Age related blood flow around the Achilles tendon during exercise in humans

Injuries due to the overuse of tendons increase with age, and it has been s uggested that this correlates with hypovascularity of the tendon. In the pr esent study, the peritendinous blood flow was determined using xenon-133 wa shout at rest and during standardised intermittent exercise of the calf-mus cle (1.5 s contraction, 1.5 s rest, 40 min) in young (n = 6; 26 years), mid dle-aged (n = 6; 48 years), and older (n = 6; 74 years) individuals. At res t, the older individuals had a lower peritendinous blood flow compared with the two other age groups. During exercise, blood flow in all three groups rose 2.5-3.5-fold to reveal similar blood flows [2.7 (SEM 0.5) to 7.8 (SEM 1.0) ml 100 g tissue(-1) min(-1) (young group); 3.0 (SEM 0.4) to 7.3 (SEM 1 .6) ml - 100g tissue(-1) min(-1) (middle-aged group); 1.6 (SEM 0.2) to 5.5 (SEM 1.1) ml 100 g tissue(-1) (.) min(-1) (older group)]. The findings demo nstrated that the peritendinous blood flow to the zone of the tendon with t he highest incidence of injury from overuse is unaltered by age during exer cise, and indicates that factors other than blood flow are important for th e increased incidence with age of injuries from overuse.