders in
eccentric hip adduction to abduction, hip medial to lateral rotation and knee flexion to
extension peak torque ratios. Isokinetics and Exercise Science. 19, 127-133.
Acknowledgements
• We would like to acknowledge all participants who gave up their time to be in our
study, Gary Williamson for his expertise, the Administrative Sciences faculty for SPSS
assistance, and Dr. Rhonda Cross Beemer for being an outstanding mentor.