Rl. Gajdosik et al., INFLUENCE OF AGE ON CONCENTRIC ISOKINETIC TORQUE AND PASSIVE EXTENSIBILITY VARIABLES OF THE CALF MUSCLES OF WOMEN, European journal of applied physiology and occupational physiology, 74(3), 1996, pp. 279-286
The purpose of this study was to investigate the influence of age on c
oncentric isokinetic torque (CIT) and passive extensibility (PE) varia
bles of the calf muscles of healthy women. Ten younger women [31.9 (SD
6.1) years] and ten older women [71.1 (SD 6.6) years] were tested usi
ng a KIN-COM 500H dynamometer. The PE was tested by stretching the mus
cles from relaxed plantarflexion to the maximal dorsiflexion (DF) angl
e at 5 degrees . s(-1) without raw electromyogram (EMG) activity excee
ding 0.05 mV. The maximal CIT was tested from the maximal DF angle 60
degrees into plantarflexion at four randomly ordered velocities of 30,
60, 120, and 180 degrees . s(-1). Separate analysis of variance (ANOV
A) tests showed that the standardized (% body mass) concentric peak an
d mean torques were lower for the older women for all isokinetic veloc
ities (p < 0.001). The ''angular delay'' from the onset of concentric
activation to peak torque was smaller for the older women at 120 and 1
80 degrees . s(-1) (p < 0.05). Age showed negative relationships (Pear
son r) with all standardized peak torques (p less than or equal to 0.0
01) and mean torques (p < 0.001), and the ''angular delay'' at 120 and
180 degrees . s(-1) (p less than or equal to 0.05). Independent t-tes
ts showed that the maximal DF angle and the change in the PE angle fro
m an initial angle (defined at 10% of the maximal passive torque) to t
he maximal DF angle were less for the older women (p < 0.05). Age was
negatively related to the maximal DF angle and the change in the PE an
gle (p < 0.01). The results suggest an age-related decrease in calf mu
scle CIT, muscle length and PE. The smaller ''angular delay'' for the
older women at 120 and 180 degrees . s(-1) indicates that CIT testing
at rapid velocities can be used to examine age-related changes in calf
muscle contractile properties in relation to rapid velocities of move
ment.