Purpose  The study aimed to determine whether additional cognitive demands interfere with simultaneous mobility and whether normal ageing magnifies the dual-task interference. Subjects Eighteen younger subjects (aged 23.4 ± 5.7 years) and 16 older subjects (aged 73.6 ± 4.6 years) were recruited.   They were physically active and free of pathological conditions.  Methods  Subjects walked an obstacle course in the single-task condition.  In the dual-task condition, subjects negotiated the obstacle course while simultaneously performing a cognitive visuo-spatial task.  A two-way repeated measures ANOVA was performed.  Results  Results demonstrated that all subjects slowed down and made more errors while completing the obstacle course in the dual-task condition.  There was a significant interaction between age group and condition such that older subjects experienced greater dual-task interference by making significantly more errors than the younger subjects in the dual-task condition.  Conclusion  Both groups showed deterioration in dual task performance, however the older group experienced significantly higher dual task interference. 

A Comparative Study of Open and Closed Kinetic Chain Exercise Regimes in Patients with Knee Osteoarthritis.
Lim BW.

Purpose.  The aim of the study was to compare the effects of open and closed kinetic chain exercise regimes on pain, disability and muscular performance in patients with osteoarthritis (OA) of the knee. Methods.  Thirty-two subjects (six men, 26 women) with knee OA aged between 45 and 80 were randomly organised to perform open kinetic chain quadriceps exercises or close kinetic chain exercises with a leg press machine.  All subjects did ten minutes of warm-up and 20 minutes of exercise twice a week for six weeks.  In addition all subjects were given 15 minutes of short wave diathermy.  Knee pain, stiffness and physical function were assessed using the Western Ontario McMaster Osteoarthritis Index (WOMAC). Isometric quadriceps strength was measured using the Kin-Com dynamometer.  Results.  There were no significant differences between the two groups. Subjects in the closed kinetic regime generally showed greater improvements compared to those in the open kinetic regime.  Pre and post treatment results for all subjects showed significant improvements in knee pain, stiffness, physical function, peak torque and average torque after 6 weeks of exercise (p<0.05, paired t-test).  Mean improvements were 50.4%, 32.1%, 42.2%, 31.6% and 32.9% respectively.  Conclusion.  A treatment programme using either open or closed kinetic chain exercise regimes and shortwave diathermy twice a week for six weeks could significantly improve quadriceps strength, knee pain, stiffness and disability.