2 | NEW ZEALAND JOURNAL OF PHYSIOTHERAPY INTRODUCTION Connective tissue is known to lose extensibility as part of the ageing process (Maharam, Bauman, Kalman, Skolnik, & Perle, 1999; Mazzeo et al., 1998). This change is thought to be related to adaptations in the collagen architecture of tissues. For instance, ageing causes an increase in the crystallinity of the collagen fibres and increases their diameter, leading to less extensibility of muscles, ligaments and tendons (Maharam et al., 1999; Mazzeo et al., 1998). As a result of such changes, reductions in joint range of motion have been demonstrated in elderly participants and particularly those with a history of falling (Gajdosik, vander Linden, & Williams, 1999b; Kerrigan, Lee, Collins, Riley, & Lipsitz, 2001; Kerrigan, Xenopoulos, Sullivan, Lelas, & O’Reilly, 2003; Menz, Morris, & Lord, 2005). Another factor that adds to a reduction in joint range of motion commonly seen in older adults is degenerative joint disease. Osteoarthritis (OA) of the knee, is a common condition affecting a large proportion of the community (Thomson et al., 2005). It is a condition characterized by joint pain and swelling causing loss of strength, range of motion and function (Dieppe, 1999; Fitzgerald, Childs, Ridge, & Irrgang, 2002; Messier, Loeser, Hoover, Semble, & Wise, 1992). In people with knee OA, the joint loses flexion and extension range of motion. As knee extension range of motion is a common movement loss with OA, the hamstring muscles in particular may be affected by being maintained in a shortened position over time, specifically the extensibility and stiffness of the tissue may alter over time. Gajdosik, VanderLinden and Williams (1999a) have demonstrated that range of motion of the ankle joint and elasticity of the calf muscles reduces with age when compared to younger participants, and that these characteristics are most evident closer to the terminal range of the joint motion. The combination of the ageing process and the arthritic process affecting the knee joint in participants with OA may have an even greater impact. These changes have not been explored in the OA population. One way of improving range of motion in both the short and long term is to undertake stretching exercises. While periodic or long term stretching programmes have been investigated in older populations (Feland, Myrer, Schulthies, Fellingham, & Meason, 2001; Gajdosik, Vander Linden, McNair, Williams, & Riggin, 2005; Girouard & Hurley, 1995; Kerrigan et al., 2003; Raab, Agre, McAdam, & Smith, 1988), the majority of these studies have used range of motion as the primary variable of Effects of a six week lower limb stretching programme on range of motion, peak passive torque and stiffness in people with and without osteoarthritis of the knee RESEARCH REPORT Duncan A Reid DHSc and Peter J McNair PhD Health and Rehabilitation Research Institute, School of Rehabilitation and Occupation Studies, Auckland University of Technology ABSTRACT The purpose of this study was to compare the effects of a six week stretching programme on knee extension range of motion (ROM), passive resistive torque and stiffness in older adults with and without osteoarthritis (OA) of the knee. A randomized controlled trial design was utilised. Twenty two females and seventeen males aged between 60 and 78 years (mean 68.7, SD: 4.8) participated. Twenty participants of the 39 participants had OA of the knee joint. Participants were randomly assigned to stretch and control groups. The intervention used was three 60 second stretches to all major muscles in the lower limb, five days per week for six weeks. Using a Kincom dynamometer, knee extension ROM, peak passive torque and stiffness in the final 10% of knee extension ROM were measured. A significant (p<0.05) increase in knee extension ROM, peak passive torque and stiffness was observed in the stretch group following the six week intervention period. No changes were observed in the control group. There was no significant difference in these variables across OA and non OA groups. For knee extension ROM, the mean (95% CI) change was 7.7 degrees (2.6 to 12.7) in the stretching group and 1.8 degrees (-5.8 to 2.1) degrees in the control group. For peak passive torque, the mean change (95% CI) was 7.1 Nm (2.9 to 11.3) in the stretching group and 1.0 Nm (-6.0 to 4.1) for the control group. For stiffness in the final 10% of knee extension range of motion, the mean change (95% CI) was 0.22 Nm/deg ( 0.06 to 0.35) in the stretching group and 0.06 Nm/deg (-0.2 to -0.1) in the control group. These results indicate that older adults with and without arthritis of the knee are able to demonstrate sustained improvements in joint range of motion with stretching interventions. This is important as the study demonstrated that simple stretching exercises are effective as part of the long term management of knee osteoarthritis and as way of improving range of motion in older adult populations. Reid DA, McNair PJ (2011): Effects of a six week lower limb stretching programme on range of motion, peak passive torque and stiffness in people with and without osteoarthritis of the knee. New Zealand Journal of Physiotherapy 39(1) 2-9. Key Words: Range of Motion; Knee Extension; Flexibility; Older adult; Arthritis