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Leg strength and muscle morphology of older athletes
Leg Strength
and Muscle
Morphology
of Older Athletes
K. Tarpenning~'2.,M. Hamilton-Wessler~,R. Wiswell2& S. Hawkins2 'CharlesSturtUniversity,Bathurst,Australia 2UniversityOf SouthernCalifornia,Los Angeles,USA It has been reported that maximal strength peaks around 30 years of age, plateaus and remains relatively stable for the next 20-30 years, with an age-related decline in strength becoming significant by age 60. Much of the research attributes this decrease in peak force to ageassociated reductions in muscle mass, with a selective atrophy and reduction in Type II fibre area and number being the primary factors. The influence that chronic endurance training has upon ageassociated changes in muscular strength and muscle morphology has been largely undetermined. The purpose of this investigation was to examine the influence of chronic endurance training and age on knee extensor strength, and muscle fibre size and type distribution. Male (n = 107, age range = 40-88 yr) and female (n = 67, age range = 43-69 yr) Masters runners were tested for maximal strength of the knee extensor muscles. A sub-group of 30 male athletes participated in muscle biopsy testing. The effects of age were addressed by sub-dividing the sample into ageassociated cohorts, corresponding to decade of life. For both males and females, peak isokinetic concentric torque did not differ between age groups until after age 70 yrs. For the men, Type I and Type II fibre area and distribution did not differ between age groups through age 80 yrs. These data suggest that chronic endurance training can delay the age of onset of significant decrement in muscle strength and morphology characteristics of the vastus lateralis.
Dynamic
function
after ACL reconstruction
is r e l a t e d
to graft
type K. Webster*,J. Feller,R. Gonzalez,C. Kinmont& J. Wittwer La TrobeUniversityMusculoskeletalResearchCenre
Anterior cruciate ligament (ACL) reconstruction is a common procedure. However, considerable debate continues as to whether the patellar tendon (PT) or the hamstring tendon (HS) graft is preferable. It is therefore important that functional differences associated with these two graft types are understood. In this study, two experiments were conducted to examine lower limb biomechanics after HS and PT ACL reconstruction. In experiment 1, the gait patterns of 18 PT ACL reconstruction patients, 18 HS ACL reconstruction patients and 18 matched controls were compared. In experiment 2, single-limb landing patterns were compared between 10 PT ACL reconstruction and 10 HS ACL reconstruction patients. For both experiments a 3-dimensional motion analysis and force plate system was used to determine sagittal plane kinematics and kinetics of the lower limb. Results for experiment 1 showed significant differences in the moments about the knee that related to graft type. The PT patients had a reduced external knee flexion moment at mid stance whilst the HS patients had a reduced external extension moment at terminal stance. Experiment 2 results also showed a reduction in the external flexion moment about the operated knee for the PT group compared to the non-operated side but no difference between knees in the HS group. These combined results suggest that there are graft specific differences in knee biomechanics following ACL reconstruction that appear to relate to the donor site.
101
and Muscle
Morphology
of Older Athletes
K. Tarpenning~'2.,M. Hamilton-Wessler~,R. Wiswell2& S. Hawkins2 'CharlesSturtUniversity,Bathurst,Australia 2UniversityOf SouthernCalifornia,Los Angeles,USA It has been reported that maximal strength peaks around 30 years of age, plateaus and remains relatively stable for the next 20-30 years, with an age-related decline in strength becoming significant by age 60. Much of the research attributes this decrease in peak force to ageassociated reductions in muscle mass, with a selective atrophy and reduction in Type II fibre area and number being the primary factors. The influence that chronic endurance training has upon ageassociated changes in muscular strength and muscle morphology has been largely undetermined. The purpose of this investigation was to examine the influence of chronic endurance training and age on knee extensor strength, and muscle fibre size and type distribution. Male (n = 107, age range = 40-88 yr) and female (n = 67, age range = 43-69 yr) Masters runners were tested for maximal strength of the knee extensor muscles. A sub-group of 30 male athletes participated in muscle biopsy testing. The effects of age were addressed by sub-dividing the sample into ageassociated cohorts, corresponding to decade of life. For both males and females, peak isokinetic concentric torque did not differ between age groups until after age 70 yrs. For the men, Type I and Type II fibre area and distribution did not differ between age groups through age 80 yrs. These data suggest that chronic endurance training can delay the age of onset of significant decrement in muscle strength and morphology characteristics of the vastus lateralis.
Dynamic
function
after ACL reconstruction
is r e l a t e d
to graft
type K. Webster*,J. Feller,R. Gonzalez,C. Kinmont& J. Wittwer La TrobeUniversityMusculoskeletalResearchCenre
Anterior cruciate ligament (ACL) reconstruction is a common procedure. However, considerable debate continues as to whether the patellar tendon (PT) or the hamstring tendon (HS) graft is preferable. It is therefore important that functional differences associated with these two graft types are understood. In this study, two experiments were conducted to examine lower limb biomechanics after HS and PT ACL reconstruction. In experiment 1, the gait patterns of 18 PT ACL reconstruction patients, 18 HS ACL reconstruction patients and 18 matched controls were compared. In experiment 2, single-limb landing patterns were compared between 10 PT ACL reconstruction and 10 HS ACL reconstruction patients. For both experiments a 3-dimensional motion analysis and force plate system was used to determine sagittal plane kinematics and kinetics of the lower limb. Results for experiment 1 showed significant differences in the moments about the knee that related to graft type. The PT patients had a reduced external knee flexion moment at mid stance whilst the HS patients had a reduced external extension moment at terminal stance. Experiment 2 results also showed a reduction in the external flexion moment about the operated knee for the PT group compared to the non-operated side but no difference between knees in the HS group. These combined results suggest that there are graft specific differences in knee biomechanics following ACL reconstruction that appear to relate to the donor site.
101